Commercial solar in Wales

Commercial solar covers panels on farms, businesses and community buildings. The roof or land is bigger than at a home, and so are the planning, grid and finance questions. Welsh rules also differ from the English ones in places.

This page explains what a commercial project involves in Wales and what to ask in a quote. Solar Cymru is an independent guide and enquiry service, and we do not install panels ourselves.

What a commercial solar project involves

Many commercial projects start with a roof, such as a farm building, a business unit or a community hall. Others use ground-mounted arrays in a yard or field. Each route has its own planning and grid steps.

The installer checks the roof, the power supply and how you use energy. Then they size the system to match your demand. Panels make power in the day, so daytime demand matters most.

The MCS standard for solar, MIS 3002, covers systems up to 50 kWp. However, for larger systems, ask each installer which standards they follow. Our post on MCS certification explains what the mark covers.

What affects the price

Our price ranges cover small systems only, because larger projects vary too much. Government data for 2025-26 shows about £1,400 to £1,950 per kilowatt for systems up to 10 kW. The Welsh figures sit inside that range. Larger commercial systems therefore need their own quote.

Several things move a commercial quote. For example, the strength of the roof, the length of cable to your main supply and the kit you choose all matter. The network operator may also need to strengthen the local grid, and it can ask you to contribute.

Tax treatment is a matter for your accountant. Meanwhile, the 0% VAT relief on solar covers homes and buildings used solely for a relevant charitable purpose. Check any other building before you assume a rate.

Planning rules for Welsh businesses, farms and community buildings

Solar on a business, farm or community building in Wales needs no planning application if the conditions are met. There is no kilowatt cap. A 2019 change to the rules removed the old 50 kW limit, yet older research documents still show it, so ignore them.

However, the conditions are strict. The site must not lie within 3 km of an airport or aerodrome. Panels must stick out no more than 200 mm from a wall or pitched roof.

On a flat roof they must rise no more than 1 m and sit at least 1 m from the edge. The rules also exclude listed buildings, buildings in the grounds of one and scheduled monuments.

On designated land, panels cannot go on a wall or roof slope that fronts a highway. That land includes national parks, Areas of Outstanding Natural Beauty and conservation areas. Our post on solar panels in Wales’s national parks covers that point. Our planning permission guide explains the wider rules.

Ground-mounted solar is different, however. A stand-alone array in the grounds of a building is exempt only for the first installation. It must also stay within 9 square metres. As a result, a farm-scale array needs a planning application.

Welsh policy treats grades 1, 2 and 3a farmland as the best and most versatile land. It prefers solar on lower-grade land. Projects from 10 MW up to 350 MW go through the Developments of National Significance process. Smaller schemes go to the local council. Our post on ground-mounted solar and planning looks at this in more detail.

Grid connection and export

Commercial systems often exceed the simple G98 limit of 16 amps per phase, which means 3.68 kW on a single-phase supply. Therefore they follow the G99 route. Under G99 the installer applies to the network operator and agrees the connection before the system starts up.

Sometimes the operator has to strengthen the network before a generator can connect, and it can ask the customer to contribute. For that reason, apply early. National Grid Electricity Distribution serves South Wales and SP Energy Networks serves North Wales. Our post on G98 and G99 in Wales explains the process, and our grid and export guide covers the metering.

Solar up to 5 MW in Great Britain can qualify for the Smart Export Guarantee. Since suppliers set the rates, compare tariffs. Read our post on the Smart Export Guarantee before you sign.

Finance and advice

The Development Bank of Wales Green Business Loan Scheme combines funded consultancy, discounted fixed-rate loans and flexible repayment. In particular, it lists solar PV as a typical eligible project. A grant covers up to 50% of an independent energy audit, up to £10,000. Business Wales Resource Efficiency Advisors give a funded first review.

Meanwhile, farmers can use the Farming Connect advisory service, which includes advice on renewable energy generation such as solar PV. The Development Bank of Wales Sustainable Agriculture Loan Scheme was still in development in October 2026. Our post on solar panels for Welsh farms looks at the farm case. Our solar funding guide covers the household routes.

What a good quote contains

Because projects differ, a good commercial quote names the equipment, the system size in kWp and the expected annual generation. It states the assumptions behind that figure, including shading and roof direction. It also sets out who handles planning, the network application and metering.

Ask about the roof warranty, the structural check and the maintenance plan. Ask what the quote leaves out. Finally, compare at least two written quotes. Our guide to choosing an installer lists more checks.

How the Solar Cymru enquiry works

Use our get quotes page to describe your building and project. Solar Cymru passes the enquiry to MCS-certified installers through the MoreLeadz lead system. An installer then replies about a survey and quote. The step is opt-in, because you decide whether to go ahead.

While we are not an installer, lender or broker, we do cover homes too. See our pages on home solar panel installation and solar battery storage.