A new scheme that will see the government dish out £15 billion on green energy loans and grants has been slammed by an eco-billionaire and Labour donor. Taking aim at the cost of the scheme and the value for money for those who use it, Labour donor Dale Vince branded heat pumps "sh**e".

Mr Vince, who handed Labour nearly £5 million at the last general election, is the owner of the electricity firm Ecotricity. Born in Norfolk, he has an estimated net worth of around £100 million and has long campaigned on a range of environmental issues.

A vegan, Mr Vince had campaigned to abolish the farming of animals, and pushed for the abolition of a law in England that encouraged schools to serve meat and dairy. A long time supporter of the Labour Party he told the Times newspaper that he thought heat pumps, central to the governments environmental building plans,where "sh**e".

The criticism comes just days after the energy secretary, Ed Miliband, announced a scheme that would see billions handed out in green energy loans and grants to UK households. Intended to reduce bills and bring down emissions, the scheme was blasted by critics as adding to household costs at a time when energy bills are already high.

Mr Vince told the Times that would "have focused on cost effectiveness, value for money, affecting the most people in the best way" if he had been in charge of the multi-billion pound scheme. He added that the "least best way to do that is heat pumps" in a damning criticism of the government's plans.

A contradictory man, he also said: "I'm a donor that thinks there shouldn't be donors; I'm a rich person that thinks rich people should pay more tax; and I'm a green energy advocate that thinks heat pumps are sh**e."

Mr Vince had a range of commercial interests, including developing new technology that he intends to use to help human beings eat grass. His plan would see the extraction of proteins, vitamins and minerals from turf, which would then be turned into a powdered supplement to make food.

He said it would be done in the same way "soya protein or wheat protein or pea protein". When asked by a journalist if he himself had ever eaten grass he Mr Vince confirmed he had "chewed it".

Humans cannot eat grass in the same way normal food would be consumed. Mr Vince addressed this point saying: "You need four stomachs to eat it up until now. But we're going to change that."