element energy study - Exeter and East Devon Growth Point

In November 2007 the Exeter and East Devon Growth Point Delivery Team commissioned Element Energy to undertake a strategic analysis of CO2 emissions from the new developments in the Exeter and East Devon Growth Point over the period to 2020.

Over the same period, new national policy (such as the Code for Sustainable Homes, CSH) requires a significant reduction in CO2 emitted from new buildings. This will necessitate significant improvement in building design, combined with the use of microgeneration technologies (such as solar photovoltaics, heat pumps and micro wind) and distributed generation technologies (such as district heating and combined heat and power).


1) Early adoption of Code for Sustainable Homes
Domestic Heat Interface UnitThe analysis shows that a basic set of improvements to building fabric is a relatively cost-effective means of carbon reduction. Furthermore, the same set of measures still form part of the solution for all carbon reduction targets through to zero carbon (Code for Sustainable Homes Level 6).

Improving building fabric performance measures now would futureproof building designs against all but the highest Code level. Legislating for code 3 compliance mainly through fabric measures would pay dividends by putting in place a good construction standard that need not change for some time to come, despite changes in national legislation.

2) Site energy systems
The analysis shows that district heating systems are (by a large margin) the least costly means of achieving significant carbon reductions (i.e. above Code 4). With the exception of development within Exeter city centre, policies should be developed to require all developments in the Growth Point to develop district heating systems to supply low carbon energy to end-users.

It is recommended that the Regional Infrastructure Fund is used to provide the required cash flow for the development of a district heating infrastructure for the higher heat density town centre area of Cranbrook. Also, the Growth Point / developers should open discussions with utilities / Energy Supply Co’s to understand how they may be able assist in the development and maintenance of site energy systems.

3) A dedicated low carbon strategy for Exeter “City Centre” and “Rest of City” developments
Parts of the Growth Point where smaller pockets of development will occur are not suited to dedicated site-wide energy systems that are applicable at larger sites. The development of a Sustainable Planning Guide targeted at smaller city centre type developments is recommended, covering building based technologies, the connecting to existing supply systems, or using a new development as a catalyst to bring together and supply a number of existing heat users.

4) District heating networks at commercial sites
The higher heat densities of the commercial sites in the Growth Point result in better economic viability for district energy systems. It is recommended that district heating should be made a requirement for large commercial developments such as the Science Park and Sky Park. Further CO2 reductions could be achieved through the use of biomass or waste streams and the feasibility of using these should be examined.

5) An electricity system (private wire) linking the Sky Park and Inter Modal Freight Facility
The analysis shows that private wire systems linking site energy systems at the Skypark and IMFF could improve the economics of these site energy systems. Any study examining the feasibility of district energy systems at commercial developments should include the beneficial aspects of private wire.

6) Energy from waste
An energy from waste facility in the Growth Point is likely to be economically viable and an important source of low carbon energy. The amendment to the Renewables Obligation and the increasing cost of landfill (high gate fees) combine to make advanced energy from waste plants a commercial proposition. However, there is some uncertainty surrounding availability of waste resource in the area and also the commercial readiness of the advanced conversion technologies (pyrolysis/gasification).

Further investigation has shown that a small 'energy from waste' plant in the Growth Point, linked to a community or site energy system is required. This would comprise a detailed study into waste resource availability (focussed on commercial and industrial arisings) and the commercial readiness (bankability) and economics of small advanced treatment technologies.

7) Further work on large wind in the Growth Point
Large wind (MW scale) energy systems are predicted to be amongst the most economic means of reducing carbon emissions. Therefore large wind is a strategically important low carbon technology. However, initial screening suggests that there are few (if any) suitable sites in the Growth Point. A detailed study to assess the potential for the installation of large scale wind turbines proximal to Exeter Airport is needed to confirm this.

8) Biomass supply chains
The most cost-effective means of meeting high Code for Sustainable Homes levels and meeting regional policy for renewable contribution to commercial developments is site-wide, biomass fuelled CHP systems. This will require substantial biomass resource. The woodfuel resource in the South West is sufficient, but the amount of woodland within proximity to the Growth Point is quite limited. Mapping exercises performed by the Renewable Energy 4 Devon (RE4D) and as part of the Revision 2020 exercise has identified significant potential for energy crops (particularly miscanthus).

The Growth Point needs to encourage the growth of biomass supply chains in the surrounding area. Consultations should be initiated with the Regen SW Bioheat programme, RE4D, BiCAL, the Forestry Commission, South West Wood fuel and local farmers & landowners, to discuss ways to generate a sustainable biomass supply in the area.

Client:Exeter and East Devon Growth Point Partnership
Consultant: Dr Shane Slater, Director, Element Energy