Technology
Left: How SGN’s H100 Fife end-to-end system will power several hundred homes in Levenmouth using ‘green’ hydrogen.
Opposite page: A hydrogen renewable energy production facility.
What’s more, this most elemental gas can be sourced directly from water via a process called electrolysis, which uses an electric current to prize apart the two hydrogen atoms inside the liquid’s molecules from its one oxygen atom. The method is, admittedly, energy intensive, but SGN hope that by tapping the power from a nearby wind turbine owned by the UK’s Offshore Renewable Energy Catapult, they can not only obtain enough electricity to keep the electrolyser going indefinitely, but also do it in a purely sustainable manner.
“Our project is turbine tip-to-burner, if you like,” explains Angus McIntosh, director of energy futures at SGN. “There is a vast opportunity to exploit indigenous resources, particularly off the coast of Scotland, where there’s very good load factors and plenty of space for offshore wind to be constructed.” Part of the UK government’s Gas Goes Green initiative, H100 Fife is intended to demonstrate the feasibility of using green hydrogen to decarbonise the country’s heating systems. The platform for doing so may be small – 300 homes in Levenmouth in the first phase of the project, 1,000 in the second – but if it’s successful it could provide a winning template for greening the entire national gas network, essential if the UK is to meet its net-zero carbon emissions target by 2050. In truth, though, the residents of Levenmouth will be party to an experiment with much grander implications than simply greening boilers – the production of green hydrogen at scale, according to a model that could manufacture enough fuel to not only decarbonise heating, but energy storage and transportation into the bargain.
Potted history Theoretically, hydrogen is the perfect fuel. So named because its main by-product when burned is water (‘hydro’ from the Greek for water and ‘gen’ from gene, or ‘born-of’), science was first alerted to its potential for generating power in 1801, when British scientist Humphry Davy invented the fuel cell, which produced electricity via chemical reactions between oxygen and hydrogen. Five years later, the French engineer François Isaac de Rivaz built a rudimentary internal combustion engine driven by a mixed hydrogen-
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oxygen fuel source. For over a century afterwards, however, hydrogen’s practical applications remained largely theoretical, with the exception of its use in airships as a lighter-than-air gas – a fashion that quickly ended with the spectacular explosion of the Hindenburg in 1937. Only with the Space Race between the US and Soviet Union did the full majesty of hydrogen as a fuel substance become known, the element serving as a major component in the liquid fuel rocket engines of the period.
Barely any of the hydrogen being produced at this point was ‘green’. Over 95% continues to be captured from coal or natural gas to produce so-called ‘grey hydrogen’ – processes that, according to the International Energy Authority, release 830 million tonnes of carbon dioxide into the atmosphere annually. Electrolysis, meanwhile, was hardly practiced at all outside of scientific demonstrations in secondary schools. The reason why, says Kevin Harrison, is that the cost of the electricity needed to produce hydrogen at scale using this method was too high. “Electricity costs have to be low,” explains the senior engineer at the National Renewable Energy Laboratory (NREL), headquartered in Golden, Colorado. One recent study in the journal Energy found that it was up to six times less cost-efficient to produce green hydrogen using solar than through traditional methods. Patently, any future hydrogen economy has to be cheap and cheerful. “That is your number one goal if you want to produce green hydrogen competitively,” says Harrison. Even if we’re not quite at that stage yet, the stars seem to be aligning for an affordable green hydrogen production base. For one thing, the cost of manufacturing turbines has fallen considerably in recent years, fuelling demand for new wind farms across Europe and North America. Thanks to ongoing research efforts by institutions including NREL, the efficiency of electrolysers is constantly being boosted, while the cost of running them is predicted to fall in the next decade – by up to 75%, according to predictions by the US Department of Energy. That, in turn, has coincided with burgeoning public demand for renewable energy and the progressive decarbonisation of the world economy. “I’m working
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The estimated tonnage, in millions, of
hydrogen produced globally on an annual basis.
International Renewable Energy Agency
15
SGN
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