Green hydrogen is better than blue for both cost and emissions, says studyNovember 23, 2021
Researchers from an Australian study underscore that using fossil fuels to make H2 is highly polluting.
Green hydrogen produced using processes powered by renewable energy such as solar and wind is less expensive than blue H2 produced using fossil fuels and carbon capture and storage technology, say researchers from the Australian National University (ANU).
The researchers published a paper in which they compared the financial and environmental costs.
The paper was published in the Applied Energy peer-reviewed engineering journal. In it, they stated that both the emissions and financial costs from producing H2 using fossil fuels and storing captured carbon emissions was greater than that of producing green hydrogen with renewable energy.
This cost comparison is an interesting one as one of the most significant barriers to renewable H2 adoption is that it is viewed as more expensive to produce than forms made using fossil fuel such as natural gas, followed by carbon capture and storage (CCS) to help control the resulting greenhouse gas emissions. Many countries that have hydrogen plans have been focusing on blue H2 for this reason. Australia’s former chief scientist Dr. Alan Finkel endorsed the use of blue H2 as a path to building industrial capability.
ANU researchers found other substantial drawbacks in blue H2 over green hydrogen.
The ANU researchers said that even with CCS, blue H2 produced using fossil fuels would still cause “substantial” greenhouse gas emissions. They determined that current estimates show that CCS fails to capture methane emissions. That greenhouse gas is notably more potent than CO2 and is emitted in large amounts during natural gas extraction.
As those emissions are not captured by CCS, the methane emissions would continue rising due to the extraction of the natural gas. Moreover, because the production of H2 using natural gas is not fully efficient, it requires more gas to produce the H2 than would be needed to simply burn the natural gas as a fuel in the first place. The researchers stated that these emissions will only continue rising as extraction increases to meet export market needs.
On the financial side, the researchers stated that blue H2 using CCS becomes more expensive as a facility approaches 90 percent emissions capture, because it gets harder to capture CO2 as its concentrations lower. However, green hydrogen is reducing in cost – something the researchers expect to continue quite quickly with rising demand – to the point that researchers see a far greater financial incentive to invest in green over blue.