By Mark Prigg For Dailymail.com
Published: 00:21 GMT, 7 December 2018 | Updated: 00:24 GMT, 7 December 2018
A radical new 'city battery' is capable of storing excess heat in molten silicon.
MIT researchers say their 'sun in a box' could store excess energy from solar and wind power, and deliver it back into an electric grid on demand.
This would allow cities to be powered not just when the sun is up or the wind is high, but around the clock.
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The 'sun in a box', officially called TEGS-MPV, for Thermal Energy Grid Storage-Multi-Junction Photovoltaics, stores heat in large tanks of white-hot molten silicon. It can then converts the light from the glowing metal back into electricity when it's needed.
The new design stores heat in large tanks of white-hot molten silicon.
It can then converts the light from the glowing metal back into electricity when it's needed.
The researchers estimate that a single storage system could enable a small city of about 100,000 homes to be powered entirely by renewable energy.
'One of the affectionate names people have started calling our concept, is 'sun in a box,' which was coined by my colleague Shannon Yee at Georgia Tech,' Asegun Henry, the Robert N. Noyce Career Development Associate Professor in the Department of Mechanical Engineering, who is leading the project, said.
It would be vastly more affordable than lithium-ion batteries, which have been proposed as a viable, though expensive, method to store renewable energy.
The 'sun in a box', officially called TEGS-MPV, for Thermal Energy Grid Storage-Multi-Junction Photovoltaics, converts electricity generated by any renewable source, such as sunlight or wind, into thermal energy, via joule heating — a process by which an electric current passes through a heating element.
The system would consist of a large, heavily insulated, 10-meter-wide tank made from graphite and filled with liquid silicon, kept at a 'cold' temperature of almost 3,500 degrees Fahrenheit.
A bank of tubes, exposed to heating elements, then connects