The sun.Mainstream energy companies may finally be seeing the light when it comes to solar power.How do we know when solar becomes a mainstream energy source?

One tip-off: when mainstream energy companies get serious about solar.

For example, take NRG, a Fortune 250 wholesale energy generator with about 26 gigawatts of capacity in its portfolio. Most of that is coal, natural gas, oil, and nuclear.

That’s the past.

Going forward, as per a recent Platts article:

About 85 percent of NRG Energy’s committed investments for the next three years will go to solar projects, mainly for three utility-scale projects that have received federal loan guarantees, the company said Thursday.

Next year, the independent power producer expects to spend $705 million on its solar projects compared with $120 million on conventional projects. From 2013 through 2014, the company intends to spend $315 million on its solar projects and $65 million on conventional projects …

Solar development will come more from rooftop projects, according to Crane. “The distributed, residential is going to end up swamping the bag-scale projects,” he said.

NRG plans to install 733 megawatts (MW) of solar panels over four years on [a] warehouse owned by ProLogis under a partnership backed by DOE and Bank of America.

A form of Moore’s law — the doubling every two years of the number of transistors that can be placed on an integrated circuit — applies to photovoltaic technology, according to Crane. In the last two years, the delivered cost of energy from PV was cut in half, he said. NRG expects the cost to fall in half again in the next two years, which would make solar power less expensive than retail electricity in roughly 20 states, he said. The expected drop in solar costs has “the potential to revolutionize the hub and spoke power system, which currently makes up the power industry,” he said.

While the solar industry has benefitted from federal support, the driver for the industry has been state renewable portfolio standards, led by California’s 33 percent mandate, according to Crane.

In defense of solar in a “highly politicized post-Solyndra world,” Crane said that PV puts less strain on air, water, and land resources than other forms of power generation. It is also more predictable and reliable than wind farms, he said …

The company is also open to buying coal-fired generation, Crane said. “We’re not afraid of owning conventional generation,” he said. “We would like to own more generation in the Northeast.” However, the outlook for coal plants in the Northeast is dim, according to Crane. “The economics of coal plants in the Northeast are phenomenally challenged right now,” he said. “It’s not a pretty picture.”

It reads like an April Fool’s joke or an Onion article as written by a Koch-funded anti-renewable true believer, if that’s not too meta.

In the same vein, General Electric CEO Jeff Immelt made clear that he’s seen the future, and the future’s solar-powered. GE is building a 400 MW solar manufacturing facility in Colorado. How do they feel about the prospects of solar in a post-Solyndra world? Pretty good:

“We are all-in. We are going to invest what it takes … Because I know by 2020 this is going to be at least a $1 billion product line. I don’t care about Solyndra or any of that other stuff, we did this with no government funding. We can do this,” Immelt said.

Solar. It’s not just for hippies anymore.