As residential solar energy systems become more common, so too will solar batteries. Since the sun doesn’t shine all the time, a solar battery is a useful component in any solar system. And in systems that are disconnected from the grid, a solar battery is crucial.
While most of today’s solar batteries use lead-acid technology, lithium-ion batteries are becoming increasingly common. Tesla’s PowerWall, for instance, is a lithium-ion battery, as are the batteries offered by high-end solar panel manufacturer LG Energy.
Lithium comes from two sources. One is brine mining, a process in which lithium and other useful materials are. But recovering lithium from brine requires large amounts of water and energy, which makes it expensive. The other, more conventional source of lithium is in mines.
The U.S. has few domestic lithium resources, though exact numbers are rarely published in order to avoid the disclosure of proprietary data. In 2013, the last year that domestic production numbers were published, the U.S. produced 870 metric tons of lithium and imported 2,210 metric tons. More than half of the lithium imported to the U.S. comes from Chile, Argentina, and China.
But lithium isn’t just for solar batteries － lithium ion batteries also power our phones, laptops, cordless power tools, and other gadgets. The biggest consumer of all is the electric vehicle industry, which consumes about half of all lithium-ion batteries.
And demand isn’t slowing anytime soon: last year, both Ford and GM announced they would offer at least 20 different electric car models by 2023, up from just a handful of models currently in production. And Tesla’s “Gigafactory,” located in Nevada, was built to produce batteries for home energy storage and electric vehicles. Tesla expects that when the Gigafactory achieves full production capacity, the company will be able to manufacture 500,000 cars per year.
As these technologies have matured and become more common over the past several decades, the scramble for lithium has intensified. Between 2010 and 2014, lithium-ion battery consumption increased 73 percent, but production levels only increased 28 percent.
The increasing scarcity and high demand for lithium have also driven its price up dramatically. In 2012, lithium cost just over $6,000 per metric ton. In 2016, the same amount cost $7,400 － a 23 percent increase.
These lopsided metrics have some researchers worried about the sustainability of lithium usage. An article published in Nature last year, for instance, warns that the projected demand will quickly outstrip current production levels and reserves. The researchers recommended greater investment in new lithium mining and recovery operations.
But another article in Joule, a journal devoted to sustainable energy issues, concluded that lithium supplies probably won’t run out anytime soon. New and untapped reserves in Bolivia and elsewhere, they suggested, will help meet the world’s growing lithium requirements.
On the other hand, researchers don’t seem to have a clear grasp on how much lithium there actually is. Between 2008 and 2010, five different estimates of global lithium reserves arrived at five vastly different amounts. The lowest estimate was 3.9 million metric tons; the highest was 39 million metric tons.
Even if lithium supplies do run dry, substitutes like calcium, magnesium, zinc, or mercury could be used in its place.
Hopefully, substitutions won’t be necessary, since new technologies should make it easier to procure lithium. Canada’s MGX Minerals, for instance, has developed a nano-filtration system that can sift 70 percent of lithium from wastewater produced by oil operations. The process might soon lead to a strange marriage between renewable energy companies and the fossil fuel industry.
A bigger issue could be the other materials used in the production of lithium-ion batteries. Cobalt, for instance, is primarily found in the Democratic Republic of Congo, a politically unstable country where mines often employ slave and child labour. Globally, China controls around 95 percent of the market for rare earth metals. As it develops its own electric auto industry and continues to lead the world in solar panel manufacture and production, the world’s most populous country might be reluctant to trade these precious materials away.
While devices that contain lithium can be recycled, there is no recycling technology capable of yielding lithium pure enough for use in new lithium-ion batteries. Going forward, lithium-consuming industries will need to collaborate in order to develop recycling processes and infrastructure that can better recover lithium and the other precious materials that go into lithium-ion batteries.