A German story :
The synthesis of hydrocarbons is a century long story due to the need of emancipating from the limited oil ressource in Europe. It was first and foremost in Germany that this branch of the chemical industry emerged in a country that scooped up nearly all the Nobel Prize of Physics and Chemistry between 1896 and 1939, thanks to a large scientific community.
Several solutions have been discovered, all from coal, then the main source of energy and hydrocarbon material. In 1923, at the Kaiser Wilhem Institute, Franz Fischer and Hans Tropsch discovered the F-T synthesis, which obtained gasoline, then the main fuel. This is an evolution due to the initial discovery of two Frenchmen, Paul Sabatier and Senderens who obtained methane as early as 1897, for this princeps discovery, they receved a Nobel Price of Chemistry in 1912. Rapidly, several industrial firms developed several variants : in 1937, fifteen industrial demonstrators offered a wide range of synthetic liquid hydrocarbons : gasoline, diesel,… Too complicated and expensive, those solutions will not be massively deployed during the Second World War, but will be the object of a major transfer of technology after 1945 for the benefit of the Allies (particularly in the context of Operation Paperclip), without having been publicized like von Braun rockets.
Since then, the adaptation to other sources of energy and hydrocarbon materials has opened up new opportunities : from natural gas in the 1970s and from biomass in the 1990s. However, carbon neutrality cannot be obtained with natural gas ; the quantitative potential of biomass is very limited on a planet that will have to feed 10 billions inhabitants.
New pathways for the 21st century :
In order to produce these non-fossil synthetic hydrocarbons according to with the criteria of carbon neutrality, starting is sufficient from non-fossil fuel and hydrocarbon sources. The main solution developed in Germany over the past ten years uses hydrogen produced by electrolysis. The electricity being the source of energy, must be from non-fossil origin. When it comes to carbon, we can count on the reuse of CO2 emitted by industrial activities : we must also start from non-fossil sources, which do not add carbon resulting from a geological storage. The CO2 already present in the atmosphere allows it, the difficulty being to concentrate it, ie via the DAC process. Several solutions have been explored and we have passed the “proof of concept” stage. The only one having reached a pre-industrial stage in Europe is the Swiss solution of a small start-up : ClimeWorks.
Another German start-up, Sunfire, produced a few barrels of diesel in 2015.
The energy source being electricity, whose main origine in the coming decades will be more and more renewable, can be obtained in different ways, either from the exceeding electrical power that begins to appear in the European electricity grids, which will allow the emergence of Power-to-X type uses, developed in Germany as part of the “Kopernikus Projek“; or through the establishment of large, fully dedicated renewable primary generation electrical capacity in regions where the production costs are the lowest, especially since the cost of electricity represents up to half the cost of hydrocarbons thus synthesized.
A first industrial site has to start producing about 8 000 ton of kerosen per year in Norway, as soon as 2023 : « Nordic Blue Crude » which have been renamed “Nordic ElectroFuels”. In 2026, production will reach 80 000 ton. “Norsk e-Fuel” have projected to produce 800 000 ton in 2032.
Porsche have annonced to produce MTG gasoline in Chile in the comming years, with Siemens and Exxon-Mobil. Production will start in 2022, 40 000 ton as soon as 2024 and 400 000 ton in 2026. Projects for 2030 : 4 000 000 ton.
Production cost is expected to not exceed 1 to 1.5 €/liter in 2025/2030, with electricity at an estimated cost of 30 to 40 €/MWhel, with CO2 captured from the atmospher at 100 to 250€/ton. Also, they could be blendend up to 20%. In the futur, cost from solar production of these carboneutral fuels should reach 0.8 €/l in 2050.
The development of the production of synthetic fuels is organized in Germany by a group of industrialists called : Power to X Allianz, which rely on carbon removal from industrial sources at a limited cost of 40/50 € per ton of CO2.
Similarly, there is a large project on a global scale led by the Germans : Global Alliance Powerfuels which rely on DAC process and dedicated renewable electric sources.
For more information about deployment of these electrofuels, see : https://www.efuel-alliance.eu/en/studies
In 2016, cost of electricity from PV in the intertropical strip have been 25 $/MWhel. In April 2021, it have reached 10 $. None other kind of renewable energy production reached this level of cost in the coming decades.
Further more, EROI of photovoltaic have been recently re-evaluated at 40/50 : that means EROI ( Energy Return on Investissement ) of solar energy carriers will be over 10, number to be surpassed for a viable civilisation.
Also, Solar Hydrogen will be the lowest cost solution to produce Green Hydrogen : about 1.5 €/kg in 2025/2030, 0.75 or 0.6 up to 2050. With 1,000,000 km2 of photovoltaic arrays ( 60 TWp, 40 TW of alcalin electrolyser ) in the intertropical band, this should produce 5 000 Mtoe of synthetic hydrocarbon for 10 billions inhabitants in 2060.
Long-term prospects :
Even more surprising, other tracks are also possible. What is at stake is using solar energy , more than superabundant, without going through the expensive intermediate stage of the electricity to obtain hydrogen. This track has been explored for about twenty years, in Switzerland, in the United States.
Multiple tracks about on innovative scientific principles using solar energy are being studied in internationally renowned research laboratories like photoelectrocatalysis, artificial photosynthesis, …
Production of these carbon neutral synthetic fuels from abundant solar energy could reach up to 50 toe/ha in desertic land, also 10 fold the production of ethanol from sugarcane.
Equally surprising is the ability to obtain carbon from another, less expensive source : by concentrating dissolved sodium bicarbonate in the oceanic surface layer, the DOC process. Imagined more than fifty years ago, in the heart of the Cold War, this solution also reached the stage of “proof of concept” in 2014, which is an American discovery.