Liquid air could work better than batteries or hydrogen for storing excess energy produced from wind turbines or other renewable energy sources during off-peak times, according to the Institution of Mechanical Engineers. A company in the United Kingdom is testing how the liquid air method—originally developed to power vehicles—could help use some of this “wrong-time” energy.
The method would use electricity from off-peak hours to take in air—removing carbon dioxide and water vapor in order to chill air to a cryogenic state. This turns what’s left, which is mostly nitrogen, to a liquid that is stored in giant vacuum flasks until demand increases and it can be warmed again. Re-expanding air could be used to drive turbines.
While the growth in renewables is among the contributing factors to the 9 percent reduction in carbon dioxide emissions in the U.S. since 2005, one analysis says this decline is unlikely to continue unless there are major departures from the way energy is currently produced and used. The report lays out specific energy-related changes that would need to occur between now and 2035 to have a chance at reducing carbon dioxide emissions to 38 percent below 2005 levels. These include: growth in renewables beyond the 5 percent electricity makeup today to 31 percent by 2035 as well as gains in residential, commercial and industrial energy-using equipment.