The lack of economical and efficient grid-scale renewable energy storage systems is one big stumbling block in our progress toward better clean energy infrastructure, but one young inventor and her startup are making big strides in their pursuit of green energy storage.
Thanks to an additional $37.3 million in venture capital, green energy storage startup LightSail Energy gets another boost on their goal of supplying cheap, reliable energy storage, in the form of a regenerative air energy system (RAES).
The technology is the brainchild of founder Danielle Fong, who initially wanted to use compressed air to power scooters, but has since turned her attention to a larger order of storage: grid-scale.
"This investment round will enable LightSail to bring its first grid-scale energy storage products to market. We’ve proven that our transformative thermodynamics technology works at scale. With the support of a truly extraordinary group of investors, LightSail is well positioned to tackle, once and for all, a problem that’s bedeviled the electrical industry for a more than a century. We want to democratize energy – to enable renewable sources to supply energy on demand locally and at a lower cost than centralized fossil-fuel based generation." - Steve Crane, co-founder and CEO of LightSail Energy
While compressed air storage isn't a new invention, by any means, Fong's innovations greatly improved the efficiency of this type of system, which has been hampered by efficiency losses of up to 50%. Fong's improved version uses a mist of water sprayed into the air storage tanks, which acts to absorb and store the heat generated from the compression (and release it on expansion), allowing the LightSail system to achieve a 90% thermodynamic efficiency in the process, and a 70% overall round-trip efficiency.
"To store energy, an electric motor drives an air compressor. To deliver energy, we reverse the process - the air compressor becomes an expander, and the electric motor becomes a generator.
Heat from compression is stored or rerouted to nearby buildings, providing heating. During expansion, heat is extracted from storage, or buildings providing air conditioning. This dramatically increases building energy efficiency."
The prototype storage tanks from LightSail are made with a proprietary compound that is said to enable them to handle higher pressures, without having to be buried under the ground, and because the tanks will be within 20 degrees of the surrounding air temperature, won't need the same level of insulation as similar systems did in the past.