Hydrogen from renewables will play a crucial role in the global transition to net zero emissions. Like electricity, hydrogen is an energy carrier that can store, move and deliver energy generated by other sources, such as wind, solar or fossil fuels.
While clean energy generation, electrification and efficiencies will play the biggest part in global decarbonisation efforts, the unique properties of renewable hydrogen mean it can reduce emissions in certain sectors where electrification is not feasible. This includes shipping, aviation and the production of metals and chemicals. However, because hydrogen is much less efficient than electricity, it is not useful for anything that can be easily electrified, such as home heating, cooking and cars.
Of the many different types of hydrogen, only ‘green’ hydrogen produced from renewables can advance decarbonisation. However, the fossil fuel industry claims that ‘blue’ hydrogen, made from methane-based fossil fuel natural gas, is also a clean energy solution. Companies are also pushing hydrogen use in unsuitable sectors, such as replacing gas in pipelines and boilers for home heating. Mounting evidence discredits the feasibility of these claims. “These hydrogen-centric plans are a bad bet for consumers and the climate”, writes Senior Policy Analyst Daniel Esposito.
Utilising hydrogen where it is not suitable also risks delaying the cheaper, cleaner and safer transition towards a fully net-zero economy. Ultimately, there are many applications of hydrogen that are beneficial – and many that are damaging, highlights Professor Mark Z. Jacobson.
Australia’s hydrogen strategy
Like many nations around the world, Australia has developed a hydrogen strategy to benefit from new green industries. For example, the government is investing AUD $70 million into a green hydrogen hub in Queensland. The development is expected to create tens of thousands of jobs and inject AUD $50 billion into the local economy by 2050.
However, also like other nations, Australia plans to use hydrogen in sectors that experts warn against. Namely:
- Blending or replacing natural gas for homes and cooking
- For fuel cells to generate electricity to power cars
This is outlined in the government’s Australia’s National Hydrogen Strategy, released in 2019. However, in an accompanying government video, it clarifies that the plan is adaptive and can be revised over time. Given the growing evidence that hydrogen use in these areas is expensive, inefficient, and perhaps even dangerous, the need for a revision of these plans is pressing.
A climate solution for every sector
Solutions to decarbonise all sectors of the economy already exist. Wind, water and solar energy technologies plus storage are already well established to provide clean electricity around the world. In 2021, renewables powered 32.5 per cent of Australia’s electricity. The national government has set a target of 82 per cent renewable generation in Australia’s largest grid by 2030.
For heating, air or ground source electric heat pumps are the best clean solution to keep houses warm in winter and cool in summer. For cooking, induction hobs are efficient, safe and quick to heat. Electric vehicle (EV) sales are also growing exponentially, as people look for lower-carbon transportation options. Towns and cities are also investing in clean public transport, including electric buses, trains, trams and ferries. Moreover, when powered by 100 per cent renewables, these technologies emit zero greenhouse gas (GHG) emissions.
Importantly, electric technologies also remove the deadly health risks of toxic indoor air pollution (such as from gas cookers in homes) and outdoor pollution (such as tailpipe emissions from petrol and diesel vehicles). They also run far more efficiently than their fossil fuel-fired alternatives and are therefore often cheaper to run. This is particularly the case if households have a home solar system generating clean electricity to power them. Moreover, government grants, economies of scale and price wars will continue to drive down purchase costs.
However, some areas of the economy emit huge GHG emissions, but are difficult to decarbonise using electrification directly. Where sectors cannot be easily electrified, hydrogen from renewables can be the solution.
Fossil fuel vs renewable hydrogen
Hydrogen from natural gas
At the end of 2021, fossil fuels generated 96 per cent of hydrogen. The industry is therefore highly polluting, responsible for more than 900 megatonnes (million tonnes) of carbon dioxide (CO2) emissions annually. The gas lobby is using the “hydrogen hype” to keep its current model alive, writes journalist Johnna Crider. This refers to a “centralised, fossil fuel-based energy model, owned and controlled by just a small group of big energy corporations.”
Hydrogen from methane-based natural gas – or ‘grey’ hydrogen – is the most common form of hydrogen. Fossil fuel companies are backing a future for ‘blue’ hydrogen – also produced from gas but where GHG pollution is theoretically captured and stored (CCS). Companies use this to promote blue hydrogen as a ‘clean’ fuel. However, in reality, CSS is a largely unproven technology with low capture rates. Blue hydrogen also has the problem of methane leakage. Methane is a climate pollutant 80 times as potent as CO2 over a 20-year period. Therefore, rather than being a clean fuel, research has found that blue hydrogen can have a significant GHG footprint, even worse than burning coal, oil or natural gas directly.
Hydrogen from renewables
Hydrogen from renewables – or ‘green’ hydrogen – is generated by splitting water into hydrogen and oxygen using electrolysis. It is an emissions-free source of energy that can therefore advance net-zero plans. “The best hydrogen, the green hydrogen derived from electrolysis – if used wisely and efficiently – can be that path to a sustainable future”, said researcher Robert Howarth.
However, the latest figures show that hydrogen made via electrolysis only comprised four per cent of global hydrogen production. But, given the average global renewable share of electricity generation, this equated to just one per cent of genuinely green hydrogen output. One reason has been historically higher production costs relative to fossil fuel hydrogen. However, in 2022, the cost of green hydrogen production fell quickly, while fossil fuel prices rose around the globe, highlights energy expert Justin Mikulka. “This has resulted in a situation no one predicted: In Europe, green hydrogen is now cheaper than liquefied natural gas”, he said. “And oil and gas companies, in turn, are increasingly investing in green hydrogen instead of using methane to produce blue hydrogen.”
