This 100MW molten salt solar thermal power plant in Dunhuang, in China's north-western Gansu province, is a powerful generator.

Molten salt solar thermal power plants work by using thousands of heliostats to focus solar energy onto a single central tower.

The heliostats, arranged in a circular formation around the tower, are basically large computer-operated mirrors on pillars that track the sun continually and reflect its energy onto the top of the tower.

The solar energy is used to heat up salt to temperatures of more than 500 deg C.

Unlike water, which boils at 100 deg C and subsequently becomes harder to store, the salt remains in a liquid state at these high temperatures, making it an ideal medium.

The molten salt is used to ge-nerate steam to turn a turbine and generate electricity. The molten salt can also be stored and used to generate power on demand, even at night.