One of the biggest problems in renewable energy is what to do when the sun sets or the wind dies down. Some companies like Tesla are building giant rechargeable batteries to store extra energy for later, but these batteries are expensive and only last a few years. Google's moonshot factory is working on something that could be better.
Google's moonshot factory, officially called X, is responsible for the company's Project Loon, a balloon internet service project, and it kickstarted the self-driving car company Waymo. Now the moonshot factory is turning its attention to solving the energy crisis with a new design for an energy storage device that uses molten salt and ultracool antifreeze.
The project is codenamed "Project Malta," and it's designed to store energy as heat. The setup features four gigantic insulated vats, two containing salt and two containing antifreeze. When supplied with electricity, a heat pump sends hot air into the salt vats and cold air into the antifreeze vats. There, the energy can be stored for hours or even days before it needs to be used.
Once a switch is flipped, air from the two sets of vats can be mixed together, and the mixing of hot and cold air creates powerful gusts that spin a turbine, reproducing electricity. The process is less volatile than Tesla's lithium-ion batteries, can store much more energy, and can be built in more places for less cost.
None of the technology used by Malta is new or groundbreaking, but the challenge for the project is building the facility without using expensive materials. It would be easy to make the salt very hot or the antifreeze very cold, but then the vats would need to be built out of steel or ceramic, making the project much more costly. Instead, the Malta team is trying to figure out how to efficiently store energy without raising or lowering temperatures to extremes.
The project team has already built a small prototype, and they are looking for a partner to help build a full-scale version for an energy grid. If Project Malta is successful, they could allow energy companies to provide much more power with renewable energy, dramatically reducing our reliance on fossil fuels.
Source: Popular Mechanics