The energy supply in the world needs to change from fossil fuels to renewable alternatives. Biogas is such a renewable alternative, and there is potential to increase the biogas production in the world. In recent decades, many countries have increasingly been upgrading biogas to vehicle fuel. In the last few years, the interest has also increased in liquefying biogas for heavier transports. Biogas can also be a raw material for other fuels by gasifying the biogas, for example Fischer-Tropsch fuels, methanol, dimethyl ether and hydrogen. This study provides an overview of vehicle fuels that can be produced from biogas, their technological maturity and their respective potentials as substitutes for fossil fuels in the transport system. A common factor for all of them is that they are most often produced from fossil fuels. Compressed and liquefied methane are the only fuels being commercially produced using biogas. The other fuels all have strengths that both compressed and liquefied methane lack, for example the possibility of emission-free fuel cell vehicles. However, they are all less mature technologies than compressed and liquefied methane. The greatest short-term potential is thus for expanded use of biogas as compressed and liquefied biomethane.

Contemporary environmental problems require a transition to renewable energy. Biogas is one alternative, which besides being renewable has many other benefits. For further expansion of biogas production, it seems necessary to develop new areas of biogas usage where biogas can replace fossil fuels. This article presents an analysis of the drivers for and barriers to increased biogas usage in three sectors where biogas usage is undeveloped in Sweden: manufacturing, road transport and shipping. Several of the identified drivers and barriers, such as unstable and shortterm policies, lack of infrastructure, and contract requirements, have also been found in previous studies even though they may be slightly different depending on the context. A new driver observed in this study is that of intergenerational thinking in family-owned businesses. The study also reiterates the significant influence of policy in the form of subsidies, tax exemptions and regulations on the adoption and use of renewable energy in general and biogas specifically. The results suggest the need for future policymaking to be guided by long-term trajectories, which can be a relevant basis for adopters to make investments into biogas technologies.

Many Swedish regional transport authorities want bus fleets driven on renewable fuels. However, it may be difficult to know what technology, or combination of technologies, to choose. There is a need for improved knowledge and supportive methods for sustainability assessments that can support public procurement processes. In the companion article (Part I), a multi-criteria assessment (MCA) method for assessments of public bus technologies’ sustainability was established, consisting of four key areas and 12 indicators. In this article, the purpose is to apply the method established in part I on different bus technologies by looking at a general Swedish case and assessing buses driven on diesel, Hydrotreated Vegetable Oil (HVO), Fatty Acid Methyl Ester (FAME), ethanol, natural gas, biomethane and electricity. Each technology is assessed on a scale from Very Poor to Very Good according to the indicators: technical maturity, daily operational availability, total cost of ownership, need for investments in infrastructure, cost stability, non-renewable primary energy efficiency, greenhouse gas emission savings, air pollution, noise, local/regional impact on land and aquatic environments, energy security and sociotechnical systems services. The results show the strengths and weaknesses of each technology, which are later discussed. We also critically reflect upon the usefulness and accuracy of the MCA method.

This article departs from the perspective of Swedish regional transport authorities and focuses on the public procurement of bus transports. Many of these public organizations on the county level have the ambition to contribute to a transition involving the continued marginalization of fossil fuels and improved sustainability performance. However, there are several renewable bus technologies to choose between and it can be difficult to know what alternative (or combination) is preferable. Prior research and the authors’ experiences indicate a need for improved knowledge and supportive methods on how sustainability assessments can support public procurement processes. The purpose of this article is to develop a multi-criteria assessment (MCA) method to support assessments of public bus technologies’ sustainability. The method, which was established in an iterative and participatory process, consists of four key areas and 12 indicators. The article introduces the problem context and reviews selected prior research of relevance dealing with green or sustainable public procurement and sustainability assessments. Further on, the process and MCA method are presented and discussed based on advice for effective and efficient sustainability assessments. In the companion article (Part II), the MCA method is applied to assess several bus technologies involving biodiesel, biomethane, diesel, electricity, ethanol and natural gas.

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