A California ballot measure that called for a dramatic increase in the share of renewable power to half of electricity generation by 2025 appeared headed for defeat on Tuesday night. With about 31 per cent of the state's precincts reporting, Proposition 7 "no" votes had 65 per cent of the vote.

The measure called for an increase in renewable power by about two per cent of electricity generation a year until it reached 40 per cent by 2020 and 50 per cent by 2025. Opponents called the measure well-meaning but ill-conceived and that it would constrict rather than expand renewable power generation in California.

Currently, about 13 per cent of California's power is generated by renewable sources including solar and wind. California has a goal of 20 per cent of electricity from renewable sources by 2010, which the state's utilities are not expected to meet. Gov. Arnold Schwarzenegger supports a 33 per cent renewables goal by 2020.

Environmentalists teamed with major utilities including Pacific Gas & Electric Co. and Southern California Edison in a campaign to defeat the measure.