“Energy storage is such a Swiss Army Knife,” says GE's Johanna Wellington, “it gives me the opportunity to dream with a whole bunch of new solutions in my toolkit.” Image credit: GE.

“The amount of power that we now have in that 20 foot shipping container, just a few years ago you might have built a 70 foot building to store,” says GE's Wellington. Image credit: GE.

Johanna Wellington is standing next to what looks like a shipping container. Her safety goggles are the only clues that this container isn't quite what it seems. A look inside reveals a large array of batteries and sophisticated electronics. It's a prototype for the GE Reservoir, the most energy-dense storage solution ever conceived. This container's cargo is electricity.Since 2016, Wellington has worked as the Energy Storage Breakout Leader at GE's Global Research Center in Niskayuna, New York. She leads a team of scientists and engineers working to reimagine the future of energy storage and revolutionize the way our electric grid works.When complete, the GE Reservoir will hold 26 metric tons of lithium ion batteries, electronics, and climate control with a total energy capacity of more than 4 megawatt-hours — all packed into a 20 by 8 square foot container, or roughly the size of four king-size beds. That's enough energy to power 135 American homes for an entire day.Who needs to store that much battery power?Until very recently, no one. In fact, up until a few years ago, when you thought of batteries, you probably thought of the AAs in your television remote. Now, you think of lithium-ion batteries, the pesky power sources inside our laptops and smartphones that always seem to need a charge.But long before they powered our consumer electronics, batteries were energizing the first wave of scientific research into electricity.The story of the battery begins in 1800, with Italian scientist Alessandro Volta. By soaking paper in saltwater brine and sandwiching it between discs of two different metals, Volta generated a steady, reliable electric current for the first time. His voltaic pile is history's first battery.Volta's invention inspired countless scientists and tinkerers to investigate the nature and possible uses of electricity. In the next half century, batteries based on his original design were used to discover the elemental composition of water, create the first artificial electric light, and power the first electric motor. Entrepreneurs who sought practical applications for battery power weren't so lucky. Early attempts at creating battery-powered cars, locomotives, and boats were dismal failures.The battery was finally put to more practical use with the invention of the electrical telegraph in 1837. By mid-century, telegraph operators the world over were using battery power to send messages between stations across a vast network of wires, often depending on daily battery deliveries. This same “milk bottle” system, it seemed, might be used to power electric light.Edison's Pearl Street Power Station put an end to such schemes in 1882. Since Pearl Street, the world's electric power systems have been built to match supply with demand in the moment, right as it happens. Even so, Edison himself considered creating a version of the grid that incorporated battery storage. In 1879, the same year he patented his famous incandescent bulb, Edison designed a system whereby electric customers would install two storage batteries in their homes or businesses. This way, one could be charged by a centralized power plant while the other supplied electricity.The system did not live up to Edison's expectations. In 1893, he told a reporter, “The storage battery is, in my opinion, a catch-penny, a sensation, a mechanism for swindling by stocking companies…Scientifically, storage is all right, but, commercially, as absolute a failure as one can imagine.”Flash forward over a century, and breakthroughs in renewable energy generation have finally made grid-scale energy storage attractive. The price of energy generated by renewable sources like solar and wind has plummeted, and these sources produce practically no greenhouse gas emissions. No wonder the share of energy produced by renewable sources in the US has risen sharply - up 15 percent in the year from 2016 to 2017 alone.But renewables aren't without complications. The output of wind farms and solar plants can't be precisely controlled by power producers—they work when the wind blows and the sun shines. But if the sun is shining when demand is low, producers can be forced to take solar panels offline, a process known as curtailment. Because of this variability, producers are forced to keep conventional plants, like natural gas turbines, burning fuel without generating power—in case of unexpected spikes in demand.Recent innovations in lithium-ion battery technology were the last piece of the grid-scale energy storage puzzle. Back at the Global Research Center, Ms. Wellington gestures toward the Reservoir test unit and smiles. “The amount of power that we now have in that 20 foot shipping container,” she says, “just a few years ago you might have built a 70 foot building to store.”Reservoir's chief engineer, Ken Rush, emphasized the impact the Global Research Center had on the development process. In the course of the design process, the Reservoir team worked with experts in power electronics, edge computing, and materials science. “To be able to pull on that kind of brainpower,” he says, “was a really tremendous opportunity for us.”By integrating the Reservoir into the grid, GE hopes to to turn intermittent renewables into “full time renewables.” Power that was once curtailed can be stored in the Reservoir at times of low demand and dispatched when demand peaks.As they look toward the future, GE scientists are already figuring out ways in which the Reservoir can make today's grid better. Last year,Southern California Edison and GE debuted the world's first; the addition of battery power allows SCE to keep the turbine in standby mode - no fuel required. A jolt of power from the battery reserves allows the turbine to spin up quickly, the moment demand surges. The innovations in the Reservoir will only improve these hybrid systems.According to Rob Morgan, CEO of GE Power's Energy Storage business, it's a simple proposition for power producers: the Reservoir is “safer, denser, more efficient, and has a longer life.” To be precise, it's 5 percent more efficient than other grid-scale energy storage solutions, with a 10 percent better cost. Its power electronics are designed to maximize battery life and ensure safe operation. Its modular design will let power producers upgrade batteries as technology improves. Its small footprint and plug and play functionality will also allow power to be stored close to the source.For Johanna Wellington, this is just the beginning. “Energy storage is such a Swiss Army Knife,” she says, “it gives me the opportunity to dream with a whole bunch of new solutions in my toolkit.”