Electric buses’ sustainability effects, noise, energy use, and costs

Abstract

Electric buses are growing in numbers in Sweden, which contributes to the development of a fossil fuel free society and a reduction of emissions. Earlier studies of bus systems have identified a need to further investigate societal costs, total cost of ownership, energy use on a yearly basis to account for seasonal variations, and noise during acceleration. Addressing those needs was the purpose of this study. Investigations were made in five cities in Sweden that have recently implemented different electric buses in their respective public transport system. Based on results from these investigations and earlier studies, new and developed models where designed and applied on electric buses on route 1 in Karlskrona, as a representative example. It was found that there were significant savings in societal costs and total cost of ownership when compared to diesel and biogas powered buses, mainly due to decreased noise, no emissions in the use phase, and decreased energy use. ARTICLE HISTORY

Total Cost of Ownership Model and Significant Cost Parameters for the Design of Electric Bus Systems

“…The fuel cost of HVO buses used in this paper is 3.5 SEK/kWh for traction energy, and 4.0 SEK/kWh for biogas. They are based on prices from Reference [1], which indicates a HVO price of 1.46 SEK/kWh and a biogas price of 1.25 SEK/kWh, and this paper has assumed an average powertrain efficiency of 36%.…”

“…The results in this paper are theoretical but based on experiences where the authors have been involved in or lead earlier projects with electric buses (e.g., [1,7,15,20,21]). Results from testing the proposed methodology for the TCO of electric buses is well in line with these previous experiences, as well as other recent studies with comparable economic prerequisites (e.g., the Nordic countries) [22].…”

“…Electric cars and buses has been proposed by several studies and authorities as a long-term solution for the sustainable development of transport systems, mainly because of their high efficiency, very low emissions when being driven, low noise levels, and the possibility of using renewable sources for their electricity (e.g., [1][2][3]). Several predictions estimate that electric vehicles will dominate the sales within the next decade (e.g., BloombergNEF believe electric cars will dominate after 2036, and electric buses after 2030 [4] and IEA believe that sales of EVs will be 70% in 2030 [5]) as the price for batteries is likely to decrease and governmental incentives are likely to increase to support such development of the transport sector.…”

“…However, bus operators have been reluctant to use electric buses in their operations, mainly because of higher purchase costs and a lack of knowledge regarding how to design, operate, and maintain electric bus systems [7]. Contradictory, a study by Borén [1] summarized several studies about electric buses 2 of 28 in Sweden and showed that electric buses can reduce the total cost of ownership for bus operators by more than 10% over a 10-year period, as well as societal costs due to low life-cycle emissions and noise levels when compared to buses powered by diesel and gas (methane). This depends on country-specific conditions, and a recent study in Texas (USA) show that electric buses can become cost competitive in about 5 years [8], while a study in India show that electric buses can be cost competitive within 25 years [9], and a study in Turkey showed that electric buses have twice as long pay-back time (almost six years) than diesel buses [10].…”

“…While there can be many environmental and health-related advantages to switch from fossil-fuelled buses to electric, it is important to make that transition relatively easy and cost-efficient to get bus-operators (and taxpayers in the long run) onboard. There have been analyses completed and models/tools designed that focus on charging systems' design and costs [13], location of charging infrastructure [14], costs and sustainability for electric buses [1], life-cycle environmental impacts [12], and procurement processes [15]. There are also several commercial tools (e.g., HASTUS, PtMS, and Optibus [16][17][18]) used by public transport authorities and bus operators for the calculation of costs related to bus traffic, but without the integration of electric bus systems.…”