Energy
Management AB
A Chalmers Industriteknik Company
SUNSTORE 4
WP5 - European level concept study
Feasibility/simulation studies
Deliverable 5.4
Mari-Liis Maripuu
Jan-Olof Dalenbäck
CIT Energy Management AB
April 2011
-1-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Table of Contents
1. Introduction………………………………………………………………………….4
1.1 Executive summary……………………………………………………………4
1.2 Readers guide………………………………………………………………….5
2. Definition of case study conditions..……………………………………………...6
2.1 Introduction……………………………………………………………………..6
2.2 Geographical regions for the case studies……………………………….....6
2.3 North-Europe: Sweden…………………….………………………………….7
2.3.1 The geographical and climate conditions…………………………….7
2.3.2 Energy mix and prices………………………………………………….8
2.4 North-Europe: Denmark…………………….……………………………… 11
2.4.1 The geographical and climate conditions………………………….. 11
2.4.2 Energy mix and prices………………………………………………...12
2.5 South-Europe: Italy…………………….……………………………………..14
2.5.1 The geographical and climate conditions…………………………...14
2.5.2 Energy mix and prices………………………………………………...15
2.6 East-Europe: Czech Republic………………….……………………………17
2.6.1 The geographical and climate conditions…………………………...17
2.6.2 Energy mix and prices………………………………………………...18
2.7 Central-Europe: Germany…………………….……………………………..20
2.7.1 The geographical and climate conditions…………………………...20
2.7.2 Energy mix and prices………………………………………………...21
2.8 West-Europe: France…………………….…………………………………..23
2.8.1 The geographical and climate conditions…………………………...23
2.8.2 Energy mix and prices………………………………………………...24
3. Load conditions for the case studies..…………………………………………..26
3.1 Typical DH systems in Sweden……………………………………………..26
3.2 Typical DH systems in Denmark……………………………………………26
3.3 Typical DH systems in Italy………………………………………………….27
3.4 Typical DH systems in Czech Republic……………………………………27
3.5 Typical DH systems in the region of South-West of Germany…………..28
3.7 Typical DH systems in France………………………………………………28
3.7 Overview of the selected case study conditions for the concept
study……..…………………………………………………………………….28
4. Definition of hybrid concept characteristics…………………………………….30
4.1 Introduction…………………………………………………………………....30
4.2 Different renewable energy technologies of interest in SUNSTORE-4
project………………………………………………………………………….30
4.2.1 Large scale solar heating systems…………………………………..30
4.2.2 Thermal energy storage………………………………………………32
4.2.3 Large biomass boiler system………………………………………....35
4.2.4 Combining biomass boiler system with ORC………………………37
-2-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
4.2.5 Large heat pump system……………………………………………..38
5. Choice of hybrid system concepts and their characteristics………………….40
5.1 Hybrid concept 1: Solar collector, seasonal water pit storage, HP and
biomass CHP………………………………………………………………………40
5.2 Hybrid concept 2: Solar collector, seasonal water pit storage, HP and
biomass boiler……………………………………………………………………..41
5.3 Hybrid concept 3: Solar collector, seasonal water pit storage and biomass
boiler………………………………………………………………………………..42
5.4 Hybrid concept 4: Solar collector, seasonal ground (borehole) storage,
HP and biomass boiler……………………………………………………………43
5.5 Hybrid concept 5: Solar collector, short-term water tank storage, and
biomass boiler………………………………………………………………….….44
6. Feasibility assessment tool………………………………………………………46
6.1 Introduction……………………………………………………………………46
6.2 Overview of the Excel tool…………………………………………………...46
6.2.1 Input data……………………………………………………………….47
6.2.2 Results………………….………………………………………………49
7.References……..…………………………………………………………………..52
Appendices……..…………………………………………………………………….53
Appendix 1: Questionnaire – WP5……..…………………………………………..54
-3-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
1. Introduction
1.1 Executive summary
The SUNSTORE- 4 project aims to promote the 100% RES systems with high solar
fraction on European scale and involve partners in different countries for planning and
building these kinds of RES systems. For the purpose of this project a number of
representative countries have been chosen where the feasibility of the hybrid concepts
will be studied in detail. An example of European regions with representative countries
for feasibility study is following:
• North-Europe (e.g. Sweden, Denmark);
• South- Europe (e.g. Italy);
• East-Europe (e.g. Czech Republic);
• West-Europe (e.g. France);
• Central Europe (e.g. Germany).
For the purpose of the SUNSTORE 4 project it is of great interest to study the
feasibility of the specific hybrid concept of 100% RES system at different climate,
geographical and load conditions. The type of hybrid system that is built and tested in
Marstal in Denmark includes solar collectors with long term thermal heat storage
system that can cover approx 55% of total energy need, biomass boiler, integrated heat
pump and ORC system. It is of great interest to evaluate if this type of hybrid concept
would be applicable also in other regions and what kind of hybrid concepts can be
adapted to the local conditions.
Five different hybrid concepts will be analysed in detail in the feasibility study in WP5.
For the purpose of the current project, which aims to have at least 55% solar energy and
the rest should be covered by biomass, a large scale solar collector system and biomass
boiler will be incorporated to all of the hybrid concepts that will be studied in detail.
Additional interest in the feasibility study is to analyse what kind of thermal storage
system would be most suitable considering the local conditions, performance factors
and economical aspects. Here three alternatives will be analysed: seasonal water pit
storage (PTES), seasonal ground storage (BTES) and short- term water tank storage.
Combining heat pump to the hybrid concept of 100% RES district heating can provide
considerable benefits in terms of system optimisation and overall efficiency. However,
the question is if this will be feasible in all cases. Thus hybrid concepts without the heat
pump integrated will be analysed.
Further interest in the SUNSTORE 4 project is to combine heat and electricity
production by including the Organic Rankine Cycle (ORC) to the system. In the
feasibility studies the cost effectiveness of the ORC will be analysed.
The aim is to identify the feasibility of the selected hybrid concepts with different
conditions (climate, energy prices, etc.). The study will thus be based on the annual
performance of the hybrid concepts. The feasibility of the hybrid concepts will mainly
be influenced by investment conditions, specific investment costs for the components,
-4-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
energy prices (biomass and electricity) and the cost for the alternatives (typically CHP
or boiler on natural gas, in some cases biomass CHP or boiler).
It is preliminary decided that the study will be carried out for three load sizes:
10 GWh/a, 30 GWh/a and 100 GWh/a respectively. Based on the DH system analyses
in the representative regions the first load size is common for smaller villages and
residential areas. The second load size corresponds to rural villages and small
settlements, e.g. Marstal. The third load is common for smaller towns.
A simple feasibility evaluation tool has been created for the SUNSTORE 4 project WP5
for feasibility/simulation studies of hybrid concepts. The feasibility tool is based on
Excel program. The aim with the development of such tool has been to provide to the
different stake holders in the process of planning and building such DH plants described
in SUNSTORE 4 project a simple method to estimate the feasibility in an early stage.
1.2 Readers guide
Chapter 2 “Definition of case study conditions” provides background information about
the representation case studies chosen for the feasibility studies in a SUNSTORE 4
project. The feasibility of the hybrid system concepts which have high solar fraction
and use of other renewable energy sources depends on local climate, geographical and
load conditions as well as local energy system context (energy mix and prices). These
parameters and characteristics will be described in details.
Chapter 3 “Load conditions for the case studies” comprises a description of the typical
DH systems in the different case study countries and provides an overview of the
chosen load conditions for the concept study.
Chapter 4 “Definition of hybrid concept characteristics” comprises a description of the
different renewable energy systems applicable for the concept study, the advantages and
challenges of these systems and specific investment costs for the components.
Chapter 5 “Choice of hybrid concepts and their characteristics” describes the chosen
hybrid concepts for SUNSTORE 4 feasibility study in WP5. Five different hybrid
concepts have been chosen for the concept study.
Chapter 6 “Feasibility assessment tool” gives an overview of the feasibility evaluation
tool that has been created for the SUNSTORE 4 project WP5 for feasibility/simulation
studies of hybrid concepts.
-5-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
2. Definition of case study conditions
2.1 Introduction
This chapter provides background information about the representation case studies
chosen for the feasibility studies in a SUNSTORE 4 project. The feasibility of the
hybrid system concepts which have high solar fraction and use of other renewable
energy sources depends on local climate, geographical and load conditions as well as
local energy system context (energy mix and prices). These parameters and
characteristics have been described in detail for the chosen case study conditions.
2.2 Geographical regions for the case studies
For assessing the feasibility of a district heating plant with high solar fraction, one of the
main parameters to take into account is the available solar resource. Global irradiation
on a horizontal plane related to the location where the plant will be installed, expressed
in kWh/m2 per year is key figure used for this assessment. Figure 1 shows the average
global solar irradiation in Europe on horizontal surfaces [1].
Figure 1. The map of average global annual irradiation in Europe. Source: Meteonorm
4.0 [1].
The SUNSTORE- 4 project aims to promote the 100% RES systems with high solar
fraction on European scale and involve partners in different countries for planning and
building these kinds of RES systems. For the purpose of this project a number of
representative countries have been chosen where the feasibility of the hybrid concepts
-6-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
will be studied in detail. The details of the geographical and climate conditions for the
representative countries are described in the following chapters together with the energy
market characteristics and potential for the 100 % RES systems. This information has
been provided by different partner in SUNSTORE-4 project. A special questionnaire
was formed and sent to different project partners. This questionnaire is presented in
Appendix 1.
An example of European regions with representative countries for feasibility study is
following:
• North-Europe (e.g. Sweden, Denmark);
• South- Europe (e.g. Italy);
• East-Europe (e.g. Czech Republic);
• West-Europe (e.g. France);
• Central Europe (e.g. Germany).
2.3 North-Europe: Sweden
2.3.1 The geographical and climate conditions
Sweden locates in Northern Europe on the Scandinavian Peninsula. The country has a
long coastline on the eastern side and the Scandinavian mountain chain (Skanderna) on
the western border, a range that separates Sweden from Norway. It has maritime borders
with Denmark, Germany, Poland, Russia, Lithuania, Latvia and Estonia.
Sweden is heavily forested, with 78% of the country being forest and woodland.
Southern Sweden is predominantly agricultural, with increasing forest coverage
northward. About 15% of Sweden lies north of the Arctic Circle.
Borehole, tank and pit thermal energy storage systems have been realized in the
country.
