Fuels from electricity for sustainable transport
The transport sector is one of the main obstacles to the declared goal to cut anthropogenic emissions of carbon dioxide – the main responsible of the increase of greenhouse effect and of the subsequent global warming – within 2050. Electric cars can be a possible solution for short-range road transport, shifting the emissions problem towards power generation plants, but batteries cannot be easily used for heavy transport and especially for shipping and aviation. In this perspective, the key solution is represented by the so-called “e-fuels”, liquid and gaseous fuels produced from renewable electricity.
According to the European Environmental Agency, about 25% of anthropogenic greenhouse gas emissions come from the transport sector. Among them, a little bit less than three fourths (72.8%) are related to road transport whereas more than one quarter (26.1%) come from shipping and aviation sector. It means, in Europe, more than one billion tons per year of CO2 released into the atmosphere, corresponding to the emissions of some 300 medium-scale coal-fired power generation plants.
A huge impact to CO2 emissions reduction in transport sector is expected by the exponential growth of the market of electric cars (promoted by the development of batteries that allows long life and reliability and especially competitive costs): 300,000 vehicles in 2013, more than five millions in 2018 and some 250 millions expected in 2030, according to the International Energy Agency (IEA). This will allow a reduction of direct greenhouse gas emissions of about 800 million tons per year.
Unfortunately, despite the remarkable technology development, batteries for electric vehicles still show significant environmental problems (related to the disposal of exhausted batteries). And, in particular, a limited capacity, not suitable for heavy wheeled transport, and even less for shipping and aviation, except for very small-scale applications (such as the Airbus E-Fan project, a small electric plane presented in 2014 for the transport of just two passengers).
In this respect, the most promising solution to reduce CO2 emissions in the transport sector is represented by e-fuels. Hydrogen, methanol, dimethyl ether, diesel, and many other fuels produced from the excess of renewable electricity and from CO2 directly captured from the atmosphere or from industrial applications still based on fossil fuels combustion. E-fuels can represent a workaround to batteries for short-range road transport and the only solution when batteries are not suitable to be applied. With the additional advantage that most of the existing infrastructures currently in use for fossil fuels can be easily used.
The benefits are countless: e-fuels production is a way to chemically store renewable electricity that otherwise is wasted (some 480 TWh per year only in Europe), with subsequent benefits on the stability of the electric grid (as already discussed here). But e-fuels are basically very clean, free of the contaminants that can be found in the corresponding fossil-derived fuels and also in biofuels. In fact, they do not come from oil refining, but from synthesis processes from high purity chemical compounds. And they are completely renewable allowing, according to IEA’s estimations, a reduction of greenhouse gas emissions up to 93%.
One of the most significant applications of e-fuels in road transport is represented by the Carbon Recycling International vehicle fleet (Iceland), fed with Vulcanol®. The fuel is basically methanol – sold in different Countries in northern Europe) produced from geothermal electricity and volcanic CO2.
The Vulcanol®-fuelled car fleet of Carbon Recycling International, Iceland. (Fonte: https://www.carbonrecycling.is)
And it is still more significant, considering the size of the application, the case of the Swedish shipping company Stena Line, which converted the “Stena Germanica” ferry for the feeding with renewable methanol.
It is still a long way. The optimization of the technologies and a significant reduction of the production costs (2 to 7 times higher than the corresponding fossil-derived fuels, according to IEA assessment) are the keywords. The scientific community, together with Sotacarbo, is working on different kinds of e-fuels production processes to improve performance and using low-cost materials. The industry is trying to better understand how to implement these technologies in an international market based on a carbon circular economy (with particular reference to the cost of electricity, which impacts for 40 to 70% on the e-fuels production cost). And the key role of the policymakers cannot be overlooked: they have to introduce incentive mechanisms that make low environmental impact technologies competitive with the unsustainable fossil fuel-based technologies. APettinau