Clean energy such as solar could solve our climate crisis but there’s the issue of intermittency. What happens when the sun is not shining? This could be easily solved if we found a way to store solar energy. 

In October of 2019, we brought you news of a Swiss startup, Energy Vault, that had one such solution for clean energy storage in the form of huge concrete blocks. At the time, the firm had received $110 million in investments from SoftBank. 

Now, the company is making headlines again for receiving $100 million more in a Series C funding, meaning its technology is that much closer to being deployed.

The technology is rather simple. It consists of a combination of heavy solid blocks (35 tons (70,000 pounds or 31,751 kg)) and a tall tower. When there is a surplus of power a mechanical crane uses it to lift the blocks 35 stories into the air.

These blocks then stay suspended there until power is needed again. At that time, they are lowered down with their weight pulling on cables that spin turbines thus producing electricity.

Energy Vault estimates its blocks will have a storage capacity of up to 80 megawatt-hours and be able to continuously discharge 4 to 8 megawatts for 8 to 16 hours. 

The company also makes sure it is sustainable so its concrete blocks are made of soil and locally sourced waste. This also saves the emissions of transporting the heavy blocks from distant locations.

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