The Stockholm Experience A Decade of Experiences with Biogas Bus Operations Articulated Buses in City Operations Comparing Diesel with Biogas Photo at Kungsträdgården towards the Old Town, autumn 2011, Volvo and MAN articulated biogas bus This publication has been produced with the assistance of the European Union (http://europa.eu). The content of this publication is the sole responsibility of Baltic Biogas Bus and can in no way be taken to reflect the views of the European Union.
The Baltic Biogas Bus project will prepare for and increase the use of the eco-fuel Biogas in public transport in order to reduce environmental impact from traffic and make the Baltic region a better place to live, work and invest in. The Baltic Biogas Bus project is supported by the EU, is part of the Baltic Sea Region programme and includes cities, counties and companies within the Baltic region. Author: Project Manager: Lennart Hallgren, Stockholm Public Transport Company Date: May 2012 Reviewed by: Petra Seidenberg, ATI. Wojciech Gis, MTI 2
TABLE OF CONTENTS Objectives and Purpose... 4 The Heritage of Trying a 30 year search for solutions... 4 Criteria s when Selecting a New Fuel... 4 Learning By Doing... 5 Developing Fuel Distribution... 6 Costs and the Environment... 8 Green pays... 9 Patience pays... 10 Expectations of tomorrow... 10 3
Objectives and Purpose Visitors mention how clean and well organised Stockholm is, we like that. SLs commissioned purpose is not only to keep it that way, but to develop and include initiatives on air quality and renewable fuels. SL s 2010 year green objectives include 50 % renewable fuels by 2011 and 100 % by 2025. The purpose is to have public transportation take leadership and fulfil their portion of the turn around that is needed. The Heritage of Trying a 30 year search for solutions SL and its operators have tried a number of technical solutions such as flywheels, retardation energy accumulators, hydrogen and low blends of many kinds. Test and evaluations has been done in close co-operation between the city, operators, bus manufacturers (OEMs), fuels- and energy suppliers and government bodies. Among all tested alternatives, ethanol buses were the first to win enough confidence among stakeholders to go from project to commercial. Biogas 1 was introduced in 2003, many years after ethanol and has also proven successful enough to expand. RME, bio-diesel based on Rapeseed, is the third fuel to fit in and may possibly join as one of the fuels for the future in Stockholm. From a competitive point of view, biogas seems to provide the most advantages from both an operational and a commercial standpoint according to the results in SLs evaluation. This report will focus on the comparison between diesel oil and biogas as a fuel for buses in the greater Stockholm area under the leadership of SL. Since 2006, SL have issued several check-points on the economic development by breaking down the costs related to fuels from a total operational point of view. Capital cost, service and maintenance, taxation, fuel costs, distribution and other costs that sum up the differences and pinpoint the strengths and weaknesses of each fuel. Societies external costs have also been included, analysed and communicated to the industry. Criteria s when Selecting a New Fuel A new fuel must be renewable and last long inside the future carbon replacement legislation, it must be available and preferably locally produced. Buses should be built by several producers to secure competition and product development. Security of supply at a time when peak oil is debated and many oil-rich areas of the world seem insecure is 1 To use biogas as transport fuel, it has to be upgraded and the upgraded product is often referred to as biomethane. In this report, however, we use the term biogas for both the upgraded and the nonupgraded product. 4
essential. Essential is also the use of cost effective distribution systems. Likewise, the repair shop staff learning curve must be a foreseeable benefit to keep buses on the streets and out of the repair booth. Beyond the operations, it is hard to justify continuation in front of both the commercial operators as the Public Transport Authority without the expectation of ending up at similar operating costs within reasonable time compared to diesel buses. SL is publically owned and funded at a 50 % rate from tax payers money. Including the external costs of the society ( societal costs ) is therefore essential to view the financial criteria s also at a political or at more macro-like level. Learning By Doing SL operators experience from repair and overhaul of diesel buses is longer than any man. Introducing biogas is a new experience and going from Diesel Cycle to Otto Cyle, from fairly low exhaust temperatures to high and high peak pressure during combustion to low peak preassure is a new lesson to learn. Lean burn Diesel combustion is replaced with stoichometric combustion, leaving oxidation catalyst cleaning technology and going to three way catalyst systems. Small changes it may seem, but learning and pointing out development needs to the OEMs has created a learning curve valuable for all parts. During 2011, we noted that there is very little difference between operating a biogas bus compared with operating a diesel bus. Below, the development of diesel and biogas separated fuel related costs occur for 2006, 2008 and 2012 (SEK/100 km). 5
Analysing the differences, only one figures stood really out - service and maintenance. Previously, the heat release from burning biogas initiated several consequences. While keeping the valve seat material from diesel cylinder heads, essential ware has been noticed on valves and seats. During spring and fall, when leaves and other organic material increase in the air, radiators needed to be cleansed daily to avoid boiling engines. By the same token, hot summer days would make the engines boil. Some of these shortcomings caused dramatic interruption in fleet accessibility, increased cost for repair and irritation at all parties involved in the business. Developing Fuel Distribution Distributing biogas is expensive, less expensive in pipeline and more expensive in containers ex-change systems. The Stockholm city gas network has been up-graded and 6
