Decarbonising the global economy and achieving net-zero emissions by 2050 will require identifying and targeting the major emitters of carbon dioxide.
According to the CSIRO, the transport sector is Australia’s second largest emitter, contributing 19 per cent towards our gross carbon emissions. Decarbonising this sector is becoming increasingly urgent. Of transport emissions in 2019, light vehicles were responsible for 62 per cent with trucks pumping out 20 per cent of total transport emissions.
To decarbonise the transport industry, hydrogen which can power a fuel cell with zero emissions, could be used as an alternate fuel for petroleum products.
The heat-energy value of hydrogen is 142 MJ/kg while the heat-energy of petroleum products is only 44 MJ/kg; hydrogen fuel releases three times the heat energy during combustion.
One kilogram of hydrogen contains 33.3 kWh of usable energy, whereas petrol and diesel contain approximately 12 kWh/kg of usable energy. The engine efficiency of an internal combustion engine is approximately 25 to 30 per cent, while the efficiency of a hydrogen fuel cell is 40 to 50 per cent. Hydrogen as a fuel carries significantly more energy than the equivalent weight of batteries.
However, for a hydrogen industry to develop, large-scale electrolysers, renewable electricity, storage facilities, water supply and infrastructure will be required — along with considerable investment.
It’s not new technology
The first fuel cell was invented in 1838 by William Grove, a Welsh judge and scientist. His battery-like cell turned hydrogen and oxygen into electricity and water, using zinc and platinum electrodes exposed to an acid.
It was close to 100 years later — 1932 — when English engineer Frances Thomas Bacon, developed the first commercial hydrogen-to-oxygen fuel cell, which converted air through a direct electrochemical process.
The Bacon fuel cell has been used by NASA since the 1960s for powering satellites and in the Apollo Moon missions.
How it works
A fuel cell is a package located under the bonnet of a motor vehicle. A pressure cylinder supplies hydrogen gas to this cell, and through a chemical process, it produces electrical energy that powers a DC circuit to the drive motors.
The fuel cell’s process involves releasing hydrogen to an anode while ambient air is ducted to a cathode.
The catalyst at the anode separates hydrogen molecules into protons and electrons which take different paths to the cathode. The electrons pass through an external circuit creating a flow of electricity.
Protons then migrate through the electrolyte to the cathode, where they unite with oxygen and the electrons to form water and heat. Electricity is produced by combining hydrogen and oxygen atoms.
Hydrogen is used in fuel cells because of its availability, high energy density and environmentally friendly by-product; it leaves only water. There is no emission of air pollutants, and an electrochemical cell, unlike a traditional battery, does not run down or need recharging.
Hydrogen can also fuel an internal combustion engine, but burning hydrogen produces nitrogen oxide emissions and is less efficient than using it in fuel cells.
Developing a hydrogen industry
Unlike traditional energy sources, hydrogen does not exist in specific locations in concentrated forms.
It can be produced using several processes from a range of resources containing hydrogen.
The process most often associated with current discussions about clean hydrogen is to use an electrolyser, which passes current through water, to make “green” hydrogen, which requires renewable electricity and water as inputs.
The alternative is to make “blue” hydrogen, which is produced using traditional means of steam methane reforming or coal gasification —processes that produce carbon dioxide.
Of the world’s hydrogen, 96 per cent is produced from fossil fuels such as coal or natural gas.
An Australian hydrogen industry would require large-scale electrolysers, renewable electricity, storage facilities, water and water pipelines, hydrogen pipelines, electricity infrastructure and refuelling stations.
A recent CSIRO report noted that hydrogen has reached price parity with diesel. Diesel therefore presents an immediate opportunity for the development of a hydrogen market.
Road transport diesel replacement opportunities include trucks and buses, which are predominantly fuelled by diesel— in 2020, there were over 600,000 diesel trucks in Australia. Of the country’s 14 million passenger vehicles, however, only 13 per cent use diesel.
In general, vehicle manufacturers acknowledge hydrogen’s carbon-reduction potential, but cannot see a current business case for conversion. Concerns include a lack of refuelling infrastructure, insufficient market demand, full lifecycle costs, a lack of a second-hand market and inconsistency with overseas vehicle in standards.
Testing the waters
One company making use of hydrogen is Fortescue Metals Group, which is decarbonising its fleet of 120 Liebherr haul trucks, representing approximately 45 per cent of its current haul truck fleet.
Truck haulage consumed approximately 200 million litres of diesel in the 2021 fiscal year and accounted for 26 per cent of Fortescue’s total emissions.
