The smoking chimneys that gave the city this nickname have long disappeared but Edinburgh is still widely and affectionately known as Auld Reekie, a Scots dialect term meaning Old Smokey. It is a fitting name for an initiative intended to reduce pollution from energy use on Edinburgh’s public bus network. 

Lothian Buses is the main bus operator in Edinburgh, and is majority owned by City of Edinburgh Council, making it the largest municipal bus company in Britain. The company operates a fleet of over 700 buses, which carried 118,400,000 passengers in 2014. As part of an ongoing strategy to reduce pollution in Edinburgh and its surrounding districts, Lothian Buses has invested substantially in measures to decrease the environmental impact of its fleet, helping to meet the City of Edinburgh Council’s commitment to cut carbon emissions by 42% by 2020.

One of Edinburgh’s central goals is to reduce the passenger carbon footprint by encouraging a shift from car to bus use. Every step of the Auld but not Reekie initiative has considered how to achieve this; from the executive design of the hybrid buses, with free on board wi-fi, to promoting the environmentally friendly buses through high profile launch events and door to door leafleting.

Lothian Buses worked with Volvo over four years to bring hybrid bus technology to Scotland. Hybrid buses are powered by a combination of battery and diesel, which runs more efficiently, smoothly and quietly than traditional bus engines.

The first 15 hybrid buses in Edinburgh went into service in 2011 on one of the city’s busiest commuter routes. These buses operate with 35% lower fuel consumption, equating to a carbon reduction of 600 tonnes per year on this route alone. By the end of 2014, Lothian buses had 65 hybrid buses in service, operating across Edinburgh’s highest pollution areas, with 20 new double decker hybrid buses on order. 

Lothian Buses has pioneered the use of selective catalytic reduction technology (SCRT) to reduce exhaust emissions from older buses. Following successful trials, 45 buses were fitted with SCRT exhausts and have achieved dramatic improvements in air quality, including a 70% reduction in nitrogen oxides, the air pollutants of most concern in Edinburgh, and a 99% reduction in other air pollutants.

The total budget amounts €24.5 million (as of May 2014). This budget covers the financing of 65 hybrid buses, 45 SCRT exhaust fitted buses and 75 buses undergoing engine management.

The project has been funded with support from the Government / City of Edinburgh Council through the Scottish Green Bus Funds with a subsidy of €5.5 million.

The Lothian Buses Ltd financed €19 million.

The results have been successful, with a 10-13% rise in passenger numbers on the hybrid bus routes. Over 90% of Edinburgh’s bus users are pleased with the new buses, and Lothian Buses has received numerous requests for additional routes to adopt the hybrid vehicles.

Emma Roy, environmental officer at Lothian Buses, explains: "Lothian Buses is committed to providing a greener and more sustainable travel offering to our passengers and to the local environment. We have heavily invested in our fleet and seen substantial savings in fuel consumption and corresponding carbon reductions. This is an ongoing journey to ensure that we provide the most modern and environmentally efficient vehicles for Edinburgh’s travelling public." 

The environmental improvements continue to accumulate, with annual reductions of 1,200 tonnes in carbon emissions, 9.6 tonnes in nitrogen emissions and 184kg in PM10 emissions. Lothian Buses is constantly looking for innovations in technology to lower environmental impacts.

SCRT exhausts were initially limited to single-decker buses due to their size. In the beginning, Lothian buses didn't have enough environmentally friendly buses to go onto every route in the city. Through re-engineering, the volume of SCRT exhausts has been reduced, allowing the compagny to also fit them to some of their 450 double-deckers. 

The Volvo hybrid buses introduced by Lothian Buses in 2013 have been largely trouble free in their operation. This smooth introduction is attributed to both a very high standard of build quality but also a rigorous adherence to servicing and maintenance schedules and comprehensive training of engineering staff and drivers on the new buses ahead of their introduction.

The City of Edinburgh Council provides Lothian Buses with the necessary support to enhance the benefits of environmentally friendly buses. The Council repairs the roads where hybrid buses are operating to ensure smooth running and targets areas of the city where improvements in air quality are most needed.

The project also relies on the strong partnership between Lothian Buses and Volvo. The latter supports the operator in both mechanical and electrical engineering of the new buses. Trainings are organized for engineers and drivers to help hybrid buses operate at their maximum potential in terms of fuel efficiency.

Cities in action - Edinburgh’s energy efficient buses, ‘Auld but not Reekie’ - EUROCITIES, March 2015.

EUROCITIES awards entry form, Auld but not Reekie – Transforming Transport Energy Use in Edinburgh, May 2014.