Improving the environmental credentials of London’s bus fleet

The scale of the London Buses operation is vast, with the largest bus fleet in Europe, consisting of more than 8,500 vehicles, plying their trade on 700 bus routes across almost a thousand square miles of Greater London. In recent years, an investment in infrastructure and services has seen a resurgence of bus ridership. In 2010, London buses carried more than 2.25 billion passengers – the highest number since records began in the 1960s. Significantly, bus journeys in London represent nearly half of all bus journeys made in the UK.

Over the last decade, we have introduced a number of initiatives to ensure that the predominantly diesel bus fleet is as clean as it possibly can be. Seventy-six per cent of buses already meet Euro III emission standards or better. The remaining Euro II and III buses have been retrofitted with particulate filters, which reduce emissions of PM10 (fine particles), carbon monoxide and hydrocarbons from the vehicle exhaust by over 90% bringing them up to Euro IV standards.

The hybrid buses are powered by a combination of conventional diesel engines and electric motors. The hybrid driveline utilises regenerative braking to capture electrical energy during braking that would otherwise be wasted as heat. This energy is stored in a battery pack which is used to drive the electric motor. Capturing and utilising this energy means the buses use less fuel and so produce less CO2.

As the operator of such a large fleet, it is incumbent on us to also look at future technology to improve our environmental credentials further. We are already actively reducing CO2 and other harmful road transport emissions such as PM10 and NOx in line with the Mayor’s environmental strategies by introducing fuel efficient, cleaner and quieter hybrid buses in the short and medium term.

There are currently approximately 100 diesel hybrid buses operating in London, with the first introduced in February 2006 on route 360 which operates between Kensington and Elephant & Castle. In March 2007, the world’s first hybrid diesel double-deck bus entered service on route 141 (Palmers Green to London Bridge Station) operated by Arriva.

During the first few years, we have operated a variety of models of hybrid diesel bus which enabled us, along with the bus operating companies and manufacturers, to run a programme that assessed the performance of the vehicles whilst in service and decide which ones work best in London. The evaluation has considered the performance of both double and single deck buses, constructed by different manufacturers that utilise both series and parallel engines.

Our efforts to improve the environmental credentials of London’s bus fleet, and in particular for our work in introducing hybrid buses, have been recognised by the presentation of an award at the inaugural Low Carbon Vehicle Partnership Awards. We were incredibly proud to accept the Low Carbon Champion Award for Buses in 2010, that recognised our commitment to reducing CO2 emissions and leading the way in trialling the technology. The judges’ citation praised our “ground-breaking initiative [that is a] key enabler to the commercialisation of low carbon buses nationally.”

One of Boris Johnson’s, the Mayor of London’s, key bus priorities has been the development of a New Bus for London. The bus has drawn inspiration from the traditional Routemaster, including an open rear platform. The vehicle will also boast a number of new features to ensure it is fit for 21st century London, including two staircases and three entrances which will deliver speedy boarding and alighting.

The New Bus for London will also make use of the latest green technologies. We have specified that it must be powered by a hybrid diesel engine and it will be 40% less polluting than current diesel equivalents. The bus is currently being developed by Wrightbus, a bus manufacturer based in Northern Ireland, and the first five prototype vehicles will be on the streets of London in early 2012.

For the last two years, the Department for Transport has run a Green Bus Fund. The fund supports bus companies and local authorities in England to help them buy new low carbon buses. In 2009, the £30 million fund resulted in the purchase of 350 new low carbon buses across England. The £15 million fund from 2010 will support the purchase of approximately 170 new low carbon buses in England.

TfL was successful in its bid for funding in both rounds. This means that we have been able to purchase 140 hybrid buses. The first 50 buses were introduced in early-2011 and the remainder will enter service by the end of the year. By 2012, we expect to have at least 300 hybrid buses in service across London. Beyond 2012, TfL will be working with manufacturers and bus operators to expand the number of hybrid buses within the London bus fleet.

In the longer term, TfL will continue to keep an eye on other technologies that may provide even greater environmental benefits. We are currently exploring whether hydrogen hybrid fuel cell buses could have a role to play in the Capital. In December 2010, TfL unveiled the first of eight zero-polluting hybrid hydrogen buses that emit only water vapour.

