The “Million Solar Homes” plan was revealed last year by controversial California Governor Arnold Schwarzenegger, proposing to provide 10 years of subsidies to encourage the uptake of solar photovoltaic systems on residential homes.

The plan failed to pass out of committee, but the revised and relaunched initiative, which extends subsidies to commercial and municipal buildings, has received support from ecologically-sensitive politicians on both sides of the US political spectrum.

If successful, it is estimated the plan would add around 3,000 megawatts of solar capacity to California, around 30 times current capacity and equal to two nuclear plants, which would make the state the largest consumer of photovoltaic technology in the world.

In addition to the power benefits, the large-scale production required would be a considerable step forward in making solar technology cost-competitive with fossil-fuel power.

Analysts are predicting that the Bill’s passage in August could be a close call. Democrats fear that the initiative would provide a great boost to the governor’s shaky popularity, and many of them have clearly stated they would oppose anything that would cement the position of the man who recently labelled them “thieves” and “girlie men”.

In addition to the partisan conflict, the plan could be derailed by union groups lobbying for the addition of a prevailing-wage requirement for installers of solar systems, a provision that would add a projected 30-40% labour cost to installation.

“Prevailing wage is the single biggest threat to the Bill,” said Republican Senator John Campbell.

“It won’t get Republican support if Democrats succumb to union pressure to add that provision.”