Two communities in Wales will receive energy from a hydro scheme using rain water in Snowdonia.
The water runs into the River Ogwen and the aim is to capture the power of its flow to produce electrical energy using hydro technology.
It would provide power for Bethesda and Llanberis whose communities funded the 700,000 project through shares.
Both schemes will be launched on Saturday.
Keith Jones, environmental adviser for National Trust Wales, said a return on its investment was only one of the reasons for the communities getting involved in the hydro projects.
“The main motivation was that the residents wanted to invest in their own area for future generations to have their own electricity supply”, he added.
“People from one of the poorest areas of western Europe wanted to control their own future and now they can.
“They have locally-generated electricity from natural water in the mountains that surrounds their homes.”