Solar and Wind Need a Place to Store Power
Between the present and a low-carbon future lies a technically vexing gap — building a better battery. Solar and wind power are cheaper than ever, but the sun doesn’t always shine and the wind doesn’t always blow. More powerful batteries could solve the problem of keeping the lights on, plus expand the market for electric cars by eliminating so-called range anxiety. Battery research today is hotter than any time since Thomas Edison and battery costs are falling faster than many had hoped. But the science is still daunting. There may be limits to how much better current technologies can be, and bolder new approaches depend on big breakthroughs. Price is an issue, as is weight for batteries used in transportation. Wind and solar were helped by tens of billions of dollars in global subsidies of a kind not available for the less-sexy work of storing power.
Most battery research today is focused on squeezing ever more performance out of lithium-ion batteries, which power everything from electric cars to iPhones. Lithium-ion work is seen as relatively low-risk but low return: Researchers are confident that they can grind out incremental improvements but not necessarily much more. General Motors and other car companies are pouring resources into the search, with Tesla Motors hoping to cut the cost of battery packs by at least 30 percent with its planned “gigafactory.” Tesla has begun selling battery packs assembled there not just to homeowners but to utilities. Some of the new approaches use vats of chemicals or liquid metal that could be made big enough to handle a utility’s needs or balance power use within a local system known as a micro-grid . Other researchers are looking into different materials like magnesium or at mixing lithium with sulfur to make longer-lasting batteries for electric cars and gadgets. Projects in Spain and Germany use excess electricity to heat gases that later run generators. China is building hydroelectric storage projects in which water is pumped uphill during the day and runs back down through turbines when it’s needed. That's an approach that accounts for almost all current utility-scale storage but needs the right terrain for expansion.The U.S. leads the world in large projects that use mainstream electro-chemical technology. Since 2011, a 64-megawatt battery facility in West Virginia has helped balance electrical flow in a regional grid serving 13 states.
Benjamin Franklin and others experimented with Leyden jars, now known as capacitors, which were capable of holding and releasing an electric charge. Alessandro Volta of Italy is credited with inventing the first electric battery, a stack of zinc and copper disks in brine, in 1799. In 1891, the first practical electric car made in the U.S. debuted in Iowa. Thomas Edison set to work building a better alkaline battery for cars, but gave up a decade later after Henry Ford’s gasoline-powered Model T transforms the auto market. Battery research didn’t come back in vogue until the oil shocks of the 1970s, when Exxon created the first rechargeable lithium-ion battery. Sony brought the technology to market in the early 1990s, and lithium-ion batteries have underpinned the digital revolution ever since. They’re remarkably durable, energy-dense and easy to recharge — although efforts to pack more energy into ever-smaller batteries has resulted in some products with a tendency to catch fire.
Lithium-ion batteries can hold more energy than the old dry batteries, but there are physical limits to how much can be pumped in and how often they can take a full charge. Even the creator of lithium-ion batteries says he thinks they can probably only become twice as efficient as they are today. Until batteries can store enough power to allow solar or wind to function without a backup power source, fossil fuels will remain utilities’ primary choice. Others argue that the need for batteries is overblown, that renewables can grow significantly just by smarter use of the existing electrical grid. Battery backers are pushing for utilities, regulators and lawmakers to enact rules and regulations that capture the full value of batteries, and 20 states debated storage policies in 2015. The cost of producing and distributing electricity is part of the current rate structure but storage isn’t. A renewables-plus-batteries system would make for a much more efficient grid, but utilities are wary of such a drastic change. Battery proponents would like more government backing of lab research in the hope that advances will lure private investment. But with little likelihood of more funding or subsidies, they’re looking for more places to adopt mandates like the one in California requiring utilities to provide 1.3 gigawatts of energy storage by 2020, enough to power a million homes.
The Reference Shelf
- The International Energy Agency looks at the various types of energy storage and where they can be implemented around the world.
- The U.S. government-backed Joint Center for Energy Storage Research is leading studies in the search for a next-generation battery.
- A Bloomberg News story looks into the commercial uses of existing and future battery technologies, and the billionaires funding startups in the field.
- A Foreign Affairs overview of the search for better batteries.
- A history of the Leyden jar and how to make a voltaic pile. Did the Mesopotamians invent batteries? Maybe yes or probably not.
First published March 31, 2015
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John O'Neil at firstname.lastname@example.org