NOTNational Grid’s green energy plans sound like a carbon-free utopia. In an animation presented as part of the New York Climate Week last week, the utility – which serves New York and Massachusetts – showed how wind farms off Long Island could power facilities to produce hydrogen, which could then provide power to ships, trucks and planes, and support the power supply region when the wind stops blowing. In addition, hydrogen could heat buildings.
Currently, much of the energy used to heat homes comes from fossil fuels. Last year, homes in the United States sucked more than 4 trillion cubic feet of natural gas, producing approximately 250 million metric tons of CO2 emissions. Part of the solution, according to gas distribution companies like National Grid, consists of using hydrogen produced from water and renewable energies to heat homes. It’s an idea that’s not only being promoted in the United States but also in Europe, where the gas lobby is trying to boost hydrogen by discredit increasingly popular electric heat pumps.
But while such moves may make sense for gas companies, they could end up costing the public much more in the long run. Heating homes directly with green electricity is more efficient and affordable than using renewables to produce hydrogen for home heating, experts say. These were the conclusions of a paper published today in Joule, which summarizes the results of 32 independent analyzes on the subject. None of them concluded that the widespread use of hydrogen for heating buildings was a good idea.
This does not mean that hydrogen is not useful for the energy transition. It is very energy-dense, making it ideal for decarbonizing so-called “hard-to-reduce” sectors of the economy where weight and volume are important considerations, such as shipping or aviation. It just doesn’t make sense for home heating when much more efficient solutions already exist, such as installing electric heat pumps or connect buildings with district heating systems, according to the study.
Much of the reason for the disparity comes down to thermodynamics. You waste energy when you use electricity to split water into oxygen and hydrogen, which can then be used as fuel. And when you burn that hydrogen in a specially designed boiler, as some proponents argue we should, you waste more energy. Electric heat pumps, by comparison, can be about five times more efficient, the study found, in part because of fewer energy conversions needed.
Not only does heating homes with hydrogen cost more due to the extra electricity needed to make it, but it means we have to build even more solar and wind farms to achieve the same decarbonization result, displacing in makes the goal posts of the amount of renewable energy needed to decarbonize the economy.
This is a big deal for anyone who wants to see the world eliminate its carbon emissions as soon as possible, a point made by study author Jan Rosenow, director of European programs at the Regulatory Assistance Project, in almost deliberately posed terms. . “The required rate of construction for renewable energy,” he wrote in the paper, “would be extremely difficult.”
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