In this study, we demonstrate that in certain cases, it can be advantageous to produce hydrogen from biogas and to use it in heavy-duty vehicles such as buses. In Luleå, it may be feasible to use hydrogen from biogas in city buses because there is a need for heating where waste heat from the fuel cell can be utilized. However, it is uncertain whether the waste heat is sufficient or if a separate auxiliary heater driven by diesel or HVO is needed. If such a heater is required, the conclusion is that hydrogen from biogas is suitable for other segments of heavy transportation, where battery electrification is not as suitable. Overall, our study shows that hydrogen from biogas may be interesting as a transitional fuel to increase the availability of environmentally friendly hydrogen until electrolyzer capacity is sufficiently expanded.
At the same time, our mapping of the policy landscape concerning hydrogen and zero-emission buses shows that biohydrogen is disadvantaged in the EU's regulations on renewable hydrogen. This means that member states are restricted from providing support for investments to produce and distribute hydrogen from biogas and other biogenic feedstocks. The reason is that renewable hydrogen, according to EU terminology, is defined in the so-called delegated act on renewable fuels of non-biological origin (RFNBO). It is established that renewable hydrogen should be based on non-biological feedstocks (i.e., from electrolysis) and must meet a number of criteria.
The results are interesting in the context of urban bus traffic rapidly moving towards zero-emission operation. In Sweden and many other countries, battery buses have become a common and obvious feature on city streets. But just like for other segments of heavy-duty vehicles, another technology to achieve zero-emission operation has also received increased attention, namely hydrogen and fuel cell buses. In Sweden, only a few fuel cell buses have been used - and moreover, only on a trial basis - but in several European cities, they have already begun to be used on a significant scale. An advantage of fuel cell operation with hydrogen from biogas is that it allows for the continued utilization of the biogas already produced and purchased for existing city bus traffic.
System study consisting of two parts
We arrived at the result by investigating the suitability of both producing hydrogen from biogas at the existing sewage treatment plant in Luleå and the feasibility for LLT to use fuel cell buses in its city bus traffic. The study has considered both costs associated with each part and climate impact from a life cycle perspective for fuel production and bus operation.