For the past year DG Cities has been closely involved in an InnovateUK funded project called IDEMA - a technical feasibility study for 11 sustainable homes in the UK. Our role in this multidisciplinary research project, has been to identify the most appropriate renewable energy technology strategy for these homes.  As the project draws to a close, this is the first in a series of blog posts about our work, learnings and recommendations for developers and local authorities.

Today, all new housing developments in London (of a certain scale) are required to maximise onsite clean energy, through the integration of renewable energy technologies. IDEMA set out to meet and exceed this policy, aiming to generate £3,000 of revenue for each dwelling, through surplus energy exports. 

Our approach 

First off, we spoke to various experts in the building and energy sector to understand how to assess the suitability of renewable energy technologies for our site. We found that the current approach to reviewing and selecting renewable energy technologies is fairly limited. Now you may be wondering, why? 

Well, for one, detailed site conditions assessments are not always conducted. Within London, this may partly be due to the fact that Energy Assessment Guidance does not specify the minimum site conditions needed for a particular technology to generate adequate energy. Additionally, developers are not actually required to demonstrate that the energy generated from proposed technologies will be sufficient to maintain their financial feasibility in the long run. The focus is primarily on deploying technologies, with less of a focus on efficacy and as a result, some developments end up being fitted with technologies that are not suitable. Indeed, we were told anecdotally that in some cases, renewable energy technologies are added simply as a box-ticking exercise to obtain planning permission.

All that being said, it might not surprise you to learn that developers are not required to consider the lifecycle environmental impacts of technologies either.  As with any product, the manufacturing of renewable energy technologies has an impact on the environment, which must be considered. How can we be sure that energy plus and self-sufficient buildings will always have a positive impact on the environment, when we don’t take into consideration the lifecycle impact of the technologies used? 

The “Renewable Energy Technology Assessment Framework” 

Armed with these insights, we knew  a holistic approach was needed to help identify the suitable  renewable energy technologies for IDEMA. So, DG Cities set about developing  the “Renewable Energy Technology Assessment Framework” - a step-by-step guide that helps developers identify renewable energy technologies for their site by considering 3 elements:

Over the next few weeks we will explore each of the elements in the framework and how we applied them to IDEMA, starting today with, not surprisingly, step 1…

Step 1: Site Conditions Assessment

Here, the framework asks developers to undertake a site conditions assessment for 6 potential renewable energy technologies: wind turbines, solar panels, biomass boilers, anaerobic digesters, air source heat pumps and ground source heat pumps.

The site conditions assessments is a detailed questionnaire that helps to eliminate unsuitable technologies. The checklist is designed to uncover site specific conditions which would impact the efficacy of technologies.  For instance, factors like the direction of the house and whether a roof is obstructed by shade would influence the appropriateness of solar panels. Furthermore, wind speeds of  15 metres / second are typically required to enable wind turbines to generate sufficient energy. Interestingly, this rules out wind turbines as a suitable technology for most of London.

The end result is to identify the most appropriate technologies and, just as crucially, determine which technologies are not suitable for a development.  In this way, we can at least from the start ensure that we are proposing technologies that have the potential to generate enough energy to meet the needs of the development. 

From undertaking this initial site conditions assessment, we determined that the most suitable technologies for IDEMA were solar panels and air source heat pumps, with anaerobic digesters warranting further investigation.

As sustainability has now firmly landed in the mainstream, it becomes ever more important that we fully understand the capabilities and suitability of renewable energy technologies.  In the midst of a climate emergency, we don’t have the luxury of making mistakes, so this first stage of our assessment framework is an essential starting point.

In future blog posts we will examine the next steps of our framework: renewable energy technology provisions and the broader environmental impact.  

If you are embarking on a development and would like to better understand our framework and how you can identify the most appropriate technologies for your site, we’d love to hear from you.  Drop us a line at info@dgcities.com