When it comes to the business of Energy there are three important aspects to it.
- Energy Generation
- Energy Storage
- Energy Distribution
In this short article, we will focus on the second aspect i.e. Energy Storage. The need for innovative solutions for energy storage is immense especially in the context of solar and wind energy — and especially for large-scale requirements. The energy so generated need to be either utilised immediately or stored efficiently or face the risk of being lost forever.
One of the recent innovations in the energy storage arena is gravity-based energy storage. This storage mechanism is a development on the pumped hydro storage (PHS) technology. PHS utilises the mass of water at different levels to store large quantities of energy. For PHS to be viable, the size of operations will have to be enormous. This is true given that the cost of tunnels used in PHS goes up two times, when the tunnel diameter is doubled. Ofcourse, matematically you would figure out that the water passing through it quadruples when the diameter is doubled.
A player in the business, Gravitricity brings a layer of innovation to the above-mentioned PHS technology. Here’s how. Instead of tunnels used in PHS, Gravitricity is designed as a standing shaft of about 1500 meters weighing about 500 MT to 5000 MT. When the weight within the shaft increases, the system is charged and the opposite happens when the weight is lowered – the system discharges the electricity to the grid. High tension wires inside the shaft keep the weights from hitting the walls within and disturbing the equilibrium of the structure.
There are other players in the business as well like the Swiss-based company, Energy Vault that uses automated system of adding/removing of blocks of upto 35 tons with the help of a coordinated array of six cranes in the open – (this is unlike Gravitricity’s method of adding individuals weights inside the shaft). Using software the system decides the stacking order and weights. The systems needs to factor in wind direction & wind speed to calculate the weighs to be loaded and unloaded.
New Energy Let’s Go uses both water and weights to achieve the purpose of storing energy. Energy is stored by resting a large rock on a piston with electrical pumps and hydraulics lifting and droping the piston.Gravity power is another player that is using gravity to store energy, may be with a variation to the above ideas.
Engineers designing these models are aware that the systems needs to be capable of switching to full output in a beat. The companies implementing the technologies are required to have complete clarity on the operationsal size, cost aspects, reliability factor, and of course the energy requirement & capacity and accordingly choose the appropriate solution.