Low & zero-carbon electricity

On-site solar PV

Rooftop or ground-mounted solar is the most accessible form of self-generation for businesses. Panels produce most in the middle of the day and in summer, which suits premises that are busy in daytime hours: offices, warehouses, shops, workshops, farms and cold stores.

The economics are driven by self-consumption. Every unit you generate and use yourself displaces a unit you would otherwise buy at your full retail rate, including network charges and levies. Surplus exported to the grid earns much less per unit under export arrangements. So a system sized to your daytime baseload usually pays back faster than one sized to fill the roof.

Before you get quotes

• Roof condition and lease. Panels last 25 years or more. If the roof needs replacing within that time, do it first. Tenants need landlord consent, and the lease should cover who owns and maintains the system.
• Structural survey. Some lightweight industrial roofs can't take the extra load without reinforcement.
• Grid connection. Larger systems need approval from the distribution network operator, which can take time and, in constrained areas, may limit export.
• Planning. Many rooftop installations are permitted development, but there are limits and exceptions (listed buildings, conservation areas, larger ground-mount arrays).
• Your half-hourly data. A credible installer should model generation against your actual demand profile, not an average.

If you lack capital, some providers offer "rooftop PPAs" where they install and own the system on your roof and sell you the power at an agreed rate, usually below grid prices. You avoid upfront cost but share the savings and sign a long contract.

Battery storage

Batteries store electricity for use later. For businesses they can:

• soak up surplus solar at midday and release it in the evening;
• charge on cheap off-peak rates and discharge at peak times;
• reduce peak demand to help avoid capacity upgrades, for example when adding EV chargers;
• in some cases, earn revenue by providing flexibility services to the grid.

Batteries do not generate energy and lose some in each charge cycle, so they only make financial sense where there's a meaningful price difference to exploit or a capacity constraint to solve. Model them carefully and be sceptical of projections that stack every possible revenue stream. Fire safety, siting and insurance also need attention.

Wind

Wind can generate more per pound than solar on a good site, and it produces more in winter and at night, complementing solar. But on-site wind is much more site-specific. It needs consistently strong, unobstructed wind, which rules out most urban and sheltered locations; a small turbine in turbulent air produces disappointingly little. Planning, noise, visual impact and ecology assessments are more involved. Farms and rural industrial sites with space and exposure are the typical candidates. For most businesses, the practical way to use wind power is to buy it through a PPA or from a supplier that sources it credibly.

Power purchase agreements (PPAs)

A PPA is a long-term contract to buy electricity from a specific generator, often a solar or wind farm, at an agreed price or price formula, typically for 5–15 years or more.

PPAs can offer long-term price certainty and a strong claim of "additionality" when they help finance a new project that otherwise wouldn't be built. They are, however, usually suited to larger consumers because of contract size, credit requirements and legal complexity. Aggregated or "consortium" PPAs let groups of smaller buyers share a single deal. Price risk works both ways: if market prices fall below your PPA price, you pay more than you otherwise would.

Green tariffs and the REGO caveat

The simplest option is a "green" or "100% renewable" tariff from your supplier. It's easy to switch to and usually costs little or nothing extra. But it's worth understanding what you're buying.

In Great Britain, renewable generators receive Renewable Energy Guarantees of Origin (REGOs), one per megawatt-hour generated. Suppliers can match customers' consumption with REGOs to label a tariff as renewable. The catch is that REGOs can be bought separately from the electricity itself, often cheaply. A supplier can therefore buy ordinary wholesale power and a bundle of low-cost certificates, and market the result as 100% renewable, without any additional renewable generation being built.

If you want your purchase to count for more, ask a supplier:

• Do you buy the power and the REGOs together from the same generators (bundled), or separately?
• What proportion comes from long-term contracts with named UK generators?
• Do you invest in or help finance new generation?
• Can you provide a fuel mix disclosure specific to this tariff?

For carbon reporting, the GHG Protocol allows "market-based" Scope 2 figures that reflect contractual instruments such as REGOs, alongside "location-based" figures using the average grid factor. Reporting both is good practice and avoids over-claiming.

Comparing the options

Many businesses combine approaches: solar on the roof for daytime load, a battery if it clearly pays, and a credible green tariff or PPA for the rest.