By Jeff McMahon, Opinion, Forbes
Only next-generation solar technology can offset humanity’s use of fossil fuels, meet our energy needs, and do so with the urgency dictated by climate change, an Argonne National Laboratory scientist said in Chicago last night.
“If we really want to scale up solar super fast, which we’ve got to do—the market’s growing already by something like 30 percent a year, massive growth, but that’s nowhere near enough—it’s got to grow much faster to solve this problem in the time frame dictated by climate disruption,” Darling said in a talk at 1871, a startup incubator in Chicago’s Merchandise Mart.
“So we need new technologies.”
Darling called silicon solar panels, today’s predominant technology, “awesome.” Silicon is abundant on earth, he said, and the panels made from silicon have become very efficient.
But they require too much energy to manufacture.
“You need super pure silicon and it’s got to be crystalline to get a high efficiency solar panel. Both of those things take energy. So you invest energy in, and it takes a while to get that energy out. It takes a few years, and there’s nothing you can do about that.”
There are lots of next-generation technologies in development, Darling said, displaying an organic solar module that relies on carbon instead of silicon. The organic mixture can be printed on a flexible panel, like ink on newsprint.
“Much less energy embedded within it, so we can scale it up much faster.”
But the organic modules degrade quickly in wet or variable weather, where solar panels need to be. So scientists are scrambling to develop coatings that can protect them without reducing their efficiency.
“Another really exciting one is perovskite solar voltaics, which have taken the solar world by storm in the last few years, with an efficiency that rivals silicon already, which came up from nothing a few years ago. Folks are really excited about that.”
Perovskite photovoltaics have a crystalline structure like the mineral perovskite, named for the Russian mineralogist Lev Perovski.
Robert Armstrong, director of the MIT Energy Initiative, also cheered perovskites last week in Chicago, in an appearance, like Darling’s, hosted by the Chicago Council on Science and Technology.
“We only started serious solar research on perovskites five years ago,” Armstrong said at the Illinois Institute of Technology. “It took 30 years for silicon solar to go from very low efficiency up to 21, 22 percent. Perovskites got from a couple percent up to more than 20 percent in five years. Really exciting and really encouraged about what you can do.”
But perovskites are also environmentally unstable, Armstrong said, and they degrade within hours of use.
“So there’s a lot of promise there, and at the same time a lot of challenges.”
The answer to those challenges, according to Darling, is research and development. “To get those technologies geared up for the market we’re going to need much more research and development.”
Some of that may be forthcoming. At the Paris Climate Conference, 20 nations including the U.S. pledged to double their funding for science research over the next five years. President Obama then submitted a budget to Congress that doubles energy research next year.
The budget proposal has to survive a hostile Congress, but if any increase survives, Darling urges that much of it go to solar research.
“I’m advocating for solar to be a huge part of the energy mix going forward,” he said. “We want an energy mix for all kinds of reasons. But the point is that solar has to be a huge piece of the story going forward. We have no choice, in fact, because we need to turn to mostly renewable energy, and it’s the only one that can give us as much as we need.”
Darling argued that other renewables, if developed to capacity, can only meet a portion of humanity’s projected energy demand in 2050.
“If you look at how much could you get from renewable energy sources, all the wind, biomass, hydropower… you can see we’re coming up short.”
It’s important to include those sources in a diverse energy portfolio, he said, but solar can provide much more energy than all of them combined.
“It is a massive amount of energy. There is enough energy hitting the surface of the earth in one hour to power the entire planet for a year.”
Humans can’t harness all that energy, but if we devoted just 2 percent of land mass to that task, at 12 percent efficiency, we would have enough, Darling said. (Darling’s 2 percent is modest compared to the 10 percent called for by climate scientist Elisabeth Moyer).
“The feasible solar energy supply is more than two times larger than the total projected global energy demand all the way out to the year 2050,” Darling said. “In fact it’s larger than the projected demand in 2100. For all intents and purposes, it’s an inexhaustible energy supply.”