Hydrogen Fuel Cell Bus Technology State of the ... - NEXTHYLIGHTS

Recommendations

Info

Hydrogen Fuel Cell Bus Technology State of the Art Review 5.2 CO2 emissions Table 9, below, summarises the range of CO2 emissions per kilometre for hybrid fuel cell buses compared with diesel and diesel hybrid buses. There is a very wide range for fuel cell hybrids, reflecting the wide range in CO2 emissions for different hydrogen production pathways. At the ultra-low CO2 end (production from renewable, nuclear or fossils fuels with CCS) the CO2 emissions are over 90% lower than a conventional diesel bus. At today‟s state of the art for hydrogen production from methane (approx. 10kgCO2/kg of H2), there is still a CO2 advantage over both diesel and diesel hybrid buses at the highest fuel economy for fuel cell buses (N.B.: next generation of FC buses are expected to achieve a fuel economy up to 40% better than diesel buses over an equivalent route at parity of calorific content). As the fuel economy drops from this point, or less efficient methane based reformation pathways are used, the CO2 emissions tend towards that of a conventional diesel bus and can even increase above those for hybrid diesel buses. This suggests that any medium term strategy for hydrogen bus rollout should target a CO2 content below 10kgCO2/kg of hydrogen and best in class fuel economy, to ensure that the deployment leads to real CO2 savings. Table 9: CO2 emissions per km travelled – comparison between selected bus technologies. The figures on the CO2 content of the hydrogen fuel reflect different production paths. Hybrid Fuel Cell Bus Hybrid Diesel Bus Fuel Economy (nominal range, current values) Fuel CO2 content Kg CO2 per km travelled 8 – 15kg/100km 0* – 0.36 kg-CO2/kWh (0* – 12 kg-CO2/kg-H2) 0* – 1.8 23 – 40 litres/100km 0.3 kg-CO2/kWh (3kg-CO2/litre) Diesel Buses 35 – 50 litres/100 km 0.3 kg-CO2/kWh (3kg-CO2/litre) Trolley Buses ~ 180-200kWh/100km depend on grid content (Average EU-27: 0.6kg/kWh) 0.69 – 1.2 1.05 – 1.5 0* - 1.12 (assuming average EU-27 grid)** Source: Stakeholder consultation. * For renewable hydrogen and electricity the CO2 content is assumed equal to zero. ** The average CO2 grid content in EU-27 was ~ 0.6 kg/kWh for thermal generation in 2005 (Source: Eurostat) 54
Hydrogen Fuel Cell Bus Technology State of the Art Review 6 Comparison with Alternative Technologies This section compares the techno-economic performance of 12m platform hybrid fuel cell buses with alternative technologies. We consider the main five bus technology alternatives to fuel cell buses: Diesel buses (currently up to 90% of the European urban bus fleet 11 ) Hybrid-electric diesel (Hybrid diesel) Compressed Natural Gas buses (CNG) Battery-electric buses Trolley buses Table 10, below, provides a detailed comparison between battery, hybrid fuel cell, hybrid diesel and trolley buses. A colour code eases the interpretation of the comparison of the technologies‟ performance with the operating benchmark, which are basic diesel buses. A green label means better performance in comparison with the benchmark, whilst a red label means worse / unacceptable performance. The intermediate colours represent intermediate performance. The table immediately illustrates the attractiveness of diesel hybrid relative to diesel buses. Diesel hybrid buses offer genuine fuel economy gains and hence CO2 saving and air quality improvements, at a capital cost closer to the conventional diesel bus (up to 50% more expensive). Furthermore, the fuel costs and infrastructure issues are the same and the availability is becoming comparable with a conventional diesel bus. For this reason, numerous European bus operators are increasing uptake of hybrid bus technology. Fuel cell hybrid buses by contrast can offer compelling environmental benefits, even compared to diesel hybrids, but suffer from: o High capital costs (see section 5) o Higher maintenance costs – which will reduce with fuel cell costs o Higher fuel costs (see section 6) o A lack of hydrogen infrastructure (section 6) o Longer fill times (section 4) 11 Source: International Association of Public Transport (UITP), http://www.uitp.org/ 55
Page 1 and 2:
Hydrogen Fuel Cell Bus Technology S
Page 3 and 4:
Page 5 and 6: Hydrogen Fuel Cell Bus Technology S
Page 55: Hydrogen Fuel Cell Bus Technology S
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131:
show all

Hydrogen Fuel Cell Bus Technology State of the ... - NEXTHYLIGHTS

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?