Solar Panels for Dairy Farms

Why dairy farms suit solar

AHDB says the use, and therefore cost, of electricity dominates fixed equipment energy use on a dairy farm, with milk cooling, water heating and vacuum pumping the most energy intensive processes (AHDB).

Source: AHDB. Separately, AHDB says the vacuum pump accounts for about 20 to 25% of energy use on a normal dairy farm (AHDB).

Milking times and solar output

Panels produce most around the middle of the day, and far more in summer than in winter. Milking often happens early in the morning and late in the afternoon. So the fit depends on the farm:

• Robotic milking. Spreads milking through the day and night, so some of it always falls in daylight
• Twice-a-day parlours. Summer milkings sit in daylight; winter ones often don't
• Cooling after milking. Bulk tank cooling carries on after milking ends, into the daylight hours
• Water heating. Can often be timed for midday to use solar rather than cheap night power
• Day and night tariffs. AHDB advises understanding your tariff and using day and night rates well; solar changes that sum

AHDB recommends metering the three big users separately so you can see the pattern (AHDB). Twelve months of half-hourly data does the same job for the whole farm.

Asbestos and fibre cement parlour roofs

Many older parlours and sheds have fibre cement roofs that may contain asbestos, are often fragile, and may not take the weight of panels. The options are overcladding, replacing the roof, or using a newer building or the ground. Our guide to asbestos cement roofs covers each, and ground-mounted solar covers arrays on spare land.

Batteries for early and late milkings

A battery charged by midday output can run the evening milking and cooling. Whether it pays depends on how much surplus the farm has at midday, the size of the herd and the price you pay for night-time electricity. If the farm already uses most of its solar output in the day, a battery adds little. See commercial battery storage.

Grants and tax relief

Farm grant schemes open and close; our farm solar grants page lists what was open in each nation when we checked. A farm business that buys the system can usually claim capital allowances. Rooftop solar is left out of business rates valuations in England, Scotland and Wales until 2035: see business rates. For the wider farm picture, see solar for farms.