A community co-operative has reached its target of raising £273,000 to build two hydro-turbines after being inundated by people wanting to buy into the project.
A total of 100 people have come forward in Llangattock, Powys, and the share offer has closed early.
Power will be generated from streams with profits being ploughed put back into the village.
It was crowned the UK's greenest community in 2009 in a competition.
Llangattock won £100,000 to be used to make the village carbon-negative and decided to try to develop hydro power schemes.
Villagers set up Llangattock Green Valleys as a co-operative business.
The share offer only opened two months ago but has reached its target with people buying shares of between £250 and £20,000.
It will fund the construction of two micro hydro schemes - Cwm Gu, near Crickhowell, and Llwmws Farm, Hillside, Llangattock.
Investors have been offered interest payments of 5% a year with profits going into a fund to finance other projects in the community.
And it is claimed that could be worth about £500,000 over 20 years.
'Sense of achievement'
The co-operative said planning applications and abstraction licences had been drawn up to move the planned projects to their next phase.
"These streams have been running for centuries and more," said investor and local vet Rob Smith.
"The technology is simple. There isn't much that is going to go wrong with it. It seemed to me to be a good idea to invest."
Llangattock Green Valleys project won the Welsh final of the British Gas challenge in 2009 and went on to win the British title in the Green Streets competition.
Back then solar panels and 100 radiator panels were installed at the school with an air source heat pump added to the hall.
Meanwhile 43 homes in Llangattock installed 655 energy efficiency measures including insulation, solar panels, a biomass boiler and multi-fuel stoves.
One of the planned new hydro turbines will be in a stream on a farm run by George Smith, who said: "Anything that will enable us to put more in the community and develop more environmentally-friendly energy schemes is good as far as I'm concerned."
The project website said full feasibility studies had been completed, with legal agreements in place with landowners.
"To see people putting money into the co-operative is a sense of achievement," said Michael Butterfield, one of the co-operative's five directors.