Fuel Cell Hybrid Taxi Well-to-Wheel Life-Cycle Analysis

In a collaboration led by hydrogen fuel cell developer Intelligent Energy, a fleet of classic London cabs fitted out with hydrogen fuel cell power systems will be produced, with the objective of having a small fleet ready for full road trials in time for the 2012 Olympics. This research develops the Well-to-Wheel (WTW) Life-Cycle Analysis (LCA) for two hydrogen powered vehicle powertrain options (fuel cell plug-in hybrid vehicle, PHEV-FC; and fuel cell hybrid vehicle, HEV-FC), in comparison to the conventional ICE Diesel Taxi and a full electric vehicle (EV). In terms of energy pathways, the introduction of these different vehicle technologies is associated with alternative energy sources in a Taxi fleet so the following fuel pathways are compared: diesel, considering the average European diesel fuel characteristics; electricity, considering the 2008 UK electricity generation mix; and hydrogen, considering the compressed hydrogen option from centralized natural gas reforming. This Well-to-Wheel analysis combines the Tank-to-Wheel (TTW), which accounts for the emissions and fuel consumption that result from moving the vehicle through its drive cycle, with the Well-to-Tank (WTT), which accounts for the fuel production stage. For the European certification driving cycle (NEDC), the PHEV-FC Taxi resulted in the lower WTW energy and CO2 emissions results (2.99 MJ/km and 159 g/km), followed by the HEV-FC Taxi (3.28 MJ/km and 174 g/km), and by the EV (3.21 MJ/km and 173 g/km), compared to the ICE Diesel (3.60 MJ/km and 280 g/km). For a more demanding London driving cycle a 33, 28, 54 and 154% increase in the WTW energy consumption and CO2 emissions is observed for the PHEV-FC Taxi, HEV-FC Taxi, EV and ICE Diesel respectively.