The greenhouse gas footprint of blue hydrogen, made from natural gas using carbon capture and storage (CCS ), is 20% worse than burning natural gas or coal for heat, concludes a study from researchers at Cornell and Stanford Universities.

Total CO² equivalent emissions from the production of blue hydrogen are only 9% to 12% less than for grey hydrogen, which is produced from natural gas without CCS, the report states.

Fugitive methane emissions are higher for blue hydrogen than grey hydrogen – 95.4 grams of CO² equivalent per megajoule (g CO2eq/MJ) versus 77.4g CO2eq/MJ – because of an increased use of natural gas to power the carbon capture.

Some fossil fuel companies argue that societies will reach large-scale green hydrogen production (made from renewable energy) via “a blue highway” and politicians are “placing expensive bets on blue hydrogen as a leading solution in the energy transition,” says Robert Howarth, a co-author of the study.

“This is a warning signal to governments that the only ‘clean’ hydrogen they should invest public funds in is truly net-zero, green hydrogen made from wind and solar energy.”

Armin Laschet, chancellor candidate of the German Christian Democrats, launches the inauguration of a green hydrogen production plant at the Shell Energy and Chemicals Park Rheinland in Wesseling, Germany, July 2021. (Photo by Andreas Rentz/Getty Images )