Sweden can be divided into three types of climate: the southern part has an oceanic
climate, the central part has a humid continental climate and the northern part has a
subarctic climate. However, Sweden is much warmer and drier than other places at a
similar latitude, and even somewhat farther south, mainly because of the Gulf Stream.
Temperatures vary greatly from north to south. Southern and central parts of the country
have warm summers and cold winters, while the northern part of the country has
shorter, cooler summers and longer, colder and snowier winters, with temperatures that
often drop below freezing from September through May.
The mean annual outdoor temperature in Sweden is +8 °C. The mean annual global
irradiation is in between 750-1000 kWh/m2. The map of mean annual global irradiation
in the different regions of Sweden is shown in Figure 2.
-7-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 2. The map of average annual global irradiation on a horizontal surface in
Sweden. Source: SMHI [23].
The relative weighted Degree-Days for Sweden based on the Eurostat Energy statistics
is approx 5350 [2].
Climate conditions in south of Sweden are similar to Denmark.
2.3.2 Energy mix and prices
The proportion of renewable energy use in Sweden amounted to 44 % in 2009. The
renewable sources that are used most in Sweden are biomass (wood chips and pellets),
hydro power, organic waste, heat pumps (large sewage, small ground source), biobased
motor fuels and wind power [3].
The energy market is largely privatized. Swedish power generation is part of the
regional Nordic market which also includes Denmark, Finland and Norway. The
-8-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Nordic electricity market is traded in NASDAQ OMX Commodities Europe and Nord
Pool Spot. The price of electricity in the Nordic countries is largely determined by
hydro power availability in Sweden and Norway, availability of the nuclear power
stations in Sweden and Finland, international price levels of various fuels and
government policy measures and incentives [3]. In specific the spot market price is
determined by the production cost of the energy, availability of the different energy
sources, energy demand, meteorology, etc.
Based on the statistics up till year 2009, the real price of electricity (including taxes) has
increased about 60 % from year 2000 [3].
Sweden has a system of green electricity certificates. It is the system where the state
decides how large quota of the produced electricity should be from renewable sources.
A green certificate is commonly given to each MWh that is produced. The customer is
obliged to have a certain quota of renewable energy in the purchased electricity. Green
certificates are market based and the income from these varies. The cost for a certificate
is approx 28 €/MWh [5] and the price depends on the interaction of supply and demand
on a competitive market [3].
District heating accounts for ca 50 TWh from the total final energy use, corresponding
to 14% of the final use [3]. District heating in Sweden consists mainly of renewable
energy sources. The division of different energy sources in district heating systems is
shown on Figure 3 [6].
Biofuels
3%
5%
1%
Waste heat
Industrial waste heat
14%
47%
Heat pumps
Fossil fuels
8%
Peat
6%
Electricity
Other
16%
Figure 3. Supplied energy to district heating systems and CHP systems [6].
A great number of district heating suppliers produce energy by CHP systems. In
combination with changes in CHP taxation the market for district heating has become
more favorable for heat producers [3].
There are significant price differences in district heating energy between the areas in
Sweden, depending on the type of heat production, fuel price, conditions for
construction of district heating systems, size of the load, etc. The district heating price
-9-
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
is also influenced by taxes and other means of economical control, like electricity
certificates, CO2 emission rights, etc. Due to the increase in CO2 taxes in general the
district heating producers have started to use more RES (Renewable Energy Systems) in
their energy production units. Most district heating companies nowadays are run as
local authority-owned limited companies. The volume weighted mean price of district
heating in 2010 was about 65 €/MWh (excl.VAT) [6]. The price for district heating in
Sweden has increased ca 3-4 % annually, ca 31 % increase in total in the mean price
from 1999 till 2010. This is partly due to price increase of fuels.
The price for biomass has increased considerably during the last years, influencing the
total price of the district heating by specific energy producers.
Table 3 gives the summary of the energy prices in Sweden. These prices will be used as
a basis for the SUNSTORE -4 feasibility study.
Table 3. Summary of energy prices in Sweden used for concept study in SUNSTORE4.
Country/
region
Sweden
Energy source
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
Electricity (heat pumps
and operation)
Wood chips
≤10
78
10
30
100
10
30
100
22
22
22
33
33
33
571) +28 eur/MWh energy
certificates2)
65 3)
Pellets
Feed-in electricity
Mean DH price
Comments:
1) Mean annual Nord Pool Spot price 2010
2) The price is a subject to trading price on the spot market
3) Volume weighted middle price incl. taxes
Natural gas is used in relatively small quantities in Sweden due to the small distribution
network in the country. However, the energy sector is expected to make greater use of
natural gas due to construction of gas-fired CHP plants [3]. The total price of natural gas
depends on the consumption and user. The price level in 2010 was the following, incl.
taxes, excl. VAT (based on data jan-dec 2010; 1 € ≈ 9 SEK) [4]:
• Industry (annual use of < 3000 MWh): 57 – 66 €/MWh
• Industry (annual use of 3000-300 000 MWh): 46- 51 €/MWh
• Industry (annual use of > 300 000MWh): 42 – 46 €/MWh
The use of oil in the Swedish energy systems has been reduced by half since 1970. The
mean price for oil for district heating plants was ca 74 €/MWh (medium-heavy fuel oil,
incl. taxes) based on data for 2009.
The main barrier for further development of new type of 100 % RES district heating
systems in Sweden can be considered as that there are already a great number of close to
100% RES systems. Most district heating systems in Sweden have some kind of
biomass use.
- 10 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
2.4 North-Europe: Denmark
2.4.1 The geographical and climate conditions
Denmark locates is the Northern European region on the Jutland peninsula and on
several islands. The country is mainly surrounded by the sea, having coastline with both
the Baltic Sea and the North Sea. In the south side it borders with Germany. The local
terrain is generally flat with a few gently rolling plains. Approx 60% of the land in
Denmark is arable; the area of forests and woodland corresponds to ca 10%.
Borehole, tank and pit thermal energy storage systems have been realized in the
country.
Denmark has a temperate climate, whereas winters are commonly mild and windy and
the summers are cool due to west winds and by the seas that surround Denmark. The
fluctuation between day and night temperatures is not big, but wind gusts and changes
in wind direction can quickly change the weather and temperatures. The wind is
stronger in winter. The mean annual outdoor temperature in Denmark is +8.6 °C. The
mean annual global radiation is approx 1000 kWh/m2. The map of mean annual global
irradiation in the different regions of Denmark is shown in Figure 4.
The relative weighted Degree-Days for Denmark based on the Eurostat Energy statistics
is approx 3400 [8].
- 11 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 4. The map of average annual global irradiation on a horizontal surface in
Denmark [24].
2.4.2 Energy mix and prices
Denmark is the second largest producer of oil in the EU, which plays an important role
in the energy mix [8]. Natural gas and renewable sources have been gradually replacing
solid fuels and oil in primary energy supply. The proportion of renewable energy use in
the total energy consumption in Denmark amounted to 18 % in 2009. The renewable
sources that are used most in Denmark are wind power, biomass (straw, wood chips,
firewood), organic waste, heat pumps and biogas and biooil [9].
Danish power generation is part of the regional Nordic electricity market traded in
NASDAQ OMX Commodities Europe and Nord Pool Spot.
The electricity produced by CHP plants is commonly sold at a market price.
Furthermore, plants larger than 5 MW are obliged to use market prices. A few small
plants use a set price, the so-called “three-tier tariff”, which is based on when the
electricity is produced.
The price of electricity for the customer varies in between 250 - 300 €/MWh including
taxes, distribution cost and VAT. The electricity prices for heat pumps is an average
90 €/MWh plus the tax 90 €/MWh.
- 12 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
The feed-in tariff for electricity by biomass fuelled CHP plant is 10 €cent/kWh (0,78
DDK/kWh) for innovative technologies (gasification, Stirling engines, ORC with same
efficiency as Stirling engines) and the market price (approx 5€cents) plus 2€cents for
other plants.
Due to extensive development of windmills and decentralized CHP plants it can happen
that the electricity generation from windmills and CHP can exceed the consumption and
lead to very low market price of the electricity. To avoid the situation that the economic
advantage of CHP actually becomes as a loss, the CHP companies can choose to
produce either electricity or heat, according to demand.
Over 80% of district heating is produced in CHP plants. Denmark has given high
priority for combined heat and electricity production. The division of different energy
sources used to produce district heating in Denmark 2009 is shown on Figure 5 [9].
Biomass
5%
2%
1%
Natural gas
8%
31%
Coal
Non-renewable waste
Oil
26%
Surplus heat
Other
28%
Figure 5. District heating production by fuel in Denmark 2009 [9].
Fuels used to produce heat are taxable, although this does not apply to biofuels,
meaning that plants using such fuels are indirectly subsidized to use biomass. Fuels
used to generate electricity are not taxable, the customers are taxed for their electricity
consumption instead.
Denmark has enough biomass resources of its own to cover biomass consumption in the
near future [10]. However, considerable amount of wood pellets and other biofuels is
imported.
Table 4 gives the summary of the energy prices in Denmark. These prices will be used
as a basis for the SUNSTORE -4 feasibility study.
- 13 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Table 4. Summary of energy prices in Denmark used for concept study in SUNSTORE4.
Country/
region
Denmark
Energy source
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
Electricity (heat pumps
and operation)
Wood chips [11]
≤10
180
10
30
100
10
30
100
21
21
21
32
32
32
1)
70-100
2)
76,5
Pellets [11]
Feed-in electricity
Mean DH price
3)
Comments:
1) Biomass fuelled CHP plants
2) According to Dansk Fjernvarmes statistics 2010, incl taxes [12].
3) Including taxes and distribution cost
The price of natural gas for DH plants is 27,6 €/MWh (57,1 DDK/GJ; 1 € ≈ 7,45 DDK),
excluding tax and VAT [11]. The price with the tax is 59 €/MWh (122,1 DDK/GJ). The
mean price for coal for power plants is ca 10 €/MWh (20,6 DDK/GJ), excluding tax and
VAT. The price for Diesel for customers is ca 60 €/MWh (105,5 DDK/GJ), excluding
tax and VAT; with taxes and VAT the price is approx 125,6 €/MWh (260 DDK/GJ).
The main barrier for the development of new type of 100 % RES district heating
systems in Denmark are considered to be political will and competing technologies,
such as utilization of surplus electricity from wind energy.
2.5 South-Europe: Italy
2.5.1 The geographical and climate conditions
Italy is located in a southern part of Europe where Alps become northern boundary of
the country and the Apennine Mountains form as backbone of the peninsula. It is a
volcanic active country. According to year 2005 estimation about 26.41 % and 9.09 %
of the land is covered by arable land and permanent crops respectively, while land for
other purposes consists 64.5%.
