Hydrogen is considered by some to be the answer to supporting a net zero world by reducing carbon emissions while increasing low-carbon fuel production.
Hydrogen has gained media attention as some consider it the future to running cars and heating homes. However, it does not come without its critics or safety concerns. This perspective provides insight and background on Hydrogen, where it comes from, the pros and cons, and how it could be used to support a net zero world.
What is Hydrogen and where does it come from
Hydrogen is the lightest, simplest, and most abundant chemical element in the Universe. It is a colour-less, odour-less, non-toxic, and highly combustible element with the potential to provide a clean and reliable fuel source.
Hydrogen can be extracted from water using a technique called electrolysis that uses a high electrical current to separate hydrogen atoms from oxygen atoms. The process is expensive primarily due to the high energy expenditure needed to generate electrical currents. An alternative common production method is steam extraction, where hydrogen is separated from carbon in methane. This technique yields large quantities, but conversely emits a lot of greenhouse gases (GHG), contributing to global warming.
Global industry produces around 55 megatonnes (MT) of hydrogen annually with an annual increase in demand of about 5% coming almost entirely from the chemical and refinery industries. Nearly 50% of the world’s hydrogen production comes from steam reforming (SR) of natural gas, 30% from higher hydrocarbons reforming from refinery-chemical industrial off-gases, 18% from coal gasification, 3.9% from water electrolysis and 0.1% from other sources.
The Hydrogen Rainbow (figure.1) is an industry used term that illustrates the different methods used to produce hydrogen. Regardless of each colour label, they are produce the same output, hydrogen.
Figure.1 – The Hydrogen Rainbow
Hydrogen in the UK today
In 2018, the UK Government committed to bringing all GHG emissions to net zero by 2050. In doing so, it became the first major economy to pass legislation to end its contribution to global warming. These targets rely heavily on mass electrification. However, not everything can or will be powered efficiently and effectively by electricity in the future, creating exciting opportunities for hydrogen. Much excitement lies around the opportunities that hydrogen can bring to UK industry especially in areas like heating. A £240M net-zero hydrogen government fund combined with private-sector funding will support the replacement of fossil fuels with hydrogen or hydrogen blends.
The UK continues to debate what percentage of its hydrogen production will come from ‘blue’ i.e., converting natural gas into hydrogen, versus ‘green’ methods i.e. using an electric current produced from renewable resources. Regardless of direction, both methods are key to achieving net zero by 2050.
Drawbacks of Hydrogen
Whilst using hydrogen as a fuel source has many benefits, it isn’t the preferred choice for clean and cheap energy amongst governments or consumers. The drawbacks include:
• Expensive extraction processes: seen by some as the real reason it is not heavily used worldwide.
• Storage complications: requires compression and storage in a liquid state due to its very low density.
• Volatility: highly flammable with a history of negative headlines. Being odourless, sensors must be installed to detect leaks.
• Transportation: tricky as it is so light. Unlike oil, hydrogen cannot be pushed through piping as easily. Unlike coal, it cannot be transported in trucks.
• Fossil fuel dependant: although renewable and clean, some separation methods require non-renewable sources like oil or natural gas.
• Integration: despite advances in clean fuel alternatives such as electric vehicles (EVs) and domestic solar heating panels, fossil fuels continue to dominate energy markets and sectors such as power and heavy transportation. Even with cheap hydrogen, it will likely take years to convert existing infrastructure and consumer mentality to fully adopt the changeover from traditional energy sources.
How does this impact…
When striving for net zero, decarbonising industry will be one of the most difficult challenges to overcome. The years ahead will unveil the vital role hydrogen has in the energy transition and the fuelling of UK industries. A range of energy solutions combined with government policy is required to ensure the UK does not lose its business competitiveness while meeting its environmental commitments. With correct planning, frameworks, and infrastructure in place, hydrogen has the potential to provide a clean energy supply while contributing towards net zero.
Manufacturing, petrochemicals, and heavy-goods transportation primarily use hydrogen as a natural gas replacement to power machinery. These areas must lead the transition and provide the most significant new demand for hydrogen through industrial fuel switching. Today’s hydrogen economy will need to scale up from its current base in the oil refining and chemical sectors to enter other industries and the wider energy system.
