Export Tariffs for Commercial Solar Explained

A commercial solar proposal can look highly attractive until the conversation reaches the electricity your site does not use. Export tariffs for commercial solar determine what happens to surplus generation sent back to the grid, and the difference between a well-matched agreement and a poor one can materially affect a project’s return.

For most businesses, the first financial priority is still using solar power on site. Every kilowatt-hour used directly can avoid buying electricity at the applicable import rate, including the non-energy elements bundled into the bill. Export income is valuable, but it should be treated as part of a wider energy strategy rather than the main reason to install solar.

What is an export tariff for commercial solar?

An export tariff is the rate paid for electricity generated by a solar PV system and exported to the public grid. It is normally measured in pence per kilowatt-hour and paid by an energy supplier, although the contractual structure can vary considerably for larger sites.

For smaller commercial installations, an export arrangement may resemble the Smart Export Guarantee, or SEG, market. Suppliers set their own rates and eligibility criteria, rather than paying a single standard rate. For larger systems or more complex businesses, a supplier may offer a bespoke export agreement, an export power purchase agreement, or a rate linked to wholesale market prices.

The practical question is not simply, “What export rate can we get?” It is, “How much will we export, when will we export it, and does the tariff structure suit our risk appetite?” A business that exports mainly during low-price midday periods may see a very different outcome from the headline rate used in an installer’s illustration.

Why self-consumption usually matters more

A unit of solar electricity consumed behind the meter offsets a unit that would otherwise have been bought from the grid. Depending on the supply contract, that avoided cost is often substantially higher than the export payment available for the same unit.

Consider a site buying electricity at 25p per kWh and receiving 8p per kWh for export. Using one extra kWh of solar generation on site is worth roughly 25p in avoided import cost, while exporting it earns 8p. The exact figures will change by contract, location and market conditions, but the principle remains the same.

That is why system sizing needs care. Oversizing a solar array can still be sensible, particularly where future electricity demand is expected to rise through EV charging, electrified heating or business growth. However, it should not be justified on an assumed export income figure without a clear understanding of the tariff and likely export profile.

Load-shifting can also improve the economics. Scheduling equipment, refrigeration, battery charging or certain production processes to run during daylight hours may increase self-consumption. This must be operationally realistic. A theoretical saving has little value if it disrupts production, staff routines or customer service.

The details that can change export income

Commercial export rates are not directly comparable unless the contractual terms are comparable too. A fixed rate provides certainty, while a rate indexed to wholesale prices can rise and fall. Neither is automatically better.

A fixed tariff may help with budgeting and make a solar business case easier to approve. A variable tariff may offer stronger returns at times, but it introduces market exposure. Some arrangements use half-hourly settlement data, which can more accurately value exported power but requires suitable metering and more active contract management.

Businesses should also check whether the quoted price is available for the full expected export volume, whether there are minimum or maximum thresholds, and whether the supplier can change the rate during the agreement. Payment frequency matters too. Regular, transparent credits improve cash-flow visibility, whereas unclear billing can leave finance teams chasing payments that were assumed in the project model.

The following points deserve attention before accepting an export agreement:

• whether the rate is fixed, variable or linked to a market index;
• the contract term, notice period and any termination conditions;
• how export is metered, validated and shown on invoices;
• whether the supplier requires your import supply contract to sit with them;
• any caps, eligibility rules or charges that reduce the effective rate.

These terms can be more important than a modest difference in the advertised pence-per-kWh rate.

Metering, permissions and data quality

Export cannot be paid accurately without the right metering arrangement. In many cases, a smart meter or half-hourly capable export meter is required to record the electricity leaving the site. Older meters may not measure export properly, may register it incorrectly, or may need replacement before payments can begin.

Grid permissions are equally important. Before installation, the distribution network operator must be involved to confirm how much generation can connect and whether export capacity is restricted. A site may be allowed to install solar but have a limit on how much electricity it can export at any one time.

Where export is constrained, the project may need an export-limitation scheme, battery storage or a revised system design. This is not necessarily a reason to abandon solar. It simply changes the financial model. A business with strong daytime demand may still achieve excellent savings with a restricted-export arrangement because much of the generation is used on site.

Accurate half-hourly consumption data makes these decisions more reliable. It shows when the business consumes power, where solar output is likely to overlap with demand, and how much surplus is realistic. Without it, projected export volumes are often broad estimates rather than procurement-quality forecasts.

Should your import and export contracts be with one supplier?

Keeping import and export with the same supplier can reduce administration. It may simplify billing, meter registration and queries over settlement data. Some suppliers also make their best export propositions available only to import customers.

However, convenience should not prevent a proper comparison. A more attractive export rate can be outweighed by a weaker import tariff, higher standing charges or unsuitable contract terms. Import electricity is usually the larger spend, so it remains the more significant procurement decision for most organisations.

There can also be timing issues. A business may be tied into an existing electricity contract when the solar system is commissioned. It should establish whether export can be arranged separately, whether the current supplier accepts it, and how the export agreement interacts with any planned renewal. Leaving this until the panels are generating can delay payments and create avoidable administration.

For multi-site organisations, the answer may differ by location. One site could have high on-site usage and negligible export, while another has a large roof, low weekend demand and significant surplus generation. A single portfolio approach should still account for each site’s load profile and network constraints.

Building an honest commercial solar case

A credible solar appraisal separates savings into clear categories: reduced imported electricity, expected export income, operating and maintenance costs, funding costs where relevant, and any battery or network expenditure. It should show the assumptions behind each number rather than relying on a single headline saving.

Sensitivity testing is useful. Ask how the payback changes if export rates fall, electricity import prices change, generation is lower than forecast, or business operating hours shift. This is especially relevant for firms with seasonal activity, flexible working patterns or plans to relocate.

Battery storage can improve the use of solar generation, but it is not automatically the right answer. It adds capital cost and its value depends on tariff structure, demand profile, export limits and the opportunity to avoid peak-time imports. In some cases, modest export income is preferable to buying and maintaining a battery that does not cycle enough to justify its cost.

The strongest projects are designed around the site’s energy needs first, then supported by a sensible export route. That approach avoids treating surplus electricity as a guaranteed profit stream and keeps the focus on controllable, long-term reductions in purchased energy.

Before committing, make sure the solar forecast, connection agreement and energy contracts all tell the same story. A clear export arrangement will not replace sound system design, but it can ensure that the electricity your business cannot use still contributes fairly to the investment.

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