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ENSLIC BUILDING
Energy Saving
through Promotion
of Life Cycle Assessment
in Buildings
co-financed by the European Commission
Intelligent Energy for Europe Programme
Grant Agreement Nº - EIE/07/090/SI2.467609
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Copyright © 2007-2010 ENSLIC, All Rights Reserved.
The sole responsibility for the content of this website lies with the authors. It does not necessarily reflect the opinion of the European Communities.
The European Commission is not responsible for any use that may be made of the information contained therein.
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ENSLIC Building
Contents - 3
Contents
1. Introduction ............................................................................................
Results and Impacts
.................................................................................
2. Benefits of LCA in buildings
4
5
..........................................................
6
Target group and key actors .....................................................................
7
3. LCA in buildings: State of the art
................................................
8
LCA methodology .....................................................................................
8
LCA Tools .................................................................................................
9
LCA Databases ......................................................................................... 11
4. Guidelines for LCA calculations in buildings
......................... 12
The life cycle stages of a building ............................................................. 12
The building process ................................................................................ 12
Target groups for the guidelines ............................................................... 13
Possible simplifications for LCA in practical building design .................... 14
The Enslic Guidelines: A recommended procedure for LCA calculations
In building design ...................................................................................... 14
Example of how to use the Guidelines ..................................................... 15
5. ENSLIC Case Studies
CIRCE ....................................................................................................... 22
IFZ ............................................................................................................ 33
ARMINES................................................................................................... 42
KTH ........................................................................................................... 51
EMI ........................................................................................................... 60
6. Conclusions ...........................................................................................
69
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4 - Introduction
ENSLIC Building
1. Introduction
The ENSLIC project (ENergy Saving
through promotion of LIfe Cycle assessment in buildings) seeks to promote the
use of Life Cycle Assessment (LCA) techniques in design for new buildings and for
refurbishment, in order to achieve an
energy saving in the construction and
operation of buildings. This action aims to
draw on the existing information generated from previous research projects regarding: design for low energy consumption,
integrated planning, environmental performance evaluation of buildings, design for
sustainability and LCA techniques applied
to buildings.
The output - compiled with the collaboration of key target groups - is a set of guidelines with a methodology which clarifies
the various aspects of the LCA, e.g., purpose, benefits, requirements, flexibility
and different techniques. This is applied to
real buildings by a number of collaborating
target groups. The results are disseminated to a wide target group through multiple
channels and the potential for energy saving highlighted.
Through this project tools for use in an integral planning process are being promoted to stakeholders who require a means
to optimize environmental performance of
buildings in a truly sustainable way.
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ENSLIC Building
Results and Impacts
Development of guidelines and a simplified methodology for LCA to be used in design and refurbishment of buildings.
Demonstrate how LCA can facilitate comparisons of
different buildings, showing influence of all variables
on a building’s life cycle environmental impact.
Promote application of LCA simplified methods to
stakeholders who require a means to optimize environmental performance of buildings in a truly sustainable way.
Remove market barriers to sustainable construction
using LCA simplified methods in order to select the
building design/refurbishment option with lowest
energy use and environmental impact over the whole
life span of the building.
Highlight links and data transfer between LCA, Life
Cycle Cost (LCC) and Energy Certification calculation
software. This will contribute to achieving long term
cost-effective investment in new building stock and
refurbishment.
Raise local authorities’ awareness of LCA methods.
The incorporation of these methods into the public
procurement procedures and /or encourage companies who tender for public contracts to use them,
would have a significant impact on energy consumption and environmental sustainability of public
buildings.
Increasing market for sustainable building products:
the dissemination of LCA simplified methods can act
as a catalyst to the wider implementation of sustainable architectural decisions.
Stimulate innovation and optimization of LCA software tools, driving database developers to amplify
their products and maintain data more up to date.
Introduction - 5
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6 - Benefits of lca in buildings
ENSLIC Building
2. Benefits of LCA in buildings
Historically
in
the
construction sector, locally obtained traditional materials such as stone, ceramics or wood for
example, with a low environmental impact have been replaced by the widespread use of globally sourced materials including
cement, aluminium, reinforced concrete, PVC and other types of plastics. The use of these modern materials has greatly increased the
embodied energy and the carbon footprint of new buildings.
At present the construction sector contributes greatly
to the global environmental load from human activities. It uses around 40% of the total energy
consumption in Europe and some 60% of the
raw materials extracted from the lithosphere.
As there is a clear interaction between all the
stages of the life of a building (production-construction-use and maintenance and final disposal), only the application of a global methodology
such as Life Cycle Assessment (LCA) will permit
the global environmental impact to be assessed
effectively. Consequently LCA provides better
decision support when optimizing environmentally favourable design solutions that consider the
impacts caused during the entire lifetime of the
building.
Because competition within the construction sector grows stronger day by day, the
minimization of costs, which LCA permits, is
in reality a necessity, not an option. This includes the environmental costs, the use of energy,
materials and water which all play a relevant. Consideration for the environment continues to gain respect in the marketplace and businesses operating in the
construction sector have to modify their strategies and differentiate their buildings by taking advantage of the widespread possibilities that LCA has to offer. The principle
benefits of the application of
LCA to a building are:
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Benefits of LCA in buildings - 7
ENSLIC Building
Taking of decisions by construction companies, go-
Evaluation the potential for energy saving and the re-
vernmental and non-governmental organizations with
duction of emissions associated with the implementa-
a view to strategy planning, the establishment of prio-
tion of different construction and architectural solutions
rities, the design or refurbishment of buildings, the se-
of low impact at a local, regional and global level.
lection of suppliers and materials, the establishment
of strategies to manage residues, taxation policy, I+D
programs etc.
Combination with life cycle cost assessment in order
to obtain a greater economic return related to the
construction investment contributing to an improve-
Identification of those opportunities to improve the
environmental aspects associated with the construction sector over the complete life cycle of the building.
Promotion of the construction of Life Cycle Zero
Emission Buildings with a null environmental impact,
integrating advanced techniques in architectural ecodesign, bio-construction, saving energy, water and
materials and renewable energies, obtaining the maximum efficiency of the resources available and the
greatest thermal comfort.
ment in the energy management of buildings. This
combination may for instance be used for: choosing
alternative technical solutions, identifying the technical solution that meets an environmental target with
the least cost, recount environmental impact into
costs, and evaluating a building investment.
Considering the life cycle linked to the energy certification process of the buildings allows the promotion
of sustainable buildings with low energy consumption
and high efficiency and favours innovation in the
Environmental labeling of buildings, being environ-
construction sector.
mentally progressive, marketing benefit, obtaining
loans and subsidies, reduction of local taxes as a
For commercial actors, LCA supports Corporate So-
consequence of the reduction in environmental im-
cial Responsibility (CSR) strategies and enables re-
pact, etc.
porting
of
environmental
performance,
which
supports the value of goodwill.
Comparison of the environmental impact of buildings
located in different geographical zones, with different
uses, for example, the influence of all the variables involved in the lifecycle of a building.
Target group and key actors
Evaluation of the influence that the initial decisions
adopted in the design phase of a building related to
The main target groups are architects, construction federations,
the maintenance and associated operational costs
architecture institutes, local authorities, civil engineers and buil-
have over the real environmental impact of the building.
ding owners.
Application of LCA in the building sector.
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8 - Lca in buildings: state of the art
3. LCA in buildings: State of the art
LCA methodology
The methodology of the LCA consists of 4 main phases:
Definition of objectives and scope
of application: The purpose of the
study, the limits of the system, the
necessary data, etc.
Inventory Analysis: All inward and
outward energy flows of the system
during its entire useful life are
quantified.
Impact evaluation: A classification
and evaluation of the results of the
inventory analysis relating its results to observable environmental
effects by using a collection of impact categories (acidification of
soils, ozone layer depletion, toxicity, resource depletion, etc.).
Interpretation: The results of the
preceding phase are evaluated together in accordance with the objectives defined in the study in
order to be able to establish conclusions and final recommendations. Different techniques are used
to do this including sensitivity
analysis on the data, an analysis of
the relevance of the different stages of the process and an analysis
of alternative scenarios.
ENSLIC Building
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ENSLIC Building
LCA in buildings: State of the art - 9
At present, the LCA methodology is standardized in ISO 14040:2006 and ISO
14044:2006. This standard describes the principles and framework for LCA, but it
does not describe the LCA technique in detail, nor does it specify methodologies for
the individual phases of the LCA. The intended application of LCA or LCI results is
considered during definition of the goal and scope, but the application itself is outside the scope of this International Standard.
The CEN/TC 350 “Sustainability of Construction works” standard is under development. This standard will provide a calculation method based on LCA to assess
the environmental performance of a building and give the means of communication
of the outcome of the assessment.
The ENSLIC guidelines and simplified methodology aims to provide a simplified method for architects which aim at bridging barriers to LCA use by providing a basic
lesson in what LCA is, what it can be used for and how it can be performed, all
adapted to the design process of buildings.
LCA Tools
Due to the large amount of data required to perform an LCA, it is recommended to
use a software application that makes the study much more efficient. At present,
there are various assessment applications on the market and they allow LCA studies
to be carried out to various degrees of detail.
When developing the proposed guidelines, three levels of performing an LCA were
considered:
Basic: Basic calculations in Excel sheets with simple input and output
only covering one or a few environmental impacts. Little or no experience
is needed.
Medium: LCA calculations made with help of building tools such as Ecosoft, EcoEffect, Equer, Legep, Envest, Beat, etc. These specific applica-
Life cycle stages of a building
currently suggested in the forthcoming
CEN/TC 350 standard.
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10 - LCA in buildings: State of the art
ENSLIC Building
tions have been developed to facilitate the use of LCA in the building sector, with more appropriate interfaces for buildings studies. Nevertheless
some experience and training are required to use these tools.
ECO-QUANTUM
http://www.ivam.uva.nl
LEGEP
http://www.legep.de
EQUER
http://www.izuba.fr
ATHENA
http://www.athenaSMI.ca
OGIP
http://www.ogip.ch
ENVEST 2.0
http://envestv2.bre.co.uk
BECOST
http://www.vtt.fi/rte/esitteet/ymparisto/lcahouse.html
BEES
http://www.bfrl.nist.gov/oae/software/bees.html
GREENCALC
http://www.greencalc.com
ECOEFFECT
http://www.ecoeffect.se
ECO-SOFT
http://www.ibo.at/de/ecosoft.htm
Advanced: General and comprehensive LCA tools such as SimaPro, Gabi,
etc. Much experience is needed to handle these software applications on
a building level. These tools demand much training and profound understanding of LCA models and they might not even be suitable for application in early design phases.
BOUSTEAD
http://www.boustead-consulting.co.uk
ECO-IT
http://www.pre.nl
ECOPRO
http://www.sinum.com
ECOSCAN
http://www.ind.tno.nl
EUKLID
http://www.ivv.fhg.de
KCL ECO
http://www.kcl.fi/eco
GABI
http://www.gabi-software.com
LCAIT
http://www.ekologik.cit.chalmers.se
MIET
http://www.leidenuniv.nl/cml/ssp/software
PEMS
http://www.piranet.com/pack/lca_software.htm
SIMAPRO
http://www.pre.nl
TEAM
http://www.ecobilan.com
WISARD
http://www.pwcglobal.com
UMBERTO
http://www.umberto.de
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ENSLIC Building
LCA Databases
All software applications that perform LCA studies include various databases that
are used within the phase of Life Cycle Inventory (LCI). It should be noted that a
study can be carried out using data from a single database or by combining information from different databases, depending on the quality of data that have been
identified for the study. In addition most programs allow you to edit the databases
included and create new ones.
Some examples of databases for studies of LCA are:
EU’s ELCD core database (http://lca.jrc.ec.europa.eu/lcainfohub/
datasetCategories.vm): It comprises Life Cycle Inventory (LCI) data from
front-running EU-level business associations (http://lca.jrc.ec.europa.eu/
EPLCA/AdvisoryGroup.htm) and other sources for key materials, energy
carriers, transport, and waste management. Focus on data quality, consistency, and applicability.
Ecoinvent v2.0 (http://www.ecoinvent.ch): The ecoinvent data v2.0 contains international industrial life cycle inventory data on energy supply, resource extraction, material supply, chemicals, metals, building materials,
waste management services, and transport services.
