Mapping Birmingham’s solar PV potential
Helping Birmingham City Council to prepare for a renewable energy future
Project duration: December 2016 to March 2017
We have created a map for Birmingham City Council (BCC) that shows potential areas in the city for installing solar PV arrays. This map uses a number of data sources to depict not only the best geographical sites for establishing solar arrays, but also areas where local residents are most likely to take up a council-supported solar PV scheme.
The map uses irradiance, a 3D digital surface model and other GIS mapping datasets to estimate the solar PV resource on all roofs and open areas across the city, after applying a set of assumptions and constraints.
We were commissioned to do this as part of a wider study to explore solar PV opportunities for BCC’s proposed municipal energy company, and to help BCC understand how to meet their legal target to reduce carbon emissions by 60% by 2027, against 1990 levels. The council faces substantial barriers to achieving this as long as they are reliant on electricity supplied by the National Grid.
Installing solar PV is a potential way to support meeting this target as it would help to reduce BCC’s overall carbon emissions, whilst generating revenue, lowering fuel bills and increasing Birmingham's resilience to future changes in electricity supply and demand.
How we created the map:
For the last 17 years the Environment Agency has used lasers to scan the landscape from above in order to create detailed maps. This data is called Light Detection and Ranging Data (LIDAR) and was made public in 2015.
We used this data and combined it with address level sociodemographic data to show BCC where they could potentially install solar, how much energy these installations would produce, and where households would be likely to install their own solar PV.
CSE’s Project Manager Martin Holley explains further: “The model we’ve used accounts for year-round localised cloud cover patterns and shading from nearby obstacles. This allows us to estimate the amount of sunlight reaching a particular surface and the likely energy output of a typical PV array sited at that location.”
What we found:
The mapping work showed that solar PV rooftop installations across Birmingham could potentially reduce BCC’s annual carbon emissions by over 4%. At the moment, existing solar PV arrays result in carbon savings equivalent to less than 0.2% of total annual emissions.
The report also highlighted some key challenges in making the installation of solar PV profitable. As a direct result of the feed-in tariff (FiT) subsidy scheme introduced in 2010, solar PV saw a huge increase in UK installed capacity over the last seven years, reaching nearly 12 GW at the beginning of 2017. However a staged reduction in government financial incentives has signified that the industry needs to prepare for a transition towards a zero subsidy regime.
Recent changes to the law which will see business tax rates for self-owned commercial rooftop solar increase by six to eight times are also likely to affect BCC's eventual business plan for installing solar. Despite these challenges there is still a market for solar PV; installation rates continue to grow and have been boosted by a surge of innovation in funding models and falling installation costs.
Richard Rees, BCC's Strategic Energy Officer, commented on these changes: "Despite changes to the financial landscape since our initial investments in solar PV [BCC has previously invested in solar PV in a project called Birmingham Energy Savers], it is clear that with improving technologies and lowering costs solar will continue to have an important role in Birmingham’s future energy supply."
As well as outlining potential financial models for widespread installation in the Birmingham area, the report also highlighted some of the other benefits that would result, namely the positive effects on local jobs and supply chains and the environmental benefits of generating electricity from a completely renewable source. "The project helps to identify our priority areas for investment as well as the new business models that can help to realise the solar opportunity for the people and businesses in Birmingham” said Rees.
Martin described how he hopes the mapping will help BCC: “It’s important for public authorities like Birmingham City Council to be able to accurately understand the potential for installing renewable technology and the effects it will have on their energy supply, budgets and climate targets. Our report demonstrated a big opportunity for BCC to take advantage of the benefits that solar power brings. With our map, the council can now rapidly identify and target sites with the best potential.”
Digital surface model: Environment Agency (Crown Copyright)
Buildings and roads (e.g. the lines and shapes): OpenStreetMap
Satellite image: Google