Techno-economic analysis of diesel, natural gas, electric and hydrogen buses

Abstract

Listen

Translate article

Abstract Many regions and cities are implementing Electric (BEB – Battery Electric Bus) and hydrogen (FCB – Fuel Cell Bus) buses instead of the diesel (Diesel) and natural gas (CNG – Compressed Natural Gas) traditional ones. Many papers and reports compare the different Total Cost of Ownership of these buses but not always clarify mission, powertrain and context data. This study, starting from literature analysis, referring to a specific typical urban bus mission (17 km/h average speed per 12 h daily service), quotes techno-economic-environmental buses (purchase, maintenance, energy consumption and CO2 emissions costs), powertrains (combustion engine, battery, fuel cells, hydrogen storage) and context (diesel, CNG, electricity, hydrogen costs) data. Furthermore, a comparative analysis is carried out considering different operational scenarios based on high or low consumptions, high or low electricity costs, three hydrogen production ways and current (current, batteries and hydrogen technologies costs) and future (15% increase of diesel and CNG costs and decrease of batteries and hydrogen technologies costs) so evaluating 24 scenarios. The results shows that TCO is mainly constituted by every year costs (i.e. maintenance plus emissions and energy consumption,) respect to the one-time cost (so divided by the lifetime, i.e. purchase costs) except in the more competitive hydrogen scenarios where these 3 costs correspond equally to a 30% of the overall TCO. Thus, the bus choice, have to be made on the specific technologies and energies context costs instead on the international buses purchase cost. In fact, it is not possible to define a best technology for any scenario, especially for the future scenarios (so with a variation of diesel, CNG, battery, fuel cells, electricity and hydrogen costs). The best technology will depend on the specific context, and so specific analysis have to be made before to choose the technology to be applied. Indeed, CNG in the current scenarios is always the best technology followed by diesel, but CNG and diesel have emission costs and fossil fuel cost are expected to increase. BEB in the current and future scenarios are never the best technologies but it can be the best technology in scenarios with lower autonomy. FCB in the future scenarios are the best technology for 10 of the 12 scenarios analysed, that it is possible to say that FCB, taking into account the great possibilities of hydrogen production and the flexibility in power and energy respect the electric, even with the lower powertrain efficiencies respect to electric, is a technology that can be applied in many different contexts.