Taking the bus instead of a car on your daily commute offers a boost to the environment, as more people on buses means fewer cars on the road and less emissions. This is despite many buses being gas guzzlers and notoriously dirty.
So imagine the results if the buses were to clean up their act?
Well, now a consortium brought together by low carbon experts at the University of East Anglia has launched the first bus in the UK to run on biomethane gas. The dual fuel diesel-biomethane bus is expected to reduce greenhouse gas emissions by half.
A Mercedes Benz engine has been adapted to run for 60-80 per cent of the time on low carbon biomethane, which is chemically identical to the methane in natural gas but is made by bacterial action on bio-wastes. It is extracted from landfill sites or from biogas produced in anaerobic digestion facilities.
Diesel is still required as the ignition source in dual fuel engines but with the oil ignition gas injection system, the engine will use 100 per cent diesel at idle with gas injection and diesel reduction commencing when engine speeds increase.
According to Dr Bruce Tofield, of the University of East Anglia's Low Carbon Innovation Centre, the vehicle is able to run on diesel, which provides flexibility, but it can also run on biomethane gas which is much cleaner and less polluting. What's more is that the cost of conversion of a diesel bus to dual fuel use is just a small fraction of a new natural gas bus.
Biomethane has a number of benefits including reducing the number of particulate and nitrogen oxide emissions by around half; reducing operating costs; and reducing greenhouse gas emissions by around half.