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Methane for transport and mobility (RMTM)

 

Synthetic natural gas (SNG) as a renewable fuel can contribute to sustainable road transport. The technologies and a large part of the infrastructure for this purpose are available today. The two most important parameters that need to be improved are the (life-cycle) CO2 emissions per km and the production costs of SNG.

Hintergrund (completed research project)

The use of renewable synthetic fuels such as SNG is promising as it solves two problems at once. (i) The expansion of photovoltaics and wind as energy sources will lead to large fluctuations in electricity production. The conversion of electricity into fuels can help to stabilise the electricity grid and make reasonable use of surpluses. (ii) Even though Switzerland has committed to the Kyoto climate protocol, CO2 emissions from road transport, which account for 50 % of Switzerland’s anthropogenic CO2 emissions, are not decreasing. In addition to the efforts to change mobility behaviour, SNG as a fuel is a sensible complement to electric mobility for sustainable road transport.

Aim

The aim of the project was to evaluate the potential of SNG as a fuel for road transport in order to contribute to the implementation of the energy strategy 2050 and reduce CO2 emissions in road transport.

Results

The production of SNG requires water, CO2 and electricity. The limiting factor on the supply side is the amount of renewable electricity available. In order to produce SNG for a passenger car with an average travelling distance of 12’000 km, 12’000 kWh of electrical energy per year are required, which corresponds to a photovoltaic area of 90 m2.

On the demand side, the SNG price at the filling station and acceptance by consumers are the limiting factors. The most relevant influencing factors for the production costs are the electricity price and the investment costs for the electrolyser. Under optimal conditions, production costs of 12 Rp./kWh (HHV) are achievable, under normal conditions the price is in the range of 30 Rp./kWh. The price difference between renewable SNG and fossil fuels can be influenced primarily by regulatory measures, such as free usage of the electricity grid or the introduction of a steering charge on fossil fuels.

It can be said that the extent to which SNG fuel is used in the future is principally a political rather than a technical issue.

Relevance

Implications for research

This is the first time that the main carbon flows in a country have been comprehensively identified and presented. Based on this, the researchers were able to present arguments as to which CO2 sources would allow for the production of renewable SNG.

For the first time, SNG production plants have been integrated into a simulation tool for Swiss electric power production and consumption at intervals of 15 minutes. This makes it possible to study different plant operating strategies.

For further research towards more efficient electrolysers, a parameter model for calculating efficiency was developed.

Implications for practice

According to the findings of this project, there are almost no restrictions on the expansion of photovoltaics and wind power. Any surplus can be used for the production of SNG.

Apart from the construction of SNG plants, only a few adaptations are necessary for the widespread introduction of SNG as a fuel: the gas filling station grid must be expanded and, depending on the amount of SNG injected, the gas grid must be extended to bidirectional operation.

Original title

Renewable Methane for Transport and Mobility (RMTM)

Principal Investigators

  • Prof. Markus Friedl, Institut für Energietechnik, Hochschule für Technik Rapperswil, Rapperswil
  • Prof. Andreas Züttel, EPFL Valais Wallis, Sion
  • Peter Graf, Sankt Galler Stadtwerke, St. Gallen
  • Prof. Karl Frauendorfer, Institut für Operations Research und Computational Finance, Universität St. Gallen
  • Prof. Urs Baier, Institut für Biotechnologie, ZHAW Wädenwsil