How and why did you start thinking about mass-scale energy storage?

At Southern California Edison, I had to match supply and demand 24/7, in almost real time, and the reason that’s so hard is you’re doing it with a product that can’t be effectively inventoried. If you think about it conceptually, there are two ways to address it, one good and one bad. The bad way is to back it up with fossil fuels. That to me is counterproductive to the whole idea of getting green. The second way is to have cost-effective, large-scale energy storage, where, when I have excess generation—say those windmills are cranking in the middle of the night—I can store it and then discharge it when people need it most.

What are some of the storage options that are out there?

You can do fast-response, relatively small-scale energy storage with things like flywheels. Moving up into a slightly bigger scale, how do I power my vehicle? With batteries! There are a number of competing battery technologies, whether it’s lead-acid, lithium-ion, nickel-zinc. They all have promise, but at this point, when you look at the notion of storing energy from a big wind or solar farm, battery scale isn’t even close.

What technology is up to the task?

The proven historical answer is pumped-storage hydroelectricity. It’s wonderful technology, but it requires massive construction. You typically take canyons and dam them off and flood them, and you have to build tunnels and pipelines and put in a big powerhouse. Permitting and licensing can take a decade or longer. And then you have to worry about water management in areas that are typically arid, and you have competing demands for fish,
recreation, and irrigation. It becomes a resource that serves many social goals.

How did you and your team at ARES come up with the idea for rail energy storage?

The proven historical answer is pumped-storage hydroelectricity. It’s wonderful technology, but it requires massive construction. You typically take canyons and dam them off and flood them, and you have to build tunnels and pipelines and put in a big powerhouse. Permitting and licensing can take a decade or longer. And then you have to worry about water management in areas that are typically arid, and you have competing demands for fish, recreation, and irrigation. It becomes a resource that serves many social goals.

How does it work?

We recognized that if we used electric locomotives with cars full of mass—essentially concrete blocks—and moved them up a slope, we could store energy effectively, and when we brought them down the slope, we could use that motor as a generator to produce electricity. We built a 1,000-foot-long track and a six-ton car in Tehachapi, California. We like to run on a 6 to 9 percent grade, which is very gentle, and we run less than 20 mph in most instances. We silently chug up and down, with no water, no fuel, no emissions, no hazardous substances. In Tehachapi, we used what we call a trackside conductor rail. An arm comes out of the side of the car and into that enclosed rail, and it acts like an extension cord that goes back to the grid.

Why do you see storage as being critical to the success of renewables?

The quickest way to kill renewable energy is to have it not work—to have poor reliability, to have people’s lives and businesses adversely affected. So it’s incumbent on us in the industry to do good by doing well—to make this work the way it should so people will see little disruption in their lives. We always say that ARES is not the solution; it’s part of the solution. We think batteries have a great role. Flywheels, pumped-storage hydro—all of these things are complementary, and we have a shared goal of enabling a cleaner future.

Appears In

Energy Storage Expert Jim Kelly Brings Renewables to Railroads