Could eFuels be the future?

July 11, 2023

Synthetic fuels can potentially run almost CO₂-neutral internal combustion engines. They should, however, be produced with renewable energy, writes HEIKE HIENTZSCH.

From a global perspective we are rich in energy, thanks to the inexhaustible resources of the sun and wind. On a local level this is not necessarily the case, as regions with limited wind and sun may struggle to cover even a small amount of their energy requirements from these sources.

In Germany, for example, wind turbines operate at full capacity just 66 days out of the year on average. According to Bundesnetzagentur*, wind supplied 25.9% of the electricity consumed by the country in 2022.

When it comes to electric vehicles, a portion of renewable energy plays a key role in the lifecycle assessment of mobility. But there are currently around 1.3 billion existing vehicles with internal combustion engines worldwide, most of which will remain on the road for many years. Eco-friendly operation will require other solutions, such as so-called eFuels: synthetic fuels produced in a virtually carbon-neutral manner. Porsche is doing its part, with a new production facility in South America.

Pilot project in Patagonia

Punta Arenas, in the Patagonia region of southern Chile, has a population of around 130,000. It is the southernmost large city in the world and the most important trade centre on the west coast of the Strait of Magellan.

This area is known for its strong winds, which blow incessantly across the barren landscape, almost always from the same direction. They’re so powerful that they can transform trees into bizarre sculptures known as “flag trees”. Here, wind turbines could operate at maximum capacity for 270 days per year, yet the region does not use wind power.

Porsche has an 11.6% share in Chilean company Highly Innovative Fuels (HIF), and is eager to tap into this resource with international partners. The aim is to use the bountiful wind to generate power for manufacturing synthetic fuels. Inaugurated in December 2022, the production facility near Punta Arenas is called Haru Oni, which means “land of winds” in the local dialect. The production schedule for the current pilot phase is 130,000 litres of eFuel annually.

The finished fuel consists of nothing other than CO₂ and water and, like other fuels, can be accessed at a regular fuel pump.

During the manufacturing process, CO₂ is filtered directly out of the ambient air.

Fuel from air and water

Electrolysis for hydrogen production is the first step in manufacturing eFuels. It requires a great deal of energy, which is why the perpetual availability of green electricity is so important. Water (H₂O) is a very stable chemical compound: two hydrogen (H) atoms bond with an oxygen (O) atom to form a water molecule. Extracting hydrogen from these molecules is extremely energy-intensive. In regions with limited energy, any electricity produced has to be used directly for the greatest benefit; because the Patagonian wind offers inexhaustible energy, affordable hydrogen can be generated there more sustainably.

In addition to hydrogen, eFuel production requires a second component: carbon dioxide (CO₂) – a greenhouse gas that at high atmospheric concentrations promotes global warming. It can be filtered from the air using direct air capture, a process by which air flows through a ceramic filter similar to a car’s catalytic converter. However, rather than precious metals, the flow channels use a chemical substance to bind CO₂ molecules. Once all of the spaces are filled with CO₂, the filter is closed, vacuumed, and heated. The heat releases the CO₂, which can then be vacuumed into a tank. In concrete terms, one litre of eFuel requires hydrogen from three litres of desalinated seawater and CO₂ from 6,000m³ of air.

Preparation and use of eFuels

After extraction, a synthesis plant binds the hydrogen and CO₂ to create methanol, which is age resistant and suitable for storage and transportation. Ship engines are currently designed for operation with methanol. Use in passenger cars and trucks requires further processing, however, with additional carbon compounds added in the final step of synthesis. The process of synthesis produces eFuels, including carbon-neutral methanol, carbon-neutral petrol, and carbon-neutral Liquefied Gas (eLG).

To reiterate: the fuel produced in Chile therefore consists of nothing other than air and water and can be sold at fuel stations around the world. It’s also worth noting that all internal combustion engines can be operated with eFuel. Once availability reaches a certain level, combustion will release no more CO₂ than the amount extracted from the ambient air during the production process, closing the circuit.

Annual eFuel production in Punta Arenas should reach 55 million litres by the middle of the decade and 550 million litres two years later, and it will continue to grow. That’s only equivalent to 1.2% of Germany’s passenger car fuel requirements, but it’s a great start.

*Bundesnetzagentur is Germany’s main authority for infrastructure. It promotes market competition for energy and other sectors, and acts as a consumer protection authority.