A new technology using gravity-based battery systems could provide a simple solution to a complex problem. As the world gears up to use alternative energy solutions such as solar and wind power, creative companies are also looking for back-up energy systems when renewables occasionally falter, like on a cloudy or windless day. One such solution is gravity-based battery systems. A Swiss-based company called Energy Vault is currently testing the waters at two sites, one in the United States and the other in China. The technology is fairly basic: using a combination of heavy, solid blocks and a tall tower, a crane can lift the blocks up to 35 stories high, which stores the surplus kinetic energy. The system keeps the blocks suspended until power is needed—for instance, when clouds prevent the sun from providing solar power. When this occurs, the crane lowers the blocks, which then pull-on cables, spinning a set of turbines and producing electricity.
Interestingly, the heavy blocks, which weigh 35 metric tons each, consist of their own environmentally friendly materials. Made up of soil and locally sourced waste, they serve the double purpose of helping produce energy and remove waste from landfills. The blocks are purported to store up to 80 megawatt-hours of energy, continuously discharging power for up to 16 hours. After testing at the two sites, Energy Vault hopes to progress gravity-based battery systems technology so that it can be automated, using proprietary algorithms. Time will determine if the concept has a realistic future.
