Late Wednesday night, BrightSource Energy, a start-up formed to build solar thermal power plants, was forced to make a humbling admission: Despite a year of hopes and efforts, it could not find the market it wanted for its stock. The company canceled its initial public offering of shares just hours before trading was to begin.

Not too long ago, the prospects for BrightSource seemed so limitless that the company incorporated the word into its logo. It had raised tens of millions of dollars from leading venture capitalists, struck partnerships with corporations like Google, Siemens and NRG Energy and secured a coveted $1.6 billion federal loan guarantee for its signature Ivanpah plant in the California desert. Supported by state policy that encouraged utilities to buy lots of solar power, BrightSource had also signed long-term deals to sell much of its planned electricity output to two large utilities.

Then prices plunged for power generated by competing energy sources like natural gas and traditional photovoltaic solar panels. Government subsidies dried up. And investors who once clamored to get a piece of any clean-energy company started shunning all of them.

“The continued market and economic volatility are not optimal conditions for an I.P.O.,” John Woolard, BrightSource’s chief executive, said in a prepared statement announcing the withdrawal of the stock offering.