Around two years ago, Empa opened “move”, the demonstrator for the mobility of the future, with a view to revealing various paths for mobility with renewable energy. After two years of practical tests, the first project phase has now been completed successfully. The focus was on a plant to produce and refuel on hydrogen – together with the corresponding vehicles, a hydrogen-powered road sweeper and a delivery van that ran on a hydrogen and biogas mixture. The next phase will be centered around converting hydrogen and CO2 into synthetic methane to power gas vehicles.
Fossil energy has expedited the economic and social development of the western world in the last 50 years, from which Switzerland has also greatly benefited. But it has also led us to energy dependencies, polluted the air and accentuated climate change. The mobility demonstrator “move” on Empa’s campus in Dübendorf should now reveal how these dark sides of mobility can be turned into opportunities by processing unusable renewable electricity on the power market into local, clean energy and making it usable for the mobility sector. Not only can the impact on the climate be reduced as a result, the economic efficiency of renewable energy production can also be improved.
For Switzerland, the conversion to renewable energy primarily means the expansion of photovoltaic plants. However, these mainly produce electricity in the summertime, when the majority of the country’s electricity demand – even without NPS – can already be covered with hydropower. As our neighboring countries are investing in the same technology, it may therefore become increasingly difficult to break even on the European market with electricity from photovoltaic and hydroelectric power stations – which may in turn have a negative economic impact on the expansion of photovoltaics.
Three mobility paths: electricity, hydrogen, gas
“move” provides a prime example of how excess electricity can be transferred in the summertime and used as a replacement for fossil fuels. For instance, the temporary excess electricity can be stored in a battery during the daytime to charge electric vehicles at night. Or it might be used in an electrolysis plant to produce hydrogen. The gaseous hydrogen is then condensed to 440 bar and can either be used directly in fuel cell vehicles or as an admixture for biogas in gas vehicles that have been optimized accordingly. Almost every day, the “move” plant is visited by school children, students, companies, associations and other interested people. And judging by the reactions, Empa researchers have succeeded in arousing enthusiasm for the new mobility concepts at “move”.
Within the scope of the first expansion phase of “move”, the researchers analyzed in detail the efficiency level behavior of the individual energy storage and conversion paths, and the interplay between the consumption behavior of the corresponding vehicles in reality. Besides an electric vehicle from the Empa fleet, they used a hydrogen-powered road sweeper, which was developed in conjunction with the Paul Scherrer Institute and Bucher Municipal and utilized by the Dübendorf Roads Authority for the daily street-cleaning. To analyze the hydrogen and biogas mixture, a delivery van powered by it was used for the parcel service. This mobility path came about in collaboration with the Swiss gas industry, Iveco and Swiss Post.
Guide for the expansion of a hydrogen refueling station network
This first expansion phase at “move” was backed by the ETH Board, the Swiss Federal Office of Energy (SFOE), the City of Dübendorf and Glattwerk AG as core partners. Together with Suva, a practical leak test was devised for the hydrogen pumps – a necessary step to be able integrate this kind of pump in conventional gas stations. This and other safety measures are currently being compiled with specialist departments and authorities in an authorization manual for hydrogen refueling stations – as a legal and safety-related guide for the expansion of the hydrogen refueling station network in Switzerland.
The first operating phase was also used by other “move” partners to test new technologies in practice. These include the thin-film photovoltaics plant developed by ETH Zurich/Empa spin-off Flisom, the use of a hydrogen condenser by AtlasCopco in dynamic operation or a new high-pressure connection technology by Swagelok. With the pump supplier Linde, a refined hydrogen sensor is also being tested at the “move” refueling station, and a calibration process for hydrogen refueling stations is being developed in conjunction with the Federal Institute of Metrology (METAS) as part of an EU project. As a result, Empa hydrogen refueling station is one of the first calibration refueling stations in Europe. Thanks to experience gathered within the scope of authorizing the refueling station and the development of safety concepts, a lot of data and many models for the propagation of these technologies are on hand today.
Next step: methanation
Meanwhile, the second phase has been launched, which enables the compression of the locally generated hydrogen to 900 bar and the refueling of fuel cell cars in a matter of minutes. The third expansion phase is currently in the pipeline. Together with CO2 from the atmosphere, hydrogen is to be converted into synthetic methane (CH4) in a catalytic process, which can be stored in the gas network and used to power gas vehicles. In order to increase the efficiency of the entire plant, a novel waste heat usage concept is being developed and realized.