Why we need to replace fossil fuels with renewable energy
Fossil fuels are the leading drivers of climate breakdown and the cause of the world’s biggest environmental health threat. The result is an escalating humanitarian and economic crisis, and scientific evidence clearly suggests that the world needs to abandon fossil fuels immediately. Therefore, the ‘hype’ for blue hydrogen risks prolonging the massively polluting fossil fuel era. It is also a dangerous distraction to the urgent shift to truly clean, renewable energies. Using gas to produce hydrogen “defeats the point“ of it being a sustainable energy source, says Mark Z. Jacobson. However, for the industry, it may be an “attractive path to continue business-as-usual and a lifeline to maintain their market share”, says Daniel Esposito.
However, as the costs of renewables and electrolysers plummet, market forces may well speed up the full shift to renewables. Already, there are more people employed in the clean energy sector than in fossil fuels. Industries helping the world transition to net zero could be worth about AUD $14.7 trillion to the global economy by 2050, according to a report by Arup and Oxford Economics. Renewables and green industries are also the solution to today’s cost of living crisis and spiralling inflation around the world, according to think tanks Ember and E3G.
Where hydrogen from renewables can advance net zero effectively
Because hydrogen is many times less efficient than using electricity directly, it is not suitable for anything that can be easily electrified. Moreover, while producing green hydrogen with 100 per cent renewable energy is an emission-free process, hydrogen leakages can contribute to climate change. This is because hydrogen is an ‘indirect’ greenhouse gas, with a warming potential 33 times that of CO2 over 20 years. Therefore, “if 10 per cent leaks during its production, transportation, storage or use, the benefits of using green hydrogen over fossil fuels would be completely wiped out”, scientists told Reuters.
As hydrogen is a much smaller molecule than methane (natural gas), it would much more easily leak from gas pipelines. Therefore, “transporting hydrogen through existing gas pipelines is generally not feasible without changes to the infrastructure”, summarised the Intergovernmental Panel on Climate Change (IPCC). Hydrogen also “burns very differently” than methane, said Jussi Heikkinen. It burns as an explosion, bringing safety and engineering challenges, and meaning electronics must be explosion-proof, he said.
The best uses of renewable hydrogen
Replacing fossil fuel hydrogen
Due to the 900 megatonne annual carbon footprint of the fossil fuel hydrogen industry, “switching those sectors to low-emission hydrogen use is a priority”, says the International Energy Agency. This also presents a minimal technical challenge as it is a “like-for-like substitution rather than a fuel switch.” The impact would be a reduction of carbon emissions equivalent to the whole of Germany, says Justin Mikulka.
Long-distance, heavy transport
Green hydrogen can power emission-free transportation via fuel cells, known as fuel cell electric vehicles. However, it mainly benefits long-distance, heavy transport, highlights Jacobson. This includes ships, some aviation, trucks, buses and trains.
The reason is that for personal EVs, using conventional batteries is much easier, more efficient and cost-effective. However, there is a point at which the weight of too many batteries will lead to a loss of efficiency, indicating that green hydrogen fuel cells become the more sustainable option, Jacobson said.
Industrial processes
The industrial sector is responsible for over one-third of the world’s energy consumption and emissions. Replacing fossil fuels with green hydrogen will therefore dramatically reduce emissions from certain industries. Hydrogen can provide process heat for industrial needs or be used in the metal sector via the direct reduction of iron ore, according to the IPCC. Clean hydrogen can also be a feedstock for producing various chemicals and synthetic hydrocarbons.
Energy storage
Hydrogen can be stored either in gas or liquid form in specialised storage containers. Hydrogen is therefore able to provide long-term electricity storage to support variable renewable generation. Another use is to enable the trading and storage of electricity between regions to “overcome seasonal or production capability differences”, says the IPCC.
Where to avoid using hydrogen
Electricity production
While hydrogen can be used in electricity production, it is inefficient and results in significant energy loss, says Jacobson. Therefore, the focus should be on “maxing out” renewable energy for grid electricity before moving onto hydrogen, he suggests. At that point, its best use is to complement the variability of clean electricity production by adding “time and space option value” to store future electricity via a fuel cell or turbine.
Heating
Heating homes with clean hydrogen is far more difficult, expensive and inefficient than using electric heat pumps. Boilers burning green hydrogen are up to six times less energy efficient than heat pumps, and so would require up to six times as many wind turbines or solar panels. Moreover, it would require building owners to upgrade wall and underfloor gas pipework to handle smaller hydrogen molecules. Cookers and gas boilers would also need replacing to facilitate the switch.
Small vehicles
A green hydrogen-powered car would require two to two-and-a-half times as much renewable energy as an EV. Moreover, due to their complex technology, they are more expensive to buy upfront. They will also be more expensive to run due to the additional costs to compress, transport and store the hydrogen gas.
Hydrogen should not distract from massive renewable deployment
While green hydrogen has a part to play in decarbonising hard-to-abate sectors, most emissions reduction impacts will come directly from renewable generation, electrification and increased efficiency. The renewables available include “onshore and offshore wind, solar photovoltaics on rooftops and in power plants, concentrated solar power, solar thermal for heat, geothermal electricity and heat, existing hydroelectric power, tidal power, and wave power”, outlines Mark Z. Jacobson.
Australia only began establishing an offshore wind industry in 2021, which is set to massively increase the country’s clean generation. Around the world, water energies, such as wave and tidal, remain massively underutilised, as is space for solar panels like rooftops and carparks. Therefore, the emphasis should be to massively deploy new renewable generation capacity and a corresponding push to ‘electrify everything’ wherever possible and as quickly as possible.