The Liebherr haul trucks will be powered by both battery electric and hydrogen fuel cell technology and will be operational within the Fortescue mine sites by 2025.
Elsewhere, a wastewater treatment plant in Goondiwindi, Queensland, is likely to become one of Australia’s first to expand into hydrogen production and create a hydrogen economy for the region.
Power generation from a 2.5 MW solar farm to an electrolyser system will produce “green” hydrogen that will be sold to local customers, including the agricultural and industrial markets.
The oxygen produced during the production process will be redirected into aerating the plant’s wastewater.
Climate Smart Engineering 2023 (CSE23) will be held 29-30 November 2023 at the Melbourne Convention and Exhibition Centre. Call for abstracts and registrations are now open.
Abstract submissions close 11.59 pm AEST on Wednesday 12 April 2023.
One thing to mention, though. The Hydrogen molecules are not split into electrons and protons but into electrons and Hydrogen positive ions. The H2 molecule would then become 2H(+) + 2e(-).
Obtaining free protons would equate with a nuclear fission process which is not the case.
Hydrogen fuel cells will certainly be one of several components to a greener transport future, as Sunshine Hydro’s Advanced Energy Storage Optimisation Program (AESOP) will also assist in a greener transport future as well as “Keeping the Lights On®.”
Check out https://sunshinehydro.com/
Sounds very interesting BUT what about the safety issues? (Remember the Hindenburg) If I remember correctly, hydrogen’s low Atomic Weight makes seal design problematic and can also cause serious safety issues if seals are not properly serviced and maintained. Reading the article seems to imply that the technology is all ready to go – Is it really?
I went to UK’s Bristol University more than 50 years ago and at that time the university’s engineering department was putting a lot of effort into ‘developing’ a practical form of hydrogen fuel cell for use in motor vehicles, etc. At that time, they were making a lot of noise about their progress and how this device will revolutionise the transport industry (amongst others). 50 years on, the lack of an economic and effective form of such a device would seem to imply that efforts to date have not been successful! Has the R&D work finally paid off and when will we see a safe, economic and commercially viable unit on the market?
Goondiwindi Regional Council are very forward thinking with the approach of using both hydrogen and oxygen – both green products produced from solar energy!
An excellent article indeed. I am curious as to whether there has been any comparative analysis on the lifetime Greenhouse footprint between electric vehicles and Fuel cell vehicles that includes the lifetime CO2 emissions from the manufacture of the vehicles, the batteries, the infrastructure etc, as well as the operational footprint. I have also heard arguments that instead of using solar energy to produce green Hydrogen in an electrolyser system, it is more efficient to use that solar energy directly as a power source to charge electric vehicle batteries. I do not know if these arguments take into account the lifetime CO2 footprint however. There seems to be so much conflicting information.
Comparing the heat energy value of H2 vs. fossil fuels was confusing, given that fuel cells was almost entirely what was discussed. The carbon footprint of methane based fracking almost always lacks numbers. They should be shown. While it’s reasonable to consider blue hydrogen for a bridging purpose while building out the markets and infrastructure, lets not ignore pushback from vested interests that might point out blue hydrogen isn’t substantially better than the status quo the way green hydrogen is.
The build out of infrastructure is going to be expensive. The pressure tanks for storage are a lot higher spec than the LNG BBQ tank most are familiar with. If we start relying on economic narratives so much the large amount of work the economic transition actually requires is underappreciated, it’s entirely possible to end up with no feasible green hydrogen future pipelines.
There’s a lot of numbers that could be quoted. It’s important, I believe, to show the right ones right from the get go.
Please note that Engineers Australia has partnered with the Auatralian institute of Energy to run the Hydrogen Industry Technical Series each Wednesday, 5:30 to 8:30 pm, 15 February to 19 April, at the Victoria Division Office, 600 Bourke St, Melbourne. The series is heavily focussed on practical, real world learning led by experienced hydrogen engineers and includes three hydrogen industry site visits. For more information and to register, please refer to the series website.
Engineers Australia is also proposing to establish an Area of Practice – Hydrogen Engineering. For enquiries or to register your support and interest please contact Dr. Ling Chen Hoe, AoP Manager, Engineers Australia Email: [email protected].
I am always asking for a forum on efficient Hydrogen Production, and one method told to me by researchers in USA is a new form of catalytic separation using a new far more eficient catalyst. I was sent a paper on this and it seems to generate more hydrogen with less energy required. I think we need to stop thinking about the obvious methods and look and compare all methods.