Geological conditions vary regionally. Storage facilities might be distinct regarding to
local conditions. Geologically, Po Plain is one of the most well-known alluvial plain in
northern sector which deposits origin both from the Alps and the Apennines. Deposits
are composed of limes, clay, and sand, gravel where reservoirs have great importance
for aquifer thermal storage (ATES) that might be characterized as a type of feasible
storage in future projects.
Italy has different climates, such as humid subtropical (e.g.Turin, Bologna), oceanic
climate is seen inland and Mediterranean climate prevails west coastal areas and south
mostly. There are huge temperature differences between north and south particularly in
winter; for instance, Rome is +7–+8 °C while the Po valley's mean temperature varies
between -1–+1 °C. Heat island effect is seen in cities such as Milan and Turin that
causes observing different temperatures in the city centre and outskirt of the city. Mean
- 14 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
annual outdoor temperature in Italy is +16°C [13]. The mean annual global radiation on
a horizontal surface in Italy varies in between 1000 - 1 800 kWh/m2 corresponding to
variation in between northern and southern part of Italy respectively. The map of mean
annual global irradiation in the different regions of Italy is shown in Figure 6.
Figure 6. The map of average annual global irradiation on a horizontal surface in Italy
[24].
The relative weighted Degree-Days for Italy based on Eurostat Energy statistics is
approx 2040 [8].
2.5.2 Energy mix and prices
The shares of thermal energy sources by district heating network are shown in Figure 7.
- 15 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
18%
29%
Renewable energy
Cogeneration fossil fuel
base
Boilers fossil fuel base
52%
Figure 7. Distribution of thermal energy sources for district heating production in Italy.
Table 5 gives the summary of the energy prices in Italy. These prices will be used as a
basis for the SUNSTORE -4 feasibility study.
Table 5. Summary of energy prices in Italy used for concept study in SUNSTORE-4.
Country/
region
Italy
Energy source
Electricity (heat pumps
and operation)
Wood chips
(20% water content)
Wood chips
(30% water content)
Pellets
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
≤10
140
10
30
100
10
30
100
10
30
100
33
33
33
20
20
20
43
43
43
66-115,5 + 180 - 420 eur/MWh
bonus for renewable energy
CHP
56-94
Feed-in electricity
Mean DH price
The price for biomass is variable and depends on the area of biomass retrieval, transport
costs and demand. Pellets are more expensive and depend more on the market
fluctuations.
The feed-in tariff of electricity varies in between 65.9-115.4 € /MWh and the price is
different depending on the tariff period of the year, e.g. during peak period of the year
the market prices increase. There are subsidies if plants are operated by renewable
energy resources and it varies in between 180 €/MWh to 420 € /MWh. Every year
AEEG fixes the average sale price of electricity for the quantification of the placement
price in the market for the green certificates. The average value in 2010 was
66.90 €/MWh. It is estimated that the price for electricity will increase from
74.56 €/MWh in 2012 to approx. 84 €/MWh in 2015 [14].
- 16 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Standard price of natural gas for boilers is 39.7 €cent/Sm3 (excl. VAT but including
excise taxes). The price is depending on the energy market and local conditions of
provinces. Furthermore, the price is valid only in case of subsidized tariff for CHP
plants. The economic conditions for natural gas are set by AEEG (Authority for Electric
Energy and Gas).
The main barriers and challenges for the 100 % RES district heating systems in Italy
are:
• Lack of full involvement of actors and more political support;
• High cost of innovations for potential improvement in current systems and
investment cost of new plants;
• Low financial support/subsidies and no promotions;
There is a need for exchange of information in common forums and better
understanding of reliability of RES district heating systems.
2.6 East-Europe: Czech Republic
2.6.1 The geographical and climate conditions
The country comprises three historical lands - Bohemia, Moravia and
Silesia. Administratively, the Czech Republic is divided into 14 regions. The Bohemian
basin is surrounded on all sides by an important mountainous belt. Only eastward from
Moravia is it then separated by the lower Czech-Moravian highlands.
Czech Republic lies in the temperate climate zone, which is characterized by cool
summers and cold, cloudy and humid winters. The climate differs among the regions of
the Czech Republic, depending on the height above sea level.
The weather at any given time may differ considerably from the long-term average. This
changeability of the weather is caused primarily by the variable location and magnitude
of two main pressure centres – the Icelandic Low and the Azores High. During the
warm period of the year the high pressure projection causes warmer and drier
temperatures, whereas the Icelandic Low manifests itself with a greater number of
atmospheric fronts, which bring more clouds and precipitation.
Mean annual outdoor temperature in Czech Republic is +8,8°C. The global irradiation is
between 950 and 1200 kWh/m2a, while the lowest values go with the north-west of
Bohemia. Highest values of the global irradiation can be measured in the south-east part
of Moravia, along the border with Austria. The map of mean annual global irradiation in
the different regions of Czech Republic is shown in Figure 8.
- 17 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 8. The map of average annual global irradiation on a horizontal surface in Czech
Republic [24].
The relative weighted Degree-Days for Czech Republic based on Eurostat Energy
statistics is approx 3520 [8].
2.6.2 Energy mix and prices
Approximately 38 % of total heat consumed in the Czech Republic is supplied from
district heating systems. The division of the energy sources is shown in Figure 9.
2%
3%
8%
Coal
Natural gas
20%
Biomass and other RES
Heating oil
Others
67%
Figure 9. Energy sources in Czech district heating systems
- 18 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Prices of fuels varies according regions, consumed amount and chosen supplier. The
price for natural gas is around 50 €/MWh (incl. VAT) and the price for heating oil is
over 75 €/MWh (incl. VAT).
The Czech biomass market is not stable these days and prices vary from contract to
contract.
Table 6 gives the summary of the energy prices in Czech Republic. These prices will be
used as a basis for the SUNSTORE -4 feasibility study.
Table 6. Summary of energy prices in Czech Republic used for concept study in
SUNSTORE- 4.
Country/
region
Czech
Republic
Energy source
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
Electricity (heat pumps
and operation)
1)
Wood chips
≤10
72
10
30
100
10
30
100
10
30
100
19
19
19
31
31
31
37
37
37
141
65
Wood chips
Pellets
2)
3)
Feed-in electricity
Mean DH price
Comments:
1) Wood chips with calorific value 2.78 MWh/ton
2) Wood chips with calorific value 4.17 MWh/ton
3) Pellets with calorific value 4.86 MWh/ton
Large district heating plants that were built during last three years “collect” wood chips
from large forest areas in their surroundings. Therefore, it is assumed that there will be a
lack of wood chips at the market in the near future and the price will rise in next few
years.
The feed-in tariffs and green bonuses for electricity made in RES are determined by the
Price Decision of the Energy Regulatory Office every year. The price depends on the
type of the biomass. Feed-in tariff for electricity produced by new CHP based on
biomass is:
• 183.2 €/MWh for biomass category O1: e.g. purposefully cultivated plants and
their separate parts coming from agricultural production that are primarily
intended for energy use and have not been technologically treated; purposefully
grown energy crops (wood grown outside of forests); biomass is completely
used to energy production etc. Green bonus for this category is 144.4 €/MWh;
• 141.2 €/MWh for biomass category O2: e.g. biomass (wood chips) produced as
a remain of logging. Green bonus for this category is 102.4 €/MWh;
• 105.2 €/MWh for biomass category O3: e.g. biologically decomposable remains
from kitchens; biologically decomposable parts of sorted industrial and
municipal waste. Green bonus for this category is 66.4 €/MWh.
- 19 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
It is up to plant operators to decide what type of support they want to use. They get
141.2 €/MWh from grid operator in the case of biomass category O2 when they decide
to supply all produced electricity to distribution grid. Alternatively they can decide for
the green bonus. The Green bonus means that the plant operator receives 102.4 €/MWh
for every MWh that was produced in the plant and also consumed there or in its local
distribution grid. So the green bonus is advantageous for plant operators with some local
distribution grid where it is possible to consume produced electricity. Most of the plants
in the Czech Republic work in the feed-in tariff operation because it means fixed price
for every produced MWh regardless the consumption in the grid.
The main barriers for the 100 % RES district heating systems in Czech Republic are
considered to be:
• low price of heat from the coal based district heating systems;
•
higher temperatures in distribution systems;
•
high investment costs of new sources e.g. solar district heating;
•
it is difficult to obtain land for placing the collectors.
References according to [15].
2.7 Central-Europe: South-West Germany
2.7.1 The geographical and geological conditions
The geographical and geological situation in Germany varies significantly. The country
borders with the Alps in the south, crossing the North European Plane up to the North
Sea and Baltic Sea.
Southern Germany's landforms are defined by various linear hill and mountain ranges.
The Alps on the southern border are the highest mountains, but relatively little Alpine
terrain lies within Germany compared to Switzerland and Austria.
Borehole, tank and pit thermal energy storage systems have been realized in the region.
Most of Germany has a temperate seasonal climate. The climate conditions are
influenced by the North Atlantic Drift, the northern extension of the Gulf Stream, which
affects the areas bordering the North Sea. Most of Germany has a temperate seasonal
climate in which humid westerly winds predominate. Winters in this region are mild and
summers tend to be cool. However, temperatures can exceed +30 °C.
In central and southern Germany the climate vary from moderately oceanic to
continental. In addition to the maritime and continental climates, the Alpine regions and
some areas of the Central German Uplands have a mountain climate with lower
temperatures and greater precipitation. The average annual ambient temperature in
south-west of Germany is between +7 - +12 °C.
- 20 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
The global radiation in south-west of Germany varies in between 1000 - 1200 kWh/m2a,
whereas the lower values correspond to central and north part of the Germany and the
higher values to the south-east and South-West part of the Germany. The annual global
irradiation in South-West of Germany is shown in Figure 10.
Figure 10. The map of average annual global irradiation in South-West of Germany.
Source: Deutscher Wetterdienst [17].
The relative weighted Degree-Days for Germany based on the Eurostat Energy statistics
is approx 3200 [8].
2.7.2 Energy mix and prices
In south-west of Germany the most common type of energy systems is central heating
systems, but also individual heating systems occur. The division of different energy
sources is the following:
• Natural gas 50%,
• Oil 35%,
• Biomass and other 5%,
• District heating 10 % (mainly cities).
The main secondary heating systems are based on biomass and solar thermal energy.
Borehole, tank and pit thermal energy sources have been realized as seasonal storage.
