Regenerative fuels –
a possible solution for public transport?
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The EU Directive 2019/1161, also known as the Clean Vehicles Directive (CVD), requires that public transport companies successively convert their vehicle fleets to alternative drivetrains. In addition to cost-intensive vehicle purchases, switching from the internal combustion engine means that companies have to establish a new technological infrastructure, with new expertise and lots of capital – all in more or less record time. For small companies in particular the challenges of the CVD would seem too great. Thus, powering conventional diesel engines with regenerative fuels offers a potential solution for an industry that must fulfil its responsibilities in the effort to meet climate targets.
Regenerative fuels as contributors to carbon-neutral mobility
Public transport companies are facing massive change. On the one hand, this is due to the pandemic, which since early 2020 has led to huge cuts in public transport and has given rise to and accelerated far-reaching socio-economic change. On the other hand, the industry is subject to regulatory measures by the state due to the growing problems caused by climate change.
Thus, on 15 June of this year a Clean Vehicle Procurement Act (SaubFahrzeugBeschG) came into force. It lays down the rules for implementing the EU Directive (EU) 2019/1161, known as the Clean Vehicles Directive (CVD) in Germany, as well as for funding of clean and energy-efficient road vehicles.
Since 2 August 2021 this act, which envisages full implementation of the CVD, for the first time lays down minimum legal requirements for procuring low and zero-emissions heavy-duty utility vehicles.
By 2025, at least 45 per cent of procured public transport buses, rising to 65 per cent by 2030, must employ alternative drivetrains, powered by electricity, fuel cells, natural gas, synthetic fuels or biofuels. At least half of these base targets must be met with zero-emissions vehicles.
Demands for quicker progress
However, to date no substantial moves have been made to establish a supply of regenerative fuels. Despite a noticeable increase in electric buses, regenerative fuel technology has yet to emerge from the starting blocks. This sentiment is echoed by Baden-Württemberg, by its own description the only federal state to have formulated a roadmap for building supplies of regenerative fuels. Only last October, the state’s transport minister Winfried Herrmann criticised protracted proceedings at EU and federal level, and demanded that the European Union and German government step up efforts and the availability of funds for regenerative fuel projects.
Regenerative fuels are needed very soon in order to meet climate targets, says Winfried Herrmann. These fuels have been sufficiently researched and tested for practical use. According to him, it is high time to switch from a research environment to industrial mass-scale production.
“We have been waiting for almost two years for the Federal Ministry of Transport and Digital Infrastructure to issue a call for tender for the development of systems capable of producing more than 10,000 tons annually.“ On the other hand, in Berlin they are waiting for the publication of the Delegated Act on the Certification of Green Hydrogen from the EU, so that 42 to 48 months could elapse before a funding project begins, he said. At the very least, pending a final decision, a certificate of non-objection needs to be issued to clear the way forward, Herrmann said at a session of the state parliament.
In addition to this demand, the states of Baden-Württemberg, Brandenburg and Hamburg have applied to amend the Federal Immission Control Act to be able to market undiluted synthetic (PtL) fuels at petrol stations. The Federal Association of German Bus Operators supports this move.
Regenerative fuels project at the Karlsruhe Institute of Technology (KIT)
Since 2019, as part of its roadmap to build supplies of regenerative fuels, Baden-Württemberg has invested five million euros in the project ’ReFuels – Rethinking Fuels’ at the Karlsruhe Institut of Technology (KIT). The automotive industry, supply industry and mineral oil industry have also funded the project with 15 million euros.
To date, as part of the project, two test facilities have been set up to produce and test fuels. According to the KIT, the bioliq® and Energy Lab 2.0 have already produced several thousand litres of regenerative fuels. Tests have also been conducted on internal combustion engines. The goal is to optimise the synthesising process for creating regenerative fuels to reduce primary emissions.
Researchers have now reached a point where they consider synthetic fuels to be ready for wide-scale use in the transport sector. “If they are blended and prepared to meet current fuel standards then they can be used in all internal combustion applications.“ That was the assessment reached following vehicle and fleet tests.
“The regenerative fuel blends tested in our facility to date satisfy the current standards for petrol and diesel fuels. In tests conducted on an existing car fleet we were unable to identify any negative characteristics in regenerative fuels. In certain cases, pollutant levels were slightly improved – both in diesel and petrol-driven vehicles“, said Uwe Wagner of the Institute of Piston-driven Engines (IFKM) of the KIT. Tests were also conducted on a fleet of six HGVs. The results there also demonstrated no problems in practical use.
However, in order to fully exploit the potential of regenerative fuels to reduce greenhouse gases, the electricity used must be 100 per cent from renewable sources. The CO2 required for the synthesising process is extracted from the atmosphere or from biogas and waste treatment plants. In order for this technology to be effective PtX systems must operate sufficient hours under full load.
Prof. Roland Dittmeyer, an expert at the KIT, predicts synthetic fuels will be market-ready in 2026.
Using regenerative fuels would also have another benefit. They could replace diesel fuel reserves in order to supply vehicles, the police and emergency services in the event of natural disasters.
acatech et al. (2017a): acatech, Leopoldina, Akademienunion. „Sektorkopplung“ – Optionen für die nächste Phase der Energiewende. Stellungnahme, November 2017 www.acatech.de/de/publikationen/publikationssuche/detail/artikel/sektorkopplung-optionen-fuer- die-naechste-phase-der-energiewende.html
Agora Verkehrswende and Agora Energiewende (2018): The Future Cost of Electricity- Based Synthetic Fuels: Conclusions Drawn by Agora Verkehrswende and Agora
Energiewende. In: Agora Verkehrswende, Agora Energiewende and Frontier Economics (2018): The Future Cost of Electricity-Based Synthetic Fuels.
Bundesministerium für Verkehr und Infrastruktur: https://www.bmvi.de/SharedDocs/DE/Artikel/G/clean-vehicles-directive.html
Bundesverband Deutscher Omnibusunternehmen e.V.: SN41 Positionspapier - Nationale Umsetzung der Clean Vehicle Directive
Karlsruher Institut für Technologie (KIT): https://www.kit.edu/kit/pi_2021_066_refuels-fur-den-breiten-einsatz-geeignet.php, https://www.refuels.de/107.php
Öko-Institut: eMobil 2050 Szenarien zum möglichen Beitrag des elektrischen Verkehrs zum langfristigen Klimaschutz