By Paul Rincon
BBC News Online science staff, at the BA festival
A new generation of rechargeable lithium batteries would help reduce global warming, a leading expert says.
The government has set targets for alternative energies
Professor Peter Bruce says the batteries could be used to store electricity produced by renewable energy sources such as wind power.
So-called hybrid cars incorporating lithium batteries, along with petrol
or diesel power, would help reduce our reliance on fossil fuels, he says.
The St Andrew's University expert was talking at the BA Festival of Science.
Hybrid road vehicles would help the UK meet the government's renewable energy targets for 2020, he told an Exeter audience.
They would be fuelled by a combination of petrol and electric battery technology which is charged by the petrol engine.
They could help contribute to reducing the greenhouse gases believed to be responsible for our warming climate, added Professor Bruce.
But they will need more development if they are to catch on as a serious alternative to fossil fuels.
Hybrid cars and fully electronic vehicles that draw their power from lithium batteries already exist.
But new materials will be needed along with significant advances in engineering before vehicles based on this battery technology can match the performance of cars that are entirely based on petrol or diesel.
"We have to develop new materials that will help us develop new technologies with better performance," said Professor Bruce.
Need for fuel
Compared with conventional batteries such as lead acid or nickel cadmium, lithium rechargeables can store up to three times the energy per unit weight and volume, he added.
This would lead to significantly smaller and lighter batteries in hybrid vehicles.
They would also lack the toxic metals like lead and cadmium contained in some batteries.
Honda Civic hybrid adds an electric motor to its existing petrol engine
"It's not realistic to row back to some earlier age when we used far less energy," he said.
"We have to find technological solutions to provide us with the electricity storage and generation we need to really fuel our economies over the next several decades."
Renewable energy should provide 20% of the UK's electricity supply by 2020, according to UK government targets.