Sweden has spent decades greening its public transport, and the city of Stockholm has been a big part of this shift. The region reached a fully renewable-fuelled bus fleet in 2017 and is now taking the next step by planning a transition to electric buses by 2035. With around 2,000 buses serving 500 lines across 10,000 kilometres, the transition builds on long-standing experience with biofuels and biogas.<\/p>\n
\u201cWe are in the early days of this transition,\u201d explains Karolina Wennerblom, from the Stockholm Region Public Transport Authority. \u201cToday, only about 20% of the buses are electric, but by the end of this year, we expect to reach around 30%.\u201d<\/p>\n
This evolution is possible because Sweden laid strong foundations decades ago. The country\u2019s public transport sector has long stood at the forefront of sustainable mobility, supported by clear political leadership, long-term procurement plans and close cooperation between public authorities and private operators.<\/p>\n
A system built on long-term procurement<\/p>\n
Sweden\u2019s transformation is anchored in its governance model. A national Public Transport Act requires each county to establish its own Public Transport Authority (PTA). These authorities, guided by elected local representatives, set strategies and fund public transport, while private Public Transport Operators (PTOs) deliver most of the services under extended contracts.<\/p>\n
Johan Wadman, CEO of the Swedish Public Transport Association, emphasises this structure: \u201cNinety-nine percent of all the bus traffic in Sweden are under the PTA responsibility, and most operations are handled by private operators.\u201d The PTA determines the goals and requirements; operators implement them.<\/p>\n
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The ten-year duration of these contracts gives operators room to invest in new technology and develop stable services. As Anna Gr\u00f6nlund, Deputy Managing Director of the Swedish Bus and Coach Federation, notes, \u201cIt takes at least two periods of contracting to test, develop and establish a green public transport system. This has been a long-term and very determined work from the regional counties and municipalities.\u201d<\/p>\n
Thanks to this continuity, Sweden now operates one of the cleanest public transport systems in Europe. Ninety-five percent of its buses run on renewable fuels or electricity. Stockholm\u2019s fleet has already operated entirely on renewable fuels for almost a decade. Much of this success stems from Sweden\u2019s early adoption of biofuels.<\/p>\n
The next step: electrifying Stockholm\u2019s bus fleet?<\/p>\n
Building on this strong base, Stockholm is gradually transitioning to fully electric buses. The city is introducing electric requirements as contracts are renewed, ensuring a smooth and predictable rollout.<\/p>\n
Because the PTA owns all depots, it must also design and deliver the charging infrastructure. \u201cWe own all the depots in Stockholm, which means that we also need to plan for the infrastructure development that is needed to enable efficient charging,\u201d says Wennerblom. This arrangement helps coordinate the shift and reduces risk for operators.<\/p>\n
The move to electric also affects contract structures. Electric buses come with higher initial costs and heavier components, while the global shift in manufacturing has extended delivery times. \u201cWe have had to adjust our contracts to allow operators to start with older buses and transition into electric buses within the first year,\u201d Wennerblom explains. She expects the situation to stabilise in the coming years but acknowledges the pressure it currently creates.<\/p>\n
Electrification also raises new questions about responsible sourcing. Some battery components originate from regions with increased human rights risks. \u201cIf certain parts of the manufacturing process happen in what the global index assesses as a high-risk country, then we ask for additional proof of adherence to the supplier code of conduct,\u201d Wennerblom says. Independent audits are now required, though transparent reporting remains difficult.<\/p>\n
Despite these complications, the shift promises clear advantages for residents: quieter streets, improved energy efficiency and a more attractive public transport system. At the same time, this frees up renewable fuels for other modes that are harder to electrify.<\/p>\n
A model of cooperation between authorities and operators<\/p>\n
Sweden\u2019s model works because it depends on strong collaboration. \u201cI sometimes refer to it as a marriage between the PTA and the PTO. They have to live together a long time and take care of the system, sometimes under challenging circumstances,\u201d says Wadman.<\/p>\n
Political commitment is a key part of this relationship. Local politicians set the long-term climate and mobility goals, and these ambitions guide the PTAs\u2019 procurement strategies. With contracts lasting a decade, the targets issued by political boards create a stable direction that operators can plan around.<\/p>\n
\u201cThis has been a long-term and very determined work from the regional counties and municipalities,\u201d stresses Gr\u00f6nlund. Clear political mandates give PTAs authority to require cleaner fleets, and they give operators confidence that investments in new technologies will be supported over the full lifetime of a contract.<\/p>\n
Operational cooperation reinforces this strategic alignment. PTAs define the ambitions, funding and environmental standards, but they rely on operators to translate these into workable solutions on the ground. Both sides have a shared interest in solving problems together. Instead of reacting through strict contractual enforcement, the framework encourages joint problem-solving and anticipatory planning.<\/p>\n
