Comparing Carbon Intensity in Hydrogen Production

The Truth About Color and Carbon Intensity

Hydrogen is a clean fuel that, when consumed, produces no emissions other than water. But the upstream processes that produce and deliver hydrogen to the point of use result in carbon emissions. The carbon intensity of different methods of hydrogen production can vary greatly. Factors such as energy consumption, transportation, liquification and feedstock source all contribute to the total emissions of carbon dioxide and other greenhouse gases of each method.

This chart is a summary of carbon intensity associated with different methods of hydrogen production.

Colors Can be Deceiving

Hydrogen is often oversimplified and associated with a color based on the source of the molecule. Each color is meant to represent a different method of hydrogen production based solely on the associated emissions profile at generation and does not include all the steps associated in the entire transportation to the use point of the hydrogen. When carbon intensity for the entire value chain is accounted for, we are presented with a very different picture including a wide range of results that challenge many long held beliefs in the hydrogen sector.

Carbon Intensity Drivers

It’s easy to overlook some of the factors contributing to carbon intensity in hydrogen production and  transportation. Electrolysis is often associated with the “green hydrogen” but when an electrolyzer draws electrical power from the grid, the carbon impact can be significant.  Based on EIA 2019 statistics, the US only produced 17% renewable energy. Today’s grid is not ideal for providing the electricity demanded by electrolysis because of the amount of energy required due to the low efficiency of electrolysis and the greenhouse gas emissions resulting from grid power largely derived from fossil fuels. While aggregating large electrolyzers in remote areas with plentiful access to renewable power lowers carbon emissions from hydrogen production, gains are undercut by the energy and emissions intensive liquification and long haul transportation of the hydrogen to deliver it to market for use

Going Carbon Negative

On-site hydrogen production with BayoTech’s reformer technology can have a lower carbon intensity than electrolysis using California’s 32% renewable electric grid or hydrogen produced at large, central plants. Biomethane sources such as animal waste and landfill gas represent an opportunity to further reduce carbon intensity. When we compare the carbon intensity of a BayoTech on-site hydrogen generator using biomethane sourced from landfill gas, for example, the overall carbon impact is significantly reduced.

Using biomethane sourced from animal waste even makes it possible to produce green, renewable hydrogen with a negative carbon intensity using BayoTech’s onsite hydrogen generators. The U.S. total methane potential in raw biogas is estimated at about 16 million metric tons per year. This represents a tremendous opportunity for hydrogen production.

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