Dive Brief:
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General Electric is working on an energy storage technology that can use captured carbon dioxide.
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GE’s technology combines several steps to store power as heat and cold and then release the stored energy through a “sunrotor” that GE has developed.
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GE says the sunrotor is small enough to sit on a desk, but is capable of producing up to 10 MW.
Dive Insight:
Carbon dioxide is often maligned as a harmful industrial byproduct, but if technology being developed by GE Research pans out, captured CO2 emissions could be put to use to store energy for later use.
GE’s research draws on an existing technology, concentrating solar power (CSP), which uses an array of mirrors to focus sunlight on a fluid in a tower. The heat from that fluid can be used to make steam to drive a conventional turbine. That heat can also be used to melt salt, which turns molten at over 1,000° Fahrenheit, and holds the thermal energy long enough to be used to create steam to run a turbine into the evening hours.
Scientists at GE Research say they have found a way to improve the efficiency of that process by combining the heat of the molten salt with the cold of frozen CO2, commonly known as dry ice. CO2 freezes at -109.3°F. When subjected to the heat of molten salt, it can be turned into a supercritical fluid, a state of matter that is neither liquid or gas.
GE says it has created a type or turbine – they call it a sunrotor – that can harness the energy of supercritical CO2 at high efficiency.
Stephen Sanborn, senior engineer and principal investigator at GE Global Research, says sunrotors could yield as much as 68% of the stored energy back to the grid.
GE has developed a prototype sunrotor and is working on a full scale, 33-MW model that would be capable of generating up to 100 MWh. Sanborn says it could take five to 10 years to move the system from concept to market.