Power Purchase Agreements Explained for UK Businesses

Power purchase agreements explained

A power purchase agreement, usually shortened to PPA, is a contract for buying electricity from a renewable energy system at an agreed price over a fixed period. In practice, PPAs are often used by businesses that want the benefits of onsite solar without paying the full upfront installation cost themselves.

For many organisations, that makes a PPA worth considering. Energy costs are a major operating expense, and greater price certainty can be attractive when grid electricity prices are hard to predict. A well-structured PPA can also support carbon reduction goals and make better use of available roof or land space.

Switched On works across solar installation, wind power, EV charging and wider renewable energy solutions in the UK, including support for businesses exploring commercial renewable energy solutions.

How does a PPA work?

The basic model is straightforward.

A developer, funder or energy partner pays for and installs a renewable energy system, often solar PV, at your site. That provider usually owns the system for the length of the agreement. Your business then buys the electricity it generates at a price set out in the contract.

In an onsite solar PPA, the electricity is used directly by your building first, which can reduce the amount you need to import from the grid. If the system produces more than you are using at that moment, the treatment of that excess power will depend on the agreement and the site setup.

The contract term is often long enough to give the provider confidence to invest in the equipment. In return, the business avoids or reduces capital expenditure and pays for generated electricity instead.

Why businesses consider PPAs

Lower upfront cost

The biggest attraction is usually financial structure. If your business wants solar but would rather preserve cash for core operations, a PPA can remove the need to fund the system yourself.

More predictable electricity pricing

A PPA normally sets a pricing method in advance. That may be a fixed rate, an index-linked rate or another agreed mechanism. While no contract removes every risk, it can offer more certainty than relying entirely on grid supply.

Carbon reduction and reporting support

For businesses with net zero plans, ESG targets or customer reporting requirements, using renewable electricity generated onsite can be a practical step forward.

Operation and maintenance may be included

Many PPA structures place system performance, servicing and repairs with the owner of the asset rather than the host site. That can reduce internal management burden, especially when paired with AI monitoring for energy systems to track output and flag issues early.

What types of PPA are most common?

Onsite PPA

This is the model most relevant to commercial buildings, warehouses, schools, farms and industrial sites. The renewable system is installed at your premises, and you use the electricity where it is generated.

Offsite or sleeved PPA

These are more common for larger organisations with higher energy demand across multiple locations. The electricity is generated elsewhere and supplied through a more complex contractual structure.

For many small and medium-sized UK businesses, the onsite model is the most practical place to start.

Key contract terms to check

Not all PPAs are the same, so the detail matters.

Electricity price and review mechanism

Check whether the unit rate is fixed, rises annually by a set percentage or is linked to inflation or another index.

Contract length

Longer terms can improve project economics, but they also reduce flexibility. Make sure the agreement suits your business plans and likely site use.

Performance expectations

The contract should set out how generation is measured, what happens if performance falls short and who is responsible for investigating problems.

Maintenance and access

If the provider owns the system, they will usually need rights of access for inspection, maintenance and repairs. Service standards should be clearly written down.

End-of-term options

A good agreement should explain what happens when the contract ends. That may include extension, removal, transfer of ownership or replacement.

Property and landlord issues

If you lease your premises, you may need landlord consent. Roof condition, structural checks and lease length also matter.

When a PPA makes sense

A PPA can be a strong fit if your business:

• has a building with suitable roof space or land
• uses a good share of electricity during daylight hours
• wants to avoid upfront capital spend
• values price visibility over part of its energy use
• needs a practical route to lower operational emissions

Sites with regular daytime demand often benefit most from onsite solar because more of the generated electricity can be used directly.

If your site is suitable, solar installation services can form part of a wider commercial energy strategy rather than a standalone project.

Potential drawbacks to weigh up

A PPA is not automatically the best option for every organisation.

First, long-term contracts require careful review. If your business may move, downsize or significantly change how the site operates, flexibility matters.

Second, the savings are not always as simple as comparing one electricity rate with another. You need to consider your existing tariff, expected onsite usage, export arrangements and the shape of your demand through the day.

Third, building suitability is crucial. Roof age, structural condition, shading and electrical infrastructure can all affect whether the project works well.

PPA vs buying a solar system outright

If your business has available capital, owning the system can deliver stronger long-term returns because you keep the full financial benefit of the electricity generated.

However, ownership also means taking on the upfront cost, asset responsibility and performance risk. A PPA shifts much of that burden to the provider in exchange for a contracted electricity price and a share of the value created.

There is no universal winner. The right route depends on cash flow, appetite for ownership, tax position, energy profile and property constraints.

Final thoughts

Power purchase agreements can be a practical route into commercial renewables for UK organisations that want lower upfront cost, more predictable energy pricing and progress on sustainability goals. The strongest projects start with a proper site assessment, realistic usage analysis and a careful review of contract terms.

If you are weighing up a PPA, outright purchase or a wider onsite energy project, it helps to talk through the options with an experienced team.

Ready to explore whether a PPA could work for your site? Speak to our commercial team for straightforward advice on the right renewable energy setup for your business.