As global carbon emissions that stem from fossil fuels keep adding to our ever-growing climate change issue, energy companies have turned their focus on renewables to generate fuel.
One of those companies is Synhelion from Switzerland. The company harnesses the energy of the heat of the sun and converts the collected carbon dioxide into synthetic fuels, in turn offering a green and sustainable solution.
How does it work?
The system is quite genius. Synhelion uses a mirror field filled with heliostats to reflect the radiation of solar power. The radiation is then concentrated in the solar receiver and turned into clean, high-temperature process heat at around 2.732°F (1.500°C). Next, the produced heat is turned into a CO2 and H2O mixture in a thermochemical reactor. The end product, the syngas, is then turned into gasoline, diesel, or jet fuel with a gas-to-liquid technology process. What makes this sustainable is the fact that the company's thermal energy storage (TES) saves the excess heat after each process which keeps the operation going 24/7.
In an interview with The Engineer, Dr. Gianluca Ambrosetti, co-founder and CEO of Synhelion, explained the process by saying “When you burn a fuel, you basically have the production of heat and water and carbon dioxide... Basically, what we do is look at processes that reverse that, and the most straightforward way is to take CO2, water vapor and use heat to try and reverse that process.”
And how does the solar receiver work?
The company says the technology is inspired by nature. To reach ultra-high temperatures, the solar receiver mimics Earth's greenhouse gas effect. The chamber is filled with greenhouse gases that are usually water vapor or water and CO2 mixtures. After solar radiation collected with heliostats enters the chamber, the black surface of the chamber absorbs the heat, thermalizes, and re-radiates it. The greenhouse gas then absorbs the thermal radiation, acting as a heat transfer fluid (HTF), which can, later on, be turned into any type of liquid fuel. And liquid fuels are easy to transport which makes them low-cost compared to their solid counterparts.
About the solar receiver's thermochemical technology, Ambrosetti says “it is for sure one of the key elements. Many processes need this temperature to become viable, to become feasible. And these high temperatures that can be achieved with our technology is really a necessary step to get to the thermochemical processes that we use for the production of fuels.”
Synhelion thought about it all. When there's no sun, the HTF flows through the TES in the opposite direction to recover the previously stored thermal energy. The hot HTF from the storage drives the thermochemical processes in the reactor that keeps the operation working.
Lower carbon emissions for a greener future
The company states that through this technology, it can provide fuels at a cheaper price with a 50 to 100 percent lower carbon footprint compared to fossil fuels. In addition to Synhelion's aligned motives with the Paris Agreement's CO2 reduction targets, it is supported by larger industries looking to cut their emissions -- and eventually achieve net-zero -- by 2030.
Today, fossil fuels such as oil, coal, and gas make up 80% of the energy we use in our houses, according to NRDC. However, while they've been in popular demand for some time, these fuels have taken a toll on both our and our Earth's health. While fossil fuels cause air and water pollution, in addition to contributing to global warming, greener fuels with lower carbon emissions such as synthetic fuels could help us change the course of climate change and consequently save the future of our planet.