Sat. Sep 24th, 2022

How can we make wind a more versatile energy source?  By adding storage.
enlarge / How can we make wind a more versatile energy source? By adding storage.

An energy storage startup that gained a foothold in Alphabet’s X “moonshot” division announced last week that it will receive $26 million in funding from a group of investors led by Breakthrough Energy Ventures, a fund funded by Jeff Bezos. and Michael Bloomberg as investors and whose chairman is Bill Gates. The startup, called Malta, uses individual barrels of molten salt and antifreeze-like liquid to store electricity as thermal energy and send it to the grid when needed.

Malta’s system stores electricity by taking that electricity, using a heat pump to convert the electricity into heat, and storing that heat in molten salt. Then, when electricity is needed again, the system reunites the molten salt with the cold liquid, using a heat engine to convert the thermal energy back into electricity, which can be sent back to the grid.

The concept is outlined in a July 2017 paper in the Magazine for renewable and sustainable energystating that “Round-trip efficiency … appears to be competitive with that of pumped hydroelectric storage.” [Update: Ars is seeking a number more specific to Malta’s system and will update again when that number is made available.] Pumped hydroelectric storage is one of the oldest forms of electricity storage, using electricity when it is cheap and plentiful to pump water up a hill, then releasing that water through hydroelectric turbines when electricity is expensive and scarce. .

In fact, many parallels can be drawn between Malta’s system and other forms of energy storage. A liquid air energy storage system in the UK uses temperature differences (as Malta does) to expand condensed air and put more electricity back into the grid when needed. Solar thermal systems send concentrated sunlight to a central tower to heat molten salt, which can store that heat long before it’s used. This allows solar thermal systems to continue sending energy to the grid after sunset.

Malta’s business story is that its thermal pump storage system can be placed anywhere (unlike hydroelectric pump storage, which requires elevation changes, or compressed air storage, which is primarily deployed near natural underground caves). It can be easily expanded and, unlike chemical batteries, such a system is made of common and cheap industrial materials with a service life of 20 years.

Storage has been a major concern among energy industry viewers in recent years. As it becomes more urgent for the world to refrain from burning fossil fuels, it is also clear that the intermittent solar and wind energy makes these two sources insufficient on their own to replace fossil fuels. However, with large-scale, cost-effective energy storage solutions, it is becoming increasingly possible to add more and more renewable energy to the grid.

Malta claims its system can store energy for weeks and add value to both renewable and traditional electricity sources. “Malta has the potential to make existing capital investments in both fossil and renewable generation more productive while dramatically improving the stability and resilience of the power grid,” the company’s press release said.

Currently, large-scale energy storage is an expensive solution, but ideas like Malta’s address many of the cost issues, at least on paper. Starting up a pilot project will be the next test.

List image by Germanborrillo

By akfire1

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