The U.S. Department of Energy (DOE) Office of Fossil Energy supports activities to advance coal-to-hydrogen technologies, specifically through the process of coal gasification with carbon capture, utilization, and storage. DOE anticipates that coal gasification for hydrogen production with carbon capture, utilization, and storage could be deployed in the mid-term time frame.
How Does It Work?
Chemically, coal is a complex and highly variable substance that can be converted into a variety of products. The gasification of coal is one method that can produce power, liquid fuels, chemicals, and hydrogen. Specifically, hydrogen is produced by first reacting coal with oxygen and steam under high pressures and temperatures to form synthesis gas, a mixture consisting primarily of carbon monoxide and hydrogen.
Coal gasification reaction (unbalanced):
CH0.8 + O2 + H2O → CO + CO2 + H2 + other species
After the impurities are removed from the synthesis gas, the carbon monoxide in the gas mixture is reacted with steam through the water-gas shift reaction to produce additional hydrogen and carbon dioxide. Hydrogen is removed by a separation system, and the highly concentrated carbon dioxide stream can subsequently be captured and stored. Learn more about carbon capture, utilization, and storage.
Why Is This Pathway Being Considered?
The United States has an abundant, domestic resource in coal. The use of coal to produce hydrogen for the transportation sector can reduce America's total energy use and its reliance on imported petroleum while helping create jobs through the creation of a domestic industry. The production of hydrogen from coal also offers environmental benefits when integrated with advanced technologies in coal gasification, power production, and carbon capture, utilization, and storage. The integration of these technologies facilitates the capture of multiple pollutants such as sulfur oxides, nitrogen oxides, mercury, and particulates, as well as greenhouse gases such as carbon dioxide. When hydrogen is used in efficient fuel cell vehicles, emissions from the transportation sector can be nearly eliminated.
Research Focuses on Overcoming Challenges
There are several challenges to using coal gasification to produce hydrogen at target costs and with near-zero greenhouse gas emissions. Additional R&D is needed to:
- Develop carbon capture, utilization, and storage technologies that ensure minimal carbon dioxide is released in the production process
- Develop new technologies that can replace the cryogenic process currently used to separate the required oxygen from air.