IVAM (http://www.ivam.uva.nl): The IVAM database is a database to be
used for environmental life cycle assessment (LCA). It consists of about
1350 processes, leading to more than 350 materials. The data can be used
for LCA applications in various sectors.
Boustead (http://www.boustead-consulting.co.uk) - UK based data general and building specific. There are nearly 13 000 individual unit operations, covering a vast number of materials processing and fuel production
processes.
IDEMAT (http://www.tudelft.nl): Developed by the Delft University of Technology in Holland compiling various data sources. It is focused mainly towards the production of materials covering a total of 508 types of
processes in the release of 2001.
Athena (http://www.athenasmi.org/tools/database/index.html): Canadians
building products database containing data for energy use and related air
emissions for on-site construction of a building’s assemblies; for maintenance, repair and replacement effects through the operating life; and for
demolition and disposal.
Also it is possible to obtain inventory data from EPDs (Environmental Product Declarations), which are Type III declarations (third party control, ISO
14025). Information about EPDs can be found in the International EPD®
system web site (http://www.environdec.com) and the GEDnet web site
(http://ww.gednet.org).
LCA in buildings: state of the art - 11
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12 - Guidelines for LCA calculations in buildings
ENSLIC Building
4. Guidelines for LCA calculations
in buildings
A general problem when applying LCA in a design process is that in early design
phases the options for choosing different solutions are many and data on the products, which are needed for LCA calculations, are scarce. Later in the process, when
more decisions have been taken, it is possible to perform better LCAs but the possibilities to utilise the results for alternative designs are then restricted.
There are different ways to overcome this problem, mainly comprising ways to obtain better information about alternative options early in the design process and to
speed up calculations of rough results. A toolbox with a set of calculated results is
a possible solution. Introducing facilities to easily create alternative options and extract data with new computer programmes, such as Building Information Modelling
(BIM), could also be considered.
The life cycle stages of a building
By definition, making an LCA or determining the LCC of a building covers the whole
life cycle of a building. This means that generic information about the potential environmentally negative activities related to each stage of the life cycle is needed
from the very beginning of the process. The life cycle stages of a building include
according to CEN/TC 350 the product stage, construction stage, use stage and end
of-life stage.
The building process
The process of developing a new building is commonly referred to as the building
process. This process is mainly the same everywhere, but details, sub-divisions of
phases and terms may differ from country to country. In general, the building process can be described as in the next table. For refurbishment projects, the same
phases are followed but many preconditions and boundaries are already fixed.
General illustration of the relationships
between choice options and product data
availability during a design process.
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Guidelines for LCA calculations in buildings - 13
ENSLIC Building
The building process and examples of options for taking LCA-based decisions in different phases
Target groups for the guidelines
The ENSLIC guidelines are directed at professionals working in the early design phases of building development or refurbishment projects who want to achieve energy savings and environmental improvements with regard to the entire lifetime of the building.
Architects and other consultants are the
main target group, since they are the professionals involved who can perform an
LCA assessment. However, clients such
as property developers and urban planners are also targeted, since these groups
can demand better buildings and associated assessments to prove this.
The goal for the simplified excel tool proposed is to support advancement on the
basic and medium levels, i.e. getting inexperienced people to first carry out simple
LCAs and then try the buildings tools.
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14 - Guidelines for LCA calculations in buildings
ENSLIC Building
Possible simplifications for LCA in practical building design
The complexity and uncertainties of LCA results are often seen
Since calculations are performed by computers, simplifying the
as the main barriers to more frequent use of LCA. It is inevita-
calculations is less important than simplifying the tool interface
ble that if unreliable data are used, unreliable results will be ob-
and usability. Data acquisition is the most prominent problem
tained. However, rough estimates of the environmental impacts
since buildings contain a huge amount of different materials and
over the life cycle are still better than ignoring these impacts. In
the availability of quality-assured production data is restricted.
producing rough estimates, there are a number of possible sim-
When the aim is to simplify the LCA process, it is important to
plifications that can be made with the aim of promoting LCA to
identify the most important data for a particular life cycle stage.
wider group of users:
Communication of clear and useful results is also a very important question since this is the key to increasing demand for LCA.
Simplify the acquisition of building data by focusing
on larger building elements, omit transport, etc.
Simplify the inventory analysis by focusing on the
most important substances that contribute to a certain impact category, omit the end-of-life of the building, only use generic emission data, etc.
Simplify calculations by focusing on only a few impact categories.
Reduce the time of building data acquisition by improved CAD applications.
The Enslic Guidelines: A recommended procedure
for LCA calculations In building design
The ENSLIC building project recommends a step-by-step pro-
for impact calculations and any specifications on building cha-
cedure for using LCA in building design. The procedure is
racteristics and building data. Such collected information im-
based on the standardized process of conducting life cycle as-
proves the transparency of the LCA calculations and helps to
sessments according to the international standard on life cycle
interpret the results. These sheets are synchronized with the
assessment, ISO 14040:2006. To provide extra support and
present version of recommended LCA calculations for buildings
simplify comparisons in a standardized way, two Excel files
developed by the CEN working group TC 350 [29].
have also been developed.
The second Excel file, “ENSLIC BASIC ENERGY & CLIMATE
The first of these, the “ENSLIC TEMPLATE”, contains a number
TOOL”, is a work sheet that allows simplified LCA calculations
of sheets following the recommended procedure which are
in a building design phase to be carried out in the most basic
meant to standardize collection of data, made assumptions,
way. Building dimensions and cross-sections are inserted and
etc. and communication of building LCA results. Environmental
the programme calculates the quantities of materials needed
targets can also be specified here. The information includes an
and their related environmental impacts, and roughly estimates
overview of the purpose of the assessment and the type of buil-
annual energy use and its associated environmental impact
ding being assessed, the quantitative assessment results, any
when energy sources are inserted. This file normally needs to be
specifications on use of energy, materials, water, etc. needed
complemented with national data.
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ENSLIC Building
Guidelines for LCA calculations in buildings - 15
The ENSLIC Basic Energy & Climate Tool.
The guidelines and the templates deal with LCA on the scale of an individual building. However, the principles can also be used for assessment at other scales, such
as building component level or city district level.
Example of how to use the Guidelines
This paragraph describes a step-by-step procedure for implementing the ENSLIC
guidelines. A simple theoretical example is used to illustrate the procedure.
1) State the purpose of the study
The purpose governs important methodological choices and the interpretation of
results and is therefore of great importance.
Example: The LCA study is intended to provide decision support for designing a
simple single family house of 120 m 2 , demanding only 50% of the operative
energy use required by Swedish regulations and low CO2 emissions from a life
cycle perspective.
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16 - Guidelines for LCA calculations in buildings
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2) Choose assessment tool
The choice of assessment tool depends on requirements such as the indicators of
interest, the purpose of the study (since some tools are more adapted to specific
purposes than others), the required precision of the calculation and the way in which
the results are presented. In practice, the tool needs to be easily accessible, which
means that it is often natural to choose a tool developed in the national context.
Example: The “ENSLIC Basic Energy & Climate Tool” is used since it allows rough
calculations to be made of the indicators of interest (testing different amounts of
energy and material use and making comparisons with regard to the results in CO2equivalents).
3) State the system boundaries for the assessment
The assumptions made in the study as well as the boundaries for the object being assessed need to be clarified. It is highly important that this information is clear and consistent if comparisons are to be made with other studies. Important decisions include:
The reference time (assumed life-span of the building) chosen; 50 years is
often used as a default value since it is impossible to foresee the real life
span. The relationship between the impacts of the use stage and those of
the product stage is dependent on this choice. The shorter the reference
time chosen, the more important the impact from the product stage. Testing different reference times when carrying out the assessment often provides interesting information.
Life cycle stages and activities/processes included in the assessment.
Delimitation of the features of the building to be assessed, e.g. whether
user electricity is included in the energy use, or which building elements
are assessed.
Example: The building reference time is set to 50 years. The use stage is considered regarding energy use but without including household electricity. The product
stage is considered regarding production of building materials. Other life cycle stages are omitted. Building materials considered are major materials in the basic building elements (slabs, external walls, internal walls, attic, roof and windows).
4) State scenarios for the reference time
For the given reference time, assumptions or scenarios about what will happen to
the building during this time need to be formulated. This can include assumptions
with regard to maintenance, refurbishment, end-of-life scenarios, occupant behaviour, etc. If transport and/or LCC are used, further assumptions regarding these issues are necessary.
Example: A steady state during the reference time is anticipated. Normal maintenance is assumed but not accounted for in the assessment and normal user behaviour is anticipated. No end-of-life scenarios are assumed, since this life cycle stage
is excluded from the study.
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Guidelines for LCA calculations in buildings - 17
5) Define targets, references and benchmarks
In order to interpret the results later on, targets, reference values and/or benchmarks are
necessary for comparison. If specific environmental targets have already been decided
for the project (for instance set by a municipality or the developer), these may define the
indicators that need to be included in the assessment. In the present version of CEN/TC
350, the indicators preferred can be chosen from next table. When performing an LCA
according to the coming CEN standard, these indicators ought to be included.
Environmental indicators currentl
y suggested in the CEN/TC 350 standard.
Example: Targets for the example include maximum permissible energy use (household electricity excluded) of 55 kWh/m2 per year. The CO2 target is set to less than
10 kg CO2-equivalents/m2 per year.
6) Describe the building
Next, the building under study needs to be described in as much detail as possible depending on how far the building process has progressed. This includes information
about building size, type, etc. An important issue is to state facts regarding the functional
equivalent, i.e. information about the function of the building, such as type of use, number of users and requirements regarding indoor air quality, thermal climate, safety, etc.
If comparisons are made with other buildings, these criteria need to be the same.
Example: The interior dimensions of the building are 6 m by 10 m, on two floors.
The location is Stockholm. The building is a residential block intended to house 4
tenants. The indoor temperature in winter should be 22ºC and the building should
meet the requirements in the Swedish building code.
7) Collect data
There are two types of data that are necessary for the calculations: building-specific data such as amounts of building materials and energy use; and emissions related to the production of the building materials and energy (normally included in the
tools). In the conceptual design phase, data on energy and material use can either
be estimated or simulated using software applications such as Sketch-up and Revit
with alternative default solutions. This is also possible in some of the existing building tools, such as Equer.
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Minimum data requirements
for LCA studies of buildings.
In other cases, estimations of u-values and material amounts are necessary from
early sketches. In the “ENSLIC Basic Energy & Climate Tool”, the amounts of building materials, u-values and energy use during operation are estimated automatically when building specifications are inserted. These include for example building
dimensions and information on cross-sections.
Data uncertainty is a major concern when making LCA calculations. For the building data, the main issue is to gather enough information for a reliable assessment.
For the emission data, the main issue is data quality. ISO 14040 states data quality
requirements in general terms, including time-related, geographical and technological coverage, precision, completeness and representativeness. For simple life
cycle approaches these requirements are hard to fulfill, but data taken from large
and well-known databases are controlled in terms of quality.
Example: Building dimensions, types of building materials and their thicknesses are
taken from drawings. Generic data are taken from IVL and the self-declared building product declaration, which is less rigorous than an EPD.
8) Perform the assessment
Once assumptions are made, boundaries for the study delimited and data collected,
the calculations are made. If the “ENSLIC Basic Energy & Climate” tool is used,
CO2-equivalents (contributions to climate change) are calculated automatically once
the data on material and energy use have been inserted into this Excel file. Most
LCA building tools can calculate even more indicators. The type of assessment depends on the purpose.
Example: In the example, the purpose of the study is to use LCA in order to design
a single family house that lives up to targets regarding energy use and CO2 emissions. The assessment in the example therefore involves testing different design
and technical solutions with help of the Excel tool, to investigate how the targets
could be reached. Next table summarizes this procedure/assessment.
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Guidelines for LCA calculations in buildings - 19
ENSLIC Building
Actions taken step by step to reach the target for energy and CO2 emissions for a new single family house initially designed
to fulfill the requirements of the Swedish building code.
9) Present results
The results of the LCA can be presented in many different ways. The way in which
they should be presented depends on the purpose and the user of the results. If a
building tool is used, the tool provides options regarding how to present the results.
