Stanford students turn oil wells into batteries

This article was published by on the Stanford News website on May 14, 2020, and was written by Matthew Vollrath.

In the winter of 2019, Kemp Gregory, a graduate student in Civil & Environmental Engineering at Stanford University, got a call from Walker Colt. Friends since childhood, they had both begun their careers as petroleum engineers in Houston, Texas, but hoped to transition to something greener. Now, Colt had an idea for how they could do that.

Renewell Energy’s engineering lead Stefan Streckfus, left, and co-founder and team lead Kemp Gregory. (Image credit: Diana Go)

“He said we should take inactive oil wells and turn them into energy storage devices,” recalled Gregory, who at first thought his friend’s idea was a stretch.

But the more the pair researched, the more sense it seemed to make. The United States has 3.1 million inactive oil wells. Decommissioning these wells is hugely expensive, so oil companies are eager to pass them off. Also, oil fields are connected to power grids, so the infrastructure for bringing in electricity and sending it back out already exists.

Colt was inspired by something called a Gravity Light, a reading lamp for off-gridders powered by a descending weight. With a bigger weight, he suggested, they could use the same principle to store power on a large scale. Gregory pointed out that one piece of oil-drilling equipment, the electric submersible pump, generates power when it accidentally spins backward. By exploiting this flaw, they could potentially create a system similar to pumped-storage hydropower, he said.

After several weeks of back-and-forth, the pair settled on a few promising designs. With some quick calculations, they discovered that their plan could generate just enough power to work.

It was time to get serious. Gregory knew about a course on energy entrepreneurship at Stanford, one that taught students how to create a viable business, get advice from industry experts and, ultimately, attract funding.