Centre for Alternative Technology marks 40th anniversary
A Powys eco centre is marking 40 years since members started developing ideas on sustainable technology which have now become mainstream.
The Centre for Alternative Technology charity near Machynlleth was set up in a disused quarry in 1973.
Their work included developing wind turbines and solar energy panels.
"I think people's understanding of environmental issues has grown enormously in the last 40 years," said chief executive Adrian Ramsey.
"What was once, perhaps, considered a fringe activity is now a mainstream concern.
"People care about the future of the planet, they know we need to reduce our carbon footprint, that we need to take action to protect biodiversity and create a healthier society at the same time."
Describing themselves as "crazy idealists", the group played its part in the green movement in Britain.
They based themselves in a quarry which was abandoned and in ruins, led by entrepreneurial aristocrat and environmentalist Gerard Morgan-Grenville