Lightsail Energy: Store and Recoup Energy Using Compressed air

Storing energy in the form of compressed air is a solution that would accompany the rise of renewable energies and help the world meet the ever-increasing energy demand.

With the increasing share of renewable energies in the power generation mix, novel solutions of mass energy storage should be developed to guarantee the availability of renewable energy production so that their share of energy consumed can continue to increase.

Compressed Air Energy Storage

The storage of power is an important issue in the energy transition because that helps to avoid wasting energy produced during off-peak hours by intermittent energy sources. The most common renewable intermittent energies are solar and wind–which also happen to be the most popular renewable energy source.

Renewables intermittency issue notwithstanding, compressed air energy storage (CAES) would overcome the limitations of existing storage solutions, such as site constraints, efficiency, costs, scaling or environmental impact.

The PNNL (Pacific Northwest National Laboratory) and Bonneville Power Administration, along with other technical partners, conducted a feasibility study of CAES in Washington and Oregon.

The PNNL seeks to develop grid-scale CEAS capacities and, after screening suitable sites, they designed two CEAS plants, one conventional (running on gas) and the other hybrid geothermal, using geological cavities as reservoirs.

Currently, there are only two operating CAES facilities worldwide; the first (290 MW) was built in 1978 in Germany, and the second (110 MW), commissioned in 1991, is situated in McIntosh, Alabama.

LightSail Energy’s CAES System

Bill Gates, Vinod Khosla (Khosla Ventures), Peter Thiel and other billionaire investors and major companies, like the French oil company Total, all have shelled out millions of dollars to LightSail Energy during different funding rounds.

Not to be confused with Lightsail, which is the name of the Planetary Society’s project to develop a space sail propelled by the momentum of traveling photons.

Founded in 2009, LightSail Energy is a California-based startup specializing in innovative systems that enable storing large quantities of energy in the form of compressed air. (update: the company has ceased operation due to lack of funds.)

To overcome the issue of heat (from energy compression), LightSail’s system uses a mist of water spray during the compression process. Heat absorbed is captured and stocked for later use and the compressed air gets stored in a tank.

The process is reversible as power can be restored by means of a hot water spray: the energy of the heat contained in the water is absorbed by the compressed air and then converted into mechanical energy.

The compressed air can be stored in standard carbon-fiber tanks or, for large scale plants– such as the above-mentioned two plants in Washington and Oregon–in underground caverns.

LightSail Energy claims its system to be the cleanest and most economic CEAS in the world, with an unparalleled thermodynamic efficiency that translates to a low cost per kW.