Solutions to climate change generally fall into two categories: adaptation and mitigation.
Adaptation is taking measures to live with and minimize the damage resulting from climate change. Make no mistake, we have no choice but to adapt as best we can to the effects of climate change that have already occurred, such as rising sea levels and more intense and frequent storms.
Mitigation solutions proactively try to reduce the greenhouse gas (GHG) emissions that are responsible for climate change. Decarbonization has advanced as a key element of mitigation, and there has been much emphasis by lawmakers and scientists to significantly reduce the use of fossil fuels.
Unfortunately, we are not yet at a point where we can depend entirely on renewable energy as our only sources of power, and one of the activities most affected by eliminating fossil fuels is transportation. Our cars (in spite of the push for EVs), trucks, buses, trains, ships, and planes all depend on fossil fuels, and even so-called “clean” fossil fuels emit significant amounts of GHG.
Synthetic fuels have long been advanced as an alternative to fossil fuels. However, there is a lot of confusion about what constitutes synthetic fuels.
In Current Opinion in Biotechnology, Vol. 81, June 2023 (102919), the authors' definition of synthetic fuels “does not depend on a particular consideration in the use of fuels, such as fuel scarcity, independence from foreign oil, carbon dependency, or climate change. Further, synthetic fuels can be contrasted to fuels produced via fractionation of crude oil. Creating a definition instead that encompasses all considerations allows for a more holistic approach in assessing the energy landscape: Synthetic fuels are fuels produced via chemical or biological reactions…”
There are many synthetic fuels: biofuels like biodiesel, bioethanol, and biogas, produced from biological materials like vegetable oils and animal fats; hydrogen-based fuels; power-to-liquid (PtL) fuels, produced using renewal electric power sources; and gas-to-liquid (GtL) fuels that typically use natural gas as feedstock. The latter, of course, is still relying on a fossil fuel energy source.
Now Synhelion, a spin-off of the Federal Institute of Technology Zürich (ZTH Zürich), a public research university in Switzerland, has launched the first industrial-scale solar fuel plant. Designated Plant DAWN, Synthelion claims that it will produce several thousands of liters of synthetic fuel per year, beginning this year, and demonstrate the viability of commercial production.
The plant relies on a 20-m (66-ft) tall solar tower, containing a solar receiver, thermochemical reactor, and thermal energy storage for 24/7 production. Concentrated sunlight is directed to the tower by heliostats, and solar energy provides all of the heat required for production. The synthetic crude oil produced by DAWN is subsequently processed into certified solar kerosene for aviation and solar diesel and gasoline for road and marine transportation.
Although its primary focus is initially on aviation – partners include Lufthansa, Swiss International Airlines, Zürich Airport, and Pilatus Aircraft – solar diesel and gasoline products could conceivably allow us to use our internal combustion engines for a while longer.
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