Today, some brilliant scientists are doing the same thing to create electricity. No, there is not a huge magnifying glass hovering over the earth to focus the solar rays on creating intense heat, but there are solar power towers that are converting the sun’s rays to electricity. These do not operate like the solar panels on your home or business; they work to harness the heat of the sun, just like the magnifying glass.

This technology uses many large sun-tracking mirrors, commonly referred to as heliostats, to focus sunlight on a receiver at the top of a tower filled with a fluid (usually molten salt). That heated fluid in the receiver is used to boil water into steam, which turns a generator and produces electricity.

But it gets even better. After the molten salt boils the water, it’s pumped into large storage tanks, which are designed to trap the heat and keep the salt molten. When the sun goes down, the molten salt is pumped out of storage and used to boil water again, creating steam and producing electricity when the sun is not shining. Twice the production from the same solar energy.

According to my research, there are ten thermal solar power stations in the United States, which are meeting the electric needs of over 500,000 people, but only two are solar power towers, the rest are solar troughs (which is the same concept, without the tower). The solar reflectors are U-shaped, and there is a pipe filled with molten salt running above the reflectors. Thus, instead of focusing the sun’s reflection on a tower, it is focused on the pipe running above the trough.

According to the National Renewable Energy Lab in Golden, Colorado, solar thermal plants were considered the future technology of solar power, receiving intense research to make them more efficient. However, the dramatic drop in costs of photovoltaic cells (solar panels) has shifted the market away from thermal plants due to the plummeting cost curve in solar panels and the surrounding technology.  Thermal solar plants are providing hundreds of thousands of Americans with electricity, and their use is expanding in other countries all over the world.  They are an important piece in the renewable energy mix, and when combined with the storage of the thermal heat for re-use, makes a strong economic argument for continued research and deployment.