Money.Prop 23 opponents have raised $5 million in the last few days, compared to $10,000 for supporters.Photo: Daniel BormanWhen Silicon Valley’s elite gathered at Google’s headquarters in August to rally opposition to Proposition 23, the ballot measure that would suspend the state’s global warming law, one speaker darkly warned that the Texas oil companies backing the initiative would spend as much as $50 million to ensure its passage.

As it turns out, the No on 23 campaign is outspending the Texans. Big time. Case in point: Over the past few days, the No forces have collected $5 million from venture capitalists, New York financiers, renewable energy companies, and other deep-pocketed backers, according to California Secretary of State records.

The Yes campaign, meanwhile, has received only a single $10,000 donation over the past week, from a Houston company that provides services to the oil and petrochemical industries. The last big contribution to the Yes coffers was a $100,000 donation made on Sept. 13.

Of course, Texas oil companies Tesoro and Valero and the billionaire Koch brothers, who earlier contributed $1 million to the Yes effort, could drop $10 million on the campaign tomorrow. But there appears to be a fundraising enthusiasm gap between the campaigns during the home stretch sprint to Election Day.

Take a look at the growing roster of No partisans willing to put their money where their mouths are — not to mention their self-interest.

Ann Doerr, the wife of leading Silicon Valley capitalist John Doerr, gave $1 million to the No campaign on Thursday while her husband contributed $500,000 (in addition to the half million dollars he previously donated). Thomas Steyer, founder of the Farallon Capital Management hedge fund and co-chair of the No on 23 effort, put another $2.5 million into the campaign. San Francisco venture capitalist Paul Klingenstein contributed $100,000.

On the other coast, New York hedge fund manager Julian Robertson of Tiger Management kicked in half a million dollars on Thursday.

Renewable energy companies stepped to the plate as well. The U.S. division of Spanish wind giant Iberdrola Renewables gave $25,000; Santa Monica-based Solar Reserve, a developer of solar power plants, pitched in $50,000; and Google executive Jonathan Rosenberg contributed $10,000.

The Consumers Union, the Union of Concerned Scientists, the Kaiser Foundation Health Plan, and Working Assets also gave a collective $100,000 over the past week.

With absentee voting beginning in California today, expect to see that cash put to work influencing those who plan to vote early.