A net zero report published by the climate change committee (CCC) identified hydrogen as a particularly important fuel source for the heavy goods vehicle (HGV) sector as powering HGVs cannot rely on conventional EV batteries. To succeed, we will need a significant increase in hydrogen fuelling stations that can accommodate HGVs.
Hydrogen also has the potential to play a significant role in reducing GHG emissions from large ships where, like HGVs, conventional EVs are unsuitable. The CCC suggests that container ships could be powered using hydrogen and ammonia. However, cross collaboration of governments on a global scale is required to completely decarbonise the sector.
Finally, the rail industry is typically recognised as an environmentally friendly mode of passenger transport. However, 2,400 diesel-powered trains remain on UK tracks. The government has pledged to remove these by 2040, providing opportunity for hydrogen to replace diesel.
To ensure supply continues to meet growing demands for clean energy, the UK must significantly increase its existing hydrogen production levels while increasing production and capacity of carbon capture and storage units (CCSUs) to ensure carbon output remain low.
The UK is a leader in hydrogen production from offshore wind. Infrastructure already exists, making the process effective and efficient. See Figure.3 for the offshore wind powered hydrogen life cycle.
Figure.3 – Offshore wind powered hydrogen life cycle
Alignment can also be made with the nuclear sector, particularly through large-scale, small, and advanced modular reactors. The Sizewell C nuclear power station is launching a demonstrator project to produce hydrogen powered by electricity from neighbouring Sizewell B. A 2MW electrolyser could potentially produce 800kg of hydrogen per day, scaling to meet ongoing demand. The hydrogen produced could power vehicles and machinery to lower emissions during the construction of Sizewell C. Excess hydrogen could be used for public transport.
Aligning hydrogen with nuclear technologies to enhance production supports lower prices in the short and medium term. The challenge is storage and transportation from nuclear sites to end destination. If investment is found, there is great potential for the UK to capitalise on exporting hydrogen to feed world demand.
Homes and domestic customers
Repurposing existing gas networks to carry cleaner-burning hydrogen could be the answer to heating emissions problem. Currently, 85% of UK homes are heated by natural gas. Introducing hydrogen allows customers to continue choosing which energy i.e. gas or electricity heats their homes while reducing heating-related emissions. Significant investment already exists to develop prototype appliances such as boilers and cookers that run on hydrogen.
In July 2021, Gateshead held a pilot where Northern Gas Networks successfully opened the UK’s first home with household gas appliances fuelled entirely by hydrogen. The home was built in a partnership with Cadent Gas and the Government’s Department for Business, Energy, and Industrial Strategy (BEIS). The successful pilot provided the public with an opportunity to experience a zero-emission hydrogen-fuelled home of the future. The home intended to showcase hydrogen fuelled applications in a real-world domestic setting.
Introducing hydrogen into natural gas systems may seem simple since existing systems already transport mixtures of natural gas and hydrogen. Unfortunately, as the physical and chemical properties of hydrogen are significantly different to natural gas, it is not possible to simply exchange natural gas for hydrogen in existing systems. The limiting factor is the durability of existing pipelines. Some degrade when exposed to hydrogen over time, particularly in high concentrations and pressures. Making the necessary modifications is costly, however this pales in comparison to the cost of creating new networks.
Establishing a society where hydrogen is a major part of the energy landscape requires further exploration of delivery methods. Sceptics continue pointing to the lack of existing infrastructure as a major barrier to its adoption.
The government’s ten-point plan remains ambitious. By 2030 they aim to create 120,000 new jobs to support the expansion and development of offshore wind, nuclear, and domestic and public infrastructure. 45GW of clean energy will be produced from renewable sources like offshore wind and hydrogen which can support fuelling industries, electrically powered transportation, and domestic housing.
Generating large volumes of clean energy will continue playing an important role in helping to achieve their plans but so does removing GHG. By 2030, government investment hopes to expand and develop technology to remove 10MT of carbon dioxide from the air. In addition, planting 30,000 hectares of trees every year should make the governments’ ambitious targets more achievable.
October 2021 sees the COP26 conference in Glasgow, presenting an exciting opportunity for world leaders to discuss a collective direction for climate change, where hydrogen will surely feature heavily.
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