In the ENSLIC Building Project, a series of forthcoming case study reports will provide examples of useful ways of presenting results related to LCA studies with different purposes. For an LCA intended at act as decision support, the central
consideration is to provide total transparency of the results and the underlying calculations, both of which should be open to scrutiny. The “ENSLIC TEMPLATE” Excel
sheet is intended to serve as a way of providing transparent documentation.
Example: The simplified Excel tool currently presents the main results as shown in
the next Table, which shows the results after all the actions taken as described in
last paragraph. To provide transparent results, a results table such as this should be
drawn up for each action taken.
Summary of specific annual energy use
and CO2 emissions for the single
family house (120 m2).
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Here follows a few additional examples on result presentations taken from the ENSLIC case studies. Next table shows the assessment result as it is saved in the “ENSLIC TEMPLATE “excel sheet. This example relates to a multi-family house designed
Example of how assessment results
are compiled in the ENSLIC TEMPLATE
excel sheet (a multi-family house of 2900 m2).
for 94 users and heated with district heating. It shows the evaluation of the environmental indicators considered in all stages of the building.
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Página 21
ENSLIC Building
Guidelines for LCA calculations in buildings - 21
Next Figure shows an example on how results can be presented in a graph. This
example relates to an office building with a heated floor area of 3,314 m2 and illustrates the basic calculations for the climate change impact category disaggregated
into operating energy and building materials and also showing the impacts per building element.
10) Validate and control the results
Finally, the results should to be checked against the purpose of the LCA. In a complete LCA according to the ISO standard, the results should be examined by an external reviewer and this is particularly important if the results are to be presented to
the public, used for marketing, etc. Calculations with a simplified tool are purely intended for internal use. Sensitivity analysis performed by varying different parameters one at a time gives valuable information about the robustness of the results.
Example of presentation of LCA results
(an office building of 3314 m2).
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22 - ENSLIC Case Studies
ENSLIC Building
5. ENSLIC Case Studies
LCA methodology of calculation under the guidelines develo-
BUILDIND DESCRIPTION (Construction Year, Buil-
ped by ENSLIC are the source and the result their own appli-
ding Type, Floor Area/Volume, Number of Floors)
cation in a number of case studies carried out by all partners in
different countries all over Europe.
LCA METHODOLOGY (Functional Unit, Reference
Database, Software, Simplifications, Final energy de-
This section lists 15 case studies selected. Each case study fo-
mand calculation, Electric Mix of production…)
llows a different purpose. Some analysis intended to highlight
the need to quantify the embedded energy in materials calling
into question some well known energy efficiency standards,
INDICATORS (Primary Energy Demand, Global Warming Potential…)
other studies seek to compare buildings with different materials
from LCA point of view, sometimes the goal is to value some
simplifications made regarding life stages of the building, other
CUMULATIVE ENERGY DEMAND (Heating, Cooling,
Lighting…)
times the reason is to assess environmental improvement of a
building refurbishment beyond the comfort quality, perhaps
RESULTS
while deciding heating facilities it comes to value a centralized
or distributed generation, it may be also possible that regulations require to quantify equivalent CO2 emissions reduction in
a construction action…
Each purpose meets some specific needs during design or
planning phase of the building. Following cases show how the
methodology of the GUIDELINES easily achieve to answer various questions at that stage aiming to improve the sustainability of our buildings.
The following table shows the list of selected CASE STUDIES,
whose main characteristics are discussed bellow:
PARNTER
LOCATION
GOAL
BUILDING IMAGES
CLIMATE
CONCLUSIONS
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ENSLIC Case Studies - 23
ENSLIC Building
Partner
Picture
Type of building
Construction year
Location
Size (m2)
1
CIRCE
New Dwellings
2006
Zaragoza/Spain
7,641
2
CIRCE
New Dwellings
2006
Zaragoza/Spain
8,607
3
CIRCE
New Office Building
2008
Zaragoza/Spain
1,700
4
IFZ
New Dwellings
2003
Weiz/Austria
113.7
5
IFZ
New Office & Laboratory
2007
Weiz/Austria
3,068
6
IFZ
Housing
2009
Gutenberg/Austria
202.4
7
ARMINES
New Dwellings
2007
Formerie/France
264
8
ARMINES
Apartment Block
Refurbishment
1969
Montreuil/France
5,124
9
ARMINES
Mix Comertial, Offices
& Dwellings
Not built yet
Not decided/France
6,600
10
KTH
Offices
2009
Gävle/Sweden
3,314
11
KTH
Dwelling Retrofitting
1972
Sollentuna/Sweden
146,349
12
KTH
Dwellings
Not built yet
Sollentuna/Sweden
10,000
13
EMI
Family House
Not Built Yet
Herend/Hungary
108.2
14
EMI
Dwellins Retrofitting
1968/2007
Budapest/Hungary
25,138
15
EMI
Nursery
Not built yet
Nagykovácsi/Hungary
1,348.7
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24 - ENSLIC Case Studies
1
Partner
ENSLIC Building
CIRCE
Location
ZARAGOZA/SPAIN
Goal Since 1998 many social housing buildings have been constructed in Spain. Valdespartera is one of these municipal initiatives that tried to meet this social need by planning a new ECOCITY next to Zaragoza. This plan gained a research &
demonstration CONCERTO program called RENAISSANCE, which is focused on CO2 emissions reduction by decreasing
heating and cooling needs of buildings. This study widens this scope by calculating the impact of some of these reference buildings (P12 &P24) from a LCA point of view (including construction of materials).
Additionally, this study aims to compare P12 & P24, P12 is supposed to be high efficient building but constructed in
synthetic materials (metal external layer, polystyrene…) while P24 external walls are isolated with natural cork and covered with lime mortar. The report intends to clarify how important this is in terms of primary energy use and warming
potential emissions.
Building pictures
Climate
1942 degrees-day (18/18 calc base),
Aver. Min Tª (jan)=2ºC, Aver Max Tª(jul)=31.3ºC
Building description
Contruction year
Building type
2006
Dwellings
Fl. Area/ vol
Nº floors
7,641 m2 / 23,465 m3
5
(NET conditioned area)
LCA methodology
Functional unit: building (50 years lifespan) considering construction standars
in 2009.
Reference database: Ecoinvent v2.0 (2007)
Software: SimaPro v7.1.8.
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building strture
and building envelope materials.
Building USE phase is limited to the final energy consumption required for heating, cooling, DHW and lighting.
Final energy demand calculation: CALENER VYP (official tool Energy Efficiency
Certification according to RD47/2007 - EPBD transposition - see: www.mityc.es,
dynamic calculation engine: LIDER).
Electric mix of production: Technosphere resources for the production of 1kWh
in Spain.
Hard coal, at power plant/ES U
0.217
Lignite, at power plant/ES U
0.03
Oil, at power plant/ES U
0.02
Natural gas, at power plant/ES U
0.232
Industrial gas, at power plant/ES U
0.003
Hydropower, at power plant/ES U
0.11
Nuclear, at power plant/ES U
0.20
Production mix PV, at power plant/ES U
0.002
Wind power plant/ES U
0.1
Cogen ORC 1400kWth, allocation exergy/ES U
0.01
Cogen with biogas engine, allocation exergy/ES U
0.006
Natural gas, allocation exergy, at micro gas turbine 100kWe
0.06
Hydropower, at pumped storage power plant/ES U
0.01
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ENSLIC Case Studies - 25
ENSLIC Building
1
Indicators
PRIMARY ENERGY: expressed in equivalent Megajoules (MJ-Eq) calculated according to the impact assessment methodology
“Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 7.1.8.
GLOBAL WARMING POTENTIAL: expressed in kilograms carbon dioxide equivalent: kg CO2-Eq); 1.01 version of calculation
method implemented in SimaPro v 7.1.8, based on the characterization factors given by IPCC for 2007 and taking into account
a time horizon of 100 years.
Results
Heating Fin En. (kWh/m2*y)
11.2
Cooling Fin. En. (kWh/m2*y)
15.1
Lighting Fin. En. (kWh/m2*y)
5.8
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1
ENSLIC Building
Conclusions (common to P24)
Since 1998, but especially after 2000 the building market in Spain lived a tremendous bubble that crashed in 2008. During these years many buildings were built with old energy standards (NBE-CT79), leaving an energy mortgage that we will
have to assume during next years, unless new retrofitting policies are promoted. Only in 2006 these old standards changed, following EPBD and based on real experiences like Valdespartera Ecocity. However buildings like P12 in Valdespartera do achieve to reduce heating needs even bellow Passivhaus Standard (11.2 kWh/m2*y compared with 15 kWh/m2*y
in a Passivhaus), the final impact of the entire building is high. This study shows that building sector energy policies only
oriented to energy demand reduction are not sufficient. A low energy demanding building like P12 consumes 42,079 GJEq for its materials’ production. This is 40% of total Primary Energy consumption in a lifespan of 50 years. This percentage is obviously bigger in low energy buildings, but it is big enough to be taken into account.
In this total concrete structure (pillars+slabs+part of roofs) account for more than 25% of primary energy demand, and more
than 35% when it comes to global warming potential. The impact of this material is quite significant in this “traditional” way
of Spanish construction and its high thermal conductivity does not help the bioclimatic behavior of the building.
When we compare P12 and P24 and see the results of simplified LCAs in both cases we are surprised to see both have
very similar impact in terms of primary energy (103,893 vs 101,181GJ Eq) and global warming potential (6,184 vs
6,162tCO2 Eq).
At a first sight, even if they look similar, the use of natural materials in P24 envelope made think of it being more ecologic.
This fact is actually true. If we look at the global warming potential and see the impact of walls we see that in P24 the buildings behaves as CO2 emissions drain of –24 tons, compared with the 410 t CO2 Eq of walls in P12.
However, if we analyze P24 building composition we find out that it includes a second basement floor. This and the thickness
of slabs increase the weight of concrete and its impact in more than 800 t CO2 Eq, almost the same quantity gained by natural materials and windows.
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ENSLIC Case Studies - 27
ENSLIC Building
Partner
CIRCE
Location
2
ZARAGOZA/SPAIN
Goal Since 1998 many social housing buildings have been constructed in Spain. Valdespartera is one of these municipal initiatives that tried to meet this social need by planning a new ECOCITY next to Zaragoza. This plan gained a research &
demonstration CONCERTO program called RENAISSANCE, which is focused on CO2 emissions reduction by decreasing
heating and cooling needs of buildings. This study widens this scope by calculating the impact of some of these reference buildings (P12 &P24) from a LCA point of view (including construction of materials).
Additionally, this study aims to compare P12 & P24; P12 is supposed to be high efficient building but constructed in
synthetic materials (metal external layer, polystyrene…) while P24 external walls are isolated with natural cork and covered with lime mortar. The report intends to clarify how important this is in terms of primary energy use and warming
potential emissions.
Building pictures
Climate
1942 degrees-day (18/18 calc base),
Aver. Min Tª (jan)=2ºC, Aver Max Tª(jul)=31.3ºC
Building description
Contruction year
Building type
2006
Dwellings
Fl. Area/ vol
Nº floors
8,607 m2 / 23,947 m3
5+2
(NET conditioned area)
LCA methodology
Functional unit: building (50 years lifespan) considering construction standars
in 2009.
Reference database: Ecoinvent v2.0 (2007)
Software: SimaPro v7.1.8.
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials.
Building USE phase is limited to the final energy consumption required for heating, cooling, DHW and lighting.
Final energy demand calculation: CALENER VYP (official tool Energy Efficiency
Certification according to RD47/2007 - EPBD transposition - see: www.mityc.es,
dynamic calculation engine: LIDER).
Electric mix of production: Technosphere resources for the production of 1kWh
in Spain.
Hard coal, at power plant/ES U
0.217
Lignite, at power plant/ES U
0.03
Oil, at power plant/ES U
0.02
Natural gas, at power plant/ES U
0.232
Industrial gas, at power plant/ES U
0.003
Hydropower, at power plant/ES U
0.11
Nuclear, at power plant/ES U
0.20
Production mix PV, at power plant/ES U
0.002
Wind power plant/ES U
0.1
Cogen ORC 1400kWth, allocation exergy/ES U
0.01
Cogen with biogas engine, allocation exergy/ES U
0.006
Natural gas, allocation exergy, at micro gas turbine 100kWe
0.06
Hydropower, at pumped storage power plant/ES U
0.01
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Página 28
28 - ENSLIC Case Studies
ENSLIC Building
2
Indicators
PRIMARY ENERGY: expressed in equivalent Megajoules (MJ-Eq) calculated according to the impact assessment methodology
“Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 7.1.8.
