Can Solar Panels Power a Whole Farm? Month-by-Month Output

It is the question behind almost every enquiry about solar panels for farms: could the panels on the sheds run the whole place? The honest answer has two halves. Measured over a year, a well-sized array can generate as much electricity as many farms consume. Measured month by month, no UK farm array can carry a farm on its own, because British sunshine is heavily seasonal. The size of that swing — and how it lines up with what your farm actually runs — decides how much of your bill solar can take.

This guide uses real generation data rather than rules of thumb. Every figure below comes from the European Commission’s PVGIS tool (version 5.3, SARAH3 satellite data for 2005–2023), queried on 26 September 2026 for 1 kWp of rack-mounted crystalline panels facing due south, with 14% system losses.

How much a farm roof generates in each month

The table shows kilowatt-hours generated per kilowatt-peak (kWh/kWp) in each month for two farming areas and two roof pitches: a shallow 10° roof, typical of portal-frame sheds and grain stores, and a steeper 30° roof.

Month	York, 10° roof	York, 30° roof	Exeter, 10° roof	Exeter, 30° roof
January	21	33	27	39
February	35	47	43	56
March	70	83	78	90
April	103	111	113	120
May	123	124	130	130
June	120	118	131	128
July	121	120	130	128
August	106	110	111	114
September	78	88	86	95
October	47	59	54	66
November	26	38	33	46
December	17	29	22	33
Year	868	960	957	1,045

Source: PVGIS v5.3 (EU Joint Research Centre), queried 26 September 2026. Monthly values are rounded, so they may not sum exactly to the annual figure.

The seasonal swing is the whole story

Look at the first column. A 10° roof near York makes about seven times as much electricity in June as in December (120 against 17 kWh per kWp). Near Exeter the ratio is about six to one. Further north it is steeper: the same roof near Aberdeen produces 119 kWh per kWp in June and only 10 in December — nearly twelve to one.

Put differently, the April-to-September half of the year produces about 75% of a shallow York roof’s annual output (73% near Exeter, 78% near Aberdeen). The three darkest months, November to January, produce only about 7% of the year’s total on that same roof.

For a concrete example, a 50 kWp array on a 10° barn roof near York would generate about 43,400 kWh over a year (50 × 868). In June that is roughly 6,000 kWh (50 × 120); in December, about 850 kWh (50 × 17).

Why roof pitch matters more on a farm than people expect

Steeper roofs flatten the curve. Moving from a 10° to a 30° roof near York adds about a tenth to annual output (960 against 868 kWh per kWp), but the gain is concentrated in the months when it is most useful: December output rises from 17 to 29 kWh per kWp, and the November-to-January quarter goes from about 7% to about 10% of the year. If a farm has a choice between a shallow general-purpose shed and a steeper south-facing roof, the steeper roof usually gives the better year-round match — before any other factor is considered. The trade-offs by building are covered in our farm buildings guide.

Matching the curve to how your farm uses power

Whether solar can “power the farm” really means: how much of the electricity you buy could be replaced by electricity you generate at the same time you need it? That depends on your load shape, which only your half-hourly meter data can show. In broad terms:

• Summer-weighted loads — ventilation in livestock housing, cooling, irrigation pumping and early harvest work — line up well with the solar curve. These farms can use a high share of what they generate.
• Year-round loads — milking and milk cooling on a dairy, feed systems, workshops — use solar well in summer but still need the grid through the winter months when output is a fraction of its peak.
• Winter-weighted loads — heated buildings, winter lighting, lambing-shed demand — are the weakest match. Solar will cover little of that peak, so size the array to the rest of the year rather than to the winter bill.

Electricity you generate but cannot use is exported. You can be paid for it under the Smart Export Guarantee if you have an export tariff, but an export tariff is typically worth less than the import price you avoid by using the power yourself — which is why sizing to daytime use, not to roof area, is what makes the numbers work.

What batteries can and cannot do

A battery moves solar energy from the middle of the day into the evening and night — useful for milking times, night ventilation and evening yard lighting. What a battery cannot do is move June’s surplus into December. The seasonal gap in the table above is measured in months, and farm batteries are sized in hours. For how batteries fit farm load profiles, see our farm battery storage guide.

So how big should a farm’s solar array be?

Start from the data, not the roof:

1. Pull 12 months of half-hourly consumption from your supplier. It shows exactly when the farm uses power across the day and the year.
2. Overlay a generation profile for your postcode (PVGIS gives this free) for each roof you might use.
3. Size to the daytime load you can realistically use, especially in the summer half, and treat export as a bonus rather than the business case.
4. Choose the roof that best fits the curve — often the steeper south-facing roof, if the structure and sheeting allow.
5. Check the grid route early. Practically every farm array needs a G99 application; see G98 and G99 explained for farm solar.

The panels matter too: modules on or near livestock buildings should be tested for ammonia corrosion, and coastal farms should look for salt-mist certification — both explained in our guide to choosing farm-grade solar panels.

The bottom line

Solar panels will not power a whole UK farm through the year on their own, and anyone claiming otherwise should be asked for their December figures. What they can do is supply a large share of a farm’s daylight electricity from spring to autumn, at the times many farms use the most. Built around real consumption data and the right roof, that is where the value of farm solar lies.