Gerard Morgan-Grenville (l) with Prince Philip at CAT in 1974
An Old Etonian who transformed a derelict slate quarry in a remote part of mid Wales into one of Europe's leading eco-centres has died.
Gerard Morgan-Grenville, who founded the Centre for Alternative Technology (CAT), near Machynlleth, Powys has been described as an environmental pioneer.
His family said he twinned his campaign for a greener world with an "infectious sense of fun".
He died aged 77 at his home in Dorset after a long battle with cancer.
Mr Morgan-Grenville's family said he was raising issues about alternative power sources and sustainability three decades before the current debate about global warming.
The great-grandson of the last Duke of Buckingham and Chandos, he was driven to build CAT in the early 1970s largely by his opposition to nuclear power.
He founded the centre on the site of Llwyngwern slate quarry in 1974 on a shoestring budget, to show there were alternatives to high-polluting technologies in energy, food production and construction.
However, at the time the site was littered with slate waste, derelict buildings, overgrown birch trees and rhododendrons bushes.
But word spread quickly about the project and a mix of ecologists, hippies, engineers and academics banded together and rebuilt the ruined buildings, established gardens and started generating electricity.
A few months later more than 20 people, including 10 children, were living on the site.
Early visitors included Prince Philip and Prince Charles.
CAT has since flourished and calls itself Europe's leading eco-centre with 65,000 visitors a year and 150 staff.
His family said: "He was an environmental pioneer who twinned his campaign for a greener world with an infectious sense of fun.
"(He) was accused of betraying his establishment background but he touched a public nerve with his enthusiasm and easily-understood exhibits three decades before global warming became a driving force for a shift to alternative energies."
Roderick James, the first director of CAT, said: "I think his way of combining both fun and the environment is his most enduring legacy, which of course manifests itself in the centre we know today."
Peter Harper, head of research and innovation at CAT, which offers advice on energy policy, said a new education centre being built at the site aimed to be like Morgan-Grenville: "smart, professional, respected, quirky, radical, with one foot in the 18th Century and another in the 21st."
Mr Morgan-Grenville's early projects at CAT included some of Britain's first windmills for generating electricity.
He also established businesses and wrote books about barging holidays in France.
He is survived by his third wife, Margaret, and two sons and a daughter from his first marriage.