several bus depots as well as public refuelling stations are linked to the same network where three production plants provide gas. More buses are made available for biogas operation as the network expands part by part and the cost is kept under control. The parties involved are actively searching and in investing solutions to increase biogas volumes and distribution networks. In 2020, some 500 GWh biogas is expected to be available in the Stockholm area, of which SL operators will use almost 200. Distributing and fuelling biogas is done at a cost of some 0,1-0,15/Nm 3. The Stockholm Gasworks Company has made its network available after up-grading an old pipe of little use. Parties involved include SL, The City of Stockholm, the three production plants, Government bodies with an interest in opening new routes for green fuel distribution and AGA Gas Company. The cooperation has been essential to the success in expanding the use of biogas for fuel not only for buses but also for taxis and other market segments. Several public refuelling stations are outside this network, but as it expands some of them and other depots can be connected to the pipe. This is a solution that fits tomorrow s distribution demands. To secure supply, LNG has been installed, as the pipe is too short to keep enough storage. The LNG supply is natural gas based, but several projects aim at liquefying biogas to reduce the climate impact further. Biogas network in Stockholm area. Red is biogas production, green is a bus depot and blue is public refuelling station.. MAN bus as Lidingö depot during refuelling Introducing biogas meet several demands that is has been on the City, the Bus Operations and on our nation. The gas is already there, as is the production plants and an upgraded pipeline. From a climate point of view, there is virtually no, or very little, fossil heritage in the gas as long as the LNG back up is not needed. Having three biogas production plants, they serve as back up for each other to some extend. Biogas for fuel fits 7
Stockholm and the heritage that the city want to keep alive in being a leading Clean and Green City in the world. The stakeholder group have found biogas to be a useful fuel for Stockholm, they include; Gas Distribution, OEMs, SL, Bus Operators, the City and Government bodies. Raising individual prices, such as the gas distribution cost, can prove fatal for the development of a growing initiative that is sensitive to cost development. Costs and the Environment Costs for introducing biogas as a fuel in buses have been high. The decision grew among the political leadership and SL early this century when trials needed to be expanded beyond ethanol. After operating the first buses for a few years, the issue arose of what kind of costs that bus operation would cause the city that is not directly linked to any of the annual budgets or annual reports that the stakeholders issue. Air pollution, climate change and noise are the main components in the calculation of the societal cost. As SL is owned by the city, ultimately steered by its politicians and funded at a 50 % level by taxes, there would not be a fair comparison between diesel, biogas and other efforts if the societal costs were not visible. Sweden and the EU issued the ASEC - figures from which it was possible to calculate the societal cost for any vehicle operation and any 8
fuel or other use of new technology. The 2008 follow up report by SL on biogas, diesel and ethanol operations, included the ASEC figures, concluding that biogas and diesel operation costs equalled. ASEC figures is a relic from the late 1990ies, whereas Swedish Authorities released new figures on societal costs in 2010. Parallel to the Swedish up-grade of standpoint, the county of Rogaland in Norway issued a state of the art report for their purposes, with which SL could compare ways of reasoning and calculations. The Swedish figures were three-folded on climate gases and 10-folded on other exhaust gases compared with ASEC (IPCC). Rogaland figures ended up at a somewhat lower level but was mentioned as probably too low in the report. Green pays Introducing biogas in Stockholm is an investment. After a decade of experiences where maintenance has caused costs beyond long terms acceptance, the repair shop staff learning curve and increasing competition among bus suppliers (OEMs), this cost is now under control. Operational costs do not vary much, but societal costs do. Conserving the environment thereby comes for free. SL operates both biogas and ethanol buses as established technologies and the aim is to expand them at the cost of reducing fossil diesel oil. Biogas and ethanol operations can therefore no longer be considered trials, but main stream SL business. RME is already on its way and it is likely that other fuels and technologies such as hybrid may be introduced and accepted if they are cost effective and all included. Introducing non-fossil fuels in several countries has been partly market driven and from there also politically driven. The use of new fuels has forced legislation nationally but also in documents like Directives inside EU legislation. SL s effort is therefore to continue to add biogas to the fleet where distribution cost and infrastructure allow. Other fuels and technologies will continue to be evaluated, introduced and possibly also expanded. Looking into diesel cycle biogas operation to further increase fuel efficiency is an area of great interest. 9
Patience pays During the early days of biogas operation inside SL, boiling engines and toeing buses was daily habits. Spare parts were not in stock, injectors where clogged by silicon-pebbles like materials and lubricants for other type of engines were used. The list was much longer, but is now quite short. As investment in buses and more so in infrastructure has been substantial. Therefore giving up could not be justified from a financial standpoint, well aware of the biogas or natural gas bus operation have been successful elsewhere. One by one, hurdles and barriers has been conquered. R&D has eliminated the clogging of injectors, putting OEMs under competition has led to bus technology maturity and cooperation between stakeholders have reduced gas distribution expenses. A decade of learning have brought biogas bus operation to a competitive level, so forecasted by SL in 1988. Expectations of tomorrow SL s plan is to continue, not only with biogas but biogas is for the moment the selected fuel, at least where available and can be distributed at decent effort and cost. Emission legislation will be tightened and the simple chemical composition of biogas is expected to be a benefit for further refinement as a bus fuel. Reducing energy use in total, forces all fuel supply chains to optimize for a leaner and more efficient processes are expected. The one single boost that can be added is changing from Otto- to Diesel engine when that technology is available. High climate and exhaust demands are expected to be met by biogas operations. 10
Partnership is a key to success and SL would most likely start all over again if it were not already done. Introducing new technology demand a partnership dialogue where several stakeholders develop the new, immature and sensitive business together. At this stage, a strong and long-term political support is and has proven essential. Communicating goals, objectives and results from operations and policy makers are also essential for the further development. The exchange of information is essential for the development at other locations, to attract new know how and keeps up a humble and learning attitude in the domestic organisation. Drive forces come from the expectation that we can make a difference, that there are other routes to take and that transports can be made without jeopardizing the environment. The operational cost equals that of conventional fuels and technologies and may very well develop at a slower cost rate than what is expected from staying at a traditional route. Including the unseen costs, the societal costs that a public transport service prove that substantial savings are made. 11