On a sunny spring evening in April, Translink kindly hosted members of EVANI (Electric Vehicle Association of Northern Ireland) at their bus depot Milewater Service Centre in Belfast. Translink is the public corporation for public transport in Northern Ireland and manages a fleet of 1,400 buses, coaches and trains carrying 1.5 million passengers every week.  With key emission targets for 2030 and beyond, Translink is preparing now for a future of zero-emission public transport with electric and hydrogen-powered double-decker buses.

After an initial pilot of three hydrogen-fuelled buses in 2020, Translink started its green journey in earnest with the purchase of 80 battery buses and a further 20 hydrogen buses in 2022. Another 100 buses are expected in 2024 and Translink doesn’t expect to ever buy another diesel bus. Handily, one of the leading manufacturers of buses, Wrightbus, is based a few miles north in Ballymena. The transition to zero-emissions not only requires the vehicles but the infrastructure to support them with an equivalent number of charge points and hydrogen storage facilities on the Milewater site.

Constraints on the power supply to the charging stations mean that intelligent software is used to ensure that battery-powered bus charging is matched to departure schedules (i.e. those buses leaving next are charged first) but otherwise it’s very similar to charging an EV car overnight: the 150 kW chargers even use the same plug and socket as an ordinary car (CCS2).

When it comes to hydrogen-fuelled buses, these are electric vehicles too, only they use a fuel cell to combine stored hydrogen with atmospheric oxygen to produce electricity and water, which pours out of the rear of the vehicle. I was most surprised at the amount of water produced – it’s more than you’d think – here’s a short video. The hydrogen is shipped in at the moment, but a nearby wind farm in County Antrim is setting up a hydrogen plant which will make deliveries much more convenient.

In comparison, the range of battery v hydrogen power isn’t that different, being somewhere about 200 miles. The big difference is that charging the batteries has to occur overnight, taking several hours, whereas a hydrogen bus can be refuelled in under 10 minutes. The battery powered buses work well within the urban environments, with hydrogen fuel cell vehicles potentially taking on the role for inter-city and rural transport. The new buses aren’t cheap though, with the fuel cell ones costing twice the equivalent diesel bus. However, the expectation is that reduced maintenance costs and extended lifespan will reduce the total cost of ownership.

The transition hasn’t been easy with several challenges. Obviously, it’s new technology with unknown infrastructure issues and limitations on the overall power supply to the site. Batteries were delayed because of the pandemic, and Translink had to work closely with Chargepoint to optimise the charging software. Learning the characteristics of batteries, especially in cold weather has been important as well, but a measure of the success of the move is that no bus has ever run out of charge while in service. Dealing with hydrogen had a different set of challenges, but by applying standards carefully and diligently, the buses can be worked on safely. The drivers and passengers have taken well to the buses, enjoying the quietness, lack of exhaust fumes and absence of vibrations.

Translink aren’t only looking to road transport for zero emissions. It’s early stages now, but a detailed assessment is on track for the required infrastructure and costs to electrify the rail network in the next decade.

The population of Northern Ireland is under 2 million people and the foresight of the team in Translink is a credit to the region: the corporation has the fourth largest zero emission fleet of vehicles in the UK. When you think of the other major transport networks in the country, such as Transport for London, this is a major achievement and it’s exciting for Northern Ireland to be in the vanguard for the future of public transport.

With many thanks to William, Martin and Ian at Translink for spending their evening with us.