November 16, 2011 | By Bill Gates
Taking Energy Storage to a Higher Level
My active interest in new energy technologies is fueled by my firm belief that innovation can help reduce carbon emissions – and improve the lives of millions of the world’s poorest people. A new approach to storing electricity could help lower the cost of clean, renewable energy for everyone.
I get to hear about a lot of unlikely ideas for making energy cleaner and cheaper. I have to admit that I was a bit skeptical when I heard the idea that a number of energy challenges could be solved just by moving stuff uphill. Literally.
But the idea came from the team at Idealab, led by Bill Gross, so I was intrigued. Bill and his team are remarkably creative. They’re inventing things all the time, and their track record is impressive. For example, it includes the invention of Internet keyword search, the basis of online search advertising. I especially enjoy brainstorming with Bill and his team because they’re interested in developing ideas that are broadly useful, including in the poorest parts of the world.
It turns out, Bill’s idea for storing energy could help make solar and wind energy more useful and affordable for everyone. It could also help in poor countries and rural areas where energy transmission systems are not well developed.
We use batteries all the time, so we tend to think of energy storage as being pretty simple. When we think about meeting energy needs, we often don’t think about storage, we think about ways to produce more. But storage is a critical problem if we’re going to expand the use of solar and wind power. Unlike coal or gas, solar and wind power are intermittent. They can’t just be cranked up when needed, like when demand peaks, and yet they’re also not very easy to store in batteries for later use.
When Bill first approached me with an idea for storing energy by simply moving things uphill, and then releasing them to produce energy, I thought it was a novel idea, but likely to be very inefficient. But we got a group of scientists together and talked about creative ways of coming at this. It now looks like the process may be more efficient than I first thought.
The idea is now being developed by an early-stage company, Energy Cache, formed at Idealab in Pasadena, California. There are a lot of challenges to overcome, but it’s worth exploring.
How does it work?
It’s related to the very old idea of pumping water for storage in natural ponds and pools. It’s also related to hydropower – generating electricity from the force of falling water – but on a smaller scale that doesn’t raise the siting and environmental issues associated with new hydroelectric dams. The economic model doesn't require a huge amount of space or flooding a valley.
When the weather is windy or sunny, the Energy Cache system uses surplus wind or solar power to move heavy material to a higher elevation. When the power is needed, stored material is released to generate it. Simple as that, although there are still a lot of details to be worked out.
This system could help improve the economics of alternative energy, making it a more reliable supplement to fluctuating and peak energy needs. In the developing world, where many remote communities are disconnected from the energy grid, or where the grid is subject to frequent outages, Energy Cache could be a way of creating an affordable, efficient local energy storage solution.
The company has built a prototype that shows it can likely beat the economics of traditional pumped-water storage. It has patented the methodology and is building a full-scale system at a test location.
Take a look at our photo gallery to learn more. I’m excited about the possibility that this simple yet ingenious idea could help bring cheaper, cleaner energy for people all around the world.