Energy Strategy Report
Denny St Francis New Settlement, Waterbeach
July 2012
RLW Estates Ltd
Energy Strategy Report
201942
BSE
BLL
027
A
Rep 27 DSF Energy Strategy Report_RevA.doc
27 July 2012
Denny St Francis New Settlement, Waterbeach
July 2012
RLW Estates Ltd
The Warehouse, 33 Bridge Street, Cambridge, CB2 1UW
Mott MacDonald, 10 Fleet Place, London EC4M 7RB, United Kingdom
T +44 (0)20 7651 0300 F +44 (0)20 7651 0310, W www.mottmac.com
Energy Strategy Report
Denny St Francis
Issue and revision record
Report Nr 201942/Rep 27
Revision
A
Date
27/07/12
Originator
Philip Exton/
Clare Wildfire
Checker
Tessa Hurstwyn
This document is issued for the party which commissioned it
and for specific purposes connected with the above-captioned
project only. It should not be relied upon by any other party or
used for any other purpose.
Approver
Terry Spencer
Description
First Issue
We accept no responsibility for the consequences of this
document being relied upon by any other party, or being used
for any other purpose, or containing any error or omission which
is due to an error or omission in data supplied to us by other
parties.
This document contains confidential information and proprietary
intellectual property. It should not be shown to other parties
without consent from us and from the party which
commissioned it.
Mott MacDonald, 10 Fleet Place, London EC4M 7RB, United Kingdom
T +44 (0)20 7651 0300 F +44 (0)20 7651 0310, W www.mottmac.com
Energy Strategy Report
Denny St Francis New Settlement, Waterbeach
Content
Chapter
Title
Page
Executive Summary
i
1.
Introduction
1
2.
Energy Policy Background
3
2.1
2.2
2.3
2.4
2.5
National Policy ______________________________________________________________________ 3
Environmental Assessment Mechanisms _________________________________________________ 8
Local Policy ________________________________________________________________________ 9
Summary of Policies ________________________________________________________________ 13
Financial Incentives _________________________________________________________________ 15
3.
Environmental Conditions and Collaboration Opportunities
16
3.1
3.2
3.3
3.4
3.5
Background _______________________________________________________________________
Local Climate ______________________________________________________________________
Wind Resources ____________________________________________________________________
Solar Energy Resources _____________________________________________________________
Geological and Hydrogeological Conditions ______________________________________________
16
16
17
17
18
4.
Low and Zero Carbon Considerations
19
4.1
4.2
4.3
4.4
Overview _________________________________________________________________________
Energy Efficiency ___________________________________________________________________
Decentralised Energy ________________________________________________________________
Low and Zero Carbon Technologies ____________________________________________________
19
19
20
22
5.
Conclusion
29
Figures
Figure 1.1:
Figure 2.1:
Figure 3.1:
Figure 3.2:
Figure 3.3:
Concept Framework Plan _____________________________________________________________ 2
Zero Carbon Hierarchy________________________________________________________________ 5
Seasonal temperature profile and thermal comfort band for Cambridge _________________________ 16
NOABL Wind Estimates for Denny Abbey (CB25 9PQ) _____________________________________ 17
Wind Rose ________________________________________________________________________ 17
Tables
Table 2.1:
Table 2.2:
Table 2.3:
Table 3.1:
Table 4.1:
Table 4.2:
Table 4.3:
BREEAM Energy minimum requirements _________________________________________________ 9
Local Plan timetable for implementation _________________________________________________ 11
Energy Policy Summary for Denny St Francis _____________________________________________ 14
Solar energy resources for Newmarket/Exning ____________________________________________ 18
Example specifications to achieve FEES – semi-detached & detached house ____________________ 20
Energy Supply Options ______________________________________________________________ 23
Technology Considerations ___________________________________________________________ 23
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Executive Summary
This report provides an overview of the approach to low and zero carbon development
that RLW Estates propose to apply with respect to the Denny St Francis development, in
order to enable the delivery of a scheme that embraces the challenges of a truly
sustainable development through a fundamental understanding of the changing
legislation in a forward thinking way and the application of robust and deliverable low and
zero carbon technologies and techniques.
The process of arriving at a suitable energy strategy involves consideration of the policy
issues and site opportunities and constraints described in this report, accompanied by an
understanding of stakeholder objectives. It is affected by issues such as cash flow and
market confidence.
Highly relevant to this topic are also the ambitions of South Cambridgeshire Council in
relation to wider initiatives that they wish to put in place, including the council’s
aspirations for local decentralised energy systems and the likely introduction of a
Community Energy Fund. RLW will be keen to work with the Council and look for ways to
achieve mutually beneficial outcomes and aligned objectives in this respect.
The timescales for the development are such that a high degree of energy efficiency,
coupled with extensive use of low/zero carbon technologies will be required in order to
respond to the Zero Carbon agenda being steered by government. At present it is not
possible to say whether the approach will be based largely on local building mounted
technology or a site-wide/district system. Which approach is technically suitable depends
on the density, dwelling type, energy demand, required CO2 savings, and often it is
appropriate to use a combination of the two.
Key recommendations from the report are:
 Create a flexible energy approach that allows for the inclusion of a number of different
energy solutions
 Continue to investigate the opportunities for collaboration, such as the potential to use
of heat from any suitable Amey-Cespa processes, or the opportunities for anaerobic
digestion to treat organic waste at the new wastewater treatment plant
 Develop the land use schedule to allow for inclusion of an energy centre(s), for the
event that district energy systems are required
 Develop buildings and systems to high levels of energy efficiency, including the Fabric
Energy Efficiency Standards required for Zero Carbon new homes
 Orientate building massing to optimise south facing major roof slopes where possible,
to enhance potential for solar technology.
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1. Introduction
Mott MacDonald, on behalf of RLW Estates, has prepared this report to provide an overview of the issues
surrounding low and zero carbon development for the proposed Denny St Francis development, to facilitate
the delivery of a scheme that embraces the challenges of a truly sustainable development.
Denny St Francis in Cambridgeshire is a proposed mixed-use settlement in the East of England. The site is
located in part on a former military airfield, with the possibility of re-using some existing pre-war military
buildings as part of the masterplan. The site comprises an area of brownfield and greenfield land enclosed
by the A10 on the west and the Cambridge-Ely railway to the east. The existing Waterbeach settlement lies
to the south and Denny Abbey to the north.
The proposed concept framework plan for the scheme is shown in Figure 1.1.
Achieving sustainable development means making use of resources in a manner that does not impact on
the ability for future generations to enjoy those same resources. There is a need to understand how
sustainability in development can be most effectively applied, through the need to mitigate and adapt to the
influence of climate change, to reduce energy and carbon dioxide and ensure lifestyles are more
sustainable.
RLW Estates is committed to exemplary development, and the context is set with regards to current
national, regional and local policy, which provides a framework within which the project will be designed
and delivered. The process of arriving at a suitable strategy involves consideration of the policy issues and
site opportunities and constraints described in this report, accompanied by an understanding of stakeholder
objectives. It is affected by issues such as cash flow and market confidence.
This report therefore provides a site specific backdrop of suitable performance standards and appropriate
use of low and zero carbon energy technologies against which these issues can be assessed as the
masterplan is further developed.
It is important to note that with any energy strategy work there are assumptions and approximations that
have to be made. As far as possible details of all assumptions made, and approximations used, are
supplied as part of the report.
Where information on viability and financial aspects are supplied, these are indicative and should be further
verified and examined before any final decision is made. A number of key financial incentives are still
awaiting parliamentary and/or regulatory approval and this report only represents Mott MacDonald's current
considered view on the implications of these.
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Figure 1.1:
Source:
Concept Framework Plan
LDA Design, July 2012
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2. Energy Policy Background
Attitudes to sustainable development are rapidly changing, from the average UK resident to highest political
level, there is an increasing appreciation of the issues that need to be addressed. Policy and legislation
related to sustainable development and climate change is under major review, and is expected to tighten
significantly in the coming years.
This section therefore outlines the current and emerging future policy that is likely to be relevant to the
Denny St Francis Development.
2.1
National Policy
2.1.1
National Planning Policy Framework 2012
Significant changes to the planning system have happened over recent months, with the repealing of the
old Planning Policy Statement system, and the introduction of the National Planning Policy Framework
(NPPF).
Published on the 27th March 2012, the NPPF is intended to make the planning system less complex and
more accessible, whilst protecting the environment and promoting sustainable growth. The NPPF is a
single document that replaces all of the existing Planning Policy Statements (PPS) and Planning Policy
Guidance (PPG) including sustainability policies, such as PPS1 – Delivering Sustainable Development and
PPS22 – Renewable Energy.
The NPPF is that it carries through it a ‘presumption in favour of sustainable development’. Within the
document there are twelve core planning principles that should underpin both plan-making and decisiontaking. This includes the notion that planning plays a key role in securing reductions in greenhouse gas
emissions and providing resilience to the impacts of climate change through supporting the delivery of
renewable and low carbon energy and associated infrastructure.
Section 10 of the NPPF ‘Meeting the challenge of climate change, flooding and coastal change’ states that
local planning authorities should recognise the responsibility on all communities to contribute to energy
generation from renewable or low carbon sources in order to help increase the use and supply of