All eight buses will enter service by autumn on route RV1, which runs between Covent Garden and Tower Gateway. This means that the service will be operated entirely by hydrogen buses and will make the RV1 the zero-emission bus route. The buses will form the only hydrogen bus fleet in the UK and one of the largest currently in Europe.

These state-of-the-art bespoke vehicles were specifically designed for Transport for London using pioneering technology developed by industry-leading companies Bluways, Wrightbus and Ballard. The buses are jointly funded by TfL, the Department of Energy and Climate Change (DECC) and the European Union via the Clean Hydrogen in Cities (CHIC) project.

The RV1 route passes through some of London’s most polluted areas, so its conversion to hydrogen power will contribute to the wider measures that are helping to improve London’s air quality. The buses operate from a specially designed maintenance facility housed in First’s Lea Interchange bus depot at Stratford in east London. This is the UK’s largest permanent hydrogen refuelling station and is maintained by Air Products.

Despite recent improvements, London’s air quality is still a cause for concern. We believe the development and use of alternative fuels and technologies, such as hybrid and hydrogen, will bring genuine long-term benefits in tackling CO2 emissions. The arrival of these hydrogen hybrid fuel cell buses marks an exciting new chapter for London Buses as we embrace new technologies to further build on the excellent work we are doing to improve air quality for Londoners.

London has always been at the forefront in using and developing new technology, initially pioneering the use of hydrogen buses in the UK when it took part in the Cleaner Urban Transport for Europe (CUTE) trial from December 2003 to January 2007. TfL operated three trial hydrogen buses on the route RV1. The findings from this trial and that of European partners have been used by manufacturers to develop the next generation hydrogen fuel cell buses that are operating in central London. We also took part in the one year extension of the trial, known as HyFLEET: CUTE. The overall aim of the project was to demonstrate the feasibility of an innovative, high energy efficient, clean urban public transport system and educate people about hydrogen fuel.

TfL is also a member of the Hydrogen Bus Alliance, an international partnership whose members are committed to supporting the continued and rapid development and commercialisation of hydrogen technology in the transport sector.

It has not just been the bus fleet which has seen significant and ground-breaking environmental improvements. West Ham bus station, completed in 2010, is the UK’s largest and greenest bus garage. It boasts a range of eco-friendly features including a 100kW wind turbine and a living green roof planted with sedum. The bus garage is leased by Stagecoach and has space for 320 buses and also houses their head office with staff encouraged to recycle as much as possible. The garage is expected to cut CO2 emissions by 27% compared to a building built with traditional materials and the wind turbine generates 10% of the garage’s energy needs with any surplus sold back to the National Grid.

The greening of London’s bus fleet is just one of a raft of long-term sustainable measures to improve air quality in London. These measures are set out in the Mayor’s Air Quality Strategy which was published in December 2010. Measures contained in the strategy include the introduction of Taxi and Private Hire vehicle age limits from 2012; tightening of Low Emission Zone standards and the inclusion of vans and minibuses from January 2012; encouraging the use of electric vehicles through schemes such as Source London and record levels of investment into cycling. In addition, TfL has already begun the UK’s first trial applying dust suppressants at two central London locations with high levels of particulate matter pollution (PM10). The dust suppressant is a solution made up of Calcium Magnesium Acetate that literally sticks the particulate matter to the road and prevents it re-circulating in the air. The implementation of the measures contained in the strategy is expected to reduce PM10 emissions in central London by around 13% by 2011 and by about a third by 2015 (compared to 2008). Together with the targeted local measures in priority areas, modeling suggests that this will allow London to be compliant with legal limits by 2011. The strategy will also see NOx emissions fall by 35% by 2015 (compared to 2008 levels).

We are in no way complacent and always looking ahead to new technologies and environmental initiatives, often leading the way in the country and sometimes even Europe. More hybrid buses will be entering service, including the first five of the New Bus for London from March 2012, and the entire route RV1 will be operated by hybrid hydrogen fuel cell buses.

About the Author

Mike Weston is Operations Director for London Buses. After graduating from Loughborough University in Transport Planning and Economics, Mike joined London Transport in 1985, initially in network planning and then moving on to other areas such as management of bus contracts and infrastructure. Mike became Head of Operations in 2003 and in August 2004 was promoted to Operations Director which widened his responsibility. He now manages the delivery of bus operations which includes development of the bus fleet. He is also responsible for safety and the environment for Surface Transport, and the business units of Victoria Coach Station, London River Services and Dial-a-Ride.