Injecting green hydrogen into natural gas networks, a false good idea? Tests in this direction are underway in Quebec. Scientific analyzes show, however, that the heating of buildings is one of the least justifiable uses – a “waste”, according to several specialists – of the precious molecule.
Green hydrogen, produced from hydroelectricity, is a dream of Quebec politicians. At COP26 in Glasgow last fall, its potential sparked global excitement, despite the immaturity of the technology.
Used as a fuel, hydrogen can burn a flame or activate an engine without emitting CO2. However, this “resource” does not create any additional kilowatt-hours, since it takes electricity to produce hydrogen from water.
In fact, the production of green hydrogen leads to inevitable energy losses. And this is why specialists in the field, all over the world, agree that hydrogen should be used primarily for uses for which direct electrification is impossible.
“Hydrogen is a bit like gold,” argues Johanne Whitmore, principal researcher at the Energy Sector Management Chair at HEC Montréal. Steel production, the chemical industry, maritime transport and even perhaps one day air transport are among the hard to decarbonise sectors where hydrogen could play a crucial role.
Heating buildings, however, is one of the “least sensible” uses of hydrogen, says Falko Ueckerdt, an energy transition expert at the Potsdam Institute for Climate Change Effects Research in Germany. “It’s probably the simplest energy service. Using hydrogen — a valuable resource — to replace natural gas heating is simply inefficient,” he said in a video interview. For at least a decade, green hydrogen will be very rare on the markets, estimates the specialist.
In the spring of 2021, Mr. Ueckerdt and his colleagues published in the prestigious journal Nature Climate Change an article analyzing ways to maximize the use of hydrogen-based “e-fuels”. Residential heating came in at the back of the pack, just ahead of cars. Residential water heating was also listed as a bad idea.
In these sectors, direct electrification will be almost impossible to beat. In particular because during electrolysis – the process for producing hydrogen from water – losses of 30% to 40% must be suffered, explains Mr. Ueckerdt.
“I’m not anti-hydrogen, but we don’t have the luxury of wasting it,” Ms.me Whitmore. Lots of studies show that mixing hydrogen with natural gas is one of the least efficient ways to decarbonize. »
In Quebec, the gas distribution companies Énergir and Gazifère will soon conduct tests to verify whether their natural gas network – where methane circulates – can accommodate a certain percentage of hydrogen.
Starting in May, Énergir will inject hydrogen into its experimental closed circuit in Boucherville. This “mini-grid” simulating a residential neighborhood includes streets, houses and gas-powered appliances, such as stoves. Concentrations of up to 20% hydrogen should be tested.
In an interview, Vincent Regnault, director of gas supply and renewable gas development at Énergir, explains, however, that these tests do not necessarily mean that the company wants to inject hydrogen into its pipes. They help him better understand “how the network reacts” to this less energy-dense and more corrosive gas.
“The first idea of injecting hydrogen into the network will probably not be to decarbonize heating,” admits Mr. Regnault, who rather refers to heavy industry and transport. “I agree that we will have to prioritize the uses. Because hydrogen will not be an unlimited resource in Quebec, whatever you think,” he continues.
Moreover, Mr. Regnault justifies the current tests by arguing that certain companies in Canada or the United States will end up injecting hydrogen into the North American natural gas network to which Énergir is connected. “There is hydrogen that will necessarily start to walk in networks across North America,” he predicts.
In a brief presented in January to the Quebec consultation on green hydrogen and bioenergy, Énergir tries to convince the authorities of the potential of its infrastructures to distribute hydrogen — first mixed with natural gas, then, potentially, in pure form in certain sections of its network. In the long term, Énergir would like to see the creation of “industrial-port hubs” in Quebec supplying heavy industry, heavy transport and maritime transport with green hydrogen. These poles could then be connected by a “backbone” of hydrogen, the brief reads. The consultation report was published on March 16.
Towards a Quebec strategy
According to chemical engineer Paul Martin, co-founder of the independent science group Hydrogen Science Coalition, current equipment for natural gas distributors and consumers cannot accept more than 20% hydrogen. A section of the network devoted 100% to hydrogen would therefore require massive investment.
In Martin’s view, the industry is doing nothing but trying to justify its survival by offering to inject hydrogen into its grid. “These people are not driven by a desire to decarbonize our economy, but only to stay in business. In my opinion, this is the wrong approach, ”says the man who fears a waste of public funds in this adventure.
The independent consultant believes that the physico-chemical limits of hydrogen should relegate this energy vector to very specific sectors, which certainly does not include heating. “The energy losses [dans le procédé d’électrolyse] are too high, he said. And we will not be able to innovate to get out of it: these are characteristics specific to hydrogen. The low energy density per volume, which makes hydrogen expensive to move and difficult to store, is also a unique characteristic of the molecule. »
The Quebec government is due to unveil its green hydrogen and bioenergy strategy this spring. At the same time, it requires natural gas distributors to deliver 2% of their total volumes in the form of renewable natural gas (RNG) by 2023. A bill is currently proposing to modify the definition of RNG to include hydrogen green.
To produce green hydrogen, the costs are still “very high”, remarks Mr. Regnault, of Énergir. Other types of RNG, such as those from landfills, for example, will likely contribute to meeting the quotas set by the government.
In Europe too, the gas lobby is working to play a role in the hydrogen industry. However, Mr. Ueckerdt has not heard of any European government setting an RNG or hydrogen quota for its natural gas distributors. “It’s not being debated anymore, because it’s been proven to be a bad idea,” he says. The watchword: “a massive outflow of gas”.