renewable and low carbon energy. This includes identifying opportunities where development can draw its
energy supply from decentralised, renewable or low carbon energy supply systems and for co-locating
potential heat customers and suppliers.
The NPPF states that Local Planning Authorities, when setting local standards for a building’s
sustainability, should do so ‘in a way consistent with the Government’s zero carbon buildings policy and
adopt nationally described standards’.
In determining planning applications, the NPPF also outlines guidance on what local planning authorities
should expect of new developments:
 comply with adopted Local Plan policies on local requirements for decentralised energy supply unless it
can be demonstrated by the applicant, having regard to the type of development involved and its
design, that this is not feasible or viable; and
 take account of landform, layout, building orientation, massing and landscaping to minimise energy
consumption.
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Transitional arrangements
While the NPPF takes effect there are transitional arrangements whereby emerging local policy will be
given transitional weight. In summary:
 Full weight can continue to be given for 12 months to all Development Plan Documents (DPDs) adopted
since 2004.
 For earlier DPDs, or after this 12 month period, due weight can still be given depending on their
consistency with the NPPF. The closer they are aligned, the more weight can be given to them. The
extent of this conformity will need to be tested.
 Emerging plans can also be given weight in some circumstances.
 Local Planning Authorities can continue to draw on Regional Spatial Strategy (RSS) evidence and can
reflect RSS policies where appropriate as part of a partial review of their existing plans.
 Many of the sustainability measures, including the renewable energy targets, are captured within these
RSS documents. However where no targets are in place, either from not transitioning the RSS targets
or from out-of-date Local Plans, this will significantly reduce the Local Authority scope to deliver more
sustainable development.
2.1.2
Trajectory to Zero Carbon
2.1.2.1
Domestic Buildings
The UK government’s trajectory towards zero carbon (energy in-use) new buildings started with the
‘Building a Greener Future’ document in 2007. This document contained a proposed timeline of tightened
policy amendments, to be implemented via Part L of the Building Regulations, culminating in the
requirement for all new homes to be ‘zero carbon’ from 2016. The proposals included steps of improved
carbon emissions to be implemented in the 2010 and 2013 updates to Part L.
Since the emergence of the concept of ‘zero carbon’, the definition has already changed several times and
the government is currently in the process of establishing a final definition through industry consultation.
Building Regulations Part L is now a fully devolved matter, so whilst current proposals are known to be
applicable in England, the administrations in Wales, Scotland and Northern Ireland may or may not choose
to adopt the same requirements – although all have committed to the concept of zero carbon new homes.
The emerging definition is based on a three tier hierarchical approach whereby:
 a minimum level of demand reduction through energy efficiency measures will be required;
 followed by a minimum level of carbon emission reduction through on-site measures;
 with the final element of CO2 emissions offset through the application of a set of ‘Allowable Solutions’.
Figure 2.1 shows the three elements of the emerging definition discussed above.
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Figure 2.1:
Source:
Zero Carbon Hierarchy
Definition of Zero Carbon Homes & Non-Domestic
Buildings Consultation, Department of Communities
and Local Government, December 2008
In a significant move within the Budget 2011 statement (shown below) details were clarified such that the
definition now only includes the emissions covered by Building Regulations i.e. heating, fixed lighting, hot
water and building services. All previous definitions were based on the total energy use which added
“appliance load” energy to controlled energy considered by the Building Regulations.
“The Government is announcing the regulatory requirements for zero carbon homes, to apply from 2016.
To ensure that it remains viable to build new houses, the Government will hold housebuilders accountable
only for those carbon dioxide emissions that are covered by Building Regulations, and will provide costeffective means through which they can do this.”
Emissions from cooking and ‘plug-in’ appliances using electricity, such as computers and televisions, no
longer need to be rendered zero carbon. This change has the effect of reducing the total carbon dioxide
emissions reductions required and the likely overall cost of compliance.
The most recent updates in relation to the three elements of the definition relate to domestic buildings only
and are as outlined below. The compliance definitions for zero carbon in non-domestic buildings are less
defined and are covered separately (see section 2.1.2.2).
Energy Efficiency – Fabric Energy Efficiency Standard (FEES) for Homes
It was announced by the Government in 2009 that the definition for Zero Carbon homes will include a
minimum fabric energy efficiency standard (FEES) as follows:
 46 kWh/m²/year for detached, semi-detached and end-of-terrace dwellings; and,
 39 kWh/m²/year for apartment blocks and mid-terrace houses.
These standards are intended to ensure a good base level of fabric performance, reducing the dwelling
occupant’s energy use. They are subject to consultation.
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Carbon Compliance
The carbon compliance level represents the minimum level of on-site CO2 emission reduction that will need
to be achieved.
The following represents recommendations to government from the Zero Carbon Hub for the Carbon
Compliance standards to be included within the 2016 Building Regulations. The recommendations are that
Carbon Compliance should be measured in terms of an absolute limit on the predicted emissions of carbon
dioxide per square metre of internal floor space, i.e. kilograms per square metre per year (kg CO2/m2/year),
and should apply to built performance (post construction), not designed performance:
 10 kg CO2/m2/year for detached houses
 11 kg CO2/m2/year for attached houses
 14 kg CO2/m2/year for low rise apartment blocks (four storeys and below1).
As the Carbon Compliance requirements apply to built performance and the limits above are based on a
2016 set of carbon emission factors, the recommendations cannot be directly compared with current
standards. However, in addition to any potential carbon savings achieved by moving from designed to built
performance, the percentage improvements on the 2006 standard would be approximately as follows:
 60% for detached houses (≈ 47% against BR 2010)
 56% for attached houses (≈ 41% against BR 2010)
 44% for low rise apartment blocks (≈ 25% against BR 2010)
These proposed standards are currently only recommendations to Government and a decision on the final
standards to be adopted has not yet been made. That said, the Budget 2011 statement (shown below)
provides some confidence that the Zero Carbon Hub recommendations in the Carbon Compliance Report
discussed above will be taken forward.
“The Government will introduce more realistic requirements for on-site carbon reductions, endorsing the
Zero Carbon Hub’s expert recommendations on the appropriate levels of on-site reductions as the starting
point for future consultation, along with their advice to move to an approach based on the carbon
reductions that are achieved in real life, rather than those predicted by models. This will be complemented
by cost-effective options for off-site carbon reductions, relative to the Government’s pricing of carbon, and
Government will work with industry through consultation on how to take this forward.”
Allowable Solutions
The Allowable Solutions element of the definition recognises that in most cases it is not possible to reduce
to zero all of the CO2 emissions from regulated energy use on a development using on-site renewable or
low carbon energy generation approaches alone. So after Carbon Compliance has been achieved,
Allowable Solutions give options for the remaining CO2 emissions to be offset via reductions achieved
elsewhere.
_________________________
1
They recommended that further specialised work is needed before a limit can be set for high rise apartment blocks of five or more
storeys.
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A list of proposed Allowable Solutions were included in the government’s 2008 consultation. Since then
further work has been carried out by the Zero Carbon Hub to develop a framework for Allowable Solutions
based around a fund mechanism, whereby a developer would make a payment to an Allowable Solutions
Provider (which could be the Local Authority or a third party provider) who would then invest in carbon
saving projects to ensure that the required CO2 savings are achieved.
In terms of how developers can plan their response while the details of the above are still not known, it
should be noted that there is a strong inter-relationship between Carbon Compliance and Allowable
Solutions when determining viability. Therefore, for new build projects that span the 2016 and 2019
milestones, the detail of both aspects is critical to robust decision making. The price for Allowable Solutions
is not known, but the indicative figure used in the latest zero carbon homes Impact Assessment (DCLG,
May 2011) was £46/tonneCO2 over 30 years (i.e. one-off payment of £1380/tonne CO2).
Expected further announcements from government regarding Allowable Solutions in Budget 2012 were not
forthcoming, however it is possible that a consultation will be launched in autumn 2012. Therefore at
present the industry is unsure as to how this element of the definition will unfold in reality.
2.1.2.2
Non-Domestic Buildings
A similar aspiration for non-domestic buildings exists, culminating in all new non-domestic buildings to be
zero carbon from 2019. However, the plans for how this is to be achieved in policy are significantly less
advanced, although the government have stated their intention to follow the same logic and hierarchy as
the zero carbon definition for domestic buildings.
In July 2011, DCLG published a consultant’s report which aimed to develop the evidence base for zero
carbon non-domestic buildings and included an analysis of certain options. The report recommended that
the most appropriate way to set an energy efficiency standard for non-domestic buildings would be via a
set of minimum elemental fabric standards – i.e. a different approach to the fabric performance standard for
homes. In terms of Carbon Compliance, the report investigated three scenarios, however no
recommendation was made as to which should be adopted:
 Low: 44% reduction in CO2 from Part L 2006
 Medium: 49% reduction in CO2 from Part L 2006
 High: 54% reduction in CO2 from Part L 2006
Government have not endorsed the recommendations of the report but have signalled the need for further
work. Therefore there is uncertainty surrounding the requirements for non-domestic buildings.
2.1.3
The DECC Heat Strategy
In March 2012 DECC published a consultation report called “The future of heating: A strategic framework
for low carbon heat”. The document sets out how the heat system in the UK will need to evolve over time,
and identifies the substantial changes required across the UK economy in both the built environment and
industry to make this happen.
