A new cleaner kind of double-decker bus is due to be trialled by the National Transport Authority (NTA) early next year.

The hydrogen fuel cell bus was supposed to hit the road in Dublin this September but that’s been pushed back because of Covid-19, a spokesperson for the NTA said.

Bus Éireann aims to trial three of these buses on the 103 route which runs from Beresford Place in the north inner-city up to Ratoath in Co. Meath.

A spokesperson for Bus Éireann said that the Dublin to Ratoath route was chosen because it “combines typical urban start-stop operation and higher speed outer-urban operation and therefore allows trialling of zero emissions capability in both scenarios”.

It’s the latest of several trials of alternative buses, propelled by the government’s decision to stop buying diesel-only buses from July 2019 and the need to pin down what should be used in future, instead.

Between December 2018 and April 2019, transport agencies trialled diesel, diesel hybrid, gas and electric buses in Cork and Dublin.

A cost-benefit analysis of which should win out, found that for all of them “the investments may not be justifiable”, says a report from late last year, drawn up for the Department of Transport.

Hydrogen fuel cell double-deckers are next to be tested, said the NTA spokesperson, last week.

The NTA will be assessing the bus by “the distance they are able to cover on a single tank of fuel and the speed at which, and ease with which, they can be refuelled”, the spokesperson says.

Training of bus drivers, maintenance and the availability and cost of hydrogen will also be taken into consideration, the spokesperson says.

Hitting the Road

Transport makes up 43 percent of the energy that Ireland uses, of which 97 percent is supplied by oil, according to a report on diesel-fuel alternatives for the Department of Transport.

The public urban bus fleet is just a small slice of this – accounting for roughly one percent of road energy transport demand, the same report says.

While, then, the contribution of any changes towards renewable energy targets is therefore limited, it would help, it says. “As well as demonstrating leadership in the transport sector.”

In January this year, the NTA board agreed to buy three hydrogen fuel cell double-deckers from WrightBus in Ballymena, Co. Antrim, “for operational trial and research purposes”, say meeting minutes.

The cost would be approximately €2.4 million, the minutes say. That’s about €800,000 for each bus.

A diesel only bus, like a current Dublin Bus, costs the NTA €355,000 depending on the number they order and the type of bus, a spokesperson for the NTA said.

Some in the past have questioned the amount of time it’s taking for public buses to be switched away from diesel.

In March last year, NTA Chief Executive Anne Graham told Dublin city councillors that the NTA had had “constrained funding over a number of years”. Its focus had been on getting more buses to meet growing demand in the city, she said.

How Do They Work?

“Basically all the engine does is use hydrogen and mixes it with air. This turns into electricity and water,” says James Carton, of the simple science behind hydrogen buses.

The hydrogen vehicles have a fuel cell, which converts the hydrogen and oxygen into electricity and powers the vehicle, says Carton, an assistant professor in the School of Mechanical and Manufacturing Engineering at Dublin City University (DCU).

“There’s no emissions, there’s no CO2. Water just drips out of the exhaust,” he says.

Hydrogen fuel cell vehicles are not only cleaner than a diesel engine but quieter too, says Carton. “They just have a hum off the engine like an electric vehicle.”

What’s the difference between hydrogen fuel cell cars and, say, electric vehicles?

They’re similar, says Pau Farràs, a lecturer in inorganic chemistry at National University Ireland Galway (NUI Galway).

“What moves both vehicles is a battery. The main difference is the fuel cell,” he says.

A hydrogen fuel cell vehicle can drive further and refuels quicker than an electric battery car, Farràs says. “After 10 minutes you can have the tank already full with hydrogen.”

It takes just under eight hours to charge a tank from full to empty in a standard electric car, according to the UK’s largest independent provider for electric vehicle charging PodPoint.

Says Farràs: “You can store more hydrogen in a tank than you can electricity in the battery.”

An electric battery car can only store electricity while a hydrogen fuel cell vehicle makes electricity, says Carton.

Currently, most Dublin Buses use diesel engines. A spokesperson for the NTA says that diesel-only urban buses are generally retired from service after 12 years, however they added “that’s not to say that the NTA would not retire diesel-only buses earlier if finances and circumstances permitted”.

For passengers, there would be little difference riding hydrogen buses compared to diesel buses, says Farràs – aside from the noise.

“It would be the same as an electric bus where there would be almost no noise at all,” he says.

For speed, and the number of passengers the bus could carry, it would be the same as a diesel bus, Farràs says.

The big difference between diesel, electric and hydrogen buses would be the impact they have on the environment, he says.

Trialled Elsewhere

Dublin is not the only city trialling these hydrogen buses. Transport for London, Aberdeen City Council, and Liverpool City Council have all placed orders for them too.

“We had a fleet of 10 single-deck buses and they ran for nearly five years,” says Aberdeen City Councillor Philip Bell.

The hydrogen fuel cell buses were a great success, Bell said, by phone last Friday.

“Passengers loved them. They were quiet. They were very smooth.”

The hydrogen fuel cell buses also produce heat which made them cosy in the winter, he says.

Despite this success, the bus fleet was taken off the road in January of this year, he says.

The European Union “had actually provided lots of funding to defray the cost of the fuel and that ran out basically”, Bell says.

Carton, the assistant professor at DCU, said that fuel costs are something that he thinks the NTA is looking into, adding “There are several facilities that can be used to refuel these buses, none of which are in state ownership.”

While Aberdeen City Council has taken its single-decker hydrogen fleet off the road for now, it has also ordered 15 of the newer double-decker hydrogen fuel cell buses from Wrightbus, said Bell.

“These new Wrightbus second generation buses are more economical to run and they have a better supply chain,” says Bell.

Other Options

In 2018 and 2019, the Department of Transport trialled a parade of alternative buses, as it tried to work out what should replace the buses that run routes at the moment.

They tested buses that are fully electric and others that are electric hybrid. They looked at those that are compressed natural gas, and diesel hybrid, too. (They didn’t trial hydrogen fuel cell buses.)

Overall, taking into account energy efficiency and emissions of CO2, greenhouse gases, and nitrogen oxide, an analysis of the different buses and fueling options found that investments in any of the alternative buses “may not be justifiable”.

But “given that it is national policy to transition the urban public bus fleet away from diesel only buses”, the report says, priority should be given to electric buses.

After that, preference went to those powered by hydrogenated vegetable oil diesel-hybrid, biofuel compressed natural gas, diesel hybrid and compressed natural gas.

In spite of that ranking, more diesel hybrid buses are set to enter service this year.

Seventy-four diesel hybrid double-decker buses will enter service, a spokesperson for the NTA said.

Farràs says he thinks that hydrogen buses are not far behind:“In the next five years we will see more and more of these vehicles coming in.”

Carton, from DCU, thinks that it is inevitable for fossil fuels to be replaced by resources such as hydrogen, he says.

“The Stone Age didn’t stop because they ran out of stones,” Carton says. It stopped because humans made better technology and tools to use instead, he says.

The NTA spokesperson said that “it is expected that on-street trialling of the buses will commence in early 2021.”

Donal Corrigan is a city reporter for Dublin Inquirer. He covers transport, and the southside. To get in contact with him, you can email him on donal@dublininquirer.com

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