Danielle Fong Uses Air for Green-Energy Storage

Danielle Fong’s Lightsail Energy has developed the technology to overcome the biggest obstacle to the widespread adoption of renewable energy technologies like wind and solar — economical mass storage of mega-watt hours of electricity.

Fong’s novel approach uses large tanks of compressed air in place of costly batteries that make the cost of storing energy prohibitive. Electricity from renewable sources like solar panels or wind turbines is used to power a motor that compresses air in a large tank. Later, when electricity is needed, the compressed air is used to turn a power-generation turbine.

One of the hurdles to creating an energy-efficient compressed-air system is the high temperature — nearly 1,000 degrees C — produced by extremely-high-pressure compression. Its result in large energy loss in the form of heat and requires expensive materials to contain the compressed air. Fong discovered the solution in an old book: spray water into the air being compressed. That causes much of the heat to be transferred to the water. The resulting steam is separated from the compressed air and diverted into a separate tank where its energy is captured. Fong’s compressed-air energy storage system achieves 70% energy-efficiency — about the same as the most efficient batteries. Fong has also found a material from which to build the storage tanks economically. But the compressed-air system could cost as little as a tenth of the cost of batteries over the long term.

“It could radically reorient the economics of renewable energy,” Fong says.

Fong, 24, founded LightSail Energy in 2009 in Berkeley, California, to develop air-powered scooters. Venture capitalist Vinod Khosla persuaded her to shift her focus to large-scale storage of electricity for the power grid. The technology is ready to be scaled up to units capable of powering entire cities, and Lightsail has already signed contracts to supply its systems to several renewable-energy developers. The first pilot unit will ship in 2013 or 2014.

Danielle Fong was born and raised in Halifax, Nova Scotia, Canada. She found herself frustrated by the slow pace of learning at public schools. At the age of 12 she dropped out of junior high school to attend Dalhousie University. She graduated in 2005 at the age of 17 with first class honors in computer science and physics. She pursued a PhD at Princeton’s plasma physics department but went on leave before completing the program.

“I entered college at a very young age because I found that school was not moving fast enough for me to do the things I wanted to do,” Fong said in an address to the UN’s Economic and Social Council in which she proposed the creation of an international program to encourage young entrepreneurs. “I entered graduate school at 17. I tried entering into the world’s best energy generation program in fusion energy and I found that pace was too slow as well. So I came into silicon valley… I decided to make my own way. There was no job that I could join in order to make that difference. I had to create it myself.”

In December 2011 Fong was included in Forbes’ “30 under 30”. She is a regular guest contributor to the Women 2.0 blog and was a featured speaker at the Women 2.0 PITCH Conference & Competition 2012. Her blog “Insights by Danielle Fong” features essays on entrepreneurship, green technology and various other topics.