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It’s do or die for diesel

Everyone agrees that the traditional internal combustion engine which runs on carbon fuel is not sustainable and vehicle manufacturers have been looking for alternatives for decades.

While electric vehicles are increasing in popularity, they still only accounted for 1% of the vehicles currently on roadways around the world in 2019 (source: International Energy Agency).

An alternative to the alternative is being investigated. One contender is to use hydrogen as a fuel. Hydrogen is found in water or methane, but has to be separated into pure hydrogen for use in vehicles. When generated from renewable sources, or combined with carbon capture and storage, it is 100% carbon-free. Used in combustion engines, it reduces the particulates and other emissions that effect air quality.

Companies like Toyota and Hyundai have introduced production hydrogen fuel cell vehicles (the Mirai and iX35, respectively). These use fuel cells in the powertrain, through which hydrogen and air (oxygen) pass, causing a chemical reaction. The resulting high voltage direct current (DC) is converted by an inverter to a three-phase AC which is supplied to the vehicle’s electric motor to drive the vehicle. The result is zero emissions, except for water vapour and heat.

Large commercial vehicles

Fuel cell use is effective for passenger vehicles driven in cities but a UK company is pioneering hydrogen dual fuel technology in commercial vehicles to power large vehicles, vans and trucks with modified engines. Earlier attempts to reduce the emissions of this type of vehicle have faltered as they have proven expensive, impractical or they compromise performance.

ULEMCo (Ultra Low Emission Mileage Company) modifies the engine of large compression ignition (diesel) vehicles to control the mix of hydrogen with air to burn in a combustion engine. “The engine control unit is responsible for emissions,” points out ULEMCo’s Managing Director and co-founder, Amanda Lyne. “Every kg of hydrogen used to displace diesel reduces carbon emissions. Displacing 30% of energy with hydrogen results in a 30% reduction in energy emission because there is no carbon in hydrogen,” Lyne explains.

“Hydrogen is no more expensive that diesel but [utilities and local government departments] can run fleets of vehicles to meet climate change obligations,” she adds.

The company has developed IP to optimise combustion through engine modification, replacing a percentage of diesel fuel with hydrogen. Mixing hydrogen with diesel in the engine displaces 30-70% of the energy derived from diesel and save 1kg CO2 for every gallon of diesel. Hydrogen tanks are designed to fit in around the available load space, for example, under the chassis and the vehicle’s emission controls are retained to meet emission standards. The company’s initial work was on large transit vans but now the process has been scaled up for HGVs.

Dual fuel modification

The conversion process includes installing storage tanks for on-board storage at 350 bar (5000 psi), a refuelling pressure nozzle, pipework and regulators, an injection system, a dual fuel switch and ULEMCO’s hydrogen dual fuel (H2ICED) engine control unit. Wiring and safety components are also integrated, together with a data management system if required.

The hydrogen tanks do add to the payload but this is significantly less that would be needed to give the equivalent power or range using a battery, says the company. Vans have a range of around 160 – 180 miles (257 – 290 km) in dual fuel mode. When the hydrogen in the tank runs out, the vehicle switches to diesel mode. The system includes an Eco mode which limits the overall speed of the vehicle.

The company has modified over 50 vehicles to date, including roadsweepers and water tankers in the UK, Canada and Switzerland. It has received enquiries from Australia and New Zealand and has a target of a total of 100 vehicles by the middle of 2021.

Return on investment

Lyne estimates that the process adds around 20% to the cost of a refuse truck. The largest part of the cost involved in modification is installing hydrogen tanks in the vehicle. To ensure best use of available space, the system is tailored to each vehicle. It takes about a week to modify a vehicle although some standardised solutions are becoming available, says Lyne, which reduces this timeframe.

In return, the vehicle uses less diesel, with fuel consumption of around 75-85mpg (32-36 litres/km) because around 70% of its energy is derived from hydrogen.

A two year trial investigated the practical deployment of hydrogen powered vehicles in the UK. The Low Emission Freight and Logistics Trial (LEFT) covered 11 vehicles - refuse lorries, a road sweeper, an ambulance, panel vans and a refrigerated van - displacing 20-455 of diesel fuel typically used by the vehicles. The trial covered over 37,000 miles (nearly 60,000 km). Results showed that around 45 tonnes of CO2 savings would be possible each year. The drivers and operators reported that the vehicles met their daily operational needs but that the reliability of the hydrogen infrastructure and fuel available needed to improve for them to get the most of the hydrogen dual fuel technology.

Vehicles which return to a base point, or depot, need a local refuelling station, rather than a nationwide network. It is a chicken-and-the-egg situation for the hydrogen supply infrastructure, Lyne acknowledges. “The challenge is to create a whole distribution network to be able to run whole fleets of commercial vehicles to meet our climate change obligations,” she says. It is possible to buy hydrogen now at refuelling stations around the UK but there is only a handful at present. This limits the growth of hydrogen as an alternative fuel, Lyne believes. “Building an infrastructure needs to be supported by government policy and by big companies making investments,” she advocates. She would also like to see more R&D and financial support in the form of grants, as there has been for the EV infrastructure.

Summing up, Lyne says: “We use diesel because it is the cheapest for mobile energy, but diesel is destroying the planet and our air quality. Diesel cannot happen anymore”.

Hydrogen convoy

Glasgow City Council aims to be Britain’s first zero net carbon city. It has ordered 20 road gritters from James A Cuthbertson, half of which will be hydrogen-enabled and half of which will be converted to hydrogen dual fuel.

“We see this development as part of a wider roll-out of hydrogen-fuelled fleets across the country, and are really pleased that our first such order is with a local authority so close to our factory in Biggar,” said Ewan Tolson, Sales Manager at Cuthbertson.

The company worked with ULEMCo to convert the vehicles. Glasgow City Council has a fleet of 2,000 vehicles which will have to be carbon-free by 2030 to achieve zero net status.

Working with construction equipment manufacturer, JCB, and Bucher Municipal, ULEMCo has delivered a third hydrogen road sweeper to Aberdeen City Council this month. Hydrogen fuel is used in the vehicle’s primary engine and The Bucher Municipal road sweeper was modified to incorporate a 6.6kg hydrogen storage tank. This is four times more capacity than previous vehicles. The vehicle’s auxiliary engine, provided by JCB, which powers ancillary equipment, such as the sweeper brushes, also uses hydrogen fuel. It is estimated that the sweeper will enable displacement rates of up to 40% of diesel fuel.

Earlier this year, Yorkshire Water announced what is believed to be the world’s first water tanker to use hydrogen. The 7.5 tonne bowser was converted by ULEMCo from a standard tanker and is expected to result in a 33% reduction in carbon emissions.

Author
Alex Brinkley

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What you think about this article:

The problem is that hydrogen is not a source fuel, it is better described as an energy-storage medium, and the energy has to come from somewhere else, ideally wind or solar but sometimes dirtier sources.

Hydrogen is difficult to store, it can be kept liquid at -250C or it can be kept under high pressure which requires heavy tanks, but it doesn't do steel any good. Best way to store hydrogen is to combine it with another element, for example carbon, or with nitrogen as ammonia - which has been proposed for ships.

There is a project to grow special algae, using sun and preferably concentrated CO2 from the air , which can be processed into oil and thereby replace fossil hydrocarbons with renewables.


Posted by: Rod Dalitz, 21/12/2020

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