Solar farms are among the most familiar renewable energy assets in the UK countryside, and one of the most common ways private investors put money into green energy. Compared with many alternative assets, the basic idea is easy to grasp: panels on leased land generate electricity, the electricity is sold, and investors share in the proceeds. The details, though, make a big difference to how predictable those proceeds are. This guide explains how solar farm investment works and what to look at before committing. It forms part of our wider guide to green energy investment in the UK.

How a solar farm earns money

A ground-mounted solar farm is typically built on farmland leased from a landowner for a long period, often 25 to 40 years. Once connected to the grid, it sells the electricity it generates. How it sells that power determines how stable its income is:

  • Power purchase agreements: the farm agrees to sell its output to a utility or a large business at an agreed price, often for many years. This gives predictable revenue.
  • Government-backed contracts: larger projects may win a Contract for Difference, which tops up or claws back revenue so the project effectively receives a fixed strike price for its power.
  • Wholesale market: some projects sell power at prevailing market prices, which can be very profitable when prices are high and painful when they fall.

Older solar farms built before 2016 may also receive subsidies under schemes that have since closed to new projects. These can provide a valuable index-linked income for their remaining term.

Output, weather and panel degradation

Solar output in the UK varies through the year, peaking in summer and falling sharply in winter, and from one year to the next with the weather. Project forecasts are usually based on long-term irradiance data, with an expected or "P50" figure and a more cautious downside case. It is worth knowing which one a projected return is based on.

Panels also lose a small amount of efficiency each year as they age, typically around half a percent a year for modern panels. Inverters and other equipment need replacing during a project's life. A realistic financial model allows for both.

How private investors invest in solar

Solar bonds

The most common route is a bond issued by the company that owns one or more solar farms. You lend money for a fixed term and receive interest, often with capital repaid in instalments over the term rather than all at the end. This works much like other fixed income investments, with the key question being whether the project's revenue comfortably covers the interest and repayments.

Community solar shares

Community energy groups raise money for local solar projects by issuing shares in a community benefit society. These usually pay a modest return, prioritise local benefit, and can typically only be withdrawn at the society's discretion after a minimum holding period.

Equity and funds

Some opportunities offer shares in a solar developer or portfolio owner, or exposure through listed renewable energy investment companies. Equity can benefit more if projects outperform, but it also absorbs losses first.

Operating versus development projects

One of the most important distinctions is whether the solar farm already exists. An operating project has a track record of output, a grid connection and signed contracts. A development project still faces planning, grid connection and construction risk, and grid connection delays in particular have become a major issue for new UK projects. Development opportunities may offer higher target returns to compensate, but the risk of delay or failure is materially greater.

What to check before investing

  • Project status: operating, under construction or still seeking consent and a grid connection.
  • Revenue basis: how much income is fixed by contract or subsidy, and how much depends on wholesale prices.
  • Forecasting: whether projected returns rely on average output or more conservative assumptions.
  • Land lease: the remaining lease term, and what happens at the end.
  • Security and ranking: whether a bond is secured on the project, and where it ranks against bank debt.
  • Diversification: one site carries more risk than a portfolio spread across locations and technologies.
  • Regulation: whether the platform is FCA-authorised or operating under an exemption, and what protection that gives you.

Who solar investment tends to suit

Solar investments generally suit people looking for income linked to a real, operating asset, who are comfortable committing money for the full term. Many commercial solar bonds are only available to investors who self-certify as sophisticated or qualify as high net worth. You can see how solar compares with other green energy routes on our green energy investment hub, and read about the wider risks of the asset class in are alternative investments safe?

This article is general information only and does not constitute financial advice. Solar investments can lose value, returns depend on project performance and power prices, and your capital may be locked in for the full term. If you are unsure whether any form of alternative investment is right for you, seek independent advice from an FCA-authorised financial adviser.