The report concludes with a 'framework for action" section outlining a focus on energy efficiency in this
decade and a move to low carbon heat technologies beyond that.
There is an expectation that heat pumps will be an increasing part of the solution for suburban and rural
areas. However it is clear from the document that the Government believes heat networks have the
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potential to play a significant role in the UK energy mix, and that local authorities have a pivotal role in
enabling such networks, predominantly in urban areas in the 2020’s but expanding their reach towards
2050.
2.2
Environmental Assessment Mechanisms
In addition to meeting Building Regulations the Denny St. Francis development may also be required to
meet levels of BREEAM and Code for Sustainable Homes as specified by the Council’s policy. These are
assessment mechanisms that cover multiple sustainability topics, however they each contain a high
weighted category on energy, and the energy related elements are sometimes extracted in order to form
targets for energy and carbon emissions targets.
2.2.1
The Code for Sustainable Homes
The Code for Sustainable Homes (CSH) is an environmental assessment method for rating and certifying
the performance of domestic buildings.
Assessments are carried out on each individual dwelling basis. Specific mandatory energy credits are set
for each level of the Code as outlined in the table below.
Code for Sustainable Homes – Mandatory Minimum Standards (Energy Section)
Code Level
Ene 1 – Dwelling Emission Rate
Ene 2 – Fabric Energy Efficiency
(% Improvement over 2010 DER/TER)
(kWh/m²/year)
Level 3
0% (Compliance with Part L 2010 only is required)
No mandatory requirement
Level 4
25%
No mandatory requirement
Level 5
100%
Level 6
Zero Carbon
Mandatory requirement of:
≤ 39 Apartment Blocks, Mid-Terrace
≤ 46 End Terrace, Semi- Detached & Detached
Source: Code for Sustainable Homes, Technical Guide, November 2010
The targets are based on improvements over Part L of the Building Regulations 2010 and it is important to
note that Zero Carbon as defined in the CSH has not been updated to include the emerging detail of the
zero carbon homes policy described above, so the two are not currently the same. However, according to
the 2012 Building Regulations consultation document2 the Code is due for revision, with the Government
intending to consult on a revised Code in spring 2012 and publish the final version alongside the final 2013
Part L changes. This is intended to bring the Code up to date with the changing policy background and in
particular to align it with the emerging Zero Carbon homes policy. However no consultation has yet been
issued.
_________________________
2
2012 consultation on changes to the Building Regulations in England, Section two, Part L (Conservation of fuel and power)
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2.2.2
BREEAM
The BRE Environmental Assessment Method (BREEAM) is a mechanism for describing and assessing
good environmental design and construction for non-domestic buildings. Credits are collected in a number
of categories which go towards a final overall score leading to a Rating of Pass, Good, Very Good,
Excellent or Outstanding. In addition to achieving the minimum overall percentage score, the development
may also have to achieve a number of mandatory minimum standards for certain BREEAM ratings. The
minimum energy standards for a given rating are outlined in the table below.
Table 2.1:
BREEAM Energy minimum requirements
BREEAM issue
Pass
Good
Very Good
Ene 01: Reduction of
CO2 emissions
None
None
None
Ene 02: Energy monitoring
None
Ene 04: Low or zero
carbon technologies
Source:
None
None
Excellent
Outstanding
Six credits
Ten credits
( equivalent to a
25%
improvement on
the TER)
(equivalent to a
40%
improvement on
the TER)
One credit
One credit
One credit
(First submetering credit)
(First submetering credit)
(First submetering credit)
None
One credit
(low and zero
carbon
feasibility study
carried out)
One credit
(low and zero
carbon
feasibility study
carried out)
None
adapted from BREEAM 2011 New Construction Technical Guide ISSUE 2.0
2.3
Local Policy
2.3.1
Policy Status
The Denny St Francis development will fall under the South Cambridgeshire Council Planning Policies.
The Local Plan (2004) was almost entirely replaced in 2007 by the Core Strategy and the Development
Control Policies which are currently the relevant policies. However the Council is in the process of
developing a new Local Plan, which is expected in 2016.
2.3.2
Current Planning Policies
This section outlines the current local policy requirements in relation to Energy and Carbon.
2.3.2.1
The Development Control Policies DPD
The South Cambridgeshire Core Strategy was formally adopted on 25 January 2007 setting out the overall
approach to development in the district.
The development control policies guide decisions on planning applications within South Cambridgeshire. It
is an extremely important part of the Local Development Framework, covering a wide range of topics,
including housing, jobs, services and facilities, travel, the natural environment and the Green Belt.
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The following policies relate to energy and carbon:
POLICY DP/1 Sustainable Development
‘Sustainable development:
- Where practicable, minimise use of energy and resources;
- Where practicable, maximise the use of renewable energy sources.’
POLICY NE/1 Energy Efficiency
‘Energy Efficiency:
1. Development will be required to demonstrate that it would achieve a high degree of measures to
increase the energy efficiency of new and converted buildings, for example through location, layout,
orientation, aspect, and external design.
2. Developers are encouraged to reduce the amount of CO2 m3/year emitted by 10% compared to the
minimum Building Regulation requirement when calculated by the Elemental Method in the current
building regulations for a notional building of the same size and shape as that proposed, particularly for
new or substantially demolished buildings.’
POLICY NE/2 Renewable Energy
‘The District Council will grant planning permission for proposals to generate energy from renewable
sources, subject to proposals according with the development principles set out in Policies DP/1 to DP/3
and complying with the following criteria:
1. The proposal can be connected efficiently to existing national grid infrastructure unless it can be
demonstrated that energy generation would be used on-site to meet the needs of a specific end user;
2. The proposal makes provision for the removal of the facilities and reinstatement of the site, should the
facilities cease to be operational.’
POLICY NE/3 Renewable Energy Technologies in New Development
‘All development proposals greater than 1,000 m² or 10 dwellings will include technology for renewable
energy to provide at least 10% of their predicted energy requirements, in accordance with Policy NE/2.’
2.3.2.2
Supplementary Planning Document: District Design Guide SPD
The District Design Guide SPD expands on district-wide policies included in the Development Control
Policies Development Plan Document (DPD) and policies in individual Area Action Plans for major
developments that may vary from the district-wide policies. This guidance seeks to ensure that design is an
integral part of the development process and includes more details on interfacing with the Code for
Sustainable Homes and BREEAM, as well as describing the methodology to be used to demonstrate, for
example, the renewable energy requirements,.
2.3.3
Emerging Local Plan (2016)
The South Cambridgeshire Local Plan is currently in the process of being renewed. The plan will set out
the planning policies and proposals to guide the development and use of the land in the district for the
period up to 2031. The adoption date is anticipated to be late 2015.
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The Local Plan will include:
 the spatial vision and strategic approach to development in the district, including levels of new
employment and housing;
 detailed policies relating to a range of topics including design and development principles, green belt,
housing, employment and tourism, services and facilities, natural environment, cultural heritage, and
travel that are used for determining planning applications;
 allocations for housing, employment, and other uses; and
 policies for the development and use of specific sites.
In preparing the Local Plan, the Council will be reviewing and updating the planning policies and proposals
that are currently included in the adopted Core Strategy, Development Control Policies DPD and Site
Specific Policies DPD, which cover the period up to 2016.The below table outlines the anticipated timeline
for the Local Plan.
Table 2.2:
Local Plan timetable for implementation
Event
Date
Local Plan Issues & Options public consultation
13 July - 28 September 2012
Second Local Plan Issues & Options public consultation - for site options on the edge
of Cambridge [NEW STAGE]
Winter 2012/2013
Draft Local Plan public consultation
June - July 2013
Submission of Local Plan to Secretary of State
December 2013
Public Examination of Local Plan by independent planning inspector
June - October 2014
Receipt of Inspectors Report on the Local Plan
May 2015
Consider the recommendations included in the Inspectors Report and adopt the Local
Plan
October 2015
As part of the preparation of the revised Local Development Framework the Council have commissioned a
number of studies as evidence for the emerging policies.
2.3.3.1
South Cambridgeshire Local Plan – Issues and Options Report for public consultation
The Issues and Options consultation of the Local Plan (July 2012) includes items relevant to the emerging
energy strategy for Denny St Francis. These are outlined below. It should be noted that at present these
are options being considered to form the requirements of the revised Local Plan (2016).
Renewable Energy
The consultation considers the appropriateness of including a percentage requirement for on-site
renewable energy generation for new developments. 0%, 10%, 15%, and 20% are stated as possible
requirements. The consultation also notes that the Local Plan could identify future growth areas and new
settlements as potentially suitable locations for the inclusion of renewable or low carbon district heating
systems.
An additional document, the Cambridgeshire Renewables Infrastructure Framework (CRIF), seeks to
provide a robust evidence base to promote and increase the implementation of renewable energy projects
in Cambridgeshire. It identifies South Cambridgeshire as having the second greatest potential for
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renewable energy generation in the county. The CRIF Baseline Study has been endorsed as an evidence
base document for the review of the Local Plan and as a material consideration in planning decisions.
Community Energy Fund
As a way to locally benefit from the Allowable Solutions aspect of the government’s Zero Carbon Homes
and Buildings policy, the consultation is considering the introduction of a Community Energy Fund. The
Fund would collect developer obligations for ‘Allowable Solutions’ and invest these contributions in energy
efficiency and renewable and low carbon energy projects in the County.
The council, and previously Cambridge Horizons, have commissioned a number of reports on the potential
for a Community Energy Fund (CEF) to provide an evidence base; the latest in the public domain is the
Cambridgeshire Community Energy Fund Stage 2 Final Report (Jan 2012). This report states the benefits
of setting up a CEF as providing the opportunity to:

