E-fuels: Power of the Future
How can greenhouse gases in transport be sustainably reduced? The automotive industry is focusing on e-mobility, but it will take time for e-vehicles to establish themselves on the market. Experts agree that only with a bundle of measures will it be possible to meet the CO2 reduction targets set. Synthetic fuels, produced from renewable electricity, so called e-fuels, play an important role, according to the National Platform Future of Mobility (NPM) in its latest report by the alternative drive systems and fuels for sustainable mobility work group. They can be made available using existing infrastructure, improve the CO2 balance of fleets and could enable CO2-neutral mobility if fossil fuels are substituted.
In light of the European Union’s new climate targets, 2020 is a year of truth – for the first time, the strict 95 gram CO2 guideline value applies. Which OEM meets or violates the emission standard can now be measured in practice. According to experts, the ongoing electrification of fleets and the resulting increase in electricity demand makes it all the more important to accelerate the change in energy policy and switch to renewable energies.
E-fuels offer an important opportunity to reduce CO2 emissions in existing fleets without vehicle conversions while retaining the current infrastructure, thus, making mobility less dependent on fossil fuels in the future. They are currently still in the pilot and development phase, not least because their production using PtX (power-to-x) processes is still very cost and energy-intensive.
To produce e-fuels sustainably, water is broken down into its core components oxygen and hydrogen using regeneratively produced electricity. In a multi-stage process, the latter reacts with CO2 taken from the air to form the basic product from which synthetic, electricity-based fuels can be obtained.
«Synthetic fuels are versatile and can make a valuable contribution towards reducing the CO2 emissions of the existing fleet…»
— Vehicle drive systems business consulting manager at consulting4drive
E-fuels based on hydrogen
Hydrogen can be refined with CO2 to gaseous methane or liquid methanol or synthetic gasoline and diesel fuels including kerosene (power-to-liquid). During combustion in the engine, the amount of CO2 is emitted that was previously added to the e-fuels. If the greenhouse gas is taken from non-fossil sources such as the air, for example, combustion is climate-neutral.
E-fuels can be distributed via the established network of filling stations and pipelines and, thanks to their high energy density, can be transported inexpensively over long distances. They are suitable not only for passenger cars and public transport, but above all for use in air, sea and heavy goods transport, where electrification is not practicable from today’s perspective.
“Synthetic fuels are versatile and can make a valuable contribution towards reducing the CO2 emissions of the existing fleet, which, due to an average holding period of almost ten years, also plays a significant role in our CO2 emissions in the medium term”, says Dr. Ralf Tröger, vehicle drive systems business consulting manager at consulting4drive, IAV’s management consultancy.
German energy agency sees important role for e-fuels
The EU’s goal of reducing passenger car emissions by 37.5 percent by 2030 (based on the average target of 95 g CO2/km in 2020) already makes it necessary to build up PtX capacities according to the German energy agency (dena).
“We assume that power fuels, including H2, will gradually gain market share and will and must play a major role beyond 2030”, says Stefan Siegemund, Head of Sustainable Mobility and Alternative Energy Sources at dena. “Under the known framework conditions, it is not foreseeable that it will be possible to do without liquid synthetic fuels even with a rapid and successful ramp-up of fully electric mobility.”
However, legislative changes are required to increase the potential of e-fuels. As long as the EU sticks to a tank-to-wheel approach for CO2 fleet emission targets, companies will lack the incentive to invest in infrastructure and production. In vehicle operation, engines running on PtX fuels do indeed emit CO2, even if this was previously extracted from the air. However, if the CO2 absorbed during fuel production were to be taken into account in legislation (well-to-wheel), this could promote investment in the long term.
In principle, e-fuels could be blended with fossil fuels in any quantity with restrictions, as long as the energy source ultimately complies with the relevant European fuel standard (EN 590 for diesel and EN 228 for gasoline). However, industrial production of e-fuels is not taking place, among other reasons because of the relevant but missing EU requirements for the use of green electricity, lack of political support and high production costs.
In its report from June 2020, the NPM calls for the political framework conditions to be set to prepare the production of alternative fuels on a broad scale. In order to enable market launch and ramp-up, the German government should introduce specific use quotas for e-fuels or grant tax incentives, the NPM says.
Production abroad to reduce costs
Due to the increased costs caused by the complicated production process and the lack of support measures, it cannot be assumed that e-fuels will be used in transport in the medium term. In a research report by Prognos AG commissioned by the Federal Ministry of Economics and Energy (BMWi) in March 2020, a sales price of over 4.50 euros per liter of e-fuel is calculated for the year 2030. According to the BMWi, the topic of promotion is still in the testing phase.
However, e-fuels can only be successful if their costs are significantly reduced. Dena estimates that the price per liter would fall to 1–2 euros if e-fuels were produced directly where renewable energy is cheaply generated, e.g. through solar energy in North Africa or wind power in Norway.
This option would be attractive for climate protection. A comprehensive study by IAV colleagues led by Marc Sens, head of advanced powertrain development, on CO2 emissions from the passenger car fleet in Europe based on a life-cycle analysis shows that despite rising new registrations, total emissions fall noticeably if fossil fuels are increasingly mixed with climate-neutral energy sources. See also the info graphics below “Comparison of CO2 emissions over the life cycle”.
“The introduction of CO2-neutral fuels as a substitute for fossil fuels or as a blending in rates of up to a maximum of 30 percent after 2030 shows by far the greatest leverage on the life cycle CO2 equivalent”, says Sens. “Despite the high energy consumption associated with this, this technology should therefore not be abandoned.” In order to implement a blending quota of 30 percent, however, considerably more legislative support is needed than before.
What is clear is that we need solutions that already effectively reduce CO2 emissions, because even by 2050 there will still be market segments and application scenarios in which internal combustion engines are indispensable. However, these must then be operated as cleanly and efficiently as possible – with e-fuels, for example.
The article was published in automotion 02/2020, the automotive engineering magazine of IAV. Here you can order the automotion free of charge.