Why do batteries matter? Look at all your electronic devices: from laptops to smartphones to Kindles or iPads, even your watch. Those electronics are getting better at reducing the amount of energy they need, but as they do, you get greedy and want their capability to increase. The battery, and how much energy you can store in a given volume and weight, is the defining factor in this whole field.
Then there are electric cars. If we can make batteries with double the energy density of today’s and drive the price below $200 a kilowatt-hour (versus $300 to $800 today, depending on type and weight), we could have a car with a 300-mile range, even with the air conditioner or heater turned up, that sells for $25,000 to $30,000. The Department of Energy’s goal is to get batteries to $150 a kilowatt-hour by 2020.
Finally, there are the utility-scale batteries, which are very important for renewable energy. Wind and solar power are going to keep increasing. Wind is already the second-cheapest form of new energy, after shale gas, and it will become the cheapest within a decade. Right now utility companies get about 4 percent of their power from renewable sources other than hydro—and that 4 percent is roughly all from wind. You want to see a day when renewables are 50, 60, 70 percent. Utility companies will need batteries to stabilize the flow of renewable energy into the grid, plus a better electrical control system to do the switching. People may have these batteries at their houses instead of generators.