Ensure that the investment raised from development for carbon reduction is invested locally and for
the benefit of the local economy.

Influence the delivery of attractive carbon reduction projects that are not being brought forward by
the private sector alone, due to specific barriers that the CEF funding could help to overcome.

Invest in projects that deliver wider benefits to the local community and economy, such as
generating employment in the low carbon energy sector.

Leverage additional private sector investment into delivery of carbon reduction projects in the area.
The Stage 2 Report analysed the implications that the Zero Carbon Hub proposals for an Allowable
Solutions Framework (published July 2011) might have for a Cambridgeshire CEF, and found that despite
aligning well in some respects, certain concerns/ risks were raised. The Stage 2 report continues in some
detail to develop four key aspects of the operation of a CEF:

Collection mechanisms

Structure and governance

Scale of fund and investments

Carbon accounting
In April 2012, the council made the decision to continue progressing the proposals for a Cambridgeshire
CEF, including supporting officer engagement in the next stages of development.
Sustainable Design and Construction
The consultation is considering whether to require buildings to be of a higher standard of design and
construction than national Building Regulations. This would mean building to a particular Code for
Sustainable Homes or BREEAM level. It acknowledges that there would be cost implications for this and is
consulting on whether certain types or size of development should be subject to these requirements.
Possible requirements are stated as being Code Level 4 and BREEAM ‘Very Good’ for all new buildings,
but with Code Level 5 for larger scale developments.
Sustainable Show-Home
The consultation is considering requiring all developments that provide a show home, or all developments
over 15 dwellings, to provide a ‘sustainable show-home’. This would showcase environmentally sustainable
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alternative finishes, materials, fixtures and technologies that could be purchased when a dwelling is bought
off-plan.
2.3.3.2
Summary
The policies being consulted upon for the emerging Local Plan include options for similar requirements to
the current Plan, but taking on board the implications of the NPPF and other policy development, such as
that for Zero Carbon Homes. An interesting addition from the point of view of energy strategy for the Denny
St Francis development is the work the council have been undertaking around the possible introduction of a
Community Energy Fund. For example, it is possible that the site could benefit from payments from the
fund (if implemented) to improve the viability of a community heat network serving all or some of the
development. However, this would of course be subject to a feasibility and viability study as part of a
detailed energy strategy options report.
2.4
Summary of Policies
The current version of the Core Strategy aligns reasonably well with what is likely to be imposed through
national policy on the trajectory towards zero carbon. However, a new Local Plan is due to be in place by
2016 and little information is available as to whether these policies will place more onerous requirements
on developments than national policy.
The table below represents a summary of the policy situation known to date in relation to the Denny St
Francis development. In deriving the strategies in the remainder of the document it has been assumed that
the majority of the construction will take place beyond 2016, such that the requirements for dwellings in
particular will be affected mostly by national Zero Carbon policy rather than any interim regulatory
measures.
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Table 2.3:
Energy Policy Summary for Denny St Francis
a) National Policy
New Domestic Buildings
Building Regulations
Zero Carbon from 2016

