Alphabet Inc.’s ambitious X lab is working on finding a way to store renewable energy. The project, Malta, utilizes antifreeze and salt in a system that can store renewable energy from wind and solar sources. Malta isn’t dependent on the productivity of solar panels or wind turbines and can store energy for a significant period.
The early test prototype for Malta has four cylindrical tanks, all connected through pipes attached to a heat pump. Two of the tanks contain salt and the other two have hydrocarbon liquid or antifreeze. The system creates a stream of hot air to warm the salt and cold air for the antifreeze. The hot and cold air move towards each other, creating gusts that can turn a turbine and produce electricity. The tanks’ insulation determines how long the system can store energy, which could be from several hours to even days.
A Cheaper Alternative
Malta’s head engineer, Raj Apte, reports that this thermal salt-based storage could be cheaper compared to lithium-ion batteries and other grid-scale storage technologies. Apart from cost practicalities, Malta operates at a lower operating temperature. It does this without using the expensive materials such as steels and ceramics. In addition, with Malta, energy storage works at any scale.
A challenge that could hamper Malta is the capital funding required to drive such a project. Although Alphabet has huge surplus cash, the giant has recently shown tendencies to shy away from projects not in its core area of computing.
Unlike X lab’s other projects—Project Loon (high-altitude balloons) or Project Wing (drone delivery)—Malta is not an official project. X now wants to bring Malta in full public knowledge. This is because it plans to build a prototype plant to test using stored renewable energy to feed a power grid.
Bloomberg New Energy Finance expects the power storage capacity to increase to 45 gigawatts by 2024. The corresponding market size for this capacity is pegged roughly at $40 billion.