This project involved creating a map and dataset 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.

The Centre for Sustainable Energy (CSE) was 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 solar PV map of Birmingham

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.

CSE 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 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.”

“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 study demonstrated a big opportunity for BCC to take advantage of the benefits that solar power brings, enabling the council to rapidly identify and target sites with the best potential.”

What we found out about solar PV potential in Birmingham

The mapping work showed that solar PV rooftop installations across Birmingham could potentially reduce BCC’s annual carbon emissions by over 4%. At the time of the study (2016), existing solar PV arrays resulted in annual carbon savings equivalent to less than 0.2% of total annual emissions.

The work 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, reaching nearly 12 GW at the beginning of 2017. However a staged reduction in government financial incentives signified a need for the industry to prepare for a transition towards a zero subsidy regime.

Changes to the law at the time of the study included proposals for business tax rates for self-owned commercial rooftop solar increasing by six to eight times, which risked impacting BCC’s eventual business plan for installing solar. Despite these challenges a significant market for solar PV remains; 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 at the time, 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 study 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.

As explained by Richard: “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”.

More solar wizadry from CSE

The Centre for Sustainable Energy team is building an intuitive app to support more people and communities to get solar power systems. The Solar Wizard app will provide easy, quick, accurate and independent predictions about the viability for solar PV on buildings and homes. It will be used by individual households, communities and local authorities to accelerate decision making and investment planning and you can find out more here.