Interesting Engineering reports:US tech giant Google announced on Tuesday that it will build a new data center in Pine Island, Minnesota. The new facility will be powered by 1.9 gigawatts (GW) of clean energy from wind and solar, coupled with a 300-megawatt battery, claimed to be the 'world's largest', with a 30-gigawatt-hour (GWh) capacity and 100-hour duration... The planned battery would dwarf a 19 GW lithium-ion project in the UAE... Form Energy's batteries work very differently from most large batteries today. Instead of using lithium like the batteries in electric cars, they store electricity by making iron rust and then reversing the rusting process to release the energy when needed... Form's iron-air batteries are heavier and less efficient than their counterparts; they can only return about 50% to 70% of the energy used to charge them, while lithium-ion batteries return more than 90%. However, Form's batteries have one distinct advantage. They are cheaper than lithium-ion batteries, costing about $20 per kilowatt-hour of storage, which is almost three times as cheap... It will store 150 MWh of electricity and can supply to the grid for up to 100 hours, delivering about 1.5 MW at peak output. Thanks to long-time Slashdot reader schwit1 for sharing the article.Read more of this story at Slashdot.