Here’s the Next Big Thing in Renewable Energy Storage

Renewable Energy
Source: Electrek

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.

Future Outlook

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.