Barcelona has introduced a prototype CNG (compressed natural gas) – electric hybrid bus to its city fleet, the outcome of a collaborative project between Transports Metropolitans de Barcelona (TMB) and Gas Natural Fenosa aimed at providing cleaner and more efficient public transport.Added onto an operational TMB fleet vehicle, a 12 metre Iveco bus, were two electric motors for traction, ultracapacitors to store electricity produced by a generator coupled to the engine, and a system to recover energy from braking. In this way, the bus only runs with the energy of electric motors and uses the natural gas engine as a generator of electricity when the ultracapacitors are empty.
The CNG-hybrid prototype has already undergone a comprehensive testing program, to optimise technical solutions and evaluate emission reductions, in particular fuel savings achieved with this new drive system. The results were very positive and show the hybrid vehicle can save up to 30% in fuel consumption, in this case natural gas, and a similar proportion of emissions.
CNG-powered buses are already recognised as environmentally enhanced vehicles (EEVs) because they do not emit particles and emits almost 90% less nitrogen oxide compared to a diesel bus. The new hybrid vehicle is therefore a high environmental quality, which has led to a decision to transform ten buses to CNG-hybrid operation in coming months.
(This article compiled using information from a TMB press release)