Minimum standards for fabric energy
efficiency

On-site Carbon Compliance

Remainder offset through Allowable
Solutions
Part L1: SAP model required for
compliance
New Non-domestic Buildings
Zero Carbon from 2019
Limited information available on the
definition
Part L2: SBEM model required for
compliance
b) Current Local Policy: Planning requirements for South Cambridgeshire Development Control Policies DPD
POLICY NE/1 - Energy Efficiency
A minimum 10% reduction in CO2/m²/year
compared to the ‘current Building
Regulations’3
A minimum 10% reduction in CO2/m²/year
compared to the ‘current Building
Regulations'3
POLICY NE/3 - Renewable Energy
Technologies in New Development
All development proposals greater than
1,000 m² or 10 dwellings will include
technology for renewable energy to
provide at least 10% of their predicted
energy requirements, in accordance with
Policy NE/2.
All development proposals greater than
1,000 m² or 10 dwellings will include
technology for renewable energy to
provide at least 10% of their predicted
energy requirements, in accordance with
Policy NE/2.
Supplementary Planning Document:
District Design Guide (SPD)
Stated energy targets, translated to
compare with a Part L 2010 compliant
baseline, likely to mean:
No additional requirements stated

2010 – 2013: 2010 compliance

2013 – 2016: 25% reduction on
2010 compliance

2016 + :
Supplementary Planning Document:
District Design Guide (SPD)
zero carbon, as
national definition
Code for Sustainable Homes
BREEAM
Applicants are encouraged to realise as
high a level of the Code as possible.
Consideration should be given to
achieving a BREEAM rating of at least
good for all new commercial structures
within South Cambridgeshire.
c) Emerging Local Policy: Local Plan 2016
Evidence base includes consideration of: a greater percentage renewables requirement, the introduction of a Community
Energy Fund, a requirement for Code for Sustainable Homes Level 4 (or 5 for larger developments) and BREEAM Very Good
as minimum standards for new developments, and a requirement to provide a ‘sustainable show-home’
_________________________
3
Supplementary Planning Document: District Design Guide (SPD) refers to Building Regulations 2006 as the current
regulations for comparison. Clarification may be required from the local planning authority
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2.5
Financial Incentives
The Government has recently put in place a number of financial incentive schemes in order to encourage
the uptake of certain renewable technologies. The principals of these are outlined in the following sections.
2.5.1
Feed-in Tariff
The Feed-In-Tariff (FIT) is a policy mechanism which is designed to encourage ‘small scale’ renewable
electricity generation by allowing the generator to earn a regulated income from every kilowatt hour
generated. The purpose of the scheme, introduced in 2010, was primarily to increase the proportion of UK
renewable energy generation from micro-renewable technology and to stimulate a market such that the
costs of installed systems would reduce.
Technologies that are currently eligible for FITs are:
 Solar PV
 Wind
 Hydro
 Anaerobic digestion
 Micro-CHP
2.5.2
Renewable Heat Incentive
The Renewable Heat Incentive (RHI) is aimed at providing a fixed rate financial incentive for renewably
generated heat. The scheme provides a payment for every unit (kWh) of heat generated by eligible
systems.
Phase 1 of the scheme, which began in November 2011, is for non-domestic buildings only. Technologies
that are currently eligible for the RHI on non-domestic buildings are:
 ground source heat pumps (for water heating)
 water source heat pumps (for water heating)
 deep geothermal
 solar thermal collectors
 biomass boilers
 energy from biomass proportion of municipal solid waste
 biomethane & biogas combustion.
Phase 2 which will apply to domestic properties is currently due to begin in summer 2013. An interim
measure for domestic properties called the Renewable Heat Premium Payment (RHPP) is currently in
operation which supports the installation of air and ground source heat pumps, solar thermal and biomass
with a one-off capital contribution. Heat pump and biomass payments are only available to properties which
are not on the gas grid.
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3. Environmental Conditions and
Collaboration Opportunities
3.1
Background
The investigation of local weather conditions using data sources such as Meteonorm, BERR Wind Speed
Database, Photovoltaic Geographical Information System (PVGIS) can provide an accurate picture of the
climate that the Denny St Francis development is likely to experience.
3.2
Local Climate
From the available data from Meteonorm it can be seen that the temperatures experienced in the closest
weather station, Bedford, range between -5 and 10˚C in the winter to 15 and 30˚C in the summer.
The feeling of comfort in an environment under a given set of temperature conditions is known as ‘thermal
neutrality’, measured in ˚C. This temperature is a product of the average seasonal climate and its
fluctuations. Figure 3.1 below shows the thermal comfort line for Bedford; in particular, the average
summertime temperatures are not as extreme as more urbanised environments and in addition, heating is
predominantly required throughout the year.
The green line represents the thermal comfort band for Cambridge. Therefore where the red line, the
temperature profile for Cambridge, is below the green line heating will be required in the buildings and
where it is above, cooling will be required.
Figure 3.1:
Seasonal temperature profile and thermal comfort band for Cambridge
Source: Weather Tool
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3.3
Wind Resources
Estimated wind conditions for the Denny St Francis area, extracted from the BERR Wind Speed Database
for the whole of the UK, show an average wind speed of 6.1m/s at a 45m height, 5.6m/s at 25m height and
4.9m/s at 10m height. This gives it a good potential for wind energy generation compared with many other
sites. It should be noted, however, that these estimates do not take into consideration landforms (e.g. hills
and wood stands) and are often found to over estimate actual wind conditions.
From the wind rose obtained by Weather Tool it is possible to verify that prevailing winds come from southwest.
Figure 3.2: NOABL Wind Estimates for Denny Abbey
(CB25 9PQ)
Figure 3.3:
Source:
Source:
3.4
DBERR
Wind Rose
Weather Tool
Solar Energy Resources
For an early stage evaluation about solar energy resources and the feasibility of solar technologies within
Denny St Francis development, Photovoltaic Geographical Information System (PVGIS)4 has provided
important information summarised in Table 3.1 below:
_________________________
4
http://re.jrc.ec.europa.eu/pvgis/apps3/pvest.php
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Table 3.1:
Solar energy resources for Newmarket/Exning
Location
52°15'54" North, 0°18'7" East
Elevation
14 m a.s.l.
Nearest city
Newmarket/Exning (7 km)
Optimal inclination angle is
37 degrees
Irradiation on horizontal plane
2670 Wh/m²
Irradiation on optimally inclined plane
3100 Wh/m²
Ratio of diffuse to global irradiation
0.59
Average daytime temperature
11.5 °C
24 hour average of temperature
10.7 °C
Number of heating degree-days
2725
Source: PVGIS
3.5
Geological and Hydrogeological Conditions
The ground conditions of Denny St Francis have been investigated via the Mott MacDonald Phase I GeoEnvironmental Risk Assessment study, and separately through specific British Geological Survey (BGS)
commission to establish additional information relating to transmissivity and porosity mapping. Expected
geological sequence and aquifers beneath the site have been evaluated together with ground water yields,
water level and groundwater quality.
From the “Water Borehole Prognosis” report obtained by BGS it appears that the underlying Gault
Formation (Stiff, dark clay) underneath the site is poorly permeable so it is unlikely to provide reliable water
supply for open loop type ground coupled energy systems, as clay layers and poorly permeable
sandstones underneath the site may act to impede the movement of water.
Furthermore, the Environment Agency identified that no new abstraction licences of groundwater in the
catchment are allowed, particularly for public water supply purposes, thereby effectively ruling out the use
of borehole water on-site unless an abstraction licence can be procured from an existing licence holder.
Therefore it would appear that the site is not suitable for energy strategies that involve the abstraction of
water (open loop systems). However closed loop systems may still be applicable.
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4. Low and Zero Carbon Considerations
4.1
Overview
Strategies to reduce CO2 emissions in the built environment typically follow what is known as the Energy
Hierarchy, typified by the Lean, Clean, Green mantra, originally coined by the Greater London Authority.
The approach starts with the consideration of how to reduce energy demand in the first instance, by
applying passive design principles and energy efficiency measures, to achieve a ‘lean’ design. A focus on
demand reduction should always be the first step in CO2 emission reduction, however after a certain point
a law of diminishing returns means that it then becomes more cost effective to look at tackling the
remaining CO2 emissions via technology applications.
Therefore, once demand has been reduced as far as practicable, consideration is given to supply the
remaining energy demand as efficiently as possible, for example by using waste heat from power
generation in the form of combined heat and power (CHP) supplied through a district energy system.
After demand reduction and efficient supply technologies have been applied, appropriate combinations of
renewable energy technologies are considered, with due consideration of technical and commercial
feasibility, as well as long term operation and management.
This section provides a summary of the issues relating to low carbon decision making, and follows the
hierarchy outlined above.
4.2
Energy Efficiency
The buildings on the Denny St Francis development will be designed to be energy efficient.
Typically for dwellings this is likely to be through following the Fabric Energy Efficiency Standards (FEES)
being introduced through government policy, which set minimum levels for overall fabric performance.
Achievement of the FEES is affected by building fabric U-values, thermal bridging, thermal mass, and