- 21 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Large electricity consumers in industry can negotiate electricity prices of 50 €/MWh or
even better. For hybrid concept of RES systems it is strongly recommendable to
negotiate a special contract with the net operator, which focuses on the purchase of
electricity in low tariff periods, in order to also benefit from those.
Combined heat and power (CHP) plants using biomass can benefit from the feed-in
tariffs of the German EEG [16] (October 2008, revised August 2010). Fixed tariffs
between 150 and 200 €/MWh can be obtained, which are calculated according to the
EEG:
• The base tariff depends on the system capacity:
7.79 - 11.67 €cent/kWh
• Bonus for innovative technology:
2 €cent/kWh
• Bonus for CHP:
3 €cent/kWh
Additional Boni are possible for energy crops. An annual degression of 1 % is applied.
Good prices are also achieved if the CHP operator participates in the EEX electricity
stock exchange. In normal periods prices obtained vary in between 40 - 60 €/MWh.
However, in peak periods spot market prices can be also much higher.
Table 7 gives the summary of the energy prices in Germany. These prices will be used
as a basis for the SUNSTORE -4 feasibility study.
Table 7 Summary of energy prices in Germany used for concept study in SUNSTORE4.
Country/
region
Germany
Energy source
Electricity (heat pumps
and operation)
Wood chips
Pellets
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
≤10
50
10
30
100
10
30
100
20-30
1)
20-30
1)
20-30
2)
50
78-120+ 20-50 eur/MWh bonus
for innovative technology and
CHP
55-903)
Feed-in electricity
Mean DH price
Comments:
1) FNR 2011, dry quality
2) FNR 2011, dry quality, not used for larger system.
3) purchase of ca 1 GWh/a (VEA-Fernwärme-Preisvergleich 2010)
1)
The price for natural gas in the region of south-west of Germany is 30-35 €/MWh (incl.
energy tax, which is refunded if the overall annual efficiency of CHP is over 70%).
The main barriers for the 100 % RES district heating systems in the region are
considered to be:
• CHP based on waste and fossil fuels are still dominating in existing district
heating networks;
• high capital costs for 100 % RES;
• logistics for biomass and unsure biomass prices in case of larger systems.
- 22 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
2.8 West-Europe: France
2.8.1 The geographical and geological conditions
France is located on the western edge of Europe and counts three coasts: over the
Atlantic Ocean for the western coast, over the North Sea for the north-western coast,
and over the Mediterranean Sea for the south-eastern coast.
The landscape is really diversified, with five mountain ranges: three rather small and
two higher mountain ranges.
In the south-east part of the country a Mediterranean climate prevails, with warm and
dry summers and not too cold but wet winters. In the west the climate is predominantly
oceanic with a high level of rainfall, mild winters and cool to warm summers. Inland the
climate becomes more continental with hot, stormy summers, colder winters and less
rain. The climate of the Alps and other mountainous regions is mainly alpine, with the
number of days with temperatures below freezing over 150 per year and snow cover
lasting for up to six months. In south-eastern France, the climate varies from moderately
continental to alpine.
The mean annual temperature is about +11 °C at Paris and +15 °C at Nice. The map of
yearly global irradiation [kWh/m²] is shown in Figure 11.
- 23 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 11. The map of average annual global irradiation on a horizontal surface in
France [24].
The relative weighted Degree-Days for France based on the Eurostat Energy statistics is
approx 2440 [8].
2.8.2 Energy mix and prices
Figure 12 shows the distribution of energy sources for heating of commercial and
residential buildings [19].
Natural gas
14%
1%
2%
Oil
40%
Electricity
18%
Biomass
Other renewable and
waste
Coal
25%
Figure 12. Distribution of energy sources for heating of commercial and residential
buildings [19].
There are approximately 420 district heating systems today in France, which produce
25000 GWh of heat annually. District heating represents at the moment 5- 6 % of the
total heat provided to commercial and residential buildings. The division of different
energy sources in district heating systems is shown on Figure 13 [20].
8%
Natural gas without
combined heat and power
15%
Gas with CHP
8%
Renewable energies or
waste combution
9%
Oil
29%
Coal
Others
31%
- 24 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 13. Supplied energy to district heating systems in France [20].
The district heating systems often use several different energy sources. It’s also
important to know that at the moment the Loi Grenelle allows the operators and clients
to benefit from a reduced VAT of 5,5% instead of 19,6% on heat sale for district
heating powered by at least 50% of renewable energies or waste combustion.
The wood industry in France is still under the development. The production of pellets
for example has multiplied by 9 during the last five years. In 2010 about 435 000 tonnes
of pellets were produced and pellets are now available all over the French territory.
Table 8 gives the summary of the energy prices in France. These prices will be used as a
basis for the SUNSTORE -4 feasibility study.
Table 8. Summary of energy prices in France used for concept study in SUNSTORE- 4
Country/
region
France
Energy source
Consumption
(GWh/a)
Price for fuel, €/MWh
(excl VAT)
Electricity (heat pumps
and operation)
Wood chips
≤10
70
10
30
100
10
30
100
18-30
18-30
18-30
36-44
36-44
36-44
61-91,51)
57
Pellets
Feed-in electricity [22]
Mean DH price
Comments:
1) system powered by CHP
The price of natural gas for DH plants is 40,7 €/MWh excluding tax and VAT. The
price with the tax is 42 €/MWh.
The main barriers for the 100 % RES district heating in France are considered to be:
• High temperatures at which the DH systems often run. Some systems still run
with vapor or high temperature hot water due to the need of high temperatures in
the buildings;
• Also high investment costs are considered as a barrier for 100% RES DH systems
for small villages or cities.
- 25 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
3. Load conditions for the case studies
3.1 Typical DH systems in Sweden
In Sweden there are about 414 district heating systems, whereas 58 of them are CHP
plants [6]. The most typical DH systems in the region in terms of load size, system type
and other characteristics are the following:
• Type 1. District heating systems for bigger towns and cities, >200 GWh/a. Total
number of such plants ca 45, whereas 8 of them are bigger than 1000 GWh/a.
About 32 of them are CHP plants. DH plants operate with industrial waste heat (17
plants), waste (9 plants), refined (33 plants) and unrefined biomass (21 plants), heat
pump (17 plants) and natural gas (6 plants, mostly as extra heat production during
coldest periods of the year) and are managed by local utilities or bigger energy
companies. The CHP plants operate with waste heat, biomass and peat and some
oil. Design temperatures approx 110 / 70 °C.
• Type 2. District heating systems for small and middle size towns, 50-200 GWh/a.
Total number of such plants ca 70, whereas 23 of them are CHP plants. DH plants
operate with industrial waste heat (16 plants), waste (21 plants), refined (59 plants)
and unrefined biomass (24 plants), heat pump (8 plants), natural gas (6 plants) and
oil (mostly as extra heat production during coldest periods of the year) and are
managed by local utilities or bigger energy companies. The CHP plants operate
with oil, waste heat biomass and peat. Design temperatures approx 90 / 50 °C.
• Type 3. District heating systems for villages and small settlements, 10-50 GWh/a.
Total number of such plants ca 128, whereas 2 of them are small CHP plants. DH
plants operate with refined (85 plants) and unrefined biomass (47 plants), heat
pump (6 plants), natural gas (5 plants) and oil (mostly at summer time and as extra
heat production during coldest periods of the year) and are managed by local
utilities. The two CHP plants operate with biomass and peat and oil. Design
temperatures approx 90 / 50 °C.
• Type 4. Small district heating systems for small villages and residential areas, ≤ 10
GWh/a. Total number of such plants ca 125. DH plants operate with refined (36
plants) and unrefined biomass (75 plants) and oil (mostly at summer time and as
extra heat production during coldest periods of the year), and are managed by local
utilities. Design temperatures approx 80 / 40 °C.
3.2 Typical DH systems in Denmark
In Denmark there are approx 665 CHP plants and approx 230 DH plants for both public
and private heat supply. For public heating there are 16 centralized and approx 415
decentralized district heating plants. Most plants are CHP plants whereas a small
number of the decentralized (ca one-third) still produce only heat [10].
- 26 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Among the public heat supply plants there are approx 120 biomass based DH plants, 10
decentralized straw or wood-chip-fired CHP plants, 30 plants using waste, 6 centralized
CHP plants based on biomass, approx 30 CHP plants using biogas.
The majority of CHP plants have electricity output less than 25MW, only 10 CHP
plants have more than 25MW as electricity output. Approx one third of the plants have
electricity output between 1 and 3 MW.
In addition to public heat supply there are ca 380 CHP and 100 DH plants for private
heat supply delivering heat to the enterprise, institution or residential block which owns
them. Half of them use biomass as a fuel. Several of these plants work with low
temperatures and are directly connected to the customers heating system, without any
sub-station.
The typical DH temperatures in Denmark are 80°/40°C (±10 K).
3.3 Typical DH systems in Italy
The most typical DH systems in the region in terms of load size, system type and other
characteristics are the following:
•
Type 1: DH plants, e.g. Turin; DH network is approx. 325 km long; inlet-outlet,
120-70 °C;
•
Type 2: DH plants, e.g. Brescia; DH network length is approx 358 km; inletoutlet 120°C-70 °C (mainly overheated water);
•
Type 3. Bologna: There are nine plants with the total volume 6.553.504 m3,
which corresponds to 27.000 flats (we assume a flat of 240 m3 as a standard);
DH network is approximately 40 km long and temperature of plants varies
between 120-70 °C (overheated water) and 90-65 °C (hot water).
3.4 Typical DH systems in Czech Republic
The most typical DH systems in the region in terms of load size, system type and other
characteristics are the following:
•
Large DH systems in cities – mainly coal based systems although wood chips
are burned together with coal in many sources. Three systems in the Czech
Republic use a heat from waste incineration.
•
DH systems in small towns and villages – between 10 and 50 GWh/a. Natural
gas is a typical fuel in these systems although the biomass and biogas are used
quite often in new systems. Small CHP is integrated in some of these DH
systems.
- 27 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
•
Block heating systems for residential areas – between 1 and 10 GWh/a. Natural
gas is a main fuel in these systems. Small CHP is integrated in some of these
DH systems.
