Storing energy produced from renewable sources is a challenge. One that several companies worldwide, including Tesla, want to tackle. To this, Alphabet X (the former Google X and a branch of Google's parent company) can recently be added. Its new Malta project focuses on building storage facilities that can support entire power grids.
New project
According to scientists at the Alphabet X lab, the main problem lies in a "mismatch" between the availability of and demand for renewable energy. Wind and solar energy sources, they say, are inconsistent because the sun only shines part of the day and wind is unpredictable and often at its strongest at the end of the evening. "If more energy is produced that the grid needs, the capacity of wind and solar farms is simply wasted," the lab states on its website. "Even worse is when the demand for electricity rises during periods of low generation, causing polluting 'peaking plants' to still be deployed."
With Malta, they are looking for a cost-effective technology to store renewable energy so that demand for electricity can be met when it is available.
Salt
The Malta project uses antifreeze and hot salt to store energy in a system designed to store reserve energy longer than lithium batteries.
Malta is another experiment by the ambitious X-lab, which also came up with initiatives like the self-driving car and the Google Glass. It has also already looked at several energy projects but according to Bloomberg, Malta is the most promising.
How does it work?
Two tanks are filled with salt, while two other tanks are filled with antifreeze (or a similar hydrocarbon fluid). The system then takes in electricity generated by renewable sources such as wind and solar. This is converted into both hot and cold air, which heats the salt and cools the antifreeze. The process is then reversed, with hot and cold air being drawn towards each other, causing gusts of wind to spin a turbine that again generates usable electricity for the grid.
An approach like this is needed because renewable generation normally suffers peak and off-peak hours of energy consumption. A fuel-based power generation facility can start running when the grid needs the energy on demand; solar and wind generate when the natural allows and so the schedules don't necessarily have to be in the same line as human usage.
Although Malta is not yet an official project within Alphabet X, the team has been given permission to create commercial prototype.
By: Kelly Bakker
Source: Alphabet X/Malta X
