Are our local buses getting on board with clean travel?
TTL’s Arnold Simanowitz compares the very different approaches our three local bus companies are taking to cut emissions and pollution.
The three bus companies that service Lewes are all taking some steps to reduce their emissions and it is interesting to compare what they are doing in this regard.
The largest provider by far is Brighton & Hove Bus and Coach Company whose buses provide a frequent (in normal times) service to and through Lewes. Their Managing Director explained to me the steps they have taken and are taking to help improve air quality and tackle climate change in the places and communities they serve.
For its main fleet, the company operates 55 street-deck buses in Brighton and Hove, and 27 Street Lites in Crawley which are Euro VI buses. Euro VI is the standard engine for all new vehicles and has a range of features to give a significant reduction on emissions compared to older engines – see panel.
Hybrid buses – For the past two years and as part of their roll-out programme they have also invested in the Enviro400ER hybrid (i.e. diesel/electric) double decker. These buses run in zero-emissions mode every time they enter Brighton’s Ultra Low Emission Zone (ULEZ) and in other sensitive areas too, such as near hospitals.
The Enviro400ER model is powered by a battery, which is charged by an on-board generator and kinetic energy is harvested when the driver brakes. It means the bus delivers zero emissions in Brighton & Hove’s ULEZ without needing to stop and charge during the day. The company’s daily mileage, long operating hours, hilly terrain and normally high passenger loadings mean that fully electric buses simply wouldn’t cope as well as the buses it has have chosen to invest in. To deliver the best possible benefit to the greatest number of people these buses operate on their busiest routes – route 1 and route 5.
The problem with Enviro400ER buses is their limited range which is why they have so far only been introduced on the most polluted routes in Brighton. However, the company is hopeful that their work-around hydrogen fuel cell electric buses may pave the way to achieve even greater results, either by investing in new buses where budget and technology permits or replacing older buses by converting some of their older fleet to a retrofit hydrogen fuel cell solution. This is a very new idea and Brighton & Hove Buses claims that no-one in the UK is doing this yet. They do have plans to extend the area in which they can deliver zero emissions and are currently working with bus manufacturer ADL to achieve this but that is likely to be in Brighton & Hove in the short term as this is where most journeys are made, and the highest number of people can benefit.
Plans for Lewes – Because the COVID-19 pandemic has created a setback to their more ambitious plans, at this stage Brighton & Hove Buses can’t say when they will be able to further invest in zero emissions buses that will serve Lewes. But they will continue to work towards their goal of being zero emissions across the entire fleet by 2030 .
In the interim, for Lewes, they are working with the local authorities in a bid to jointly invest in retrofitting the ‘Regency’ buses that serve Lewes on routes 28 and 29 with a treatment that improves their emissions to Euro 6 standards, producing air quality benefits for the people of Brighton & Hove and Lewes alike.
The Big Lemon, established in 2006, is the smallest of the bus companies, running only a few short routes in Brighton. From the outset, the company’s aim was to avoid all noxious emissions. So they initially ran on recycled waste cooking oil from local restaurants. They then experimented with solar power and having successfully managed to complete their longest route entirely using the cells on the roof of their bus depot they now run all their buses in that way.
The buses are charged direct from a 21kW solar array on the roof of the bus depot, taking 6.5hrs to charge from zero to full. When the buses are not on charge, the energy from the solar array powers the offices and the workshop, and any excess goes into the national power grid.
The Big Lemon is now working with people throughout the UK to bring some Big Lemon buses to their communities. They say that if communities want them to consider their area they should get in in touch. Their vision is that by 2030 every community in the UK has access to affordable, sustainable transport, using zero-emissions vehicles powered by renewable energy and owned by the local community.
Compass, which provides a number of services in Lewes, has no plans to introduce electric buses as their routes are mainly rural and often long. Overall they consider that the Euro VI model is actually a greener option once one considers every aspect of electric operation. Other options such as hydrogen are not yet fully proven and in Compass’s opinion are not really suitable for their type of operation.
How are diesel buses also cutting emissions?
Euro VI is the standard diesel engine for new buses and is used extensively by Brighton & Hove and Compass buses. According to B&H, the Euro VI has a range of features to give a significant reduction on emissions and particulates compared to previous models, including a 67% reduction on nitrogen oxide (NOx) emissions:
- A selective catalyst regeneration trap system and a diesel particulate filter are designed to reduce NOx levels and trap particles in the air.
- An electric compressor, electric power steering pump and an intelligent alternator are all electrically operated whereas other older buses are driven using a drive system from the engine, which increases the load and affects fuel efficiency.
- A regenerative braking system stores energy, reducing the need for the engine to generate it. This in turn reduces the amount of NOx released into the air. The NOx limit is 80mg/km for Euro 6 diesel vehicles.