Someone should really tell the Department of Energy (DOE) about the federal government’s spending crisis.

On Monday, it granted a $2.1 billion loan guarantee to a German developer to help finance a 1,000 megawatt solar thermal power plant in Southern California. But wait, there’s more.

Add to that a $1.6 billion loan guarantee for another plant in California’s Mojave Desert, a $1.2 billion loan guarantee for one in San Luis Obispo County, Calif., and $967 million for a location in Arizona, all since February, according to a report. That’s nearly $6 billion in taxpayer dollars to back up private industry’s green energy ventures.

But that’s just the tip of the iceberg.

According to The Heritage Foundation’s Nicolas Loris, the DOE is one of the fastest growing federal agencies with a budget that grew from $15 billion in FY 2000 to $26.4 billion in FY 2010—a staggering 76 percent increase in only one decade.

Loris has identified $6 billion in possible cuts, among them, $3.2 billion for the Office of Energy Efficiency and Renewable Energy, which is tasked with funding the research and development of “clean energy technologies” — commercializing technologies, not promoting research. Loris writes:

It is neither the DOE’s responsibility nor the role of government to make projects cost-competitive. The company that can make biofuels or any of these other alternative technologies cost-effective and environmentally efficient will reap the rewards for doing so with high profits. Increased competition will directly benefit the consumer, and the DOE should not artificially prop up these technologies and energy sources.

It’s not news that the White House is dedicated to promoting alternative sources of energy as part of its green agenda. But government has a role, and its job is not to undertake tasks better left to the private sector. And that’s especially true in a time when government spending must be contracted, not expanded.