3.5 Typical DH systems in the region of south-west of Germany
The most typical DH systems in the region in terms of load size, system type and other
characteristics are the following:
• Type 1. Large DH systems in cities, 1500 GWh/a, CHP from waste or fossil fuels,
big regional energy suppliers, 110 / 70 °C, lower return temperatures are possible
for modern systems;
• Type 2. New RES DH systems in rural villages, 10 - 50 GWh/a, small CHP, biogas
CHP, biomass heating plants, local utilities or cooperatives, 90 / 50 °C;
• Type 3. Block heating systems for new residential areas, 1 - 10 GWh/a, small CHP,
biomass heating plants, heat pumps, local utilities or ESCOs, 80 / 40 °C;
3.6 Typical DH systems in France
In France there are DH systems in all sizes. The biggest (and mainly oldest) DH systems
are located in cities. The DH system is in Paris produces 6000 GWh annually and the
heat is still mainly distributed via vapor. The second biggest is in Grenoble, which
produces about 700 GWh of heat annually. There are also smaller DH plants such as
Bordeaux or Colmar (130 GWh/a).
Several DH systems are in between 10 GWh and 100 GWh and are locating in smaller
cities or villages. These are often powered by different energy sources, mostly oil, gas
and waste combustion and often are CHP plants.
The number of really small systems, in between 0,1 GWh to 1 GWh, is increasing in
small villages nowadays. These systems are powered 80% or more by biomass and are
producing only heat. These DH systems are owned by an energy company or by the
municipality and operated by the energy company or in cases of small villages by the
public utility company.
3.6 Overview of the case study conditions for concept study
The aim for the current project is to identify the feasibility of the selected hybrid
concepts for different load sizes. It is preliminary decided that the study will be carried
out for three load sizes: 10 GWh/a, 30 GWh/a and 100 GWh/a respectively. Based on
the DH system analyses in the representative regions the first load size is common for
smaller villages and residential areas. The second load size corresponds to rural villages
and small settlements, e.g. Marstal. The third load is common for smaller towns.
- 28 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
It is decided not to study the feasibility of the hybrid concept of SUNSTORE-4 project
for the bigger towns and cities (>200 GWh/a). This is partly due to the fact that the DH
systems of this size operate with higher temperatures and it can be difficult to adapt
solar heating to the system. Furthermore, the heat and electricity production today at
this size of the plants, at least in Sweden, is managed with means that can provide rather
low price for the customers; hence it can be difficult for the hybrid concept to compete
with the price.
Table 1 lists the chosen case study conditions for the concept study, based on the
information gathered from the project partners.
Table 1. Chosen case study conditions for concept study in SUNSTORE-4, WP5
Type
Load size
(GWh/a)
Load description
1
100
middle size town
2
30
3
10
settlements and
small towns
small settlements
and residential areas
Current system type
CHP with fossil fuels, natural
gas, waste or biomass
CHP with fossil fuels, natural
gas, waste or biomass
DH with fossil fuels, natural
gas, waste or biomass
Temperatures
1)
90/50 °C
1)
90/50 °C
80/40 °C
Comments:
1) In Denmark the temperatures are normally 80/40 °C
Table 2 lists the chosen geographical locations with ambient temperature, solar radiation
and heating degree days that will be used as a basis for the concept study.
Table 2. Chosen case study conditions for concept study in SUNSTORE-4, WP5
Country/
Average
Global horizontal
region
temperature
irradiation
750-1000 kWh/a.m2
Sweden
+ 8 °C
Denmark
900-1000 kWh/m2
+ 8,6 °C
Italy
+16 °C
1000-1800 kWh/m2
Czech Rep.
+ 8,8 °C
950-1200 kWh/m2
900-1700 kWh/m2
France
+10 - +15 °C
Germany
2
1000-1200 kWh/a.m
+7- +12 °C
(south-west)
Comments:
1) Information based on Eurostat Energy statistics [8]
- 29 -
Heating degree
days1)
5350
3400
2040
3520
2440
3200
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
4. Definition of hybrid concept characteristics
4.1 Introduction
The overall objectives of the SUNSTORE-4 project is to demonstrate an innovative cost
efficient and technically reliable 100% RES for a large scale DH system based on at
least 55% solar energy. The systems that are of interest to complement the 100% RES
are biomass energy, heat pump and electricity production from biomass through an
ORC unit. This chapter describes the different technologies applicable, the advantages
and challenges of the different renewable energy systems and specific investment costs
for the components.
Technical information and some of the cost data has been provided by different partners
in SUNSTORE-4 project. A special questionnaire was formed and sent to different
project partners. This questionnaire is presented in Appendix 1.
4.2 Different renewable energy technologies of interest in SUNSTORE 4
project
4.2.1 Large scale solar heating systems
Advantages and challenges of large scale solar heating systems
The interest for large scale solar district heating systems has increased considerable all
over Europe in recent years. Solar heat is available in principle anywhere. The
development of large scale solar heating systems is supported by increased incentives in
the form of EG directives, local and regional support policies and improved
competiveness in the local heating markets. This has resulted in more than 100 plants
with more than 500 m2 of solar collectors each in operation, whereas about 40 plants
have a nominal thermal power of more than 1 MW [25].
Based on the analysis of the success factors for solar district heating systems, one
important prevailing success factor is considered to be the involvement of one or several
local actors with interest and knowledge to develop and demonstrate the new
technologies [25]. This can be a local city government, a local utility, a local
manufacturer or a combination of those.
The main advantages of large scale solar heating systems are:
• Solar energy is clean and environmentally-friendly
• Low operation cost
• Lower specific investment costs and solar costs than small solar systems
• A number of existing well functioning examples of large scale solar district
heating systems in Europe
• Professional management and operation
The main challenges of a large scale solar heating systems are:
• The solar irradiation is very low when the demand for heat is high
• Some kind of heat storage is required
- 30 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
• The implementation of solar heating requires a major investment, risk analysis for
the investment requires competence and experience
• A careful design of collector system must be considered in addition to
development of an appropriate control system.
• Limitation of operating temperatures in the DH system for the optimal
performance of solar collectors
• Areas for solar collectors can be limited or expensive
• Lack of operation experience
• Competition from cheap surplus heat from CHP, incineration or industrial
processes
• Few full scale plants in a country means low confidence to the (long time)
performance of the plants
Investment cost of solar collectors related to size
The investment costs for large scale solar systems have decreased to a level which has
made the investments interesting in different countries. It is believed that the costs will
decrease further by an increased demand for this type of applications.
Additionally, the cost is depending on the complexity of the system. The explicit solar
heat costs in the German plants are rather high due to more advanced integration of
solar collectors on buildings, new infrastructure and combined with seasonal storage.
The total cost of the solar SDH system comprises [28]:
• Cost of land
• Collectors
• Collector field installation including piping in the field
• Anti-freeze fluid
• Transmission piping (collector field to heat exchanger unit)
• Heat exchanger (HX) unit (including pumps, expansion vessels, control, etc.)
• Connection to the existing DH system
• Storage
• Control system
For the concept study it is assumed that it will be possible to install a collector array on
ground for about the same cost in all economic regions. Figure 14 shows the
investment cost of ground mounted solar collector field, including cost of installation,
piping, HX-unit, etc. [28]. The price curve does not include the cost of land and
leveling of land. In Denmark this cost is estimated to be ca 13 €/m2 of collector area
(100 DKK/m2, 1€ ≈ 7,45 DDK) [29].
- 31 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Investment cost of solar collectors
Investment cost, €/m2
300
250
200
150
100
50
Solar collector system
0
0
10000
20000
30000
40000
50000
Collector field size, m2
Figure 14. Investment cost of ground mounted solar collector field per m2 collector
installed. The investment cost includes installation, piping, HX-unit, etc. (excl storage
and VAT).
Total operating and maintenance costs of solar collector system is approx. 0.54 €/MWh
per year, including electricity consumption; maintenance approx 0.14 €/MWh [26].
For the concept study it is assumed that it will be possible to install ground mounted
solar collector fields for about the same cost in all economic regions.
4.2.2 Thermal energy storage
The energy from the solar system can be stored seasonally or short-term. In order to
increase the fraction of solar energy contribution in the DH system seasonal storage
should be applied. There are a number of different types of seasonal storage possibilities
available for solar district heating and a number of well functioning examples exist. The
main four concepts for seasonal thermal energy storage include:
• Borehole thermal energy storage (BTES)
• Pit thermal energy storage (PTES)
• Tank thermal energy storage (TTES)
• Aquifer thermal energy storage (ATES)
Advantages of seasonal storage:
• Possibility to cover much larger part of the heat load
• Possibility to integrate different energy sources
Challengers of seasonal storage:
• Higher investment cost compared to short-term storage
• SDH with BTES is particularly sensitive to elevated DH net return and forward
temperatures
• Technical and functional reliability
- 32 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
From short-term storage options a local diurnal storage and connecting the solar system
to the district heating main circuit are used, where the district heating system is used as
a buffer storage.
The size of the storage depends on several different parameters e.g. [28]:
• Collector area
• Solar fraction
• Other heat generating systems (heat pumps, gas motor, etc.)
• Total load
• Usable temperature difference
Figure 15 shows the “optimal” storage size in m3 water equivalents per m2 collector area
plotted against the solar fraction [26]. The diagram can be used as a first estimate on
storage size. For large solar fractions and if combined with a heat pump the storage size
should be carefully optimized with detailed calculations/simulations and the optimum
could be different from the values shown in Figure 15 [28].
V/A [m3 water eq/m2]
4
3
2
1
0
0
20
40
60
80
100
SF [%]
Figure 15. First rough estimation of optimal ratio between storage volume in water
equivalents and collector area as a function of solar fraction [28].
Table 4 shows a comparison between the different types of seasonal storage concepts.
Table 4. Comparison of different types of seasonal storage concepts.
Storage medium
Heat capacity, kWh/m3
Storage volume for
3
1 m water equivalent
TTES
water
60-80
water
60-80
1
1
PTES
gravel-water
30-50
1.3 - 2
BTES
soil/rock
15-30
ATES
sand-water
30-40
3-5
2-3
Investment cost of pit thermal energy storage related to size
The investment cost of pit thermal energy storage system is in a great extent dependent
on the size of the system and geological conditions. Figure 16 shows the diagram of the
investment cost of pit thermal energy storage in Denmark, depending on the size and the
design. The graph shows the costs for a relevant range of sizes. The central line on the
- 33 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
diagram is based on the results of the tender for the 75.000 m3 storage in Marstal, part
of the SUNSTORE4 project (primo 2011). The specification of the pit thermal energy
storage costs for Marstal system is shown in the Table 5 below.
The extrapolation to other sizes is based on the assumption that excavation costs varies
with the size of the storage in m3. Liners, insulation and roof foil varies with the size to
the power of 2/3 (area) and finally ‘others’ varies with the power of 0.5.
