Democrats in the US Congress have struck a deal on legislation to increase the fuel efficiency standards for motor vehicles ? the first such increase in more than three decades.

The legislation would increase the standards by roughly 40%, to 15 kilometres per litre, by 2020, while instituting a series of energy-efficiency requirements for appliances and federal buildings.

The bill would also mandate the use of 136 billion litres of biofuels annually by 2022, compared with roughly 25 billion litres this year. Of the total, 80 billion litres must come from advanced biofuels such as cellulosic ethanol and meet certain requirements for greenhouse-gas emissions.

Facing opposition from Republicans and the White House, Democrats had to jettison a federal mandate for the production of electricity from renewable sources and a tax package shifting energy subsidies from fossil fuels to renewable energies.

The Senate passed the bill on 13 December, and the House of Representatives was moving towards passage as Nature went to press this week. The president is expected to sign the bill.