GLOBAL WARMING POTENTIAL: expressed in kilograms carbon dioxide equivalent: kg CO2-Eq); 1.01 version of calculation
method implemented in SimaPro v 7.1.8, based on the characterization factors given by IPCC for 2007 and taking into account
a time horizon of 100 years.
Results
Heating Fin En. (kWh/m2*y)
12.7
Cooling Fin. En. (kWh/m2*y)
11.9
Lighting Fin. En. (kWh/m2*y)
6.3
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ENSLIC Case Studies - 29
ENSLIC Building
Conclusions (common to P12)
2
Since 1998, but especially after 2000, the building market in Spain lived a tremendous bubble that crashed in 2008. During these years many buildings were built with old energy standards (NBE-CT79), leaving an energy mortgage that we will
have to assume during next years, unless new retrofitting policies are promoted. Only in 2006 these old standards changed, following EPBD and based on real experiences like Valdespartera Ecocity. However buildings like P24 in Valdespartera do achieve to reduce heating needs even bellow Passivhaus Standard (12.7 kWh/m2*y compared with 15 kWh/m2*y
in a Passivhaus), the final impact of the entire building is high. This study shows that building sector energy policies only
oriented to energy demand reduction are not sufficient. A low energy demanding building like P24 consumes 52,606 GJEq for its materials’ production. This is 52% of total Primary Energy consumption in a lifespan of 50 years. This percentage is obviously bigger in low energy buildings, but it is big enough to be taken into account.
In this total concrete structure (pillars+slabs+part of roofs) account for more than 35% of primary energy demand and global warming potential. The impact of this material is quite significant in this “traditional” way of Spanish construction and
its high thermal conductivity does not help the bioclimatic behavior of the building.
When we compare P12 and P24 and see the results of simplified LCAs we are surprised to see that both have very similar impact in terms of primary energy (103,893 vs 101,181GJ Eq) and global warming potential (6,184 vs 6,162 t CO2 Eq).
At a first sight, even if they look similar, the use of natural materials in P24 envelope made think of it being more ecologic.
This fact is actually true. If we look at the global warming potential and see the impact of walls we see that in P24 the buildings behaves as CO2 emissions drain of 24 tons, compared with the 410 t CO2 Eq of walls in P12.
However, if we analyze P24 building composition we find out that it includes a second basement floor. This and the thickness
of slabs increase the weight of concrete and its impact in more than 800 t CO2 Eq, almost the same quantity gained by natural materials and windows.
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30 - ENSLIC Case Studies
3
Partner
ENSLIC Building
CIRCE
Location
ZARAGOZA/SPAIN
Goal
See effect of reducing stages of life cycle in a building to PRODUCTION & USE compared to the four recommended by
the Technical Committee “Sustainability of construction works” CEN / TC 350: PRODUCTION, CONSTRUCTION, USE &
END OF LIFE
Analyze the impact of office & labs with the aim to convert CIRCE building in a NET ZERO EMISSION BUILDING from a
LCA point of view.
Building pictures
Climate
1942 degrees-day (18/18 calc base),
Aver. Min Tª (jan)=2ºC, Aver Max Tª(jul)=31.3ºC
Building description
Contruction year
Building type
2008-2009
Office & labs
Fl. Area/ vol
Nº floors
1,700 m2 / 9,550 m3
2
(NET conditioned area)
LCA methodology
Functional unit: Circe building (50 years lifespan) considering construction
standars in 2009.
Reference database: Ecoinvent v2.0 (2007)
Software: SimaPro v7.1.8.
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials.
Building USE phase is limited to the final energy consumption required for heating, cooling, DHW and lighting.
Final energy demand calculation: CALENER GT (official tool Energy Efficiency
Certification according to RD47/2007 – EPBD transposition - see: www.mityc.es,
dynamic calculation engine: DOE 2.2 v4.2a).
Electric mix of production: Technosphere resources for the production of 1kWh
in Spain
Hard coal, at power plant/ES U
0.217
Lignite, at power plant/ES U
0.03
Oil, at power plant/ES U
0.02
Natural gas, at power plant/ES U
0.232
Industrial gas, at power plant/ES U
0.003
Hydropower, at power plant/ES U
0.11
Nuclear, at power plant/ES U
0.20
Production mix PV, at power plant/ES U
0.002
Wind power plant/ES U
0.1
Cogen ORC 1400kWth, allocation exergy/ES U
0.01
Cogen with biogas engine, allocation exergy/ES U
0.006
Natural gas, allocation exergy, at micro gas turbine 100kWe
0.06
Hydropower, at pumped storage power plant/ES U
0.01
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Página 31
ENSLIC Case Studies - 31
ENSLIC Building
3
Indicators
PRIMARY ENERGY: expressed in equivalent Megajoules (MJ-Eq) calculated according to the impact assessment methodology
“Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 7.1.8.
GLOBAL WARMING POTENTIAL: expressed in kilograms carbon dioxide equivalent: kg CO2-Eq); 1.01 version of calculation
method implemented in SimaPro v 7.1.8, based on the characterization factors given by IPCC for 2007 and taking into account
a time horizon of 100 years.
Results
Heating Fin En. (kWh/m2*y)
27.3
Cooling Fin. En. (kWh/m2*y)
4.4
Lighting Fin. En. (kWh/m2*y)
13.78
Primary Energy Requirement
Structure and envolopes
- Concrete
- Isolates
- Metals
Building Production
Construction Materials
- Wood
- Envolopes
- Windows and doors
SUBTOTAL PRODUCTION
Final Energy Consumption
- Heating consumption
- Cooling consumption
Building use
Operation
- DHW consumption
- Lighting consumption
- Renewable energy contribution
SUBTOTAL USE
TOTAL
GJ-Eq
%
17,217
5,619
1,827
2,129
3,011
3,831
800
17,217
15,939
10,295
4,426
88
13,912
–12,782
15,939
33,157
51.9%
16.9%
5.5%
6.4%
9.1%
11.6%
2.4%
51.9%
48.1%
31.1%
13.3%
0.3%
42.0%
–38.6%
48.1%
–
Global warming potential
Structure and envolopes
- Concrete
- Isolates
- Metals
Building Production
Construction Materials
- Wood
- Envolopes
- Windows and doors
SUBTOTAL PRODUCTION
Final Energy Consumption
- Heating consumption
- Cooling consumption
Building use
Operation
- DHW consumption
- Lighting consumption
- Renewable energy contribution
SUBTOTAL USE
TOTAL
t CO2-Eq
t CO2-Eq
1,889
697
30
133
–83
107
3.5
889
853
588
213
4
671
–624
853
1,742
51.0%
40.0%
1.7%
7.6%
–4.8%
6.2%
0.2%
51.0%
49.0%
33.8%
12.3%
0.2%
38.5%
–35.8%
49.0%
-
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Página 32
32 - ENSLIC Case Studies
3
ENSLIC Building
Conclusions
The simplification made reducing the stages of life cycle to PRODUCTION & USE seems to be reasonable. However the
recommendation of considering four stages: PRODUCTION, CONSTRUCTION, USE & END OF LIFE by the Technical Committee “Sustainability of construction works” CEN / TC 350 may be more complete, results show that indicators move
less than 30% when CONSTRUCTION & END OF LIFE are removed, and always in same proportions. See:
First figure shows percentages of primary energy consumption during four stages: production, construction, use and end
of life. Second figure shows same percentages for the global warming potential. Here the percentage represented by construction and end of life goes down to 13%, compared with 28% in primary energy.
Renewable energy contribution to reduce primary energy consumption and global warming potential are insufficient. They
only manage to balance electricity consumption for lighting. If there would be the intention to make it ZEB (ZERO EMISSION BUILDING) from USE energy point of view, then we should increase at least three times the actual contribution of
renewables.
When we consider the production of materials in a 50 years lifespan of building, we see that from both primary energy and
global warming potential points of view, the impact of this stage weights about 50% of total impact.
The bad properties of the terrain over which the building is constructed made it necessary to increase the thickness of the
foundation. This foundation itself represents next to 50% of the total impact of the construction of the building materials.
This is, almost 25% of total impact considering use stage of building. We see that most of the efforts done to reduce the
impact of this phase by using natural materials with low energy consumption are negatively affected by the increase of concrete and iron for the foundation.
Finally, we see that the bioclimatic strategy of this building is partially based on the thermal inertia. The use of radiant
fresh floor combined with solar protections, night ventilation and high thermal inertia of walls will try to reduce cooling demand. However the comfort in summer gets highly improved by these gross and heavy walls, the cooling demand reduction does not justify the increase of the impact due to the construction of wall materials.
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Página 1
ENSLIC Case Studies - 33
ENSLIC Building
Partner
IFZ
Location
4
WEIZ/AUSTRIA
Goal The building (“TANNO meets GEMINI”) under study is a semi-detached house, which is part of a so called ‘plus energy
housing development’ in Weiz. The building meets the Passive House standard (13 kWh/m2/year). 37m2 of PV panels on
the roof of the balcony are producing energy for the building and feeding residual energy to the grid. Construction and
construction materials are based on a new innovative building system based on wooden elements (OSB-panels).
This study should demonstrate the environmental impacts of buildings, caused on one hand by the energy demand for
the use stage for operating the building (heating and electricity) and the impacts of the building materials on the other
hand. Especially for Passive Houses and Plus Energy Houses this question is of relevance, as in general these buildings
have higher inputs of building materials (mainly insulation materials) to achieve their required energy performance for
heating.
Building pictures
Climate
3739 degrees-day (20/12 calc base),
Aver. Min Tª (jan)= -3.4ºC, Aver Max Tª(jul)= 18.8ºC
Building description
Contruction year
Building type
2003
Housing
Fl. Area/ vol
113.7 m2 / 284.2 m3
(NET conditioned area)
Nº floors
2
LCA methodology
Functional equivalent: Residential building (50 years lifespan) considering
construction standards and Styrian building code in 2003.
Reference database: IBO Database
Software: ECOSOFT 3.4.1 based on SimaPro v6.1.
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials. To compare the influence of
building materials with energy consumption in use stage, the replacement of building components within the life cycle of 50 years is
accounted to the production stage.
The assessment of construction and building materials is limited to
the thermal building shell and suspended ceilings.
Outside facilities are not assessed.
Building USE stage: Energy demand for heating, DHW and electricity
for a household of three persons over 50 years
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Página 2
34 - ENSLIC Case Studies
ENSLIC Building
4
Indicators
PRIMARY ENERGY: expressed in equivalent Mega joules (MJ-Eq) calculated according to the impact assessment methodology “Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 6.1.
GLOBAL WARMING POTENTIAL (GWP): expressed in tons carbon dioxide equivalent: tons CO2-Eq); 1.01 version of calculation method implemented in SimaPro v 6.1, based on the characterization factors given by IPCC for 2007 and taking into account a time horizon of 100 years.
Results
Heating Fin En. (kWh/m2*y)
10.6
Cooling Fin. En. (kWh/m2*y)
0.0
Lighting Fin. En. (kWh/m2*y)
2.7
The graphs below show the LCA results for the selected indicators within a life cycle of 50 years. Primary energy caused by building materials has a ratio of 53 % on the total primary energy demand (without solar contribution of PV panels). CO2- Equivalents for building materials show a negative value of –0.06 tons, which is caused by the huge amount of wooden building
materials. As the LCA was done only for production and use stage (no end of life scenario) the ECOSOFT - LCA tool gives
benefits for CO2 stored in the wooden building materials. CO2- Equivalents for the operation of the building are 5,78 tons (without solar contribution of PV panels).
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Página 3
ENSLIC Case Studies - 35
ENSLIC Building
Conclusions
4
In Passive Houses and Plus Energy Houses the primary energy demand for operation is on a very low level, therefore the
ratio of primary energy caused by building materials (here 53%) on the total primary energy performance is higher than in
conventional buildings (about 30% - 40%).
