Can green hydrogen replace fossil fuels?
By Robert F. Service, Science.
Excerpt: Hydrogen is often touted as the future of green energy, and the allure is clear. When burned or run through a fuel cell, the fuel produces water as exhaust, not carbon dioxide (CO2). It is energy-rich enough to drive semitrailer trucks, cargo ships, and other heavy-duty vehicles that are tough to power with batteries. And for many industrial processes requiring high-temperature reactions, such as fertilizer production and steel manufacturing, hydrogen is basically the only alternative to fossil fuels, says Kathy Ayers, a water electrolysis expert at Nel Hydrogen, a Norwegian electrolyzer producer. “Low-carbon hydrogen is absolutely essential if we are going to address the climate crisis.” ...According to the International Energy Agency, the world needs to churn out more than 300 million tons of green hydrogen annually if it is to have a shot at limiting global warming to 1.5°C by 2050. Yet today, operating green hydrogen plants, mostly in Europe and China, produce just 1 million tons per year. ...Manufacturers already produce some 97 million tons of it, largely to make fertilizer and refine oil. But almost all of it comes from steam methane reforming, which ...spews roughly 1 billion tons of CO2 into the atmosphere—equivalent to Japan’s emissions—to make so-called gray hydrogen. Green hydrogen comes instead from electrolyzers powered by renewable electricity. ...“Hydrogen may be the best way to decarbonize some sectors of the economy,” Schrag says. “But it’s a lot more expensive than people are portraying.”...