Solar, wind-powered “frozen air” electricity generator proposed for northern VT

How does it work? Where would it be built? What will it cost us?

By Guy Page

December 20, 2019 – The first-in-the-nation “liquid air” power storage and generating plant announced Wednesday could be a game-changer for solar and wind power in Vermont.

Highview Power of London, England and Encore Energy of Burlington announced plans to build a 50 megawatt power storage facility in northern Vermont.

How does it work? Like the rechargeable radio battery attached to the stationary bicycle on Gilligan’s Island, the proposed 50 megawatt Highview Power storage/generation facility would store electricity created by spinning wind turbines or photovoltaic solar panels. As planned, such a system could solve solar and wind power’s Achilles Heel of “intermittency.” Solar and wind depend on the vagaries of weather. Sure, their fuels are free, renewable and zero-carbon. But unlike fossil fuels and to a lesser extent hydro and nuclear, they’re unreliable. Imagine lazy Gilligan stopping pedaling right when the Skipper is about to find out when the rescue plane is coming, and you get the idea. Sometimes they make too much power, risking damage to power lines and other infrastructure.

Where would it be located? The press release only says “northern Vermont.” But it stands to reason that the site ideally would be located in northeastern Vermont. Intermittency has been a particular worry in the Northeast Kingdom, where wind farms and a growing number of large-scale solar facilities have raised concerns among Vermont regulators that that the grid could become dangerously overloaded. Highview said “the Vermont facility will contribute to resolving the longstanding energy transmission challenges surrounding the state’s Sheffield-Highgate Export Interface (SHEI) and enable the efficient transport of excess power from renewable energy sources, such as solar and wind power to help integrate them on the power grid.”

Utilities, regulators and transmission grid operators have puttered around the intermittency problem with better real-time weather modeling and “buffering” turbine and grid improvements. It all helps. But the basic problem is still there. That’s why battery storage is seen as the decisive longterm solution to intermittency. There’s nothing new about grid-scale battery storage, but “liquid air” technology is new and breathtaking in its simplicity – at least on the theoretical level, a Dec. 19 Environment and Energy Leader blog post explains:

Highview Power says its proprietary liquid air energy storage system, called CRYOBattery, uses excess or off-peak electricity to clean and compress air, which gets stored in liquid form inside insulated tanks at extremely cold temperatures.

“Air turns to liquid when cooled down to -196°C (-320°F), and can then be stored very efficiently in insulated, low pressure vessels,” Highview Power’s site explains. “Exposure to ambient temperatures causes rapid re-gasification and a 700-fold expansion in volume, which is then used to drive a turbine and create electricity without combustion.”

Get it? It’s just a different way to spin power-producing turbines. In a hydro dam, rushing water spins turbines. In a natural gas plant, combustion turns turbines. With the Cryo Battery, it’s warming, expanding air that spins the turbines. Then the release moves on from the “how” to the “what,” while suggesting an answer to  the always-important “how much.”

Energy generated from the turning turbine can then be used at peak times, the company said.

What will the power cost? The press release doesn’t say, because Highview and Encore don’t know – yet. However, the reference to “peak times” suggests it will be expensive. Peak power is dispatched by ISO-New England grid dispatchers when demand is high and they need to keep the lights on. Even traditional, fuel-cheap oil and coal “peak” plants are expensive, because they must recoup their costs with peak sales alone. A pilot plant using new technology and powered by already-expensive solar and wind power would have to charge a pretty penny, even if – as Highview claims – it’s safe and has half the operating costs of traditional lithium batteries:

Highview Power’s proprietary liquid air energy storage system, called CRYOBattery™, relies on low-risk, proven technology, generates zero emissions, has zero water impact and can be delivered at a cost of approximately half of the current cost of traditional lithium-ion batteries.

Who will pay? The Encore press release states, “Highview Power and Encore are in discussions with potential utility and transmission grid operator customers regarding the capabilities and services the facility can provide.” No doubt! If the plummeting cinder block of construction and operation falls on Vermonters alone, we will assuredly feel the pain. But if ISO-New England accepts the project as a valid transmission system upgrade, then the cost would be spread out equally among all consumers in all six New England states. If so, Vermont’s share could be in the single digits. And if Uncle Sam takes an interest, he might pick up a share of the cost, too.

The future of the Vermont Cryo Battery probably comes down to money. If it works for the major players, including all of the above and Vermont energy regulators, too, it might work out. If not – it’s back to Gilligan’s Island.