Photo by deeje
Our current energy system is wasteful in part because power plants have to be ready for sudden surges in demand. At present, the U.S. gets half of its electricity from coal. King Coal may be a cheap date, but coal-fired power plants can’t be turned on and off easily, so they often produce extra power. A new energy storage system could cut peak demand fuel consumption in half by using that excess energy to chill liquid nitrogen and oxygen. Then, the next time demand spikes, the mixture can be boiled using waste heat to produce power.
Researchers at the University of Leeds and the Chinese Academy of Sciences proposed the new system, which uses excess energy produced by power plants to chill a nitrogen-oxygen mixture called cryogen. Presently, when demand spikes, natural gas plants are quickly powered up. But those plants are expensive and inefficient. Boiling the cryogen at these peak times would supplant the use of some natural gas and make what is used go farther because it would be burned with the pure oxygen from the mixture.
One more benefit: burning natural gas this way produces less of the greenhouse gas nitrogen oxide. And the carbon dioxide it produces is in solid form — dry ice — making it easy to capture. So the system is not just more environmentally friendly: it’s also cheaper.
Now to get this great idea out of the lab and into the grid!