One of the biggest hurdles with solar energy is that the sun doesn’t always shine. This means that we need an effective way of storing solar energy – and molten salt could be the answer.

Molten salt energy storage is typically used with a concentrated solar power plant. This type of power plant uses mirrors or lenses to focus a large amount of sunlight to generate heat. This heat is typically used  drive a steam turbine.

So how does molten salt energy storage work? The step-by-step process is listed below:

• The salt is kept liquid at roughly 275 C in a “cold storage” tank.

• When the solar power plant is producing excess energy, the molten salt is pumped through the solar receiver to collect the additional heat.

• The concentrated solar energy heats the molten salt to over 550 C. This molten salt is then sent to a “hot storage” tank.

• When extra energy is needed (eg. at night or on a cloudy day), the molten salt from the “hot storage” tank is used to produce steam that drives a turbine and generates electricity.

The molten salt energy storage technology was first demonstrated in 1995, and has proven to be a reliable way to store energy for concentrated solar power plants. Here are some additional facts on molten salt technology:

• The molten salt storage tanks are so well insulated they can keep the salt hot for a week.

• Most molten salt mixtures can last for 30 years without the need for replacement.

• Concentrated solar power plants that utilize molten salt storage can produce more than 2X the amount of energy when compared with plants that don’t utilize any energy storage.