features which affect lighting and solar gains. It is not influenced by building services, for example heating
system, fixed lighting, or ventilation strategy.
The FEES are currently incorporated in the Code for Sustainable Homes energy standard, and to achieve
levels 5 or 6, FEES must be applied.
The following table summarises an example fabric specification to reach the Fabric Energy Efficiency
Standard for a detached and semi-detached house.
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Table 4.1:
Example specifications to achieve FEES – semi-detached & detached house
Parameter
FEES - 46 kWh/m²/year
Semi-detached house
Detached house
External Walls (W/m².K)
0.18
0.15
Heat Loss Roof (W/m².K)
0.13
0.13
Heat Loss Floor (W/m².K)
Window / Door U-value (W/m²K)
Air permeability (m3/h/m² @ 50 Pa)
Thermal bridging (y-value)
0.13
0.13
1.4 / 1.0
1.2 / 1.0
5
5
0.051 (use of Enhanced
Construction Details)
0.040 (use of Enhanced
Construction Details)
250 (Medium)
250 (Medium)
Thermal Mass Parameter (kJ/m².K)
Fabric Energy Efficiency for Part L 2013: Worked Examples and Fabric specifications, Zero Carbon Hub, February 2012
Although the FEE standard is not influenced by building services, the improvement in fabric may dictate the
ventilation strategy. For example, if relatively low air permeability is required to meet the FEES, the
consequence might be that Mechanical Ventilation Heat Recovery (MVHR) is chosen to help ensure
adequate internal air quality.
Similar approaches will be followed for the non-domestic buildings, but they will also be accompanied by a
much greater focus on efficient systems, such as heating, ventilation, air conditioning and lighting, both in
terms of technology selection and the associated controls functions and controllability.
4.3
Decentralised Energy
4.3.1
Overview
This step in the hierarchy relates to the consideration of decentralised energy, such as district heating
supplied through energy centres containing centralised boilers or combined heat and power (CHP)
installations.
CHP technology & district heating
Development-size CHP engines tend to be gas-fired and will typically produce heat for domestic hot water
and a proportion of electricity supply to the site. CHP systems can supply a single building, small clusters of
buildings/flats or a cluster of many buildings through a heat network. The more buildings attached to the
network the higher the demand, which would allow selection from a broader spectrum of CHP technologies.
District heating can be applied on a phase by phase network that remain stand-alone or connect together in
later phases to create a site-wide network. If a district heating system were to be applied at a site-wide
scale then this would increase the economies and efficiencies possible for the overall system.
4.3.2
Decentralised energy and viability
Since the role of decentralised energy in the search for CO2 emissions reduction was first raised, the
industry has been gathering knowledge in relation to the financial viability and delivery implications of such
systems. This has been acquired through collaborative industry exploration, including many reports
produced by industry focus groups, as well as government backed initiatives, such as the work of the Zero
Carbon Hub.
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Of particular interest has been the financial implications of district heating, given that the UK has little
experience or precedent to draw on. It has emerged that the cost of the distribution pipe-work has a
significant impact on viability, thus making the concept of heat density an important aspect to consider.
Early industry advice on this gave figures such as 30 dwellings per hectare and 3,000 kW/km2 as typically
being markers above which a district heating system might be viable. However, the viability equation is not
a static one and these figures are affected by issues such as:
 what constitutes 'business as usual' against which a district system is being compared, i.e. as the policy
environment tightens it is no longer possible to compare with conventional energy solutions
 the ability of the energy sector and finance industry to assist in solving the need for higher upfront
capital injection in order to implement district energy schemes
 the industry uptake of district heating such that monopoly situations don't affect the cost of pipe-work
 the ability to streamline groundwork with other trades and how the statutory authorities allow district
heating pipe-work to be accommodated in 'adopted standard' roads
 the emerging design solutions to issues such as distribution losses (which will affect both size and
specification of pipe-work and components)
 the influence of government incentivisation and cost of compliance burden on viability comparisons and
energy strategy selections, particularly with respect to 'on plot' micro based or decentralised approaches
 how local authorities are facilitating decentralised energy solutions on a local scale such that developers
can discharge their compliance burden by connection to an existing system
 how the tightening of Building Regulations policy, specifically the improvements in fabric energy
efficiency which will lead to reduced heat demand, will affect the viability
 the interplay between the existing building stock, which can provide a good customer base for the heat
sales, and the proximity of new build developments that can act as the catalyst for such systems to be
implemented.
Overall it can be concluded that, when accompanied by suitable levels of vision, district heating is often a
viable option in areas with high heat density, such as in urban areas and especially cities.
4.3.3
Planning for Energy Centres
In relation to planning the locations of and arrangements for decentralised energy plant, it should be noted
that energy centres cannot always be delivered upfront due to technical and economic reasons. In
particular a CHP system, which would ideally be sized to cater for the whole of a development in order to
achieve higher efficiencies, would not then be financially or technically viable to operate until a certain level
of build out has been achieved. This could be in the region of 60%, depending on the overall size of the
development. In an ideal world it would not be preferable to use multiple energy centres and CHP
installations because experience in other developments has shown that in the long term this increases
operational costs (including cost to occupiers) as well as technical complexity.
Furthermore, multiple centres may not be the most effective in terms of carbon emission reductions.
However it is sometimes the case that overall cost and CO2 emission reductions can be sacrificed in order
to achieve some forward momentum and this is especially likely to be true in the current climate of
uncertainty and developer need for flexibility. Delaying capital expenditure until it is needed may have
significant improvements to net present value and cash flow.
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4.3.4
Management and Delivery of a Decentralised System
In relation to the successful establishment of a decentralised energy network there will be procurement,
economic, management and delivery issues to be addressed. The most common ongoing management
solution is that of the Energy Services Company (ESCo). These can be (but are not always) a special
purpose vehicle company, set up specifically for the development, which will operate the energy facility and
provide energy services on a long term contract. They can be subsidiaries of commercial ESCo companies
and partially/wholly owned by community organisations or developers. In essence, they are not
substantially different, in the way they operate, than the existing large utility companies.
With the lack of a regulated heat market in the UK, some concerns exist over consumer protection.
However in order to achieve a fair charging arrangement there are contractual mechanisms that can
ensure the prices paid by the consumers are at or below market price. Consideration should be given to a
commitment that, through these contractual requirements, the prices charged by the ESCo are competitive
compared to current national energy prices. This can be approached through the inclusion in the contract of
a clause that ensures that the energy price supplied will be at or below a ‘basket’ of UK market energy
prices. However the specific approach that an ESCo might apply to the development is dependent on the
ESCo in question.
It may be possible for the developer to agree terms with the ESCo such that the ESCo provides the plant
and the developer pays for this via a connection charge. In this way the burden of up front costs can be
passed to the ESCo and the developer can predict a more even cashflow.
Many examples of large district heat networks in the UK have had substantial involvement from the local
authority, particularly at their initiation. Their co-ordination combined with the potential to bring large anchor
loads is often crucial to bring forward systems of a viable scale. Involvement from local authorities in
creating an opportunity for an ESCo involvement could range from reducing risk for private sector
investment to direct procurement or even to ongoing interest in the ESCo itself. The ability for the public
sector to borrow at lower cost and take a longer term view may be useful in helping to fund networks that
would be operating for many decades.
4.4
Low and Zero Carbon Technologies
4.4.1
Overview of technologies
If the right conditions exist for a decentralised energy system then it is possible that the ‘on-site’ element of
the Zero Carbon may be achieved without recourse to further low or zero carbon technology. However it is
also necessary to explore alternative options in order to assess the appropriate overall combination of
strategies.
The following is a list of typical low and zero carbon technologies that may be applicable depending on site
characteristics:
 solar thermal (ST)
 CHP with absorption cooling (Tri-generation
or CCHP)
 photovoltaic (PV) panels
 air source heat pumps (ASHP)
 wind turbines
 combined heat and power (CHP)
 ground source heat pumps (GSHP)
 underground thermal energy storage (UTES)
 biomass boilers and biomass/bioenergy CHP
 energy from waste
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Not all low and zero carbon technologies can meet all types of energy requirement, as outlined in the table
below.
Table 4.2:
Energy Supply Options
Energy
Use
ST
PV
Biomass
Wind
CHP
ASHP
GSHP
UTES
5
6
?7
Heat
Hot water supply





