U.S. Department of Energy - Energy Efficiency and Renewable Energy
Fuel Cell Technologies Office – Hydrogen Production
DOE's Office of Fossil Energy supports activities to advance coal-to-hydrogen technologies, specifically via the process of coal gasification with sequestration. DOE anticipates that coal gasification for hydrogen production with sequestration 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 via the water-gas shift reaction to produce additional hydrogen and carbon dioxide. Hydrogen is removed by a separation system, and the highly concentrated CO2 stream can subsequently be captured and sequestered. Learn more about carbon capture and sequestration.
Why Is This Technology Being Considered?
The United States has an abundant, domestic resource in coal--nearly a 250-year supply based on current estimates. 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 to 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 sequestration. 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 and sequestration technologies that ensure no 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
Develop new membrane technologies to separate and purify the hydrogen from the gas stream.