Your community energy group has money to spend and a neighbourhood full of roofs.
Energy numbers from the , a roof-by-roof solar calculator by the same author; funding modelled on Great British Energy's Community Fund and the Midlands Net Zero Hub's guide to community energy. Every source is credited under About and sources.
Worked example
This is the site on its own, with nothing else installed. In play, a community battery or the substation limit can change the figures. Every number comes from the same model as the game; the assumptions are listed under “The numbers behind the game”.
Where the energy numbers come from
Solar Street's energy sums come from an earlier web app by the same author, the Solar Potential app. This is what it is, how it works, and what Solar Street takes from it.
You pick a building on a map, or draw the outline of an area such as a car park, and the app estimates how much of it could take solar panels and how much electricity they would make in a year. It works one site at a time, using Google's Solar API, which holds roof shapes and yearly sunshine for many buildings in the UK.
It also works out the CO₂ saved, at 0.233 kg per kWh, which matches the UK government's 2020 conversion factor for grid electricity.
| Figure | Value | Where it is in the app |
|---|---|---|
| Panel capacity | 0.2 kWp per m² of usable roof (panels about 20% efficient) | Every step |
| System losses | × 0.85 | Every step |
| A year's output | kWp × full-sun hours × 0.85 | Step 1 |
| Usable share of a flat roof | 60% of the footprint | Steps 2 and 3 |
| CO₂ saved | 0.233 kg per kWh | The app's savings sum |
Solar Street doesn't call the app or Google, and needs no key: it uses the same formula and figures (the app is by the same author) and runs them on its own. It uses none of Google's data. Its roofs are typical buildings in made-up towns, not measured ones, so it uses one sunshine figure for every south-facing roof (1,050 full-sun hours a year, the game's estimate for the English Midlands and south) and a typical roof area for each kind of building. The hour-by-hour year, the batteries, the substation limit and the money are Solar Street's own.
Solar Street is a prototype game about community energy. You play a community energy group with money from a share offer and a GB Energy grant, and a neighbourhood of homes, a school, a community centre, shops, offices and a supermarket. Choose which roofs, car parks and homes to put solar on, keep within the substation's limit, and run the year to see what the plan earns and gives back to the community.
A supermarket roof on its own, as the game works it out.
One of each kind of site in the Town Centre neighbourhood, on its own, best payback first.
These published sources supply figures the game uses. Each is credited for exactly what it provides; where the game rounds or simplifies a figure, any mistake is the game's, not the source's.
Useful for a real project; the game doesn't take figures from these.
Installed costs per kWp, the community tariff (18p), grid price (25p) and export price (12p), running costs, battery and plug-in kit prices, the substation upgrade and community battery, the size of each share offer, members' interest (4%) and repayment (20 years), school term dates and holiday use, sunshine hours, and the demand of shops, schools and other buildings are the game's own estimates of typical 2026 figures. Each is marked "Estimate" under “The numbers behind the game”. Check them against local quotes before relying on them.
Solar Street has no accounts and sets no cookies. Your progress is saved in this browser's own storage and never leaves your device. Everything the game needs, fonts included, comes from this site; it contacts no other service.
Contains public sector information licensed under the Open Government Licence v3.0 (the UK Government's 2020 greenhouse gas conversion factor for grid electricity).
Solar Street is a prototype. It is not affiliated with or endorsed by Great British Energy, the Midlands Net Zero Hub, the Energy Saving Trust, Ofgem, Bath & West Community Energy, the European Commission or any community energy group; their names are used only to credit the figures above.
Neighbourhood 1
Year one
Solar generated each month against what the neighbourhood used. Summer surplus is sold to the grid, or wasted if the substation can't take it.
Click a roof, car park or field to see how much sun it gets, what panels would cost and how quickly they would pay back. Then fit panels, and batteries where they help.
Turn on the sun map (S) to colour every roof by how much sun it gets: yellow is best, purple is poor. A red sign means the owner or the council has said no.
Buildings buy the solar power they use from your group at the community tariff, cheaper than their supplier. Power they can't use is exported to the grid for less. Batteries shift daytime power into the evening, so more of it is sold locally.
The substation can only export so much. On a sunny summer afternoon, anything over the limit is wasted. A community battery soaks up the peak; an upgrade raises the limit.
When you're ready, run the year to see your plan play out, and earn up to three stars. You can always come back and improve it.
Drag to move around, scroll or pinch to zoom. Keys: S sun map, R run the year, Esc menu, arrows to pan, + and − to zoom.
Generation uses the 's formula: panel capacity is 0.2 kWp per m² of usable roof, and a year's output is capacity × sunshine hours × 0.85 for system losses. The CO₂ saving is 0.233 kg per kWh, also from the app. Each row below says where its figure comes from: a published source, credited in full under About and sources, or the game's own estimate of a typical 2026 figure.