The story of Energy Cache, a drop-dead simple energy idea
Last week Bill Gates briefly mentioned that he made an investment in an energy storage startup that he called “gravel on ski lifts.” Contributor Michael Kanellos put two and two together and guessed that Gates’ reference was to the startup Energy Cache. Well, following that article on Monday, we’ve done an extensive interview with the founder and President of Energy Cache, Aaron Fyke, and we wanted to give you the details of how the technology works, how the company came into being, where it’s headed and how Bill Gates and Bill Gross became involved.
The energy storage problem
Back in 2009, Fyke — a mechanical engineer out of MIT who has both cleantech venture investing and entrepreneurial experience — started tinkering with how to tackle the problem of energy storage. The power grid currently utilizes very little energy storage technology and constantly has to balance supply and demand in real time — that makes it pretty inefficient. In addition, with the development of clean power like solar and wind, which only generate power at certain times of the day, there will need to be a lot more energy storage technologies used to smooth out the intermittent generation.
One of the most widely-embraced forms of energy storage by utilities is currently pumped hydro, where energy is used to pump water up a hill and then when energy is needed, the water is released to flow back down the hill. This is one of the cheapest forms of energy storage — far cheaper than big battery farms that can store energy. The Electric Power Research Institute (EPRI) says that there is at least 127,000 MW of pumped hydro energy storage projects globally, and pumped hydro makes up a whopping 99 percent of the world’s energy storage technologies.
However, pumped hydro technology has a few of its own issues. One is that it can only be done in very specific locations that have both a certain level of elevation and also reservoirs for the water. Another problem is these locations can take years to permit and cite. Lastly, pumped hydro is not all that flexible when it comes to being able to provide quick bursts of power to the grid to help it run more smoothly, called frequency regulation, because water flows can be difficult to stop and reverse quickly.
