The hydrogen revolution
Boris Johnson wants hydrogen to have a key role in Britain’s “green industrial revolution”. What could the gas do for us?
What is the appeal of hydrogen?
It’s a clean fuel: it releases nothing but energy and water when burnt – no direct carbon emissions or pollutants. And being one of the most abundant elements on Earth (and the most abundant in the universe), it will never run out. Not surprising, then, that as nations scramble to meet their pledges under the Paris climate accord, it is being championed as a way of reducing greenhouse gas emissions. Hydrogen could be used in lorries, buses and cars – even ships and aircraft; it could be used for domestic heating in place of natural gas; and it could replace fossil fuels in a range of industries. “If all this came to pass, then hydrogen would become a dominating factor in human life in the way that hydrocarbons currently are,” said The Economist. “It would, in other words, usher in a hydrogen economy.”
And could it be easily adapted to such uses?
Yes, because it’s very versatile: it can be stored, transported and used in a variety of ways. There is no technical reason, for example, to stop hydrogen being “dropped in” to Britain’s natural gas grid. Gas boilers would need to be replaced, but since they only last ten to 15 years, they could be phased out and swapped for “hydrogen-ready” boilers at little extra cost to consumers. Since the use of natural gas in homes accounted for 19% of greenhouse emissions in 2019, this is an area where emissions could be slashed significantly. Hydrogen also has some clear advantages over electricity, particularly when it comes to storage: it has a much better power-to-weight ratio than lithium batteries. Thus hydrogen fuel cells could power long-haul freight lorries which can’t – so far – be run on batteries (see box).
How is hydrogen produced?
This is the catch. It isn’t a primary fuel: natural reservoirs of hydrogen are rare. Rather, it has to be manufactured, using one of three different energy-intensive processes, to each of which environmentalists have assigned a distinct colour. The first, grey hydrogen, is by far the most common. It’s also the dirtiest, as it’s made from fossil fuels: steam methane reformation is an energy-intensive process which emits around 11 tonnes of CO for every tonne of hydrogen
2 yielded. The second, blue hydrogen, uses the same process but is, in theory, cleaner, as the carbon is captured and buried underground. The third, green hydrogen, is the cleanest: it involves using renewable energy sources, such as wind or solar power, to extract pure hydrogen from water by electrolysis – separating it from oxygen by running a powerful electric current through water. Predictably, it is also the most expensive method.
How is hydrogen used today?
Hydrogen is already big business. The International Energy Agency (IEA) estimates that 70 million tonnes are produced globally every year, primarily for use in oil refining, fertiliser manufacture and the steel industry. Hydrogen manufacture accounts for 6% of global natural gas use, and produces emissions equivalent to those of Indonesia and the UK combined. As a fuel, though, it’s rare – accounting for perhaps 1.5% of UK energy use.
So why would this change?
The IEA reported last year that “clean hydrogen is currently enjoying unprecedented political and business momentum, with the number of policies and projects around the world expanding rapidly”. In July, the EU revealed plans to attract up to s470bn of investment into the sector by 2050. China, Japan and South Korea are placing their own huge bets on the gas. In 2017, the UK launched a £23m fund to encourage the uptake of hydrogen vehicles: buses in London, ferries in Orkney. The Government this week said it would invest £240m in hydrogen production; and a “world-leading” blue hydrogen plant (using carbon capture) is being built near Hull. It also aims to scale up pilot projects substituting natural gas for hydrogen in homes. (Some of these use a 20% hydrogen blend, which existing boilers can cope with.)
Haven’t we heard all this before?
Yes. In the oil crisis of the 1970s, and again in the 1990s, there was a brief vogue for hydrogen. The joke in the sector is that hydrogen is the fuel of the future – and always will be. But this time it may be different, not least because hydrogen is one of the leading options for storing energy from renewables. The cost of wind and solar power is decreasing fast, yet they remain problematically intermittent. More than a million megawatt hours of wind power per year are wasted in the UK because the grid can’t cope; this could be used to produce some 18,000 tonnes of hydrogen by electrolysis. What’s more, in the UK it’s hard to see how the home heating sector could be decarbonised without using hydrogen. The boiler manufacturer Worcester Bosch thinks that for new homes, super-efficient electric heat pumps are the best option. But for the existing housing stock, hydrogen boilers would be far cheaper and simpler to install. Even using a 20% hydrogen blend would save six million tonnes of annual CO emissions.
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So will hydrogen come good?
It will probably be an important part of the energy mix of the future. The Hydrogen Council, a lobby group, estimates that it could meet 18% of the world’s energy demand by 2050. Goldman Sachs thinks that green hydrogen could be a s10trn market by 2050. Sceptics fear that much of the cheerleading is being done by the fossil fuel industry, which is likely to be the main supplier of blue hydrogen. Green hydrogen is still prohibitively expensive, costing the equivalent, in oil terms, of $270 per barrel (the current oil price is around $44 per barrel). But the cost of both electrolysis technology and renewable energy are falling fast. Ultimately, the role hydrogen plays will depend on the regulatory and subsidy decisions that governments make. The UK government will publish its full hydrogen strategy in early 2021.