Sustainable Buildings SPD
5. Calculating the Renewables Requirement
5.1 The Council will expect the applicant to demonstrate how they have met the 10% requirement including details of the type of technology which will be installed and how this will achieve the expected energy requirement. In order to do this the Council has set out the following stages as a guide for applicants in meeting the requirement.
Stage 1 – Maximising Energy Efficiency
5.2 The development should be designed to maximise energy efficiency to ensure that the overall energy demand is as low as possible. It is important that this is undertaken in conjunction with the installation of renewables to maximise energy savings. For example, ground heat source pumps will be most effective where there is high thermal mass. The Council will not accept energy efficiency measures as being sufficient in meeting the 10% requirement.
5.3 The applicant should consider the potential to use Combined Heat and Power to reduce carbon emissions within the scheme (see section 7).
Stage 2 – Calculating Total Energy Demand
5.4 The total predicted energy demand of the development should be calculated taking account of all potential energy uses. This should not only include energy for heating, ventilation, cooling and lighting but also (where applicable) energy use from appliances which along with other unregulated emissions can account for between 40% to 50% of the total carbon emissions in new homes.
5.5 Applicants should use the Standard Assessment Procedure (SAP) calculating the target emission rate (TER) and building or dwelling emission rate (BER / DER) in order to implement the building regulations. The electricity and heating requirement per kilo watt hour should be identified and this should be multiplied by the size of development in square metres. The BER / DER should be recalculated to reflect the energy efficiency measures and addition of renewable energy equipment.
5.6 It is anticipated that a renewables toolkit will be produced to provide up to date energy data for different types of development (see paragraph 5.11). In the absence of this the applicant should use established sources of benchmark data such as the London or Oldham toolkit.
5.7 For developments where the end user is not known it may not be possible to accurately calculate the energy demand. In these cases the Council will expect the applicant to provide an estimate based on best knowledge using one of the available toolkits.
Stage 3 – Assessing different types of Renewable technologies
5.8 Consideration should be given to different types of renewable technologies and their potential suitability for the development site. The applicant should demonstrate why the chosen method of renewables is the most suitable for the site. For example, although some developments may not be suitable for renewables such as wind turbines and solar panels there may be scope for other alternatives.
Stage 4: Calculate the energy savings
5.9 The applicant should calculate the proportion of energy which will be provided by the chosen technology. To do this it may be necessary to consult specialist advice particularly as the systems output may be dependant on siting and location.
The following basic calculation should be completed:
|% Renewable Energy =|
|energy delivered by renewables system||x 100|
|predicted site energy requirement|
5.10 This should be expressed as a percentage and stated in the energy statement
Sub regional toolkit
5.11 In conjunction with other authorities in the sub region the Council will provide a renewables toolkit. It is likely that this will take the form of a spreadsheet which will enable applicants to calculate the percentage of energy which will be generated by a particular renewable energy technology. It will also assist development control officers in determining planning applications.