Green hydrogen is a form of renewable energy and an essential component of the clean energy transition. Unlike natural methane gas, when industries burn it or use it in a fuel cell, there are no direct greenhouse gas (GHG) emissions. The only by-product is water.
Hydrogen is particularly useful for ‘hard-to-decarbonise’ sectors, like heavy industry, chemicals, shipping and aviation. This means it is valuable for reaching truly zero-emissions economies.
Advantages of green hydrogen
Hydrogen is the simplest and smallest element and is light, storable and energy dense. The benefits of using green hydrogen as a fuel include:
- Clean: the only by-product is water
- Renewable: generated using natural, renewable sources like wind and solar
- Storable: industries can compress and store it for long periods
- Transportable: it is a very light element and can be handled more easily than alternatives, like lithium batteries
Green hydrogen production
There are many ways humans can make hydrogen for energy. No matter how we produce hydrogen, it does not generate direct polluting emissions when burned. However, the pathways to produce it are very different.
Using renewable energy to produce green hydrogen
Only green hydrogen is an emissions-free source of hydrogen energy. Producers create green hydrogen by splitting water into hydrogen and oxygen using renewable electricity in a process called electrolysis.
Hydrogen from natural gas and coal
However, the main type of hydrogen that industries use today is grey. Grey hydrogen is traditionally produced from natural gas methane, which emits climate-heating GHGs. Other forms of hydrogen production include blue, brown and black. These are all made using natural gas or coal and have a harmful climate impact.
Hydrogen fuel cells
A fuel cell is a device that generates electricity through an electrochemical reaction rather than combustion. In a fuel cell, hydrogen and oxygen are combined to generate electricity, heat and water.
Hydrogen fuel cell systems are a “clean, efficient, reliable, and quiet source of power“, says the Fuel Cell & Hydrogen Energy Association. Moreover, they do not need regular recharging like batteries. Instead, they continue to produce electricity as long as there is a supply of fuel source. Fuel cells are useful in a range of applications. They power buildings, hospitals and data centres and a variety of vehicles, including cars, buses, trucks and trains.
Limitations of green hydrogen
Burning hydrogen technically only results in water as a by-product. But, like any high-temperate combustion, hydrogen flames lead to reactions between nitrogen and oxygen in the air. This converts into health-harming nitrogen dioxide pollution. However, this reaction only happens with hydrogen combustion, not hydrogen fuel cells.
There is also the risk of hydrogen leakage. Hydrogen itself is a climate-heating gas, with a global warming potential around 11 times greater than carbon dioxide (CO2) over a 100-year period. This means minimising leakage is important to reap the climate benefit of green hydrogen.
The uses of green hydrogen
A number of industries and processes already use green hydrogen.
Industry and manufacturing
Some high GHG-emitting industries are difficult to decarbonise using solar and wind directly. This is because they are extremely energy intensive. The industrial sector is responsible for more than one-third of the world’s energy consumption. Replacing fossil fuels with green hydrogen will dramatically reduce emissions from industries like steelmaking, refining and chemical production.
Green hydrogen can also substitute traditional natural gas-derived hydrogen in industries like fertiliser production, which are also high-emitting processes.
Transportation
Green hydrogen is a zero-carbon solution for transportation. Transport has the highest reliance on fossil fuels of any other sector and is responsible for 37 per cent of carbon dioxide emissions.
Vehicles that run on hydrogen have a hydrogen tank that connects to the fuel cell, which generates electricity to power the engine. Hydrogen-powered fuel cells are more efficient than internal combustion engines and can vastly reduce the climate impact of long-distance trucking, trains, shipping and aviation.
Energy storage
Hydrogen is emerging as a leading option for storing energy from renewables. The variability of renewable energy sources like wind and solar makes storage necessary to harmonise a steady supply of power.
Hydrogen storage is an alternative to lithium-ion batteries. But, industry can also use hydrogen on a much larger scale. For example, a large hydrogen storage facility in Texas can hold around 1,000 times the amount of electricity as the world’s biggest lithium-ion battery complex in South Australia. Small amounts of hydrogen can be stored in steel containers or compressed in tanks, and very large amounts can be stored in underground caverns.
Power and heat for buildings
Hydrogen fuel cell systems can also power residential and commercial buildings. However, many argue green hydrogen should first be prioritised to decarbonise hard-to-abate sectors to ensure a successful path to net-zero emissions. This is because there are already low-carbon solutions to power and heat residential buildings, like heat pumps, rooftop solar panels and efficiency measures.
Green hydrogen in Australia
Australia is currently a leading exporter of coal and liquefied natural gas (LNG). However, importing countries, like Japan and South Korea, are moving away from these fossil fuels as part of their net-zero plans. With its abundant renewable resources and existing ports, Australia is well placed to become a leading green hydrogen exporter. There are also emerging new export market opportunities for Australia, for example in Europe.
Australia’s green hydrogen domestic use and exports could be a AUD $50 billion industry by 2050.
What companies are advancing green hydrogen in Australia?
Renewable energy company CWP Global is developing one of the world’s largest renewable power projects in the Pilbara region of Western Australia. That is the 26-gigawatt (GW), wind-and-solar-to-hydrogen Asian Renewable Energy Hub.
“The concept is to harness the massive renewable energy potential of large coastal desert sites, with complementary wind and solar resources”, said CWP’s Development Director Andrew Dickson. “Night-time wind with day-time solar can deliver a huge amount of steady power to electrolysers to produce green hydrogen and its derivatives, such as green ammonia.”
“There’s also the potential to use green ammonia fuels to power ships that export iron ore. This creates the conditions for new green shipping corridors to key export markets”, said Dickson.
Global Energy Ventures (GEV) has developed an end-to-end hydrogen shipping solution. GEV Managing Director Martin Carolan says GEV’s business model has expanded to become an integrated renewable hydrogen company. “We are now developing upstream projects – to produce renewable power for electrolysis to produce hydrogen gas for export”, he says.
Perth-based Long Pipes Limited has devised revolutionary technology, which could dramatically lower the cost of piped hydrogen. Its continuous, high-pressure composite pipes will be able to be constructed in the field, in sections of up to six kilometres without a joint. This removes the need for steel welding and reduces the number of construction workers required on site.
Long Pipes Executive Chairman Neil Graham says the company is currently working with major global energy businesses to reduce the cost of transporting hydrogen and raw CO2. This includes projects in remote Western Australia. The company is also in discussions in Germany and France about projects in Europe and the North Sea.