The absolute value for the primary energy demand caused by building materials in Passive Houses and Plus Energy Houses is higher than in equivalent buildings with lower energy standards. Therefore the improvement of the ecological performance of construction and building materials should be stressed for this building type. In the graphs below the role of
different building materials and building components of the building under study are shown. Although most of the materials are wood based, polystyrene (only 1% of the total building mass) for the insulation of the floor slab in ground with
17,1%, and reinforced concrete (48% of the total building mass) for the floor slab with 7,5%, have a high ratio on the total
primary energy demand of the building.
Wood based materials show negative CO2- Equivalents (CO2- storage), reinforced concrete and polystyrene have the highest CO2- Equivalents.
Highest potential for the improvement of the primary energy demand and the GWP can be realized by the substitution of
the floor slab (reinforced concrete) and its polystyrene insulation.
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Página 4
36 - ENSLIC Case Studies
5
Partner
ENSLIC Building
IFZ
Location
WEIZ/AUSTRIA
Goal W.E.I.Z. II (Energy and Innovation Centre of Weiz) is an office and laboratory building for innovative entrepreneurs and organizations, constructed in 2007. The owner of the building (W.E.I.Z., a private limited company) is highly interested in
energy efficient, sustainable building design. Both existing office buildings (W.E.I.Z. I, W.E.I.Z. II) of this company have
innovative concepts for heating and cooling. The W.E.I.Z. company is planning a third office building based on the successful energetic concept of W.E.I.Z. II. To improve the total ecological performance of the new building, a strong focus
will also be on sustainable construction materials.
This LCA study aims to compare different solutions for construction materials of W.E.I.Z. II. The main focus will be on primary energy demand and CO2- emissions caused by construction materials. LCA results are used as decision support
for the choice of materials for the new building.
Building pictures
Climate
3739 degrees-day (20/12 calc base),
Aver. Min Tª (jan)= -3.4ºC, Aver Max Tª(jul)= 18.8ºC
Building description
Contruction year
Building type
2007
Office + Laboratory
Fl. Area/ vol
3,068 m2 / 9,240 m3
(NET conditioned area)
Nº floors
4 (basement+3)
LCA methodology
Functional equivalent: Office and laboratory building (50 years lifespan) considering construction standards and Styrian building code in 2007.
Reference database: IBO Database
Software: ECOSOFT 3.4.1 based on SimaPro v6.1
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials.
Building USE phase: Replacement of building components within
the life cycle of 50 years is accounted.
The assessment of construction and building materials is limited to
the thermal building shell and suspended ceilings.
Outside facilities are not assessed
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Indicators
5
PRIMARY ENERGY: expressed in equivalent Mega joules (GJ-Eq) calculated according to the impact assessment methodology “Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 6.1.
GLOBAL WARMING POTENTIAL (GWP): expressed in tons carbon dioxide equivalent: tons CO2-Eq); 1.01 version of calculation method implemented in SimaPro v 6.1, based on the characterization factors given by IPCC for 2007 and taking into account a time horizon of 100 years.
Results
The graphs below show the indicators primary energy demand (separated into renewable and non renewable) and Global Warming Potential of the realized building (Scenario 0). The main impacts are caused by reinforced concrete and concrete based
materials, polystyrene, bituminised boards and plastic windows. The main focus for optimization of the ecological performance
was directed to the insulation materials and windows. Because of technical issues alternatives for reinforced concrete and bituminised boards were not taken into account.
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Conclusions
The graphs below show the results of the study for the optimization of impacts caused by the indicators primary energy
(separated into non renewable and renewable) and CO2- Equivalents concerning building materials. Scenario 0 represents
the realized building.
For primary energy demand the difference between worst and best scenario is 1.690 GJ (non renewable), 1.082 GJ (renewable) and 1.860 GJ in total. The selection of alternative building materials should be based on the savings of the primary
energy demand non renewable.
Regarding CO2- Equivalents the difference is 87 tons between worst and best scenario.
Concerning primary energy demand the replacement of polystyrene (for insulation of walls) against mineral foam board
leads to the best result. But concerning GWP cork would be the best option. Exchange of glass wool insulation for the roof
against cellulose fibre or hemp has also strong influence on primary energy demand and GWP. Primary energy result for
the wood fibre boards is quite high, which is mainly based on the high density (160 kg/m3, e.g. polystyrene 18 kg/m3) of
this building material.
Replacement of plastic windows against wooden windows has high impacts on the primary energy demand (–847 GJ of
primary energy non renewable) as well as on the GWP (–40 tons of CO2- Equivalents).
LCA results for the exterior wall AW01 with different insulation materials
In general the replacement of materials based on fossil raw materials against materials based on renewables causes better results for primary energy demand non renewable and GWP. But for a serious improvement of the ecological performance LCA is absolutely required (see results for mineral foam board, cork and wood fibre board in the graph above).
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Partner
IFZ
Location
6
GUTENBERG/AUSTRIA
Goal The building under study is a semi-detached residential building in Gutenberg, a village in the south-eastern part of Styria.
The energy demand for space heating is 13,1 kWh/m2 net floor area and year (result of the calculation for the Austrian
energy certificate), which is the best energy class A++. Solar heating, heat recovery and ecological building materials
(wood, straw, etc.) are further aspects of this ambitious project.
The results of this study shall be used as decision support for the choice of the construction system and the building materials of the thermal building shell. Environmental indicators used are primary energy demand (renewable + non renewable) and global warming potential emissions.
Building pictures
3705 degrees-day (20/12 calc base),
Aver. Min Tª (jan)= –3.0ºC, Aver Max Tª(jul)= 17.5ºC
Climate
Building description
Contruction year
Building type
2009 - 2010
Housing
Fl. Area/ vol
202.4 m2 / 841.9 m3
(NET conditioned area)
Nº floors
Basement+2
LCA methodology
Functional equivalent: Residential building for a household of four persons
considering construction standards and Styrian building code in 2009, 50
years lifespan.
Reference database: IBO Database
Software: ECOSOFT 3.4.1 based on SimaPro v6.1
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials. To compare the influence of
building materials with energy consumption in use stage, the replacement of building components within the life cycle of 50 years is
allocated to the production stage.
The assessment of construction and building materials is limited to
the construction system and the thermal building shell.
Outside facilities are not assessed.
Building USE stage: Energy demand for heating, DHW and electricity for a household of four persons over 50 years.
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Indicators
PRIMARY ENERGY: expressed in equivalent Mega joules (MJ-Eq) calculated according to the impact assessment methodology “Cumulative Energy Demand (CED)”; version 1.05 of CED method implemented in the SimaPro v 6.1.
GLOBAL WARMING POTENTIAL (GWP): expressed in tons carbon dioxide equivalent: tons CO2-Eq); 1.01 version of calculation method implemented in SimaPro v 6.1, based on the characterization factors given by IPCC for 2007 and taking into account a time horizon of 100 years.
Results
Heating Fin En. (kWh/m2*y)
13.1
Cooling Fin. En. (kWh/m2*y)
0.0
Lighting Fin. En. (kWh/m2*y)
10.0
The graphs below show the LCA results for the selected indicators within a life cycle of 50 years. Scenario 1 is a solid construction with bricks, concrete ceilings and insulations based on fossil, non renewable raw materials. Scenario 2 is a light weight
construction with wooden walls and ceilings, and insulations based on renewable raw materials. Weight of scenario 1 (254 tons)
is 44% more than of scenario 2 (176 tons). Both scenarios have the same systems for heating and DHW (combined system, solar
heating and split logs). Total primary energy (renewable + non renewable) caused by building materials for scenario 2 is 30%
higher than for scenario 1. Looking to primary energy demand non renewable (which is the more important indicator) scenario
1 shows a 35% higher value than scenario 2. Concerning CO2- Equivalents for building materials scenario 1 shows the highest
value with 50,66 tons of CO2- Equivalents, whereas scenario 2 has negative values, which is caused by the benefits of CO2 storage in renewable raw materials.
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6
Scenario 2 (light weight construction with wooden walls and ceilings, and insulations based on renewable raw materials)
definitely shows better values concerning the selected indicators primary energy demand non renewable and global warming potential (CO2- Equivalents). The total energy demand of building materials in scenario 2 is higher, which is mainly
based on the higher amount of primary energy demand renewable and in the ratio specific weight/heat conductivity of insulation materials based on renewables. For example straw has the highest amount of total primary energy demand in scenario 2, but concerning the more relevant indicator primary energy demand non renewable it has one of the lowest values.
In scenario 1 worse results concerning primary energy demand non renewable and global warming potential are mainly caused by reinforced concrete, concrete based materials, honeycomb brick and insulation materials like polystyrene, extruded polystyrene and rock wool.
Highest reduction of primary energy demand non renewable and CO2- Equivalents was achieved in exterior wall AW
(Change from honeycomb brick and polystyrene in scenario 1 to timber-frame construction with straw insulation in scenario 2).
In both scenarios walls and slabs against ground show high values of primary energy non renewable and global warming
potential. This is mainly caused by reinforced concrete and sealing sheets like bituminised boards. Improvements for these
building components are quite difficult, as technical alternatives are hardly available.
Based on the two environmental indicators energy demand non renewable and global warming potential (CO2- Equivalents)
scenario 2 is the more environment-friendly construction.
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Partner
ENSLIC Building
ARMINES
Location
FORMERIE/FRANCE
Goal
Life Cycle Assessment has been applied to these houses and to a theoretical building complying with the French regulation, RT2005, in order to quantify the reduction of environmental impacts by a passive design compared to a standard
design
Building pictures
Climate
3075 degrees-day (18/18 calc base),
Aver. Min Tª = –6.6ºC, Aver. Max Tª = 31.9ºC
Building description
Contruction year
Building type
2007
Houses
Fl. Area/ vol
2 x 132 m2 / 2 x 330 m3
(NET conditioned area)
Nº floors
2
LCA methodology
Functional unit: whole building (80 years lifespan).
Reference database: Ecoinvent v2.0 (2007)
Software: EQUER v1.9.6.
Les Airelles Construction, En Act Architecture
Assumptions:
The materials taken into account include the walls, the roof, the floors, the partitions, the slab, the windows, the doors, the foundations. The various materials composing the earth-to-air heat
exchanger, the heat recovery ventilation, the heat pump and the
solar panels have not been taken into account in this assessment,
assuming that the quantities and related impacts are small compared to the construction materials and the operation energy use.
Average 100 km transport distance from factory to building site for
all building materials, 20 km at end of life.
30 years life span for all windows and doors, 10 years for painting
and flooring.
80% water mains efficiency.
Home to work transport not accounted for.
Domestic waste treatment not accounted for.
40 liters hot water and 80 liters cold water consumption per person
and per day, 4 persons in each house, 47 weeks/a.
Energy demand calculation: COMFIE (one of the official tools for Energy Certification according to EPBD transposition in France, dynamic simulation).
French electricity production mix: 78% nuclear plants, 14% hydro, 4% natural gas, 4% coal thermal plants,
For heating, European average electricity production mix: 37% nuclear, 15%
hydro, 10% gas, 28% coal and 10% fuel thermal plants.
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Indicators
List of the calculated impact indicators.
Results
Heating load (kWh/m2*y)
7,9 / 80
Cooling load (kWh/m2*y)
0
Lighting Fin. En. (kWh/m2*y)
15,2
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Conclusions
The environmental assessment shows that the passive building impacts are lower than those of the standard building, except for waste. This improvement is especially visible for indicators related to the use of natural gas (CO2). The non-radioactive waste production is quite the same due to similar material quantities in both alternatives. The radioactive waste
production increases (+29 %) due to the higher electricity consumption for the passive building, using a heat pump, than for
the standard one (gas boiler).
A balance of cumulative energy demand (CED) is given hereunder for both alternatives. For the standard building the CED
for heating represents the main share (almost 50%), whereas for the passive building it is only 8%. Conversely, the CED for
electricity appliances is a fourth of the whole CED of the standard building whereas is it 49% for the passive building. The
total CED of the passive building is about half that of the standard building, but CED for construction is higher. This means
that reducing the CED of the passive building requires to deal with other aspects than space and water heating: construction phase and electricity consumption may also be treated using appropriate measures.
Distribution of the cumulated energy demand for both alternatives.
The figure hereunder shows that the relative contribution of the construction phase to several impacts is increased for the
passive building. This is mainly visible on indicators related to energy consumption (primary energy, GWP100).
Contribution of each phase of the life cycle for both alternatives and four indicators, expressed in year-inhabitant equivalent
(normalisation using French average emissions).
