Using data to develop city wide Solar PV on buildings
Planning solar PV (photovoltaic) rollout across an entire city is no easy feat. But with rising energy prices and unavoidable evidence of climate change, we need to act quickly to improve our buildings, and that includes installing renewable energy systems at both small and large scale. Luckily, the Centre for Sustainable Energy (CSE) has developed modelling tools to help identify rooftops with the best solar PV potential.
CSE works with organisations of all sizes – from city councils to community groups – to help them shape net zero ambitions, set priorities, and put plans into actions. Recently, this included work with Birmingham City Council (BCC) to give an overview of solar potential across the city and help identify specific opportunities.
Using an in-house model and city-wide building data, CSE presented solar PV opportunities on geographic information system (GIS) maps, a tool that blends maps with local data to visually see information about a location. This provides evidence which can support solar PV strategies.
Solar PV panels are attached to roofs and convert energy from the sun into electricity for the building below. Any surplus electricity is exported to the grid. Electricity from solar PV has significantly lower associated carbon emissions than electricity generated by burning fossil fuels. As solar PV is generated and used on site, it’s a more efficient way to use energy (in terms of distribution losses) and can help to reduce the building’s energy bills.
Many cities have, or are in the process of creating, net zero plans. Installing solar panels onto homes and non-residential buildings can help meet net zero targets and transform how cities use energy by reducing carbon emissions and reducing electricity costs simultaneously.
Modelling city-wide solar potential
Identifying the best locations for solar PV installations in order to plan a city-wide rollout requires a lot of data. Data such as where the buildings are, who owns them, and the pitch and orientation of the roof play a part in evaluating how viable solar PV is. Analysing each potential building one by one can be time consuming, tedious, and difficult to track.
The value lies in being able to model this at scale. CSE’s in-house methodology draws on city-wide building data to identify buildings most suited for new solar installations, providing visual GIS maps to highlight their location. Further information generated by modelling data, such as estimates for return on investment, maximum PV generation and m2 of roof space can be used to rank buildings or areas.
This modelling paints a clear picture of what is achievable and provides valuable evidence to support city-wide solar PV strategies. Maps and data tables can be generated to demonstrate rooftop potential under different scenarios, making them easier to compare, and improving the likelihood of buy-in from investors and the community.
Assessing solar potential in Birmingham
As part of the 3D project with Birmingham City Council, CSE was able to:
Develop solar PV mapping and share data for Castle Vale, Bromford and Acocks Green wards
Analyse feasibility of solar PV on 1,800 individual BCC owned buildings
Run modelling to estimate total potential solar PV for the city and for each of the 69 wards
This table shows some high level analysis of solar PV potential across the whole of Birmingham. Using this (and more granular) data makes it easier to understand generation potential and how much CO2e could be saved each year. The totals above do not include roofs where the property type was not known (including these properties would bring the total potential capacity up to 1,097 GWh/year).
Potential capacity (MW per year)
Potential capacity (GWh per year)
Estimated CO2e saving tonnes per year (total)
CSE carried out more detailed analysis for several neighbourhoods in the city, generating data for maps, including solar PV potential for different property types.
This type of modelling shows the location of the most suitable buildings to target solar installations, and provides information on how to maximise overall generation capacity.
Solar PV data can also be used for planning installation schemes, by estimating how many installations, panels, and how much roof space would be needed to reach a given target for MWh of electricity generation, and how that could be broken down to year-on-year installation targets.
It can be difficult for city councils and local authorities to demonstrate the impact of renewable energy and visualise outcomes, particularly during the initial planning stages. The information provided by this sort of modelling can really help with developing tangible plans for achieving net zero.
The bigger picture
CSE’s community carbon footprint calculator estimates total emissions for Birmingham are 6,027,959 (t CO2e) per year. If all potential roofs had solar PV installations, total emissions for the city would be reduced by 3%. This is significant, despite seeming like a small percentage. However it does highlight the importance of energy efficiency improvements alongside renewable energy generation so that when solar panels are installed, carbon savings will add to initial savings made through energy efficiency measures.
For this reason, solar modelling should generally be seen as part of a larger retrofit plan, whether that is for a city, a street or an individual building. Retrofit refers to any improvement work to make a building more energy efficient. In general, installing renewable energy technologies (like solar PV) would follow basic maintenance and thorough energy efficiency improvements – including tackling draughts, fixing leaks, installing controls and timers, and - crucially - ensuring the building is fully insulated.
Everyone plays a role in this, and several of the community projects supported through 3D have worked on projects to improve understanding, support shifts to more energy saving behaviours, put in low carbon improvements, and also encourage homeowners and owners of local buildings to analyse their own places.
Interested in solar PV planning for your city? Contact us.
This solar PV planning was part of a project funded through the ICLEI Action Fund and managed by CSE. 3D was developed to work alongside Birmingham City Council, local stakeholders and community partners to decarbonise Birmingham and reduce emissions through long-term solutions.