The lower line in the graph represents the possibility of savings by further developments
in the design of the lid. The estimate is based on ongoing experiments with a solution
based on floating elements with cores of PUR foam.
The top line represents an upper limit for situations where costs are higher than in the
actual project in Marstal e.g. because of more difficult conditions for excavation.
Investement cost per m3 waterequivalent, [€/m3]
Investement cost of pit thermal energy storage
35,0
Marstal data
30,0
New lid design
25,0
Difficult
excavation
20,0
15,0
10,0
5,0
0,0
0
50000
100000
150000
200000
250000
Pit thermal energy storage volume [m3]
Figure 16. Investment cost of the pit thermal energy storage in Denmark.
Table 5. Cost specification for the pit thermal heat storage in Marstal, SUNSTORE 4
project. The storage volume is 75 000 m3.
Cost description
Cost,
1000 DDK
2 500
2 000
5 500
2 500
1 000
500
14 000
Excavation etc.
Liners
Insulation in lid
Roof foil
In- and outlet etc.
Consultants
Total
Cost, 1000 €
(1€ ≈ 7,45 DDK)
336
268
738
336
134
67
1 879
For the concept study it is assumed that it will be possible to install pit thermal energy
storage for about the same cost in all economic regions.
Investment cost of borehole thermal energy storage related to size
- 34 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Based on the experience in Germany the investment cost for borehole thermal energy
storage has been about 90 € / m3 water equivalent with the size of 5 000 m3 and about
40 € / m3 water equivalent with the size of 10 000 m3 [26].
The price for borehole storage comprises the cost for boreholes and pipes, usually given
as a function of the length, and cost related to the top area of the storage (establishment,
connecting pipes, ground work and insulation). For the concept study it is assumed that
it is feasible to apply one storage cost related to storage volume expressed in water
equivalents. The borehole storage cost is further related to the geological conditions.
Investement cost per m3 waterequivalent, [€/m3]
For current concept study an estimated investment cost curve is applied in the
calculations for two conditions: for non-difficult excavation and for difficult excavation.
The estimated investment cost curves for borehole storage (BTES) are shown in Figure
17.
Investement cost of borehole thermal energy storage
190
170
150
130
110
90
70
50
30
10
1000
non-difficult excavation
difficult excavation
10000
100000
Storage volume in m3 water-equivalent [m3]
Figure 17. Estimated investment cost of a borehole energy storage applied in the
concept study. The diagram shows the investment cost in relation to the storage volume
in m3 water-equivalent.
For the concept study it is assumed that it will be possible to install borehole thermal
energy storage for about the same cost in all economic regions.
4.2.3 Large biomass boiler system
Advantages and challenges of large biomass boilers
The use of biomass in heating systems provides great benefits since it uses agricultural,
forest, urban and industrial remains and waste to produce heat and electricity. Examples
of biomass fuels are: fuels from trees (wood, bark, sawdust, and waste from paper pulp
production); cultivated biomass fuels (grass, rape, straw).
On combustion the emissions released into the atmosphere include besides carbon
dioxide also carbon monoxide, nitrogen oxides, volatile organic compounds,
particulates and other pollutants. With CFD simulations it is possible to improve the
furnace and boiler design in order to optimize the effect of primary measures for NOx
and deposit formation reduction, to optimize the mixing conditions, to minimize hot
spots in the furnace region and thus to achieve a high efficiency, low emissions as well
- 35 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
as high availability of the plant. This is in specific done in the SUNSTORE-4 pilot
plant. In the SUNSTORE-4 project a wood chip boiler system with high efficiency and
low emissions will be designed and built.
Advantages of a biomass boiler system:
• Availability of the biomass;
• The price for the biomass fuel is lower than the alternatives;
• High efficiency;
• The fuel is local and therefore the payment for fuel will stay in the area.
Challenges of a biomass boiler system:
• A boiler for biomass fuel need more care than a boiler for combustion oil or
natural gas;
• Need of space to store the biomass fuel;
• Emissions from the burning of wood need to be considered from the
environmental aspect and taken care of in the right way;
• Logistics of the biomass is important since the transport costs of the (bulky) fuel
can play a key factor in the plant's economics;
• Difficult to handle and burn the fuel compared to gas and oil.
Investment cost of biomass boiler related to size
It can be difficult to give a concrete estimate of the cost of a wood-fired plant, since the
specific solutions are made for each customer. Figure 18 shows the investment,
operating and maintenance costs of a biomass hot water boiler system used in the
concept study [27]. The investment cost of the biomass hot water boiler system includes
the following main components:
• Fuel supply and feeding system;
• Biomass-fired furnace;
• Heat recovery: Combustion air pre-heater;
• Cleaning system for boiler and downstream heat exchangers;
• Flue gas cleaning: Flue gas condensation unit;
• Automatic ash removal;
• Steel construction;
• Electrical equipment and controls;
• Hot Water System;
• Electric connection to grid;
• Building: civil works;
• Engineering, management.
Total estimated operating and maintenance costs varies in between 106-240 k€ per year
in a size range of 3.5 – 15 MWth output. These costs are based on the experiences from
different earlier projects and on a cost level of central Europe [27]. The larger the plant
the lower the specific investments and specific operating and maintenance costs
(k€/MWth per year). Electricity for own demand is approx 2,5% of total thermal output
(MWth).
- 36 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
For the concept study it is assumed that it will be possible to install a biomass boiler for
about the same cost in all economic regions.
Investement cost of a biomass hot water system
700
5000
600
500
4000
400
3000
300
2000
200
1000
100
0
0
0
5
10
15
Specific investment cost, [€/MWth]
Electric own demand [kW]
Operating and maintenance cost [k€/a]
Investment cost ,[k€]
Total investement cost
6000
Specific investement cost
Electric own demand
Operating and
maintenance cost
Biomass boiler system total thermal output, MWth
Figure 18. Investment cost, electric own demand and operating and maintenance cost
of a biomass hot water boiler system [27].
4.2.4 Combining biomass boiler system with ORC
Advantages and challenges of ORC
The Organic Rankine Cycle is a thermodynamic cycle used to produce electricity. When
combining the ORC with biomass boiler the thermal energy from the furnace is
transferred to the ORC unit by the thermal oil cycle. With thermal oil as a heat transfer
medium, the temperature required for operating ORC process can be achieved while
operating practically at atmospheric pressure. The net electric efficiency is nearly 20%.
Advantages of CHP with ORC:
• Green electricity and heat from wood and forestry residues;
• Low-grade (lower cost) wood with varying moisture content can be used in large
commercial / industrial systems;
• Long operational life of the machine due to the characteristics of the working
fluid;
• The ORC requires little maintenance.
Challenges of CHP with ORC:
• High specific investment cost;
• Complex controls;
• Low electrical efficiency compared with larger plants (steam turbine/combined
cycle).
Investment cost of ORC related to size
- 37 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 19 shows the investment, operating and maintenance costs of a biomass boiler
system combined with ORC used in the concept study [27]. The investment cost of the
biomass ORC system includes the following main components:
• Fuel supply and feeding system;
• Biomass-fired furnace;
• Thermal oil system;
• Heat recovery: Combustion air pre-heater;
• Cleaning system for boiler and downstream heat exchangers;
• Flue gas cleaning: Flue gas condensation unit;
• Automatic ash removal;
• Steel construction;
• Electrical equipment and controls;
• Hot Water System;
• ORC;
• Electric connection to grid;
• Building: civil works;
• Engineering, management.
Investement cost of a biomass ORC system
Investment cost ,[k€]
2000
1800
12000
1600
10000
1400
8000
1200
6000
800
4000
600
1000
400
2000
200
0
0
0
5
10
15
Specific investment cost, [€/MWth]
Electric own demand [kW]
Operating and maintenance cost [k€/a]
Electric own demand
14000
Total investement cost
Specific investement cost
Operating and
maintenance cost
Biomass ORC system total thermal output, MWth
Figure 19. Investment cost, electric own demand and operating and maintenance cost
of a biomass boiler system combined with ORC [27].
Total estimated operating and maintenance costs for a combined biomass boiler and
ORC system varies in between 200-460 k€ per year in a size range of 2.8 – 12.3 MWth
output. These costs are based on the experiences from different earlier projects and on a
cost level of central Europe [27]. The larger the plant the lower the specific investments
and specific operating and maintenance costs (k€/MWth per year). Electricity for own
demand is approx 5,5% of total thermal output (MWth).
For the concept study it is assumed that it will be possible to install a biomass CHP
based on ORC for about the same cost in all economic regions.
- 38 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
4.2.5 Large heat pump system
Advantages and challenges of large heat pump systems
Integrating heat pump to SDH system with seasonal thermal energy storage would help
to optimize the inlet and outlet temperature of the solar energy system, to reduce the
heat loss from the storage and to increase the solar heat production. The aim is to run
the heat pump when the electricity prices are low to cool the storage, provide heat to the
DH system and to increase the long term storage capacity.
Advantages of heat pump system integrated to the RES energy system:
• Helps optimize the temperatures in the solar energy system with seasonal energy
storage
• Helps increasing efficiency of solar panels
• Increased solar heat production in a RES system
• Reduction of storage size
• Can utilize “surplus” electricity from e.g. wind power and thus reduce the need of
power transmission lines (electricity regulation)
Challenges of heat pump system:
• Electricity input needed in the case of compressor driven heat pump
• Using absorption heat pump can be challenging due to limited experience in these
applications
• SPF (Seasonal Performance Factor) is dependent on the system characteristics
• Complex controls
Investment cost of large heat pump systems related to size
It can be difficult to give a concrete estimate of the cost of large scale heat pump
systems, since the investment cost is dependent besides system output also on
temperature settings chosen. It can be estimated that the typical investments for a large
heat pump system are as follows [30]:
• Specific investment 0.375 M€/MWth;
• Operating and maintenance costs: approx. 1% of investment per year;
• Electricity for operating 10-18 €/MWth, depending on heat pump performance
and electricity price (price is excluded from tax).
The given specific investment cost of a large heat pump system includes:
• Heat pump;
• Warm side: water piping + pump + flow measuring equipment + recommended
valves, strainers, manometers, thermometers;
• Cold side: water piping + recommended valves, strainers, manometers,
thermometers;
• All electrical equipment for controlling and operating the unit;
• Electrical cabinet;
• Commissioning and installation at site;
• Delivery at site.
- 39 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
The specific investment cost of a heat pump system in Marstal, part of the SUNSTORE4 project (2011) was close to 0.300 M€/MW. As mentioned before, the cost can vary
with different temperature settings.
