With solar energy getting cheaper and cheaper, it is expected to become the most common way to produce electricity by 2050. But there is another way to create electricity from the sun. It's called "Concentrated Solar Power (CSP)". It works by using many special mirrors, called "heliostats", to focus the sun's light to produce heat "Solar Thermal". CSP factories focus the light from their mirrors onto specially designed towers that can take the heat and then, usually by turning water into steam, turn it into electricity.
The biggest CSP plant in the world is Ivanpah in the Mojave Desert in California. Spain has several other large CSP factories. The highest temperature reached using concentrated solar power is 565℃. That's hot enough to make electricity. But to make many common materials, much higher temperatures are needed. An American company called Heliogen has announced a new process that can reach extremely high temperatures using only the power of the sun, which could help clean up some of the world 's most polluting processes, like making cement (水泥) that is currently responsible for around 7% of the world's carbon dioxide pollution. Heliogen says its process has reached temperatures higher than 1,000℃ for many times. At those temperatures, Heliogen's system could be used in the making of cement.
The company has been able to improve its process by doing a few things differently. For one. thing, the heliostats it uses are smaller, so they're cheaper and it's easier to make them reflect better. Another big improvement is the special computer system that Heliogen developed to watch and adjust the heliostats so that they are always focused continuously.
Heliogen says confidently that in the future it hopes to reach temperatures as hot as 1,500℃. At that temperature, it is even possible to create fuel, not causing pollution. Though Heliogen's process is new and offers several improvements over existing CSP methods, the company is still a long way from putting their system to work in the real world.
