Homes in a new Pembrokeshire eco-village could fuelled by cow dung.
The plans to pipe methane gas from a dairy are part of the winning design for the Lawrenny EcoVillage Project near Pembroke Dock.
The designs were selected earlier this week after a competition to build a carbon-neutral village.
The news will also be welcome relief to local people after the 35% rise in British Gas prices announced on Wednesday.
The proposed 30 homes will be supplied with gas from a huge vat which will collect the cattle's waste.
While it takes just 30 cows to produce a tonne of dung a day, the energy plan will see the village's existing cow herd double to 350 to ensure enough end product.
The new power system relies on bacteria breaking down cow pats in an enclosed tank, which in turn releases methane - the largest component of ordinary natural gas pumped into people's homes.
Owen Lort-Phillips, who runs the dairy, said the herd would be placed on a special diet to maximise its output.
He said it was hoped the system would meet all Lawrenny's power needs with some of the methane supplied directly as gas and the rest used to power an electricity generator.
"It is unlikely we will be able to take the houses off the national grid because we will be relying on cows and something could go wrong," he said.
"But there is the potential to be self-sufficient and that is the aim."
Lawrenny is located within the Pembrokeshire National Park on the banks of the River Cleddau and is the current holder of the Wales best village title.
It's transformation into an eco-village has come as part of a competition run by the Royal Institute of British Architects (Riba) which aims to turn Lawrenny into a green energy showcase.
Bristol-based Tom Russell Architects have been picked to spearhead the new Lawrenny's design and construction after winning the competition.
As part of this process it will build 30 carbon zero homes and workplaces powered by solar, biomass and other renewable energy resources with the development set to almost double the village's current population of less than 100.