- 40 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
5. Choice of hybrid system concepts and their characteristics
5.1 Introduction
For the purpose of the SUNSTORE 4 project it is of great interest to study the
feasibility of the specific hybrid concept of 100% RES system at different climate,
geographical and load conditions. The type of hybrid system that is built and tested in
Marstal in Denmark includes solar collectors with long term thermal heat storage
system that can cover approx 55% of total energy need, biomass boiler, integrated heat
pump and ORC system. It is of great interest to evaluate if this type of hybrid concept
would be applicable also in other regions and what kind of hybrid concepts can be
adapted to the local conditions.
Five different hybrid concepts will be analysed in the feasibility study in WP5. For the
purpose of the current project, which aims to have at least 55% solar energy and the rest
should be covered by biomass, a large scale solar collector system and biomass boiler
will be incorporated to all of the hybrid concepts that will be studied.
Additional interest in the feasibility study is to analyse what kind of thermal storage
system would be most suitable considering the local conditions, performance factors
and economical aspects. Here three alternatives will be analysed: seasonal water pit
storage (PTES), seasonal ground storage (BTES) and short- term water tank storage.
Combining heat pump to the hybrid concept of 100% RES district heating can provide
considerable benefits in terms of system optimisation and overall efficiency. However,
the question is if this will be feasible in all cases. Thus hybrid concepts without the heat
pump integrated will be analysed.
Further interest in the SUNSTORE-4 project is to combine heat and electricity
production by including the Organic Rankine Cycle (ORC) to the system. In the
feasibility studies the cost effectiveness of the ORC will be analysed. It is also possible
to combine the biomass boiler with the absorption heat pump. However this is not
considered in the current case study concepts.
The feasibility of the hybrid concepts will mainly be influenced by investment
conditions, specific investment costs for the components, energy prices (biomass and
electricity) and the cost for the alternatives (typically CHP or boiler on natural gas, in
some cases biomass CHP or boiler).
5.2 Hybrid concept 1: Solar collector, seasonal water pit storage, HP and
biomass CHP
This is the concept that is built and tested in Denmark in Marstal. The hybrid system
includes solar collectors with pit thermal energy storage system that can cover approx
55% of total energy need, biomass boiler, integrated heat pump and ORC system. The
schematic picture of the Hybrid concept 1 is illustrated in figure 20.
- 41 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Biomass
Boiler
OCR
District heating
to the town
HP
Solar
collectors
Pit thermal energy
storage
Figure 20. Schematic picture of the hybrid concept 1: solar collector, seasonal water pit
storage, HP and biomass CHP.
The performance parameters to be used in the calculations are shown in table 6.
Table 6. Performance parameters and technical data of the hybrid concept 1.
Performance and technical data of system components
Solar collectors
Annual solar collector efficiency
42 %
Technical lifetime
25 years
Heat storage
Typically 2 m3 water equivalent per m2
Storage volume/ collector area
1)
collector area for 50% solar fraction
20% of the delivered solar energy, in
Storage heat losses
combination with the HP for storages in
between 50 000 and 100 000 m3
Technical lifetime
20 years
Heat pump
Seasonal performance factor
3.6
Technical lifetime
20 years
Biomass boiler
Biomass boiler efficiency
85 % combined with ORC
ORC
Electricity output
15%
Technical lifetime of biomass CHP
20 years
1) The parameter depends on the solar irradiation and the district heating consumption during the year
and in the calculations it will be variable depending on the case study condition.
5.3 Hybrid concept 2: Solar collector, seasonal water pit storage, HP and
biomass boiler
This concept is similar to the hybrid concept 1 but the electricity production with the
OCR unit is left out. The schematic picture of the Hybrid concept 2 is illustrated in
figure 21.
- 42 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
District heating
to the town
Biomass
Boiler
HP
Solar
collectors
Pit thermal energy
storage
Figure 21. Schematic picture of the hybrid concept 2: solar collector, seasonal water pit
storage, HP and biomass boiler.
The performance parameters to be used in the calculations are shown in table 7.
Table 7. Performance parameters and technical data of the hybrid concept 2.
Performance and technical data of system components
Solar collectors
Annual solar collector efficiency
42 %
Technical lifetime
25 years
Heat storage
3
2
Typically 2 m water equivalent per m
Storage volume/ collector area
1)
collector area for 50% solar fraction
20% of the delivered solar energy, in
Storage heat losses
combination with the HP for storages in
between 50 000 and 100 000 m3
Technical lifetime
20 years
Heat pump
Seasonal performance factor
3.6
Technical lifetime
20 years
Biomass boiler
Total net efficiency
100 %
Technical lifetime
20 years
1) The parameter depends on the solar irradiation and the district heating consumption during the year
and in the calculations it will be variable depending on the case study condition.
5.4 Hybrid concept 3: Solar collector, seasonal water pit storage and
biomass boiler
This is a simple version of SUNSTORE 4 plant, which includes only solar system with
seasonal heat storage and biomass boiler. The schematic picture of the Hybrid concept 3
is illustrated in figure 22.
- 43 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
District heating
to the town
Biomass
Boiler
Solar
Pit thermal energy
storage
collectors
s
Figure 22. Schematic picture of the hybrid concept 3: solar collector, seasonal water pit
storage and biomass boiler.
The performance parameters to be used in the calculations are shown in table 8.
Table 8. Performance parameters and technical data of the hybrid concept 3.
Performance and technical data of system components
Solar collectors
Annual solar collector efficiency
40 %
Technical lifetime
25 years
Heat storage
3
2
Typically 2 m water equivalent per m
Storage volume/ collector area
1)
collector area for 50% solar fraction
20-30% of the delivered solar energy,
Storage heat losses
depending on the storage size
Technical lifetime
20 years
Biomass boiler
Total net efficiency
100 %
Technical lifetime
20 years
1) The parameter depends on the solar irradiation and the district heating consumption during the year
and in the calculations it will be variable depending on the case study condition.
5.5 Hybrid concept 4: Solar collector, seasonal ground (borehole) storage,
HP and biomass boiler
In this hybrid concept the possibilities to use borehole storage and heat pump in the
system will be studied. The schematic picture of the Hybrid concept 4 is illustrated in
figure 23.
This concept requires a buffer tank because a BTES is slow to charge and discharge.
The scheme given on figure 23 is simplified, excluding the buffer tank.
- 44 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
District heating
to the town
Biomass
Boiler
HP
Borehole thermal
energy storage
Solar
collectors
Figure 23. Schematic picture of the hybrid concept 4: solar collector, seasonal ground
storage, HP and biomass boiler.
The performance parameters to be used in the calculations are shown in table 9.
Table 9. Performance parameters and technical data of the hybrid concept 4.
Performance and technical data of system components
Solar collectors
Annual solar collector efficiency
42 %
Technical lifetime
25 years
Heat storage
Typically 2 m3 water equivalent per m2
Storage volume/ collector area
collector area for 50% solar fraction1)
20-25% of the delivered solar energy, in
Storage heat losses
combination with the HP
Technical lifetime
20 years
Heat pump
Seasonal performance factor
3.6
Technical lifetime
20 years
Biomass boiler
Total net efficiency
100 %
Technical lifetime
20 years
1) The parameter depends on the solar irradiation and the district heating consumption during the year
and in the calculations it will be variable depending on the case study condition.
5.6 Hybrid concept 5: Solar collector, short-term water tank storage, and
biomass boiler
- 45 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
This concept will combine the biomass and solar system with short term heat storage.
The schematic picture of the Hybrid concept 5 is illustrated in figure 24. It should be
noted, that this system is considered in the case studies as a reference system. It is the
most typical system concept nowadays, but the solar fraction of this system is limited to
20% maximum.
District heating
to the town
Biomass
Boiler
Solar
Water tank
storage
collectors
Figure 24. Schematic picture of the hybrid concept 5: solar collector, short-term water
tank storage and biomass boiler.
The performance parameters to be used in the calculations are shown in table 10.
Table 10. Performance parameters and technical data of the hybrid concept 5.
Performance and technical data of system components
Solar collectors
Annual solar collector efficiency
40 %
Technical lifetime
25 years
Heat storage
200 liter water per m2 collector area for 10Storage volume/ collector area
20 % solar fraction
10-30% of the delivered solar energy,
Storage heat losses
depending on the storage size
Technical lifetime
20 years
Biomass boiler
Total net efficiency
100 %
Technical lifetime
20 years
The water tank storage price is considered to be 140 EUR/m3 in the feasibility
calculations.
- 46 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
6. Feasibility assessment tool
6.1 Introduction
A simple feasibility evaluation tool has been created for the SUNSTORE-4 project WP5
for feasibility/simulation studies of hybrid concepts. The feasibility tool is based on
Excel program. The aim with the development of such tool has been to provide to the
different stake holders in the process of planning and building such DH plants described
in SUNSTORE-4 project a simple method to estimate the feasibility in an early stage.
The feasibility evaluation tool does not aim to compete with more detailed models used
to calculate and estimate the performance of the DH plants, e.g. TRNSYS models.
The different hybrid concepts presented in the calculation tool have been defined and
described in detail in chapter 5 in this report. The information about the DH system
component costs that are used in the calculations is described in chapter 4.
6.2 Overview of the Excel tool
The Excel tool contains a number of working sheets divided into 3 categories (see figure
25):
• Input data sheets (marked with orange colour)
• Results summary sheet (marked with dark green colour)
• Results sheet for each feasibility concept (marked with light green colour)
Figure 25. Overview of the Excel based SUNSTORE 4 Feasibility evaluation tool
- 47 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
6.2.1 Input data
The first sheet “Intro and print settings” provides an overview of the tool and how it
should be used. Additionally, each page has an additional information box explaining
the content of the working sheet and providing some guidelines for data fill in.
To start with the basic data of climate conditions where the feasibility of the concepts
will be analysed and load conditions of the district heating system should be entered on
the sheet "Input data - location". Additionally, the energy price conditions and
investment conditions of the project analysed should be specified on the same sheet.
Illustration of the layout of this sheet is shown in Figure 26.
Figure 26. Input data-location sheet in the SUNSTORE 4 Feasibility evaluation tool.
After the basic data has been entered, detailed technical information about the hybrid
concepts to be analysed in the feasibility study need to be checked and changed
according to the specific project. This is done on a sheet "Input data - hybrid concepts".
