“Blue” hydrogen may harm the climate more than burning fossil fuel, says a new study by Cornell and Stanford University, at a time when this fuel is being lauded by many as a clean, green energy solution to help reduce global warming.
The carbon footprint to create blue hydrogen is more than 20% greater than using either natural gas or coal directly for heat, or about 60% greater than using diesel oil for heat, according to new research “How Green is Blue Hydrogen?” published on 12 August in Energy Science & Engineering.
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Blue hydrogen starts with converting methane to hydrogen and CO2 by using heat, steam and pressure, or gray hydrogen, but goes further to capture some of the CO2. Once the byproduct carbon dioxide and the other impurities are sequestered, it becomes blue hydrogen, according to the US Department of Energy. The process to make blue hydrogen takes a large amount of energy, according to the researchers, which is generally provided by burning more natural gas.
In the past, no effort was made to capture the carbon dioxide byproduct of gray hydrogen, and the greenhouse gas emissions have been huge. Now the industry promotes blue hydrogen as a solution, an approach that still uses the methane from natural gas, while attempting to capture the byproduct carbon dioxide. Unfortunately, emissions remain very large,
…said Robert Howarth, the David R. Atkinson Professor of Ecology and Environmental Biology in the College of Agriculture and Life Sciences, who authored the research together with Mark Z. Jacobson, Stanford professor of civil and environmental engineering.
Emissions of blue hydrogen are less than for gray hydrogen, but not greatly so: perhaps surprisingly, only by about 9% to 12%. “Blue hydrogen is hardly emissions free,” wrote the researchers.
Blue hydrogen as a strategy only works to the extent it is possible to store carbon dioxide long-term indefinitely into the future without leakage back to the atmosphere.
An ecologically friendly “green” hydrogen does exist, but it remains a small sector and it has not been commercially realized, according to researchers. Green hydrogen is achieved when water goes through electrolysis (with electricity supplied by solar, wind or hydroelectric power) and the water is separated into hydrogen and oxygen. However, a recent analysis by Bloomberg NEF found that, although blue hydrogen is currently cheaper than ‘green’ hydrogen, the situation should reverse by 2030.
On Aug. 10, the U.S. Senate passed its version of the $1 trillion Infrastructure Investment and Jobs Act, which includes several billion dollars to develop, subsidize and strengthen hydrogen technology and its industry.
Political forces may not have caught up with the science yet,” Howarth said. “Even progressive politicians may not understand for what they’re voting. Blue hydrogen sounds good, sounds modern and sounds like a path to our energy future. It is not. The best hydrogen, the green hydrogen derived from electrolysis – if used wisely and efficiently – can be that path to a sustainable future. Blue hydrogen is totally different,
…concluded Howarth.
