Look up London! A day (or so) in the life of a solar energy roof-spotter

The future of our city is solar – and you can play your part by identifying new sites that are right to host community-owned solar panel installations. A veteran Lambeth Solar Energy volunteer explains how it’s done 

It’s actually 6pm the night before, when my latest roof-spotting journey begins and I join a volunteer call on Zoom for Lambeth Community Solar (LSC). This is one of eight community energy co-operatives supported by Repowering London in London. On the call there are lots of familiar faces but also a couple of new ones, which is great, so we do introductions. Even though everyone lives within a couple of miles of each other we all have different reasons for getting involved with community solar energy, and varied levels of experience. 


We talk through our progress – engineers have just visited one site, a community hall, to complete a feasibility study that will tell us whether the roof is suitable for solar panels. If it is, this will lead to a community share offer and a new source of local, green power – a big win. But we need more sites! 


We brainstorm – talking through different types of building and particular neighbourhoods. Some of us have had roof-spotting training from Repowering London, so we’ve got a good idea of what types of roof will work and which types of building would be best. I agree to spend a bit of time focusing on schools, someone else takes GP surgeries, another person will focus on leisure centres. Another person has their eye on a row of warehouses with huge roofs that they spotted from the train (top tip: trains and buses offer a great vantage point for solar roof-spotting).  


After the meeting and through the magic of the internet, I find a complete list of schools in Lambeth on the council website. I’m surprised to find there are hundreds. Exciting, but daunting too. Tomorrow, I’ll need to prioritise! 



I decide to do the initial prioritisation by size. Bigger schools should mean bigger rooftops and greater impact. The school list has pupil numbers so I use that. For now, I separate out independent schools as I figure they probably have enough resources to fund an installation of solar panels themselves (we can then support schools that need our help the most). I make a note to come back to these later. I now have a top 20 to focus on. The next step is to check out some roofs. 



I fire up the London Solar Opportunity Map. This is a great resource that estimates the solar potential of building roofs, based on their size and orientation (pitched south-facing roofs get the most sun). I have Google Maps running too, so that I can see the satellite images. This identifies a few schools that look to have great potential, based on the guidelines suggested by Repowering London, but they already have solar panels! There are also a few roofs that look to have a few obstructions, that could complicate things later so I scratch them off my list.  


One of the schools that I check out is where my children go to school. The map shows potential of more than 40,000 kWh per year, meaning around 6 tonnes of CO2 could be avoided each year!



I drop a message to the LSC volunteer Whatsapp group asking if anyone knows anyone in the handful of priority schools I’ve identified. It’s important to take advantage of our local networks, as cold emails often get lost. Sometimes it’s hard to know the right person to contact, and even if you find them, the offer of solar panels can look too good to be true and the email can be binned as spam. I get a couple of messages back. Someone’s housemate works at one of the schools, the second has a nephew studying at another.  


As I’m a veteran volunteer and know the ropes, I am confident to draft some short emails setting out the key terms of what we can offer: closer relationships with the community, no investment required, a saving on their bills and a contribution to decarbonising Lambeth. I send these out, including one to the Head of my kids’ school.  

If you are new to roof-spotting, Repowering London is happy to hear about potential you’ve found and make the initial approach to the owner or occupier. 



I go to pick up my kids. At the school gates, I mention the email I’ve sent to the Head who seems interested and says they will take a look and get back to me. Sounds promising. 



My phone buzzes. Another volunteer who has been looking into the local warehouses has had a breakthrough. He’s set up a call with an interested energy manager to go through how things might work. 



I get an email from the Head of my kids’ school, copying in the facilities manager. They are keen to find out more about the potential for installing solar panels. More progress! I message the volunteer group, feeling excited about what happens next. All in all, a really satisfying day of solar roof-spotting. 


About Alex: Alex Howard has been a member of and investor in Lambeth Community Solar since 2019 and a volunteer roof-spotter since 2021 

If you’d like to learn more about how to get involved in finding new solar sites in your area, see our Roof-spotter’s Guide as a first step. Or, if you are a site owner who would like to find out whether your roof could host community solar, email us today. 

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