The Ivanpah solar power plant is a work in progress along a stretch of California desert just west of the Nevada border.

Earlier this week, Google announced it will invest $168 million in the 370-megawatt (MW) project, which relies on solar thermal technology that’s sometimes informally called the “power tower” (pictured left). This announcement comes after the Internet search company last week made known its $5 million investment in a Germany-based solar energy facility.

Unlike photovoltaic (PV) systems, which convert the sun’s rays directly into electricity, most solar thermal technologies use the sun’s thermal energy to generate steam, which drives turbines that produce electrical current. The Ivanpah project will incorporate three such turbines that, according to the Economist, will “have a greater capacity than all the utility scale photovoltaic plants yet built in America.”

Talk about gigante. When completed, the project will be one of the largest solar installations the world has ever seen and will provide clean, renewable energy to 85,000 California homes.

It’s unlikely such an ambitious project would be possible without government backing. Indeed, the Department of Energy on Monday announced it had finalized $1.6 billion in loan guarantees to support the project, which is sponsored by BrightSource Energy, a California-based solar power project developer.

California Senator Dianne Feinstein offered the following remarks on the loan guarantee’s recent approval:

With this $1.6 billion loan guarantee, BrightSource Energy will complete construction of a solar energy facility that will create more than 1,000 California jobs and provide clean power to 85,000 homes. This is the Energy Department’s first solar generation loan in California and I hope it will be followed by many more. I believe we must support and nurture the solar industry, and the only way the vast majority of these projects will become reality is through the federal loan guarantee program.

Given its size, location and relative novelty, the Ivanpah solar project has attracted its fair share of naysayers. Conservationists have tried to block the project in court, citing concerns over the project’s impact on the local desert habitat. And free marketers will no doubt balk at the federal government’s role in providing loan guarantees (not to be confused with providing loans or direct subsidies).

Nevertheless, Brightsource has proved an adept developer, reducing the plant’s footprint to minimize environmental impact, working to relocate desert tortoises (one of the conservationists’ main points of focus) and offering to fund land conservation efforts elsewhere in the Mojave Desert.

Despite challenges, it seems Ivanpah’s power towers will continue to rise in the California desert.

Image cred: Brightsource.