How much electricity does a dairy farm use? kWh per cow, per litre and per parlour

Before you size a solar system for a dairy farm, you need to know how much electricity the farm uses. UK benchmarks are published as kWh per cow per year, and the two sources we could read and date agree on the order of magnitude but not the detail. This page sets them side by side, shows what they mean for herds of different sizes, and says what they do and do not tell you.

kWh per cow: what the published benchmarks say

AHDB and NFU Energy, in a webinar Q&A on reducing dairy electricity costs (17 March 2021), gave 400 to 600 kWh per cow per year as a typical range and described 250 to 300 kWh as very low. An older benchmark comes from the Dairy Group, as reported by Farmers Weekly on 5 November 2014: an average of 423 kWh per cow per year across a range of 231 to 811, which works out at 0.06 kWh per litre of milk (range 0.03 to 0.09).

Source	Date	kWh per cow per year	kWh per litre
AHDB and NFU Energy webinar Q&A	17 March 2021	400 to 600 (250 to 300 described as very low)	not given
Dairy Group, reported by Farmers Weekly	5 November 2014	423 average (231 to 811)	0.06 average (0.03 to 0.09)

These are published benchmarks, not measurements of your farm, and we found no per-cow figure specific to robotic herds in the sources we read.

What it works out at for a herd

The arithmetic is cows multiplied by kWh per cow. The middle column uses the Dairy Group average and the outer columns the ends of the AHDB and NFU Energy range.

Cows in milk	At 400 kWh per cow	At 423 kWh per cow	At 600 kWh per cow
100	40,000	42,300	60,000
200	80,000	84,600	120,000
300	120,000	126,900	180,000
500	200,000	211,500	300,000

Per litre, the same Dairy Group average of 0.06 kWh means a farm selling 1,000,000 litres a year would use about 60,000 kWh.

Where the electricity goes

The same Dairy Group study, as reported, found that cooling, water heating and vacuum pumps each took roughly 25 to 30% of a dairy's electricity. Together those three loads took most of it, with lighting and the rest of the equipment sharing the remainder. Milk cooling follows each milking, hot water is needed to wash the plant after milking, and vacuum pumps run while the herd is milked, so the timing of the load follows the milking times.

Parlour or robots

A conventional parlour milked twice a day has its cooling, hot-water and vacuum loads concentrated around the two milkings. A robotic herd is milked through the day and night, so its load is spread across 24 hours. The benchmarks above do not separate the two, and we did not find a per-cow figure for robotic herds in the sources we read, so a robotic farm should use its own half-hourly meter data rather than these averages.

What it means for a solar system

Annual use is the starting point, not the answer. As arithmetic only: a 100-cow herd at 500 kWh per cow uses 50,000 kWh a year. PVGIS estimates for a south-facing 35 degree roof with 14% system losses give about 886 kWh per kWp a year in Manchester, 965 in Liverpool, 968 in Birmingham, 981 in Leicester and 1,042 in Cardiff, so an array of roughly 52 kWp in Birmingham would generate about 50,000 kWh over a year. That does not mean the farm would use all of it. Solar generates in daylight, while cooling, hot water and (on a robotic unit) milking continue outside it, and whatever the farm cannot use is exported at the Smart Export Guarantee rate rather than saving the full price of imported electricity. For that reason the array with the best return is usually smaller than the annual match. The what size solar system for a dairy farm guide sets out the annual-match figure by herd size, and the dairy farm solar calculator lets you vary the share of output the farm uses.

For the money side, read dairy farm solar grants for what funding was open when we looked and the dairy farm solar panel cost guide. When you have your own figures, send an enquiry and we reply by email.

Sources, and what we did not check

• AHDB and NFU Energy, Reducing dairy electricity costs: webinar Q&A, 17 March 2021, read 31 October 2026.
• Farmers Weekly, Simple steps to energy efficient dairy farming, 5 November 2014 (Dairy Group figures), read 31 October 2026.
• PVGIS v5.3 (SARAH3), 35 degree tilt, due south, 14% system losses, run for the cities named between 18 and 30 October 2026.

We have not checked these figures against farm meter data, and we did not find a per-cow benchmark for robotic herds. Your own bills beat any benchmark.