Although battery electric propulsion is going to spread, that does not exclude combustion engines. Within the field of the automobile, there is a fleet of 1,300 million vehicles in circulation today throughout the world and that number does not seem to be going to decrease in the next two decades. In any case, it will not be easy to replace the combustion in sectors such as aviation or in specific uses, from backup generator sets in hospitals to pumps in fire-fighting vehicles.
For this reason Porsche is carrying out initiatives for the development of the production of synthetic fuels or e-fuels. At the beginning of 2022, Porsche invested US$75 million in HIF Global LLC, a group of companies developing international projects to install synthetic fuel production plants. Among those projects is the Haru Oni pilot plant in Punta Arenas (Chile), initiated by Porsche and implemented with partners such as Siemens Energy and ExxonMobil.
synthetic fuels
And one of the two main elements used in Haru Oni is air. The plant takes advantage of the exceptional characteristics of its location to make use of wind power. The wind in the province of Magallanes, in the south of Chile, is intense and always blows in the same direction. For the demonstration plant there is an SG 3.4-132 turbine from Siemens Gamesa, with 3.4 MW. In the next phase, the wind farm will be expanded to around 280 MW and, when it reaches industrial scale, it will multiply that power by 100.
The other essential element is water. With electricity thus obtained, the hydrogen and the oxygen it contains are separated. It is a reverse method to that of a fuel cell, where the combination of hydrogen and oxygen produces electricity and water. It is carried out using the same technology: a proton exchange membrane (PEM) is permeable to these particles (H+) but hermetic to gases and electrons. That is, the membrane acts as an electrical insulator between the anode and the cathode and, at the same time, separates the hydrogen and oxygen so that they do not recombine. It is a relatively simple and efficient process, low maintenance and does not require the addition of other substances.
In the next step, air intervenes again: CO2 must be extracted from it. Some Global Thermostats direct capture equipment have ceramic monoliths that, through chemical absorbents, act as CO2 sponges. Subsequently, this gas is collected with steam at low temperature.
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synthetic fuels
With hydrogen on the one hand and carbon dioxide on the other, it is already possible to make a hydrocarbon. They are combined to first form the so-called synthesis gas or synthgas and, after passing through a catalyst, it is converted into methanol. Or, more specifically, e-methanol, since it comes from a source of renewable energy and non-fossil raw materials: water and air. Once you have that hydrocarbon, it can be converted into others, such as synthetic gasoline. In the case of the Haru Oni plant, an ExxonMobil conversion process (fluidized bed) is used.
By burning this fuel, CO₂ is not added to the atmosphere, precisely because the one that was previously in it is used. In addition, since it is not fossil in nature, it lacks other undesirable elements, such as sulfur that must be removed from gasoline or diesel, a process that costs energy.