Molten salt

You know the expression, “ask ten people the same question, and get ten answers?” Here’s an exception: Ask a thousand people involved with solar energy this question, and you’ll get the same answer every single time.

Namely: “what’s the single biggest drawback to solar power?” That answer? Storage.

It’s definitely been solar’s Achilles heel, if you will. Solar-generated electricity is cheap, renewable, works on small and large scales, and the infrastructure is relatively cheap. But what do you do when it’s cloudy?

It goes without saying that electricity has to be available on demand. Previously, solar cells charged batteries (for the most part). That’s a decent solution, but batteries are expensive, bulky, and often inefficient.

A U.S. firm may just have invented the perfect solution, and it’s so high-tech you have to read the following sentence a few times to comprehend the complexity. Salt. Yes, you read that right. The world’s most common condiment may just be the future of electricity.

Okay, it’s more complicated than that – but not a whole lot more. Hamilton Sundstrand, a US aerospace company, couldn’t help but notice that when you heat salt to over 1,000 degrees, it melts and retains most of its heat energy.

The molten salt (actually a mixture of sodium and potassium nitrate) is stored in a tank until dispatched into a steam generator. The steam drives a turbine, which generates electricity. The salt retains 99 per cent of its heat per 24 hours, which is far better than most materials.

Sometimes progress is funny: a company devoted to outer space looks at a clean energy source from the skies, and improves it with…salt from the earth.