Optare electric MetroCity bus. Click to enlarge.

The introduction of the four pure electric Optare MetroCity buses is the first step of the Mayor’s plan for all single deck buses in central London to be zero emission at tailpipe, as part of the world’s first Ultra Low Emission Zone, from 2020. This brings the total number of electric buses now in service in London to six.

The first two electric buses in London have been operating on routes 507 and 521 since last December. A further two are expected to enter service later this year.

These electric bus trials will be used to establish whether the technology can stand up to the rigors of operating in an intense urban environment such as London. The manufacturer’s tests demonstrated that while the initial capital cost of these vehicles was more than that of standard diesel, the significantly lower running and maintenance costs would offset this within the typical lifetime of the vehicle.

The buses take around five hours to fully charge overnight using the 15.2 kW on‐board charger plugged into a standard industrial 3-phase socket; or two hours using 50 kW off-board fast charge technology. They support a range of up to 100 miles (161 km) depending on operating conditions.

Around eight hundred hybrid buses now operate on London roads, including the New Routemasters, with more being introduced in a rolling program. By 2016 there will be more than 1,700 hybrid buses in service on London’s streets representing 20% of the total bus fleet.

TfL has also recently completed an extensive retrofit program of more than 1,000 older buses which involves fitting them with an innovative system called Selective Catalytic Reduction (SCR), reducing emissions of harmful oxides of nitrogen (NO_x) by up to 88%.