Later Wednesday, in a move that continues the Obama administration’s romance with the clean energy industry, Vice President Biden will speak at the Solar Power International Conference in Anaheim, Calif. And the administration has announced an array of new clean energy initiatives in advance, encompassing $120 million in new research initiatives and programs to promote solar, as well as other renewables — and in particular, to get them into homes.

The majority of the initiatives are based at the Department of Energy and focus on either advancing solar technologies, so that they can achieve even better levels of performance, or helping ease the installation of solar systems in homes and increase their reliability. For instance, one new $7 million investment will push new research on how the hardware of installed solar systems degrades over time, seeking to render this more predictable and better understood.

In a fact sheet released in advance, the White House once again heralded the solar industry’s rapid growth. “Since President Obama took office, the number of homes with rooftop solar has grown from more than 66,000 to 734,000,” it noted. “Last year, the solar industry added jobs 10 times faster than the rest of the economy and solar represented 40 percent of all new electric generating capacity brought online in the first half of 2015.”

Indeed, last week, we learned that the booming U.S. solar industry, driven by a powerful pairing of industrial scale arrays and photovoltaic panels atop individual rooftops, is on course for yet another record: an estimated 7.7 gigawatts of solar capacity installed in 2015 — where a gigawatt represents 1 billion watts.

What’s more, this is happening even though two key emerging solar sectors — community or “shared” solar, in which multiple individuals invest in or derive power from one larger installation, and “solar plus storage,” in which solar energy is paired with batteries — are still in fledgling stages (but expected to grow fast).

Surveying all of this, it’s hard not to be bullish on solar. However, there are  some important questions to ask about just how fast solar is growing and what that means from a climate change perspective.

For instance, a recent report, sponsored by the Solar Energy Industries Association and conducted by Bloomberg New Energy Finance, found that by 2022, solar photovoltaics might reach between 73 and 95 gigawatts of installed capacity — a big growth over the 19 gigawatts that existed at the end of last year. The difference turns on whether the 30 percent solar investment tax credit declines in 2017, as is currently scheduled.

But what would 73 to 95 gigawatts of solar capacity in 2022, actually mean? According to Madeline Yozwiak, Bloomberg New Energy Finance’s solar analyst, and her colleague William Nelson, BNEF’s head of North America analysis, every 32 gigawatts of solar capacity translates into  roughly 1 percent of U.S. electricity generation. Thus, 95 gigawatts would bring solar to just under 3 percent of generation in 2022, and 73 gigawatts would correspond to about 2.25 percent of the total.

That’s a lot of growth over the next 7 years – solar is still under 1 percent of total generation right now — but also still a relatively small percentage of U.S. electricity. By contrast, last year Germany got 6.9 percent of its total electricity from solar energy.

2022 is also the year when the Clean Power Plan kicks in — and along with favorable economics, it too will favor solar (and wind). However, if solar is only at 2 to 3 percent of our electricity generation at that time — with wind currently at about 5 percent and also projected to grow — then seven years from now, the large bulk of U.S. electricity will still come from fossil fuels.

And indeed, the EPA’s final Clean Power Plan itself projects that even in 2030, “coal and natural gas will remain the two leading sources of electricity generation in the U.S., with coal providing about 27 percent of the projected generation and natural gas providing about 33 percent of the projected generation.”

So in sum — solar’s recent numbers prove it is here to stay. No wonder the White House is heralding this fact, and seeking to further stoke the solar revolution.

But if you’re worried about global warming and how much carbon dioxide the United States emits to the atmosphere, then you might wonder about the difference between fast solar growth, and what’s fast enough. For the Obama administration, it appears, there is much to celebrate, but also much to do.

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