When Nevada Geothermal Power was finishing construction on its plant in late 2009, there was ample reason for optimism. Boiling waters are not far from the surface at this remote site, three hours outside of Reno. It had a 20-year contract to deliver power to the state’s largest electric utility company.

But even before it applied for the Obama administration incentives, problems at the plant cropped up. Company executives have variously predicted the plant could generate as much as 45 megawatts, after accounting for energy needed to power it.

Yet when the plant started up in October 2009, only 27 megawatts of net power were initially generated from the hot water pumped from the earth. That was not enough for the company to honor its commitment to the electric utility company, or to pay back a $91 million loan — carrying 14 percent interest — that it has with a Washington-based investment firm.

Through modifications at the Blue Mountain site in Nevada — drilling new wells to produce more steam — the company has been able to get the net power output up to a steady 35 megawatts. But, as the annual report released last week reiterated, that was still not enough production to cover the company’s loans and operating costs.

And that is just the beginning of the troubles. Early last year, it was forced to shut down for more than a month, after a “faulty layout of underground cables” caused a short circuit, a company statement said. Tests by the company also show that because of mistakes made in how the wells were set up, the water temperature is dropping, potentially meaning a drop in future power production.

Geothermal projects in general have encountered complications in recent years. They are a much riskier enterprise than solar panels or wind turbines, because the drilling can take several years and the power output is not guaranteed until the work is complete.

That explains why in recent months, shares of geothermal companies have collapsed, dropping far more than the shares of most renewable energy businesses. Nevada Geothermal, as of the market close Friday, was trading at 10 cents a share, down from $1.24 when its plant opened in 2009.