What are Grid Batteries and How Can They Charge Up the Future?

By Vernon Trollinger, January 26, 2016, Energy Efficiency, News

Several factors facing the power industry drive the growth in grid battery development. With more renewable sources in the mix, grid batteries provide a flexible means of storing energy for later use. For example, West Texas wind turbines produce the most energy at night and not during the day when cities like Houston, Dallas, and Austin need electricity the most. Also, power plants in mid-Atlantic metro areas face the threat of high demand during summer heat waves. In both cases, grid scale battery storage let generators store energy when its not needed so it can be available when it is.

What are Grid Batteries and How Can They Charge Up the Future?

No, not these batteries – we’re talking about LARGE batteries that hold generated energy for later use.

Summer 2105 held a lot of promise in the development of utility-scale grid batteries. Tesla announced in August its “Powerpack” batteries already had 100,000 order reservations worth $40 – $45 million in grid battery sales. Interest was so intense that Tesla CEO Elon Musk said they were already sold out for 2016.

Even more, a Frost & Sullivan report entitled Global Utility-scale Grid-connected Battery Energy Storage Systems Market foresees utility scale battery storage could reach 12 gigawatts by 2024 and predicted $8.44 billion of “dynamic growth” starting in 2017 for companies like Tesla, GE, Samsung, and additional companies in Germany and Japan.

Why Utilities are Charged Up

What are Grid Batteries and How Can They Charge Up the Future?

Finding a workable battery for energy generated at off-peak times by renewable sources could revolutionize the energy industry.

Batteries reduce the reliance on fossil fuel generators. With the retirement of old coal-fired generators, newer generator plants, including both renewable and newer fossil fuel, can balance daily loads with battery reserves more efficiently. Not only do grid batteries improve local grid reliability, they do it without polluting emissions or the use of water.

Charging Up the Technology

While the idea behind incorporating batteries into the nation’s grid system, battery technology is still under development. At the heart of the problem is how to build a long-life battery that can store a significant amount of electricity for low cost. While current costs are high enough to prevent utilities from putting them in place, the estimate is that prices could fall by 75% within the next 15 years —all due to improving the technology.

And though lithium-ion battery storage technology works well for anything from an iPhone to a Tesla electric car, many battery developers are looking to other battery technologies capable of storing big power at a small price.

Finding the Cell that Sells

What are Grid Batteries and How Can They Charge Up the Future?

This might look absurd, but the science holds up, and revamping the old-school technology of the lemon battery could provide a way forward.

Flow batteries are currently the preferred type of large-scale, long-duration utility battery. Flow batteries use different kinds of agents (including vanadium, chromium, iron, and zinc), but they are essentially electro-chemical batteries just like a lemon battery. The difference is that the flow battery uses electrolyte solutions instead of solid poles (like the copper and zinc nails in a lemon battery). These electrolyte solutions are pumped into container divided by an ion-selective membrane that lets electrons flow from one pole to the other and creates an electrical current. Because the electrolyte solutions are circulated out of storage tanks, they can be changed out and refilled with fresh electrolyte. While the load to run pumps cuts into overall efficiency, replenishing the electrolytes makes their lifespan arguably limitless.

The drawback comes from the price of the electrolytes. Vanadium redox batteries are the the most advanced available at 80% efficiency, but their pure vanadium costs between $12 and $20 per pound, and the units must be kept below 95°F or the electrolyte becomes unstable.

One Silicon Valley start up called Imergy developed a method using low-grade vanadium found in iron ore waste, oil sludge, or power-plant fly ash. And with high operating temperatures (like 131° F), it’s very attractive to equatorial climes.

Other researchers are looking for even less expensive organic compounds that can be used as direct replacements for existing expensive pure vanadium systems. Meanwhile, one company is finding success with an zinc-iron redox system that is non-toxic and non-flammable and cheaper than vanadium.

Reducing electrolyte cost is also behind the molten metal battery developed by MIT researchers. They discovered as way to use cheap earth-abundant materials in a static enclosure that didn’t require pumps or electrolytic membranes. Two molten metals, one with a positive charge (Antimony) and one with a negative charge (Magnesium), are placed into a cell with a molten salt. These liquids settle out into layers, the positive on the bottom, the salt in the middle, and the negative at the top. Electron flow through the battery enables charging and discharging.

While these batteries are relatively inexpensive to build, they still need to be heated to nearly 1300°F to liquify the metals. Experiments with other metals have brought the operating temperature down to 518°F, but there’s still a lot of materials research to do to find a cost-effective, efficient, and practical system.

In short, large portions of the energy industry are investing good money into developing and implementing the technology of grid batteries. Being able to store unused energy for use at later dates and times will be a boon to energy efficiency at the national grid level, and it will assist in the development of additional renewable energy technology.

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About 

A native of Wyomissing Hills, PA, Vernon Trollinger studied writing and film at the University of Iowa, later earning his MA in writing there as well. Following a decade of digging in CRM archaeology, he now writes about green energy technology, home energy efficiency, DIY projects, the natural gas industry, and the electrical grid.

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