A company called Heliogen has announced a new process that can reach extremely high temperatures using only the power of the sun. The process could help reduce the pollution that’s causing the climate crisis.
Heliogen says its special process has reached temperatures many times as high as the temperature of boiling water. Using the sun’s energy to reach these high temperatures could help clean up some of the world’s most polluting processes, like making cement and melting metals.
Solar energy – energy from the sun – is expected to become the most common way to produce electricity by 2050.
The words “solar energy” make many people think of the dark panels on roofs being used to create electricity. These are “photovoltaic” (PV) panels. Photovoltaic energy has become common because it’s gotten cheaper and cheaper.
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 generate heat. Sometimes it’s also called “Solar Thermal” – thermal means heat.
If you’ve ever seen a magnifying glass burn something, you have some idea of the power of focusing the sun’s energy. Many CSP factories focus the light from their mirrors onto specially designed towers that can take the heat and turn it into electricity, usually by turning water into steam.
The biggest CSP plant in the world is in the Mojave Desert in California. Spain has several other large CSP factories.
But there have been some important limits on CSP factories. The highest temperature reached using concentrated solar power is 565º Celsius (C) (1,049º Fahrenheit (F)). That’s hot enough to make electricity. But to make many common materials, much higher temperatures are needed.
Heliogen says its process has reached temperatures higher than 1,000º C (1,832º F). At those temperatures, Heliogen’s system could be used in the making of cement or steel.
Making cement is currently responsible for around 7% of the world’s carbon dioxide pollution. Carbon dioxide is an important polluting gas that makes climate change worse.
The company has been able to improve its process by doing a few things differently. For one thing, the heliostats (mirrors) 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 perfectly focused. Figuring out how to track these mirrors was tricky, because the light from them is so strong that it can melt or burn things.
Heliogen says that in the future it hopes to reach temperatures as hot as 1,500º C (2,732º F). At that temperature, it is even possible to create fuel. Heliogen may one day be able to create oil or gas in a way that not only doesn’t pollute, but could actually remove some pollution from the air.
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.
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