Cooperation is also formalised at national level. The Public Transport Contract Committee brings PTAs, municipalities, regional authorities and operators into a shared forum to develop procurement recommendations, contract templates and operational guidance. This ensures a common understanding of expectations and reduces fragmentation across the country. \u201cAll the recommendations and standards are open to everyone. Even if you\u2019re not a member of our organisations, you can use them,\u201d points out Gr\u00f6nlund. This culture of transparency allows smaller authorities or new operators to benefit from years of accumulated expertise.<\/p>\n
Nordic cooperation adds an extra layer. Through the Bus Nordic Initiative, Sweden works with Norway, Finland and Iceland to harmonise technical requirements for buses. This means manufacturers face a clearer, more consistent set of expectations across multiple countries. For the public sector, it reduces costs by avoiding customised specifications. For operators, it lowers risk, improves vehicle availability and allows them to deploy buses more flexibly within and across regions. This shared standard-setting is a practical example of how cooperation can influence the wider market without imposing legal obligations.<\/p>\n
Another important tool is the Index Council, which adjusts contract values each year based on inflation and cost changes. This protects operators from sudden economic shifts and encourages healthier competition.<\/p>\n
Balancing electrification and biofuels<\/p>\n
Electricity may be the long-term direction, but biofuels have been indispensable to Sweden\u2019s progress so far. For more than two decades, they have enabled the country to cut emissions rapidly without waiting for electric technology and infrastructure to mature. Sweden\u2019s early shift to renewable fuels created an immediate climate impact, supported large-scale decarbonisation of bus fleets and allowed operators to convert existing diesel vehicles with minimal disruption.<\/p>\n
\u201cYou could take an ordinary diesel bus, empty the tank, and fill it with biogas, and the bus runs smoothly,\u201d Gr\u00f6nlund recounts. This switch helped cities move away from fossil fuels before battery-electric buses became commercially viable.<\/p>\n
Biofuels also fit Sweden\u2019s geographic and climatic conditions. Many regions operate long routes in cold temperatures where today\u2019s electric buses still face limitations. \u201cEven with totally green electricity, there will be parts of our country where biofuels might be the best option for many years to come,\u201d Gr\u00f6nlund says.<\/p>\n
Another advantage has been the strong domestic production of biogas and advanced biofuels. Many buses run on biogas generated from wastewater treatment plants, forming what Wadman describes as \u201ca circular energy loop\u201d that reduces emissions while creating economic and environmental value locally. This place-based approach has strengthened energy security, reduced dependence on imported fuels and supported local industries.<\/p>\n
Sweden\u2019s long-standing exemption from EU taxation on advanced biofuels has been equally important. This measure allowed regions to scale up renewable fuels at reasonable cost. With the exemption due to expire this year, Sweden is involved in discussions with the European Commission to demonstrate its success and seek an extension.<\/p>\n
Together, these factors show that biofuels have been a cornerstone of Sweden\u2019s clean transport strategy. As the country advances toward electrification, renewable fuels remain an essential complement, ensuring that emissions stay low in areas where electric technology is not yet the best fit.<\/p>\n
Collective buying power to shape the market<\/p>\n
For cities across Europe preparing their next clean bus tenders, Sweden\u2019s experience offers valuable guidance. Yet accessing the right information can be fragmented. \u201cThere\u2019s a lot of knowledge circulating online\u2026but it\u2019s not bundled,\u201d explains Peter Staelens, Head of Mobility at Eurocities.<\/p>\n
The Big Buyers Working Together (BBWT) project addresses this by consolidating essential guidance through its Community of Practice on Zero-Emission Busses. For example, an online repository gathers legislation, national frameworks, project outputs and market insights into a single place. Staelens describes it as \u201ca living document\u201d that continues to grow with new contributions. The inclusion of Nordic procurement standards now allows cities across Europe to build on Sweden\u2019s experience.<\/p>\n
The Big Buyers Working Together<\/a> project does more than exchange knowledge; it strengthens cooperation among major public buyers who face similar challenges when procuring the next generation of zeroe-mission buses. When cities coordinate their expectations, they can send clearer signals to the market. Though they face limits. Electrifying bus fleets depends on global supply chains that Europe does not fully control, and several key components for electric buses are not produced in Europe at all. This means that even when large buyers join forces, their leverage is only one part of a much broader industrial equation.<\/p>\n Approaching these issues together, public buyers build a shared understanding of obstacles such as extended delivery times, sourcing constraints and the risk of becoming dependent on suppliers in high-risk regions. This collective perspective helps them refine their tenders, set realistic timelines and engage more confidently with manufacturers.<\/p>\n While collaboration cannot instantly reshape global supply chains, it does help buyers act from a more informed and coordinated position. They can compare solutions, validate each other\u2019s requirements and identify areas where aligning expectations is practical and beneficial. Over time, this consistency can encourage suppliers to invest in more reliable production capacity, improve transparency and develop technologies that respond to European needs.<\/p>\n \u2013<\/p>\n This article draws on insights shared during a Big Buyers Working Together webinar organised by the Community of Practice on Zero<\/a>\u2011Emission Buses. The group brings together large public buyers who want to exchange know\u2011how, compare procurement practices and steer the market towards cleaner and more reliable bus systems.<\/p>\n