DIYenergy via slurry and wind
ONE Pembrokeshire dairy producer is aiming to be as energy self-sufficient as possible by using methane from slurry and wind power.
Wyn Evans produces organic milk from 72 cows at Caerfai Farm, St Davids. Most is used to make up to 5t a year of unpasteurised cheese, with some milk being delivered in green top bottles to local doorsteps.
His interest in energy generation dates back more than 20 years, when he bought a slurry digester and started burning the methane produced to heat water for the dairy and farmhouse.
Whey from cheese processing and sewage sludge from the farms campsite also go into the digester.
An old tractor engine drives a 25kV electricity generator. It is fitted with heat extractors and the energy recovered is either used to stimulate aerobic digestion or transferred to the dairys hot water system.
When visitors to the Welsh Organic Farming and Food Industry Event visited the farm, they were given a demonstration of a biogas fuelled barbecue. They also heard that after a battle to get planning permission Mr Evans would shortly erect the first wind turbine within the Pembrokeshire National Park.
The hub of the rotor of the £50,000 Gazelle machine will be 14.5m (48ft) above the ground and Mr Evans had to seek approval from two neighbours to site the 20kW machine in the most favourable location.
Surplus electricity will be sold and he hopes to recover his total investment within seven years.
"My interest in wind power was prompted by concern about climate change, but I am also worried about what is likely to happen to fossil fuel prices," he said.
"I hope that adding the turbine to other energy generation and conservation measures will allow me to milk cows, make cheese and deliver it within a 30 mile radius without using oil."
Farm generated electricity could also be used to produce barn-dried hay, he added. *
• Methane from slurry.
• Wind power.
• Power for milking.