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Partner
ARMINES
Location
8
MONTREUIL/FRANCE
Goal
Life cycle assessment has been applied to evaluate the environmental benefit of renovation, the influence of the energy
efficiency level (standard or passive), the insulation thickness and the insulation materials on several impact indicators.
Building pictures
Climate
3075 degrees-day (18/18 calc base),
Aver. Min Tª = –6.6ºC, Aver. Max Tª = 31.9ºC
Building description
Contruction year
Building type
1969
Apartment block
Fl. Area/ vol
5,124 m2 / 12,811 m3
(NET conditioned area)
Nº floors
4 (+ 2
unheated)
LCA methodology
Functional unit: whole building (40 years lifespan after renovation).
Reference database: Ecoinvent v2.0 (2007)
Software: EQUER v1.9.6.
Assumptions:
The materials taken into account include the walls, the roof, the floors, the partitions, the slab, the windows, the doors, the foundations. Average 100 km transport distance from factory to building
site for all building materials, 20 km at end of life.
30 years life span for all windows and doors, 10 years for painting
and flooring.
Home to work transport not accounted for, Domestic waste treatment not accounted for
40 liters hot water and 100 liters cold water consumption per person
and per day, 80% water mains efficiency
0.04 occupants/m², 50% during working hours (8 a.m. – 12 a.m. and
OPHLM de Montreuil
(before and after renovation).
2 p.m. – 6 p.m. from Monday to Friday) and 75% during lunch (12
a.m. – 2 p.m. from Monday to Friday).
Energy demand calculation: COMFIE (one of the official tools for Energy Certification according to EPBD transposition in France, dynamic simulation).
French electricity production mix: 78% nuclear plants, 14% hydro, 4% natural gas, 4% coal thermal plants.
District heating: 70% coal, 20% fuel, 5% gas, 5% electricity.
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Indicators
List of the calculated impact indicators.
Results
Heating load (kWh/m2*y)
7 / 85
Cooling load (kWh/m2*y)
0
Lighting Fin. En. (kWh/m2*y)
22,8
The LCA study shows the reduction of all impact indicators after renovation compared to the existing building, which is mainly
due to the reduction of the heating load. A passive renovation performs better than a standard renovation.
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Conclusions
The variation of the cumulative energy demand (CED) in terms of the insulation thickness in walls is shown hereunder. The reduction of heating load becomes smaller above 8 cm, whereas fabrication related impacts are still increasing.
In the case of glass wool, three indicators reach minimal values (water, radioactive waste and odour) whereas other indicators
continue to slowly decrease. In the case of cellulose, only one indicator reaches a minimal value (inert waste, see figure hereunder).
glasswool
glasswool
GWP and water indicators in terms of wall insulation thickness
glasswool
cellulose
The comparison between glass wool and cellulose insulation reveals insignificant difference on the environmental impacts.
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Goal
Partner
ENSLIC Building
ARMINES
Location
FRANCE
The objective of the study is to contribute in the design of a low impact building concept. The partners are a major building contractor and an architect. The reduction of environmental impacts compared to a standard building has been
evaluated for 2 types of heating energy: district heating, and a gas boiler.
Building pictures
Climate
3075 degrees-day (18/18 calc base),
Aver. Min Tª = -6.6ºC, Aver. Max Tª = 31.9ºC
Building description
Contruction year
Building type
Not yet built
Shops, flats, offices
Fl. Area/ vol
6,600 m2 / 16,500 m3
(NET conditioned area)
Nº floors
6
LCA methodology
Functional unit: whole building (80 years lifespan).
Reference database: Ecoinvent v2.0 (2007)
Software: EQUER v1.9.6.
Assumptions:
Sketch and plan
of the proposed concept building.
The materials taken into account include the walls, the roof, the floors, the partitions, the slab, the windows and doors. Average 100 km
transport distance from factory to building site for all building materials, 20 km at end of life.
30 years life span for all windows and doors, 15 years for painting
and flooring.
Home to work transport not accounted for, Domestic waste treatment not accounted for.
40 liters hot water and 100 liters cold water consumption per person
and per day, 80% water mains efficiency.
4 occupants for 70 m² in dwelling (absent from 8am to 7 pm), 1 occupant per 12 m2 in offices from 8am to 7 pm.
Energy demand calculation: COMFIE (one of the official tools for Energy Certification according to EPBD transposition in France, dynamic simulation).
French electricity production mix: 78% nuclear plants, 14% hydro, 4% natural gas, 4% coal thermal plants,
District heating: 60% heat recovery from incineration, 20% gas, 20% geothermal energy.
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Indicators
List of the calculated impact indicators.
Results
Heating load (kWh/m2*y)
3 / 10
Cooling load (kWh/m2*y)
0
Lighting Fin. En. (kWh/m2*y)
9.2 / 3.1
(offices/
housing)
The LCA study shows the reduction of all impact indicators compared to the standard building, considering 2 possible types of
energy for heating.
The results clearly show a high reduction of the environmental impacts of the efficient building compared to the standard one.
For example, the global warming potential (GWP100) is almost reduced by half in both cases (gas and district heating).
The heat produced by the district network mainly comes from waste incineration. This heat recovery reduces the influence of
heating on the global primary energy demand. This demand is mostly due to the electric consumption: use of household appliances, lighting and ventilation.
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Conclusions
The proposed concept building is compact in order to reduce heat losses, but at the same time light is needed as well as
the possibility for night ventilation in summer. This has been achieved by integrating atriums in the building.
The heating load will depend on the orientation of the building, according to the urban fabric.
North and South oriented facades
East and West oriented facades
8.5
10.9
2.8
8
8
11.2
13.6
3.9
12
10
Middle floor apartments
Top floor apartments
Offices
Shops
Total
The greenhouse gases emissions are lowered compared to a building satisfying the present French requirements for new buildings (RT2005), while other impacts remain lower, or equal in the case of radioactive waste (assuming a similar electric consumption, related to occupants’ behaviour).
Beside the reduction of environmental impacts, which was evaluated using LCA, achieving a satisfactory level of thermal
comfort was another objective of the project. Dynamic thermal simulation has therefore been used in order to estimate the
temperatures in the apartments in summer. Climatic data corresponding to the 2003 heat wave in France have been used.
The example below shows temperature profiles in different apartments (South, North and Central position).
Maximal inside temperatures remain around 10°C cooler than the external temperature.
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Partner
KTH
Location
10
GÄVLE/SWEDEN
Goal
This case study looks at a new office building situated in the town of Gävle, a bit north of Stockholm, Sweden. Four buildings, made with the same type of building technique, are already finalized and additional similar buildings are planned.
No particular environmental requirements were posed on this project. In this case study we look at one of these finalized
buildings with the aim to suggest improvements for the buildings that are still to be erected. The tool was used both to
suggest appropriate but tough target levels and to roughly look at the possibilities to reach these target levels by different types of improvement measures. An additional aim is to let the architect of this project actually sit down and work
with suggesting improvements based on life cycle assessment calculations.
Building pictures
Climate
4000 degrees-day (Sw. metereological and hydrological institute),
Aver. Jan. min. –8.0ºC, aver. July max. 21.0 ºC
Building description
Contruction year
Building type
2009
Offices
Fl. Area/ vol
3,314 m2 / 11,321m3
(NET conditioned area)
Nº floors
4
LCA methodology
Functional unit: building (50 years lifespan) considering construction standards
in 2009.
Reference database: Sw. database in EcoEffect building tool (2009), complemented with some Ecoinvent data v2.0 (2007) concerning building materials.
Emissions data on energy carriers follow the recommendations of IVL.
Software: ENSLIC BASIC ENERGY & CLIMATE TOOL (excel)
Simplifications:
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of building structure and building envelope materials.
Building USE stage is limited to the final energy use required for heating, hot water and all functions needing electricity (building and
user electricity).
Final energy demand calculation: Simplified energy calculation included in the
ENSLIC BASIC ENERGY & CLIMATE TOOL.
Electric mix of production: Used figure of the Nordic electricity mix: 100 g CO2eq/kWh.
District heating mix, Gävle: Used figure of the district heating mix of Gävle:
21.6 g CO2-eq/kWh.
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Indicators
FINAL BOUGHT ENERGY: expressed in kWh/m2*y.
GLOBAL WARMING POTENTIAL: expressed in kilograms carbon dioxide equivalent: kg CO2-Eq)/m2*y; based on the characterization factors given by IPCC for 2007 and taking into account a time horizon of 100 years.
Results before improvements
Heating Fin En. (kWh/m2*y)
87
Cooling Fin. En. (kWh/m2*y)
0
Lighting Fin. En. (kWh/m2*y)
45
Lighting Fin. En. (kWh/m2*y)
44
Results after suggested improvements
Heating Fin En. (kWh/m2*y)
18
Cooling Fin. En. (kWh/m2*y)
0
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Conclusions
10
Three targets were set: a GWP of max 4.0 kg CO2-eq/m2,y and a final total bought energy of 85 kWh/m2,y of which not more
than 45 kWh/m2,y was allowed to be electricity. The tool then allowed us to get ROUGH figures of the improvement potentials of different measures in order to elaborate with different possible solutions. (That is, the aim was not to make a complete
and detailed LCA). Based on our application of this tool we recommend to take improvement measures in the following order.
1. Try to reduce the energy use for heating and cooling as much as possible. 2. Try to reduce the CO2 emissions as much as
possible. 3. Verify that the electricity use has not increased a lot and try to reduce it as much as possible.
To install solar panels for heating of hot water on half the roof is the single most efficient measure to reduce the specific
bought energy. Other measures with moderate reduction potential included ventilation heat recovery, waste water heat recovery and extra insulation of the external walls. Windows with better u-values also reduces the specific energy use a bit, but
not very much since this building originally did not have a really large glass area/floor area ratio. These measures together
make it possible to reach the energy use target of 85 kWh/m2.
Regarding the CO2 target for this study (4.0 kg CO2-eq/m2), it is more difficult. In fact, it is obvious that very radical reductions are necessary regarding the CO2 related to energy use since the original calculation give that the building materials account for 3.2 kg CO2-eq/m2,y which is close to the set target. Probably, the target is tough since the building is connected to
the district heating of Gävle which is to a considerate proportion composed of waste heat from a nearby pulp and paper industry. This district heating therefore has a very low impact on climate change. The stand-alone most significant measures
in this case were to buy CO2 free electricity instead of electricity based on the Nordic production mix.
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Partner
ENSLIC Building
KTH
Location
SOLLENTUNA 1 / SWEDEN
Goal Sweden and Europe have adopted challenging environmental goals to be reached in the years 2020 and 2050.
40% CO2 reduction compared to 1990 (outside the emission trade).
20% energy reduction compared to 1995.
The dependence of fossil fuels shall be broken.
50% is coming from renewable sources 2050.
50% energy reduction compared to 1995.
The goal was to find out how energy use and impact on climate change for a group of existing buildings could be decreased by different measures and to what extent it could meet these environmental goals.
Building pictures
Climate
3900 degrees-day (Swe met office),
Aver. Min Tª (jan)=–7ºC, Aver. Max Tª(jul)=21ºC
Building description
Contruction year
Building type
1972
Dwellings
Fl. Area/ vol
146,340m2 / 395,000m3
(NET conditioned area)
Nº floors
3-9
LCA methodology
Functional unit: Building reference life time: 50 years ,Swedish dwelling standard 1972, Indoor temperature 22ºC,Ventilation rate: 0.5 air changes/hour.
Reference database: Ecoinvent v2.0 (2007), Own sources.
Software: ENSLIC BASIC ENERGY & CLIMATE TOOL (excel).
Simplifications:
Only climate change.
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of main building
products.
Building USE phase is limited to the energy use for space heating,
domestic hot water, electricity for building operation and user electricity. Building electricity use: 15 kWh/m2*y, Tenant electricity use:
30 kWh/m2*y.
EXISTING HOUSING AREA
~20 km North of Stockholm
Energy calculation: Basic energy and CO2 calculation tool - existing building.
CO2 content in energy carriers: Swedish electric mix 34 gCO2e/kWh, District
heating Sollentuna 50 gCO2e/kWh.
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Indicators
FINAL BOUGHT ENERGY: kWh/m2*y.
