A Texas startup’s big energy idea: storing electricity underground
The Guardian, August 25, 2016
In a field in Central Texas, Aaron Mandell and his crew are running pumping equipment to bring a former oil and gas well back to life. But they’re not trying to extract black gold. Instead, they are developing a way to turn abandoned oil and gas wells into vaults for storing electricity.
The concept behind Mandell’s startup, Quidnet Energy, sounds simple: pumping water deep into the earth to fill up the cracks in-between rocks that previously held fossil fuels. When the pressurized water is released, it acts like a spring as it races through a turbine-generator above ground, powering it to produce electricity.
Mandell, co-founder and chairman of Quidnet, is part of a growing number of entrepreneurs in an emerging market to use batteries or other technologies to bank electricity when prices and demand are low, and discharge it when they are high. The US market installed 221 megawatts of energy storage projects in 2015, up from the 65 megawatts added in 2014, according to GTM Research. The market research firm expects the annual installation to exceed 1 gigawatt in 2019.
The energy storage market is growing fast primarily because of the increasing amount of solar and wind energy being produced across the country, from rooftop solar panels to acres of wind turbines. Storing solar and wind energy for later use circumvents a big disadvantage of these two types of low-carbon energy: they can’t always produce electricity whenever needed because demand fluctuates, reaching a peak in the early evening when people return home and turn on appliances or during hot summer months.
Quidnet plans to build and operate energy storage projects for power plant owners, utilities and industrial companies. The company’s technology is similar to a widely used and cheaper energy storage setup that pumps water from a dam to an upstream reservoir when electricity prices are low. During peak times when electricity is more expensive, the water is drained back down to run through a turbine to generate power.
Instead of an above-ground reservoir, Quidnet stores water underground. The company launched a pilot project this past year in Erath County, Texas, to demonstrate the concept. Mandell and his co-founder Howard Schmidt, an engineer with oil company Saudi Aramco, used an abandoned natural gas well, which runs 2,800 feet deep, into a reservoir that could hold 50k gallons of water. The project showed that after pumping water into the well for 12 hours, their technology could generate six hours of electricity.