Many people consider hydrogen to be the fuel that will wean the world off fossil fuels and reduce greenhouse gases. The production of “Blue hydrogen” has been considered to be a positive step towards zero-emission energy production. Blue hydrogen is the term used to describe hydrogen produced from non-renewable energy sources, and in which carbon produced is captured and stored so as not to enter the atmosphere as a greenhouse gas.
An article published yesterday in Energy Science & Engineering calls into question whether Blue hydrogen really is a useful ‘green’ technology.
Title: “How green is blue hydrogen”
Authors: Robert W. Howarth, Mark Z. Jacobson
From the abstract.
“Far from being low carbon, greenhouse gas emissions from the production of blue hydrogen are quite high, particularly due to the release of fugitive methane. For our default assumptions (3.5% emission rate of methane from natural gas and a 20-year global warming potential), total carbon dioxide equivalent emissions for blue hydrogen are only 9%-12% less than for gray hydrogen. While carbon dioxide emissions are lower, fugitive methane emissions for blue hydrogen are higher than for gray hydrogen because of an increased use of natural gas to power the carbon capture. Perhaps surprisingly, the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat, again with our default assumptions.”