Can’t Completely Rely on Renewables -- For Now

(TNS) -- You don't need to know much about wind and solar technologies to realize that they're not much use when the sun doesn't shine and the wind doesn't blow. That's why power grids need some other source of energy to draw from at nights and on calm days -- most often natural gas plants that can be turned on and off quickly, so as to minimize wasted energy.

But it also appears that having those "fast-reacting" fossil fuel plants around may have actually fostered the growth of renewables as well, according to a new working paper published today by the National Bureau of Economic Research.

Researchers from France, Italy, and the United States took an historical look at the question, by measuring adoption of wind and solar energy across developed countries between 1990 and 2013. They found that over the long term, existing natural gas capacity was correlated with greater investments in renewables -- suggesting that the two are complementary, not in conflict.

Now, it's important to note what's not included in the "fast-reacting" category: Coal and nuclear plants. Those tend to operate as either on or off, making them not very useful as backup power for wind and solar. For that reason, we might not need more fossil fuel capacity overall, says study co-author David Popp of Syracuse University -- just less of the "baseload" generators, and more flexible natural gas plants.

And of course, that's already happening on its own, since the American shale boom has made gas super-cheap and abundant. The Energy Information Administration already thinks 2016 will be the year in which natural gas consumption will surpass coal consumption. Accordingly, some big companies -- like Shell -- are shifting away from oil in favor of both gas and renewables. The need for that backup capacity will also shrink as scientists come up with better ways to store energy from wind and solar, so it can be banked and deployed as needed.

That's probably true, whether or not there's a causal link between natural gas capacity and renewable investment -- which could just be correlation, cautions Patrick Luckow of the Cambridge, Mass.-based consultancy Synapse Energy Economics.

"The countries with more fast-reacting fossil fuels might have more modern power systems in general, and be more amenable to, accepting or encouraging of renewable fuels as well," says Luckow. "But it is absolutely true that flexible resources help integrate renewables significantly."

This balancing act is perhaps most advanced in California, which has set ambitious renewable fuels targets, and has also added significant natural gas capacity to help meet them. According to Luckow, there's no standard ratio of how much natural gas capacity you need for every kilowatt hour of solar or wind, but it's less than one-to-one -- meaning it shouldn't be too hard to get up to 50 percent renewables.

Or at least, the availability of backup power shouldn't be the limiting factor. As my colleague Jordan Blum reported earlier this month, there are plenty of other obstacles keeping solar energy in particular from becoming the major player many want it to be in the future.

©2016 the Houston Chronicle Distributed by Tribune Content Agency, LLC.