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Join us

This is our 288 kW array on a food factory in Shropshire.

With your help we can roll out our ambitious programme of new solar on buildings across the UK.


From factories to schools, leisure centres to steelworks, golf clubs to community centres, we have over 40 sites signed up and ready to build over the next 2 years. By buying shares you can help us to get them built – and have a significant impact on rooftop solar in the UK.

We’ve made it simple to buy shares – here’s the deal:

  • You can invest any amount from £100 up to £100,000.
  • You can opt to receive annual interest payments or reinvest your interest
  • Our target annual interest rate is 5% (or 2% above Bank of England base rate at times when that’s higher)

For each £1000 invested we can build enough new solar to:

  • Power an average house’s electricity needs for 4 months
  • Drive 3000 miles in an electric car
  • Push enough gas-generated electricity of the grid to save 1/2 a tonne of CO2 – that’s about 15% of your personal carbon footprint

And that’s just in year one – the panels will keep doing that every year for 30 years.

For all the details see our share offer document:

Investing is easy via the secure online form – you can pay by credit or debit card, bank transfer or cheque. If you prefer a paper application form you can download this here.

In joining us you’ll be in good company: we have over 450 Investor Members from all over the UK who have collectively invested over £1.2 million.

Here’s our latest update session from June 2024 with lots about our latest projects

If you have further questions before investing then please have a look at our Investment FAQ or email

Not ready to invest yet? Why not sign up to our mailing list and follow our progress:

More than one type of return

We are offering different kinds of return on investment:

Environmental: we are a carbon-first initiative and our primary concern is to fight the climate crisis. By joining and supporting the Big Solar Co-op you can be making an even larger contribution to decarbonisation than you could by investing in solar at home.

Social: you will be joining an organisation that is bringing a new model to solar, involving many more people directly in practical action. Our panels are reducing energy bills for a range of sites, from industrial users to public buildings. We’re working to bring co-operatively-owned solar to places which are less sunny and less wealthy, with all our surplus re-invested in solar.

Financial: Our interest rates are competitive and your investment in Big Solar Co-op is designed to  be flexible so it is easier to get your money out if you need it.

Invest your time

The Big Solar Co-op has been created from the ground up to enable volunteers to be more effective in fighting the climate crisis. So if you have any time to spare, there are lots of things we can do together, within a supportive and effective organisation – get involved!