Here’s How to Store Wind and Solar Energy Using Just Gravity

This startup wants to store green energy by stacking giant blocks.

Clean Energy Storage

Swiss startup Energy Vault wants to overcome the limitations of lithium-ion batteries by storing green wind and solar energy by stacking massive towers made up of 35-ton bricks, The Wall Street Journal reports.

In August, the startup locked down $110 million from SoftBank's Vision Fund. The company already constructed a 400-foot demonstration tower and is planning to eventually build cranes up to 500 feet in height.

Towers of Bricks

The concept relies on gravity alone.

A pre-programmed crane on top of a massive tower lifts and stacks colossal bricks on top of each using excess power from wind and solar plants. When demand exceeds electricity production, the crane reverses the process, recouping energy by unstacking the tower of bricks.

Just 20 cranes could provide enough power for 40,000 households over a 24 hour period, according to the WSJ.

What Goes Up Must Come Down

Lithium-ion batteries rely on rare-Earth metals, the extraction of which is steeped in environmental and humanitarian problems, and tend to lose their capacity over time.

The concept is similar to "pumped hydro" systems, which use bodies of water instead of heavy bricks and a hill instead of a tower, and have been around for at least a century.

READ MORE: To Store the Wind and Sun, Energy Startups Look to Gravity [The Wall Street Journal]

More on the startup: Giant Hanging Bricks Could Store Energy Better Than Batteries