?
Heat
Space heating (or for
cooling)








Lights, pumps and fans
(Part L regulated); small
power and appliances
(Non-regulated under
Part L)








Electricity
4.4.2
?
Implications for Denny St Francis New Settlement, Waterbeach
Table 4.3 below outlines broad brush considerations that are relevant in relation to the choice of technology
for Denny St Francis.
Table 4.3:
Technology Considerations
Technology
PV
Considerations
Roof angle, orientation and shading
Requires inverter and connection to distribution board
Impact of panel on roof
Applicable to Denny St.
Francis

Ownership (Feed-in-Tariff)
Solar Thermal
Roof angle, orientation and shading
Pipe run to cylinder
Individual twin coil DHW cylinder or communal system with
metering issues
Impact of panel on roof

Ownership (Renewable Heat Incentive)
Wind turbine (Building
mounted)
Requires inverter and connection to distribution board
Noise concerns
Output is heavily dependent on site, i.e. gable end or other
suitable exposed site on building
Industry research indicates that output is often negligible
Wind turbine (Small stand
alone)

[Not suitable for urban areas]
Output is heavily dependent on exposed site
Requires inverter and connection to distribution board
Noise concerns
Public perception and planning sensitivity issues
O&M requirements
Uncertainty over accreditation methodology for Building
Regulations compliance
_________________________
5
ASHP can supply hot water but normally with a lower efficiency.
6
GSHP can supply hot water but normally with a lower efficiency.
7
UTES can supply hot water but normally with a lower efficiency.
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Technology
Considerations
Wind turbine (Medium/large
stand alone)
Applicable to Denny St.
Francis
Issues of visual impact and planning sensitivity
Noise, radar, flicker and ecology concerns
Output is heavily dependent on exposed site
EIA and separate planning application
Requires connection to power distribution network
(probably HV)
O&M requirements

Uncertainty over accreditation methodology for Building
Regulations compliance
CHP
Energy centre
Greater space take than regular gas boiler
Only counts as renewable if biomass fuelled
O&M requirements (including ash removal if biomass
fuelled)
Planning impact of flue

Requires connection to power distribution network
Communal heat network
Wood-fuelled biomass
boilers
Energy centre(s)
Greater space take than regular gas boiler
Twin-lined flue
Fuel store and access for delivery
O&M requirements including ash removal
Planning impact of flue
Communal heat network
Air quality considerations
Ongoing cost and supply resilience of fuel
Energy from Waste

Only viable at very large scale
Energy centre(s)
Greater space take than regular gas boiler
Twin-lined flue
Fuel store and access for delivery
O&M requirements
Planning impact of flue
Communal heat network
?
[depends on collaboration
opportunities]
Air quality considerations
Public perception issues
ASHP (Air source heat
pump)
Low temperature heating system
Recent research indicates potential performance issues
unless careful attention paid to design and installation
Current Part L calculation methodology gives undue CO2
emissions reduction benefit via less onerous TER
Can require supplementary systems for extremes of
temperature
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?
[future changes in Part L
methodology likely to remove
the undue benefit]
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Denny St Francis New Settlement, Waterbeach
Technology
Considerations
GSHP (Ground source heat
pump)
Applicable to Denny St.
Francis
Greater space take than regular gas boiler
Vertical boreholes or external space required for horizontal
loop
Low temperature heating system

