Car parks across Oxford could have solar panels installed above them

The panels would generate clean energy and help to meet yearly environmental targets, council chiefs said.

And there are calls for supermarkets and businesses such as BMW to get involved, as they have some of the biggest car parks.

Other ideas being considered include heat-sharing networks, such as the one being built between the John Radcliffe and Churchill hospitals in Headington.

Oxford City Council environment boss John Tanner said the idea of solar car ports were at 'early stages', but added: "It is certainly something we are looking at.

"It would involve putting solar panels above where people park their cars, but there is no detailed scheme worked up at the moment."

The suggestion was welcomed by the Green Party's Craig Simmons, who said the city council should seek to partner up with local firms on the idea.

This has already been done across Oxfordshire by Low Carbon Hub – which received funding from the council – as part of a scheme to install solar panels on the roofs of workplaces and schools.

Mr Simmons said: "This is something that is fairly common in other countries and has been around for a while in places like California.

"It's a proven technology and makes better use of car park surface areas, but also generates money and energy.

"It could be done at virtually no cost to the council, because the cost of borrowing is so low at the moment and the scheme would end up paying for itself anyway.

"Frankly I don't know why the council hasn't looked at this before.

"We should be seeking to negotiate deals with some of the supermarkets to do this and offer to split the revenue."

In 2011 the city council pledged a 40 per cent reduction to its carbon footprint by 2020 based on 2005 levels.

Mr Tanner said the city was now close to this but needed 'one final push' to meet the target, after a report predicted it would currently achieve a 38.5 per cent reduction.

He added: "We want to thank everyone in Oxford who is working hard to bring our emissions down because it all makes a difference in keeping our city liveable for our children and grandchildren.

"We are moving in the right direction but we now want one final push to get it to 40 per cent."

Responding to suggestions about solar car ports, a spokesman for BMW said: "We have not had any formal discussions about such a plan but would be willing to hear more about it."

The spokesman pointed out Plant Oxford already had a solar array on its roof, which produces enough electricity to power 850 homes.