MIT, and Elsewhere, Energy Storage a Hot Topic

January 9, 2019

Young engineers want to go where the action is – and that means renewable energy, and dealing with climate change.

MIT News:

For renewable energy technologies like concentrated solar power (CSP) to make sense economically, storage is crucial. Since the sun isn’t always shining, solar energy needs to be somehow stored for later use. But CSP plants are currently limited by their steel-based infrastructure.

“Improving energy storage is a critical issue that presents one of the biggest technological hurdles toward minimizing greenhouse gas emissions,” explains Asegun Henry, the Noyce Career Development Professor and associate professor of mechanical engineering.

An expert in heat transfer, Henry has turned to an unlikely class of materials to help increase the efficiency of thermal storage: ceramics.

Currently, CSP plants are limited by the temperature at which they can store heat. Thermal energy from the solar power is currently stored in liquid salt. This liquid salt can’t exceed a temperature of 565 C since the steel pipes they flow through will get corroded.

“There has been a ubiquitous assumption that if you’re going to build anything with flowing liquid, the pipes and pumps have to be out of metal,” says Henry. “We essentially questioned that assumption.”

Henry and his team, which recently moved from Georgia Tech, have developed a ceramic pump that allows liquid to flow at much higher temperatures. In January 2017, he was entered into the Guinness Book of World Record for the “highest operating temperature liquid pump.” The pump was able to circulate molten tin between 1,200 C and 1,400 C.

“The pump now gives us the ability to make an all-ceramic infrastructure for CSP plants, allowing us to flow and control liquid metal,” Henry adds.

Rather than use liquid salt, CSP plants can now store energy in metals, like molten tin, which have a higher temperature range and won’t corrode the carefully chosen ceramics. This opens up new avenues for energy storage and generation. “We are trying to turn up the temperature so hot that our ability to turn heat back into electricity gives us options,” Henry explains.

One such option, would be to store electricity as glowing white hot heat like that of a light bulb filament. This heat can then be turned into electricity by converting the white glow using photovoltaics — creating a completely greenhouse gas free energy storage system.

“This system can’t work if the pipes are temperature limited and have a short lifetime,” adds Henry. “That’s where we come in, we now have the materials that can make things work at crazy high temperatures.”

Henry’s record-breaking pump’s ability to minimize greenhouse gas emissions goes beyond altering the infrastructure of solar plants. He also hopes to use the pump to change the way hydrogen is produced.

Hydrogen, which is used to make fertilizer, is created by reacting methane with water, producing carbon dioxide. Henry is researching an entirely new hydrogen production method which would involve heating tin hot enough to split methane directly and create hydrogen, without introducing other chemicals or making carbon dioxide. Rather than emit carbon dioxide, solid carbon particles would form and float on the surface of the liquid. This solid carbon is something that could then be sold for a number or purposes.



One Response to “MIT, and Elsewhere, Energy Storage a Hot Topic”

  1. Keith Omelvena Says:

    Now this is the sort of story that gives me hope for the future 🙂

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