GLOBAL WARMING POTENTIAL at 100 years: kg CO2-Equivalents/m2*y; (IPCC for 2007).
RESULTS AFTER MEASURES (Final bought energy, kWh/m2*y)
Heating & vent.
27
Domestic hot water
9
Building/User electricity
21/14
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Conclusions
To the left of the red line measures can be justified by reasonable payback time. The measures to the right are more expensive. White goods with better performance than normal has a short service life time and the saved kilowatt-hours are not that
high compared to the overall energy use and impact on climate change. PV cells and façade renovation are very expensive
in relation to their savings. The CO2 emissions associated with Swedish electrical mix are very low.
Reasonable measures up to the red line will reduce the yearly bought energy by 42% and impact on climate change by 53%.
If all measures were made the bought energy would be reduced by 56% and the impact on climate change by 65%.
With all measures the total yearly saved bought energy are 13,3 GWh and 702.4 ton CO2e. The production of extra insulation
and new windows account for 15.9 ton CO2e/y, i.e. 2% of the savings. The final savings thus ended at 686.5 ton CO2e/y.
No major changes have been done since 1990. The goal 20% energy and 40% CO2 savings to 2020 are easily reached
through employing the cost efficient measures above. There is very little fossil fuel in the district heating and it will be phased out in a couple of years. To reach 50% saving to 2050 all measures above have to be made. i.e. it is also possible to meet
the long term goals here.
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ENSLIC Building
Partner
KTH
Location
12
SOLLENTUNA 2 / SWEDEN
Goal
A new apartment building was designed in Sollentuna some 20 km north of Stockholm, applying normal performance
standard today. The goal was to find out how energy use and impact on climate change could be further reduced by applying a set of different measures.
Building pictures
Climate
3900 degrees-day (Swedish met. Office),
Aver. min temp. (jan) =–7.0ºC, Aver. max temp. (jul) = 21.0ºC
Building description
Contruction year
Building type
–
Dwellings
Fl. Area/ vol
10,000m2 / 27,000m3
(NET conditioned area)
Nº floors
4-6
LCA methodology
Functional unit: Dwellings according to the Sw. building code.Building reference life time: 50 years, Indoor temperature 22ºC,Ventilation rate: 0,5 air
changes/hour.
Reference database: Ecoinvent v2.0 (2007), Own sources.
Software: ENSLIC BASIC ENERGY & CLIMATE TOOL (excel).
Simplifications:
Only climate change.
Only 2 stages taken into account: PRODUCTION & USE.
PRODUCTION stage is limited to the manufacture of main building
products.
Building USE phase is limited to the energy use for space heating,
domestic hot water, electricity for building operation and user electricity. Building electricity use:15 kWh/m2*y, Tenant electricity use:
30 kWh/m2*y.
Energy demand calculation: Basic LCA tool - existing building.
CO2 content in energy carriers: Swedish electric mix 34 gCO2e/kWh, District
heating Sollentuna 50 gCO2e/kWh.
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12
Indicators
FINAL BOUGHT ENERGY: kWh/m2*y.
GLOBAL WARMING POTENTIAL at 100 years: kg CO2-Equivalents/m2*y; (IPCC for 2007).
Results after measures
Heating & vent.
11
Domestic hot water
12
Building/User electricity
18/27
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Conclusions
12
All measures will totally reduce the final energy use from 114 to 62 kWh/m2*y, i.e. with 45% and the climate change impact
from 12.4 to 5.7 kgCO2e/m2*y, i.e. with 54%. The figure represents the building with a concrete shell. In the original design
the building materials accounted for 36% of the yearly contribution to climate change (when distributed over 50 years). If all
the shown measures above to reduce operation energy are realized the relative yearly contribution from the building materials will rise to 80% compared to CO2 emissions from operational energy.
The same building was also tested with a wooden shell. This resulted in 32% less total yearly impact on climate change. When
all measures to save energy were taken, i.e. the relative impact from materials was 80% also the difference between a concrete and a wooden shell became relatively larger. The result was that the relative yearly impact form the concrete building
was about 50% larger than that from the wooden building.
The total yearly climate change impact was 124 ton CO2 equivalents as the building was designed. With all measures applied
the total yearly impact would be reduced to 57 ton CO2e/y and if it got a wooden shell the yearly impact would further be reduced to 29 ton CO2e/y. With the potential savings in case study 2 from Sweden (existing buildings) of 700 ton CO2e which
corresponds to more than 20 new building estates of 10,000 m2 with a wooden shell and all measures carried through.
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13
Partner
ENSLIC Building
ÉMI
Location
HEREND/HUNGARY
Goal The chosen building is now at the design phase. This is a part of a row house, which is composed of five similar blocks of
buildings. It’s one storey-high without any cellar, built with an empty attic and a garage, the total net area is 108,1 m2.
Life Cycle Assessment has been applied to this family house, in order to quantify the reduction of environmental impacts
by a passive and/or a low-energy design compared to a standard design (complying with the Hungarian regulation).
LCA calculations to 3 different scenarios:
National standard.
Low energy building.
Passive house.
Building pictures
Climate
Budapest: Average Min Tª (jan)=–1.6ºC;
Average Max Tª(jul)=+26.5°C
Building description
Contruction year
Building type
Design phase
Family house
Fl. Area/ vol
Nº floors
108.2 m2 / 292.1 m3
1
(NET conditioned area)
LCA methodology
Functional unit: building (50 years lifespan) considering construction standards
in 2008.
Reference database: Ecoinvent v1.3
Software: Excel sheets.
Simplifications: 4 stages taken into account: PRODUCTION, RENOVATION &
MAINTENANCE, OPERATION AND DISPOSAL PHASE:
Production and construction phase: is limited to the manufacture of
building materials, the transport and the construction.
Renovation and maintenance phase: number of replacements required when the actual lifetime of a building component is shorter
than the timeframe defined in the functional unit.
Operation phase: is limited to the final energy consumption required
for heating, and DHW. According to he Hungarian order, we do not
have to calculate with the energy demand of lighting and we do not
have cooling in the building either.
Disposal phase: the demolition of building, the selecting and transporting of materials, and the waste treatment (reuse, utilization of
material and energy, disposal).
Final energy demand calculation: Excel sheets, according to the Hungarian
Regulation (7/2006. (V. 24.) TNM decree.
Electric mix of production: Technosphere resources for the production of 1kWh
in Hungary:
Ecoinvent module
kWh
Electricity, at cogen ORC 1400 kWth, wood, allocation exergy
0.000085
Electricity, lignite, at power plant
0.273
Electricity, oil, at power plant
0.125
Electricity, natural gas, at power plant
0.188
Electricity, industrial gas, at power plant
0.00333
Electricity, hydropower, at power plant
0.00539
Electricity, nuclear, at power plant
0.402
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ENSLIC Building
13
Indicators
List of the calculated impact indicators:
Unit
Source
MJ-Eq
Ecoinvent v2.0 (2007)
Global Warming Potential at 100 years
kg CO2-Eq
IPCC 2001
Acidification Potential
kg SO2-Eq
CML 2001
Impact indicator
Cumulative Energy Demand
Results
Heating Fin En. (kWh/m2*y) 74.1 - 19.8
Cooling Fin. En. (kWh/m2*y)
–
Lighting Fin. En. (kWh/m2*y)
–
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Conclusions
Cumulative Energy Demand
The above diagram shows well that the energy needs of the construction, maintenance and demolition of the three different
building types hardly differ from each other (the difference is below 10%), however the cumulative energy demands of maintenance of the environmentally aware versions are 35% and 70% lower respectively related to the original building.
Meanwhile it can be observed that ratio of the cumulative energy demand of the particular life cycle phases changes related
to the whole building (e.g. although the energy demand of the demolition seems slight related to the maintenance of the first
version (2.5%), in case of the third building it gets higher importance (12%)).
It can be stated that the passive house is 73% better than the first version involving only the net heating energy demand, however considering the whole life cycle the saving is ‘only’ 51%. This saving is due to the decreasing of the maintenance
energy, which is about 50000 MJ/y in total.
According to the Hungarian order, we do not have to calculate with the energy demand of lighting and we do not have cooling in the building either.
Global Warming Potential
The global warming indicators show very similar distribution to the cumulative energy demand discussed above, with a difference that the ratios of the maintenance values are shifted (1st version 100%, 2nd version 56%, 3rd version 43%) due to
the collateral heat insulation and the complex engineering system.
Acidification Potential
The diagrams of the acidification potential show an even interesting shift. Here the second building has a much higher significance than the other two ones. This can be due to the larger acidification potential of the electric energy used for the heat
pump.
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ENSLIC Building
Partner
ÉMI
Location
14
BUDAPEST/HUNGARY
Goal The block of 360 flats was built in 1968, it is one of the earliest domestic panel buildings in Hungary. The building has a
basement, a ground floor and 9 stories, a flat roof and 12 staircases in total.
Total net area: 25,138 m2.
The dwellings are oriented into North-South direction and have 50-65 m2 size area. The building is heated by district heating, it cannot be controlled independently in the dwellings.
Life cycle assessment has been applied to evaluate the environmental benefit of renovation, the influence of the energy
efficiency level (standard or passive), the insulation thickness and the insulation materials on several impact indicators.
LCA calculations to 3 different scenarios:
Original building (without renovation).
National standard
Low energy building.
Building pictures
Climate
Budapest: Average Min Tª (jan)=–1.6ºC;
Average Max Tª(jul)= +26.5°C.
Building description
Contruction year
Building type
Fl. Area/ vol
Nº floors
Built in 1968
Renovated in 2007
Block of flats
25,138 m2 / 64,045 m3
Basement +
10 storeys
(NET conditioned area)
LCA methodology
Before the renovation.
After the renovation.
Functional unit: building (50 years lifespan) considering construction standars
in 2008.
Reference database: Ecoinvent v1.3
Software: Excel sheets.
Simplifications: 4 stages taken into account: PRODUCTION, RENOVATION &
MAINTENANCE, OPERATION AND DISPOSAL PHASE. :
Production and construction phase: is limited to the manufacture of
building materials, the transport and the construction.
Renovation and maintenance phase: number of replacements required when the actual lifetime of a building component is shorter
than the timeframe defined in the functional unit.
Operation phase: is limited to the final energy consumption required
for heating, and DHW. According to he Hungarian order, we do not
have to calculate with the energy demand of lighting and we do not
have cooling in the building either.
Disposal phase: the demolition of building, the selecting and transporting of materials, and the waste treatment (reuse, utilization of
material and energy, disposal).
Final energy demand calculation: Excel sheets, according to the Hungarian
Regulation (7/2006. (V. 24.) TNM decree.
Electric mix of production: Technosphere resources for the production of 1kWh
in Hungary:
Ecoinvent module
kWh
Electricity, at cogen ORC 1400 kWth, wood, allocation exergy
0.000085
Electricity, lignite, at power plant
0.273
Electricity, oil, at power plant
0.125
Electricity, natural gas, at power plant
0.188
Electricity, industrial gas, at power plant
0.00333
Electricity, hydropower, at power plant
0.00539
Electricity, nuclear, at power plant
0.402
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ENSLIC Building
14
Indicators
List of the calculated impact indicators:
Unit
Source
MJ-Eq
Ecoinvent v2.0 (2007)
Global Warming Potential at 100 years
kg CO2-Eq
IPCC 2001
Acidification Potential
kg SO2-Eq
CML 2001
Impact indicator
Cumulative Energy Demand
Results after measures
Heating Fin En. (kWh/m2*y) 52.5 – 36.6
Cooling Fin. En. (kWh/m2*y)
–
Lighting Fin. En. (kWh/m2*y)
–
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Conclusions
14
Cumulative Energy Demand
The above diagram shows well that the energy needs of the construction, maintenance and demolition of the two different
building renovation types hardly differ from each other (the difference is below 10%), however the cumulative energy demands of maintenance of the standard version is 56,02% and the low energy renovation is 63,3% lower respectively related
to the original building.
Meanwhile it can be observed that ratio of the cumulative energy demand of the particular life cycle phases changes related
to the whole building.
It can be stated that the low energy house is 78,9 % better than the original version involving only the net heating energy demand, however considering the whole life cycle the saving is ‘only’ 56,0%. This saving is due to the decreasing of the building use (operation) energy, which is about 560.000 GJ/year in total.
