I know that solar energy can be used to make electricity and to heat water and air. But can solar power also be used to make liquid fuels?
Until recently, the practical answer was "no."
Photovoltaic panels absorb sunlight and use it to create an electric current, while thermal solar devices use sunlight to heat water and buildings.
Liquid fuels such as gasoline, diesel, and ethanol are made mostly by refining fossil fuels such as oil or renewable fuels such as corn and carbohydrate rich plants.
But because making fuels involves chemical reactions at high temperatures, researchers are now experimenting with ways to bring solar energy into the mix.
Instead of burning coal, oil, or biomass to heat things up, scientists have found that it's possible to use solar energy.
For example, some experimental facilities use thousands of mirrors to reflect sunlight onto a large plate on a tower, heating it to around 2100 degrees Fahrenheit.
The heat is used to jumpstart a reaction that turns a mixture of water and woodchips into gas. The gas can then be refined into liquid gasoline and diesel fuels.
Cheap And Dirty
Making liquid fuel the old fashioned way, from oil, has been cheaper than using solar power. But it's also dirtier. And because oil prices are highly volatile and oil is a limited resource, gas prices can shoot up at a moment's notice.
So in many ways, making liquid fuel using solar power is an attractive option. One day, it may be a practical option, too.