**Using excess energy production to lift a heavy object, then lowering that object when production is low to keep energy levels high.** “Gravity Batteries” are an idea wherein energy is stored as **gravitational** potential energy. A gravity battery uses excess energy production to lift a heavy object, then lowering that object when production is low to keep energy levels high. This could be concrete blocks, rocks, garbage in a box, or, most common of all - water. Pumping water back up from the low side to the high side of a hydroelectric dam is a viable form of gravity batteries. There are startup companies that want to make large-scale gravitational batteries for deployment alongside generation stations. This technology may never take off. # Pros - Solves the problem that [[Energy Generation is Bursty]] - Doesn’t involve mining chemicals and producing batteries, which are hard to recycle # Cons - Gravitational batteries have a poor [[Energy Density]]. - Gravitational potential energy of a 5 gallon bucket full of water, 30 feet in the air: 0.00047 kWh Taking into account the [[Average Energy Cost]] - that’s $0.00007 - A 55 gallon barrel on your roof is approximately the same as a AA battery - Making concrete isn’t great for the environment. **** ## Source ## Related - [[Average Energy Cost]] - [[Energy Generation is Bursty]] - [[Energy Storage]] - [[Energy Density]] - [[Energy Content Reference Points]] - [[Heat Battery]]