According to the Hungarian order, we do not have to calculate with the energy demand of lighting and we do not have cooling in the building either.
Global Warming Potential
The global warming indicators show very similar distribution to the cumulative energy demand discussed above.
Acidification Potential
The diagram of the acidification potential shows an even interesting shift.
It can be observed that ratio of the acidification potential of the particular life cycle phases changes related to the whole building (e.g. although the acidification potential of the building production seems slight related to the total value of the original
version (29,1%), in case of the low energy renovation building it gets higher importance (45,3%)) and after the renovation it’s
higher than the in the building use phase.
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15
Partner
ENSLIC Building
ÉMI
Location
NAGYKOVÁCSI/HUNGARY
Goal
Nagykovácsi municipality is situated at the border of Budapest. The designed nursery school for 100 people with the necessary server rooms and the kitchen
Life Cycle Assessment has been applied to this family house, in order to quantify the reduction of environmental impacts
by a passive and/or a low-energy design compared to a standard design (complying with the Hungarian regulation).
Building pictures
Climate
Budapest: Average Min Tª (jan)= –1.6ºC;
Average Max Tª(jul)= +26.5°C
Building description
Contruction year
Building type
Design phase
Nursery school
Fl. Area/ vol
Nº floors
1,348.7 m2 / 4,362.7 m3
2
(NET conditioned area)
LCA methodology
Functional unit: building (50 years lifespan) considering construction standards
in 2008.
Reference database: Ecoinvent v2.0 (2007).
Software: Excel sheets.
Simplifications: 4 stages taken into account: PRODUCTION, RENOVATION &
MAINTENANCE, OPERATION AND DISPOSAL PHASE:
Production and construction phase: is limited to the manufacture of
building materials, the transport and the construction.
Renovation and maintenance phase: number of replacements required when the actual lifetime of a building component is shorter
than the timeframe defined in the functional unit.
Operation phase: is limited to the final energy consumption required
for heating, and DHW. According to he Hungarian order, we do not
have to calculate with the energy demand of lighting and we do not
have cooling in the building either.
Disposal phase: the demolition of building, the selecting and transporting of materials, and the waste treatment (reuse, utilization of
material and energy, disposal).
Final energy demand calculation: Excel sheets, according to the Hungarian
Regulation (7/2006. (V. 24.) TNM decree.
Electric mix of production: Technosphere resources for the production of 1kWh
in Hungary:
Ecoinvent module
kWh
Electricity, at cogen ORC 1400 kWth, wood, allocation exergy
0.000085
Electricity, lignite, at power plant
0.273
Electricity, oil, at power plant
0.125
Electricity, natural gas, at power plant
0.188
Electricity, industrial gas, at power plant
0.00333
Electricity, hydropower, at power plant
0.00539
Electricity, nuclear, at power plant
0.402
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ENSLIC Building
15
Indicators
List of the calculated impact indicators:
Unit
Source
MJ-Eq
Ecoinvent v2.0 (2007)
Global Warming Potential at 100 years
kg CO2-Eq
IPCC 2001
Acidification Potential
kg SO2-Eq
CML 2001
Impact indicator
Cumulative Energy Demand
Results after measures
Heating Fin En. (kWh/m2*y)
95.35
Cooling Fin. En. (kWh/m2*y)
–
Lighting Fin. En. (kWh/m2*y)
30
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Conclusions
Cumulative Energy Demand
Finally, the following table breaks down the impact on primary energy associated with the manufacture of various building
materials (production phase). It is remarkable the high impact of the concrete building materials used mainly in walls and slabs.
Considering CED the most significant is the serving life cycle, in this phase 79.5% of the whole energy consuming is due to
the heating and lighting.
Global Warming Potential
The diagram of the CO2 emission is proportional to the energy consuming values: regarding GWP the most significant is the
operation or use phase, in this phase 74.8% of the whole environment loading is due to the heating and lighting.
Acidification Potential
Regarding acidification during the serving life of the building the lighting (or rather the electric energy consuming) has the most
significant effect, this is nearly 70% (!) regarding the whole life cycle.
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6. Conclusions
The project ENSLIC has helped to generate and disseminate new knowledge and
provide analysis and evaluation criteria, effective and practical, that measure the
environmental impact and contribute to reduce it, saving energy and making the
construction more sustainable. This methodology is quite useful for policy makers,
construction products suppliers, builders and professionals involved in the building
process and users to make the right decision.
Definitively, ENSLIC has provided an horizontal simplified methodology, that can
provide construction players with a practical and effective instrument for buildings
to be built and planned with the best environmental standards and a comprehensive long term energy strategy, promoting construction techniques and processes
based on products of lower energy consumption and environmental impact, and
the use of high-efficiency energy equipment and the integration of renewable
systems in buildings.
Conclusions - 69
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70 - Conclusions
Barriers to LCA implementation in building work include prejudices about the complexity, arbitrary results, accuracy, problems regarding interpretation of results and
the high costs of performing an LCA. The European ENSLIC Building Project has
drawn up practical guidelines and case studies in order to promote increased use
of LCA in building design.
The guidelines were developed in consultation with clients, architects and other stakeholders within the building sector and these practitioners are currently testing
their practical relevance. Few attempts have been made in the past to actually integrate LCA expertise with the practical considerations of architects, which makes
the ENSLIC Building Project somewhat unique. Also a series of case studies on real
buildings provide further examples on the practical application of the guidelines.
In the cases studies, the impact assessment is based primarily on indicators of
energy consumption and GHG emissions in line with the current environmental problems. However, the proposed methodology allows the consideration of other environmental indicators, energetic and financial, always from a life cycle perspective.
Through case studies, construction players are able to increase their knowledge in
energy and environmental specifications of different materials and building solutions. This way they have in their hands all necessary information in order to be able
to consider energy and environmental impacts when making decisions on the selection of materials, suppliers and more eco-efficient production processes.
It can be concluded that it might be better to start with a simplified LCA tool in order
to overcome some of the existing barriers to increased LCA use. A simplified tool
that only calculates e.g. CO2 emissions for part of the life cycle may still engender
an understanding of the benefits of LCA and stimulate further interest. The Excel
sheet developed within the ENSLIC Building Project can be used for this purpose.
ENSLIC Building
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Conclusions - 71
ENSLIC Building
Some comments related to using such simplified tools should nevertheless be stressed. The impact is only related to the input data. If for instance many building materials are omitted, the user needs to be aware of this fact. Such simplifications need
to be based on relevant and well-reasoned assumptions of which processes might
play an important role and which may not. The latter can then be neglected as long
as it stands in relation to the purpose of the study. Furthermore, it can be concluded that to increase interest, LCA building tools need to be better integrated with
existing tools, for example investment calculation tools or CAD tools.
In order to make LCA calculations, it is essential to consider a materials database.
In this sense, it is always recommendable to select a database whose inventory of
construction materials suits the reality of the area or region where the building analyzed is located. Otherwise, the outcome results should be considered as an approximation to the real environmental impacts of the assessed building materials. With
the increasing numbers of environmental product declarations (EPD) for different
building products, some inventories can be obtained from existing EPDs.
Some aspects have to be considered in order to develop a simplified LCA methodology. For instance, the input data must be easy to find in the building project and
there should be as little of it as possible. The indicators and the impact categories
selected should be simple, so that architects, engineers, and final users can easily
understand the results. For example, if eutrophisation is selected as an impact category, few people will understand the result. But water consumption, embodied
energy and CO2, waste generation, etc., are well known. The indicators selected
should also complement the results of the energy certification, in order to establish
a strong link between LCA and building certification methodologies.
The energy certification processes for buildings that are being applied in European
countries, as a consequence of Directive 2002/91/EC being incorporated into national law, are a fundamental step towards improving buildings’ energy efficiency.
Nevertheless, these certification processes do not usually consider aspects related
to the life cycle of the building. Because of this, in some cases it may give rise to
the contradiction of obtaining a better energy classification, while producing higher
energy consumption or more CO2 emissions in global terms. For example, in Spain,
the certification procedure clearly encourage the inclusion of renewable energy
systems in buildings, with the risk that the design of the thermal enclosure, which
is the real key for making a building efficient and provides greater thermal comfort
for the occupants, is relegated to the background.
Considering the life cycle in the energy certification process of the buildings allows
the promotion of sustainable buildings with low energy consumption and high efficiency and favours innovation in the construction sector. Therefore, in addition to
promoting the use of renewable energy and equipment with high energy efficiency,
priority must be given to bioclimatic ecodesign and bioconstruction, the use of low
impact, natural, recyclable materials available in the local area, the minimisation of
water consumption by designing rainwater collection systems and greywater networks in buildings, the design of green roofs, etc.
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72 - Conclusions
ENSLIC Building
The results of the case studies demonstrate that the building industry uses great
quantities of raw materials which also imply important levels of energy consumption.
Each net conditioned square meter of a conventional building can lead to emission
of more than 1.5 tonnes of CO2 all over its lifetime, requiring a total of 2.3 tons of
more than 100 types of materials. If we then consider the weight of resources affected by the manufacturing process, that figure may be multiplied by 3. Choosing
materials with high content in embodied energy entails an initial high level of energy
consumption in the building stage but also determines future energy consumption
in order to fulfill heating, ventilation and air conditioning demands.
The standard "Net Zero Energy / Emission Buildings" is being promoted by both the
DOE and the European Parliament. NZE buildings produce (through on-site renewable energy generation normally) as much energy as consumed. However, this
standard is inadequate, failing to consider the indirect impacts of buildings. Institutions should advocate a new standard of "Life Cycle Zero Energy Buildings”, where
the amount of direct annual consumption (including heating, cooling, hot water, lighting, etc.) was added to the indirect energy consumption yearly expressed (including
the embodied energy in materials and systems), being the result close to zero.
A sustainable building should be characterized by a balance between the production of materials, their use for construction or refurbishment of buildings and the
amount of natural resources needed. In order to prevent the production of materials
affecting natural resources we need to promote the use of best available techniques
and innovation in production plants, and replace, as far as possible, the use of finite natural resources by wastes of other various production processes. This way we
may close the product cycles, promoting the reuse and recycle, minimizing the
transport of raw materials and products and prioritizing the use of available resources in local areas and a market. The extra-added value in products and services
should be based on minimizing the impact and the lower energy costs, that is, promoting and demonstrating that the less impact, the more competitive.
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A complete energy analysis of a energy consuming system in general, and a building
in particular, must address both direct consumption and indirect consumption. Direct consumption is the result of daily use and it is currently the focus of new Energy
Efficiency Regulations in buildings based on the Directive 2002/91/EC (EPBD). However, indirect energy or embodied energy consumption, which sometimes is as
important or more than direct energy consumption, has been ignored. Indirect
energy includes the total amount of energy used to produce, transport, install and
remove all materials and equipment used in the home at the end of their lifespan.
Although building may be very efficient from an energy point of view, the increase
of indirect energy consumption carries out that the energy consumption inducted by
the construction in global terms gets eventually increased. In this sense, we must
take into account that the implementation of the current energy efficiency regulation
framework necessarily force a reduction of the direct impacts at the stage of use of
buildings; but this is done by increasing the relative weight of the remaining stages
as part of the life cycle of buildings, especially with regard to the impact of the production of building materials used in buildings.
There are measures such as the installation of solar thermal collectors for domestic water heating whose impact in terms of global energy reduction is small. However, their social impact is very large. These efforts must be directed also to indirect
consumption, where high-impact measures can lead to very substantial decreases
in energy consumption.
As demonstrated in the project ENSLIC, life cycle analysis of all inputs and outputs
of energy and materials at all stages of the life span of buildings is necessary to
achieve real efficiency. Energy savings and emission reductions obtained by applying this global methodology improve those obtained from traditional methodologies. Moreover, these techniques permit identifying situations where the impacts
are moved in time or space, resulting that apparent advantages are not that good.
Therefore, it requires a new policy thrusts that incorporates the concept of LCA in
order to meet the challenge of adapting the construction sector to sustainability. In
this sense, policy makers in the European institutions should establish general criteria for eco-design in buildings, ruling obligations and specific and effective measures to promote good practices. On the other hand, local councils should also
incorporate these criteria into the municipal ordinances and town planning, rewarding promoters carrying out sustainable buildings beyond the minimum requirements established through grants or tax exemptions.
Conclusions - 73
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