Recent research indicates potential performance issues
unless careful attention paid to design and installation
Current Part L calculation methodology gives undue CO2
emissions reduction benefit via less onerous TER
Can require supplementary systems for extremes of
temperature
UTES (heating and cooling)
Performance dependent on aquifer or ground conditions
Low temperature heating system
Heat network and energy centre for communal system
?
Heat pump systems in buildings rather than central can
offer cost saving as district pipework is simple plastic
rather than specially pre-insulated
[ground conditions unsuitable
for use of aquifers]
A licence must be obtained for the abstraction and use of
groundwater
Improved potential of license as no net extraction
An overview of renewable energy technologies that may be appropriate for further consideration in an
energy strategy for the Denny St Francis are presented in the following sections. Low-carbon but nonrenewable technologies such as gas-fired CHP have been discussed in section 4.3 above.
4.4.2.1
Solar
Favourable conditions for solar energy capture exist within the Denny St Francis site, particularly as it is not
constrained by existing urban forms. Solar systems work best when they are planned for, or introduced
early within the development design, as this limits issues of overshadowing, inappropriate surface space,
and ad-hoc orientation and placement.
Solar design can help to reduce the associated carbon dioxide emissions through the use of the above
techniques; however, the Denny St Francis development will seek to balance solar design and urban
design requirements. Onsite solar energy generators will where appropriate include solar thermal panels
for hot water generation and photovoltaic panels for the production of renewable electricity.
Solar Thermal Panels
The two main types of solar water heating system are flat plate collectors and evacuated glass heat tubes.
For either type of collector, the most benefit can be gained if they are mounted facing within 30º of South,
at an angle of around 36º from the horizontal. Other mounting positions are feasible, but output will be
reduced.
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Photovoltaic (PV) Panels
PV panels offer a simple, proven, elegant solution to generating renewable electricity especially if
incorporated as a building integrated photovoltaic array (BIPV), e.g. as part of a roof or façade. They will be
considered wherever feasible within the Denny St Francis site, with thoughtful planning ensuring ease of
integration. PV panels have historically been a relatively expensive technology, however technological
developments and financial incentive measures introduced by government are changing this.
PV panels can contribute a portion of individual building energy, but are not appropriate for site-wide
distribution due to the low and variable output through the year. However they can help reduce the overall
carbon emissions of the site as part of a palette of solutions.
4.4.2.2
Wind
There are several issues that must be considered in the use of wind turbines. The proximity of a wind
turbine to residential, institutional and commercial type properties must be considered in relation to issues
such as noise, flicker, radar interruption, visual amenity, ice throw and bat strike. In relation to the majority
of these issues mitigation measures can be included with careful planning.
Large scale wind turbines present one of the most cost effective methods of providing renewable electricity,
and this has influenced the government’s strategy to achieve carbon emission reduction on a national
scale.
A technical feasibility study has been carried out to determine the potential for the development of a wind
farm in the near vicinity of Denny St Francis, to directly serve the development with renewable electricity.
Whilst the results have been encouraging in that the site is in a reasonably windy area and there are no
known nearby sites with national designations (such as SSSI’s, National Parks, etc) or sites of particular
ecological importance that would preclude the use of turbines, there are significant barriers to the
implementation of large scale wind turbines and RLW intends to prioritise more publicly acceptable forms of
emission reduction.
4.4.2.3
Ground-Source and Ground-Storage Systems
Ground source heat pumps make use of constant ground temperature to pre-heat a fluid that is upgraded
in a heat pump, via electricity, for use in a low temperature heat system. Ground storage systems store
energy in the form of borehole thermal energy storage (BTES) or aquifer thermal energy storage (ATES),
the latter having a higher efficiency due to the use of water as a heat transfer medium. These systems are
capable of achieving interseasonal storage, storing heat or cooling in the ground or available ground water
such that it is then available in the opposite season, the effect being an often highly cost effective provision
of renewable thermal energy to the building or development.
Hydrogeological conditions are the key to the suitability of the systems and British Geological Survey
mapping reports determine the key hydrogeological characteristics as outlined in sections above. Early
stage studies have indicated that the site is not suitable for aquifer thermal energy storage (ATES). Other
types of storage (borehole thermal energy storage or local ground source heat pumps) may be suitable to
provide a contribution to the CO2 savings required.
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4.4.2.4
Biomass
Various forms of biomass have the potential to provide a source of renewable heat, with supply
availability/security and delivery to site as key issues to consider.
For the Denny St Francis development the proximity to the A428 would be advantageous for the delivery of
solid or liquid biomass. Having a secure source of fuel for the use in biomass based energy systems is
essential to the successful implementation and operation of the technology. Few biomass suppliers have
been identified within 20 miles from the development site, however the large areas of farmland in the
vicinity mean that potentially some of this could be used to grow local biomass subject to discussions with
local farmers.
4.4.2.5
Energy from Waste
Waste that goes to landfill is a potentially valuable resource. Using waste to generate fuel can bring
environmental and economic benefits and a large variety and proportion of the municipal and industrial
wastes can be used. The energy that is recovered from wastes is classified as renewable energy and the
type of waste determines the most suitable way to extract the energy.
There are many municipal sized Energy from Waste facilities in the UK, but scale is an issue and the
opportunities to use the technology even at the scale of the Denny St Francis settlement is uncertain.
However the commercial viability of such schemes has been strengthened recently by the financial
incentive schemes outlined in Section 2.5 and can be affected by opportunities for collaboration with other
interested parties. Two such opportunities are explored below.
Amey-Cespa Waste Treatment
The location of the Amey-Cespa (formerly Donarbon) Waste Treatment Facility, which is located opposite
Denny Abbey off the A10, presents an opportunity to consider energy from waste in the overall energy
strategy.
Meetings have been held with Amey-Cespa representatives to ascertain current and future waste treatment
developments and how these might link in with the Denny St Francis energy strategy.
Amey-Cespa has a contract to manage all of Cambridgeshire’s waste for 28 years and runs a Mechanical
Biological Treatment plant near the site entrance. They are currently investigating the viability of introducing
a 5MW CHP plant, to be fuelled from some of their available waste sources, on land adjacent to the A10
there is the potential that this plant size could be increased. Recent discussions have established that
Amey-Cespa have not made final decisions regarding the technology to be used (and therefore the likely
heat to power ratios), and would be interested in exploring the potential to export the heat to the Denny St
Francis development.
This collaboration could have benefits to both parties, especially given the proximity of the Denny St
Francis development to the proposed plant. The final outcome will depend on many issues, including
logistics, phasing, timescales and the likely financial benefits achieved through government incentives for
production of renewable energy. However RLW aims to proactively continue the discussions with AmeyCespa until such time as firmer commitments can be made.
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Anaerobic Digestion (AD) at new Wastewater Treatment plant
The anaerobic decomposition process is a natural process that happens in absence of oxygen. It is a
biological process where a biodegradable waste stream is combined with certain types of bacteria to
generate biogas. The biogas could be used to power vehicles, or alternatively used in a CHP plant to
provide the heat needed to warm the digester and/or to feed into a nearby district heating network and also
electricity that can be used in-situ or sold to the grid.
Suitable waste streams come in the form of organic domestic or commercial waste, sludge from
wastewater or farm slurry. The creation of a new wastewater treatment facility for the Denny St Francis
development presents an opportunity to consider the possibilities of using use the wastewater sludge in an
adjacent AD plant. There is also the potential for this to be augmented with organic waste or slurry from
adjacent farms. Industry precedent indicates that the scale of Denny St Francis puts an AD system
designed for wastewater sludge around the borderline of commercial viability, such that more detailed
analysis would be required.
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5. Conclusion
This section contains a discussion on the possible energy approaches for the Denny St Francis
development.
The national and local policies outlined in Section 2, together with the site opportunities and constraints, act
as a backdrop against which appropriate strategies will evolve. Highly relevant to this are the ambitions of
South Cambridgeshire Council in relation to wider initiatives that they wish to put in place, including
aspirations for local decentralised energy systems and the likely introduction of a Community Energy Fund
to implement locally based Allowable Solutions. RLW will be keen to work with the Council and look for
ways to achieve mutually beneficial outcomes and aligned objectives in this respect.
The timescales for the development are such that a high degree of energy efficiency, coupled with
extensive use of low/zero carbon technologies will be required in order to respond to the Zero Carbon
agenda being steered by government. At present it is not possible to say whether the approach will be
based largely on local building mounted technology or a site-wide/district system. Which approach is
technically suitable depends on the density, dwelling type, energy demand, required CO2 savings, and
often it is appropriate to use a combination of the two.
RLW are also aware that the technical feasibility and economic viability will alter as issues evolve such as
compliance policy, financial incentives and more general commercial drivers such as the cost of capital and
energy. Over the period of the development these compliance policies and the optimum technologies to
commercially meet them will undoubtedly develop further.
Therefore the masterplan development will include a flexible approach to the delivery of energy to the
buildings, allowing flexibility for a range of options. However the overall strategy will be developed with the
following principles of good practice in mind:
 Continue to investigate the opportunities for collaboration, such as the potential to use of heat from any
suitable Amey-Cespa processes, or the opportunities for anaerobic digestion to treat organic waste at
the new wastewater treatment plant
 Develop the land use schedule to allow for inclusion of an energy centre(s), for the event that district
energy systems are required
 Develop buildings and systems to high levels of energy efficiency, including the Fabric Energy Efficiency
Standard for zero carbon homes
 Orientate building massing to optimise south facing major roof slopes where possible, to enhance
potential for solar technology
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