Illustration of the layout of this sheet is shown in Figure 27. Up to 5 different concepts
can be chosen and compared in the feasibility study. This means that not all of the 5
concepts need to be studied and shown on the results summary table. The number of
input data tables displayed in this sheet depends on the number of concepts chosen for
comparison. The concepts to be added in the analyses are chosen from the drop-down
list on the top of each input data table.
- 48 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 27. Input data-hybrid concepts sheet in the SUNSTORE 4 Feasibility evaluation
tool.
Every cell where the data needs to be entered in the input data sheets have a help note in
the corner of each cell, describing what kind of information should be filled in. The
cells, where default values are shown have an info note describing the background to
the default value. Additionally, all of the input data sheets have a help function on the
side of the data tables with green/red marked cells displaying "Yes"/"No" text. This is
a guidance to show where the data needs to be entered or checked. When the data is
entered correctly the cell will be green and show "yes". When the data is faulty or has
not been entered at all the cell is marked as "No" in a red cell. It is important to follow
these markings in order to have correct results in the feasibility calculations.
Sheet "Input data- default prices" in this evaluation tool gives an overview of the DH
system component costs and energy prices that are used in the calculations (see figure
28). The information on this sheet is based on the prices described in chapter 2 and 5 in
this report.
- 49 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 28. Input data-default prices sheet in the SUNSTORE 4 Feasibility evaluation
tool.
6.2.2 Results
The results of the feasibility study and comparison of the heat price with different
hybrid concepts are summarised on a sheet "Results - feasibility study". On the top of
the page the results are presented for one concept (see figure 29), that can be chosen
from the drop-down list. This gives a simple overview of the investment cost and
resulting heat cost of a single concept, whereas heat production (net heat gain) and
contribution of the heat price (€/MWh) of each system component is presented on the
diagrams.
Down on the same workbook sheet the comparison between the total number of
different chosen concepts are given (see figure 30). Comparison of heat price of hybrid
systems with the traditional DH system is presented on the diagram next to the results
data table.
- 50 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Figure 29. Results-Feasibility study sheet in the SUNSTORE 4 Feasibility evaluation
tool. Presentation of the investment cost and heat price of the single chosen concept.
Figure 30. Results-Feasibility study sheet in the SUNSTORE 4 Feasibility evaluation
tool. Comparison between the total number of different chosen concepts in the
feasibility study.
In the sheets "Feasibility- hybrid concept 1", "Feasibility- hybrid concept 2", etc, the
results of the feasibility analysis for the specific hybrid concept are presented.
Overview of the feasibility evaluation of the specific hybrid concept is given on the top
- 51 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
of the working sheet (see figure 31). Down on the sheet technical data, investment cost
and total heat cost of each hybrid system component is presented (see figure 32).
These sheets also include sensitivity analyses of component /energy cost. The user can
fill in the data about any other component cost and energy cost and see what the total
heat price would be then. The resulting price with alternative component cost is
presented in the cell "Heat price with alternative component/energy cost".
Figure 31. Feasibility-hybrid concept 1 sheet in the SUNSTORE 4 Feasibility
evaluation tool. Overview of the feasibility evaluation of Hybrid concept 1 (see chapter
6.1).
Figure 32. Feasibility-hybrid concept 1 sheet in the SUNSTORE 4 Feasibility
evaluation tool. Overview of the technical data, investment and heat cost and sensitivity
analyses of the cost of each hybrid system component.
- 52 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
7. References
[1] Meteonorm, www.meteonorm.com
[2] Panorama of Energy, Energy statistics to support EU policies and solutions, Eurostat
2007
[3] Energy in Sweden 2010, Swedish Energy Agency
[4] Energipriser på naturgas och el, SCB
[5] Mapping of subsidy systems and future consumption of biomass, Svensk Fjärrvärme
2010
[6] Svensk Fjärrvärme www.svenskfjärrvärme.se
[7] Trädbränsle- och torvpriser, SCB 2011
[8] Denmark- Energy Mix Fact Sheet 2007, European Commission Energy,
http://ec.europa.eu/energy/energy_policy/doc/factsheets/mix/mix_dk_en.pdf
[9] Energistatistik 2009, Danish Energy Agency
[10] Heat supply in Denmark, Danish Energy Authority, 2005
[11] Opdaterede samfundsøkonomiske prisforudsætninger, Ea Energianalyse, 2011
[12] Fjernvarmeprisen i Danmark 2010,
http://www.fjernvarmen.dk/Faneblade/HentMaterialerFANE4/Fjernvarmepriser.aspx
[13] http://www.climatetemp.info/italy/
[14] HERA S.p.A.
[15] http://www.eru.cz/; http://www.czech.cz/; http://www.tzb-info.cz
[16] Vergütungssätze und Degressionsbeispiele nach dem neuen Erneuerbare-EnergienGesetz (EEG).vom 31. Oktober 2008 mit Änderungen vom 11. August 2010
[17] http://www2.lubw.badenwuerttemberg.de/public/abt5/klimaatlas_bw/globalstrahlung/karten/globalstrahlung_jah
r.html
[19] www.cete-ouest.developpement-durable.gouv.fr/article.php3?id_article=361
[20] Enquête nationale sur les réseaux de chaleur et de froid 2009 SNCU (rapport
provisoire)
[21] Perspectives d’usage des granulés bois comme combustible dans les secteurs
collectif, tertiaire, industriel (juin 2011) ADEME, CIBE
[22] www.developpement-durable.gouv.fr/Les-tarifs-d-achat-de-l,12195.html
[23] Normal globalstrålning under ett år
(http://www.smhi.se/klimatdata/meteorologi/stralning/1.2927)
Swedish Meteorological and Hydrological Institute, SMHI
[24] PVGIS, European Commission, Joint Research Centre,
http://re.jrc.ec.europa.eu/pvgis/countries/countries-europe.htm
Šúri M., Huld T.A., Dunlop E.D. Ossenbrink H.A., 2007. Potential of solar electricity
generation in the European Union member states and candidate countries. Solar
Energy, 81, 1295–1305
[25] Success Factors in Solar District Heating, SDH Solar District Heating 2010
[26] Danish Energy Authority, Technology Data for Energy Plants, June 2010
[27] BIOS BIOENERGIESYSTEME GmbH, 2011
[28] Solar district heating guidelines. Fact sheet 2.3, SDH 2011
[29] Plan Energi, 2011
[30] Advansor, 2011
- 53 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Appendix 1: Questionnaire – WP5
European level concept study of hybrid concepts
(WP5 - SUNSTORE4)
Questionnaire for the project partners
The aim of this questionnaire is to provide background information for the feasibility
studies of hybrid system concepts in WP5. The feasibility of the hybrid system concepts
which have high solar fraction and use of other renewable energy sources depends on
local climate, geographical and load conditions as well as local energy system context
(energy mix and prices). The answers from this questionnaire will provide the input data
needed for definition of case study conditions and hybrid concept characteristics in
SUNSTORE-4 WP5.
Since the dissemination activities (WP6) in the SUNSTORE- 4 project aims to promote
the results of the whole project on European scale and involve partners in different
countries for planning 100% RES systems, it is recommended to combine some of the
activities in WP5 and WP6. Therefore, the European regions that need to be chosen
within WP5 will be based on project partners in WP6. WP6 comprises a number of case
studies to be led by CP (CZ and Poland), SIG (DE, AT and FR), MF (DK, SE and UK)
and AI (IT and ES).
To enhance these case studies we will develop the European level concept study based
on the most probable regions where CP, SIG, MF and AI plan to initiate case studies,
i.e. we would be pleased if CP, SIG, MF and AI could answer the following questions
for the regions where you plan to initiate case studies. It is also welcomed to have input
from other project partners not involved with WP6 in specific. We will select 3-5
regions with as much common as possible for the concept study.
The questionnaire consists of two parts: Part 1 and Part 2. The first part “Definition of
case study conditions” is for all of the project partners to answer, whereas the second
part “Definition of hybrid concept characteristics” is for specific project partners only.
In order to carry out the European level concept studies we need to know the present
and (expected) future investment costs of the Sunstore4 system components. According
to the project agreement, this information will be provided by the specific project
partners. Therefore we would be pleased if SM, MF, ET, BB and AV could answer the
following questions!
Jan-Olof Dalenbäck
Mari-Liis Maripuu
CIT Energy Management AB
- 54 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
The questionnaire is replied by:
The answers correspond to the geographical region/ country:
Part 1. Definition of case study conditions
(Please write your answer in the shaded area)
1) Please describe the geographical and geological conditions of your region, e.g.
what type of seasonal storage would be feasible in the region.
2) Please describe the climate conditions of your region (e.g. annual solar
radiation, average ambient temperature, heating degreehours).
3) Please describe the heating energy market in your region in terms of system
types, status of DH, energy resources (NG, bioenergy type, etc), etc...
4) Please describe max 3 most typical DH systems in your region in terms of load
size, system type (boilers, CHP, heat pumps, etc) and other characteristics (e.g.
ownership, distribution temperatures, etc.)?
Type 1.
Type 2.
Type 3.
5) What is the price for fuels (NG, wood chips, etc.) in your region?
6) What is the price for electricity for a large user in your region (i.e. to operate a
large heat pump or a large electric boiler)?
7) How much will you get if you sell electricity in your region (i.e. if you would
operate CHP / ORC)?
9) What do you see as barriers for the 100 % RES DH systems in your region?
- 55 -
Energy
Management AB
Mari-Liis Maripuu/ Jan-Olof Dalenbäck
EU report, April 2011
A Chalmers Industriteknik Company
Part 2. Definition of hybrid concept characteristics
(For specific project partners only)
1) SM: What is the present and future investment cost for large solar systems
related to size and economic region (Euro/sqm)? A diagram describing the
situation would be appreciated (describe the background and add it as a separate
document if possible).
2) MF: What is the present and future investment cost for a large water pit
seasonal storage related to size and economic region (Euro/qbm)? A diagram
describing the situation would be appreciated (describe the background and add it
as a separate document if possible).
3) MF/ET/BB: What is the present and future investment cost for a large biomass
(e.g. wood chips, pellets) boiler related to size and economic region (Euro/kW)? A
diagram describing the situation would be appreciated (describe the background
and add it as a separate document if possible).
4) MF/ET/BB: What is the present and future investment cost for an ORC related
to size and economic region (Euro/kWel)? A diagram describing the situation
would be appreciated (describe the background and add it as a separate document
if possible).
5) AV: What is the present and future investment cost for a large heat pump
related to size and economic region (Euro/kWth)? A diagram describing the
situation would be appreciated (describe the background and add it as a separate
document if possible).
- 56 -