Hydrogen Production from Western Coal Including CO₂ Sequestration and Coalbed Methane Recovery: Economics, CO₂ Emissions, and Energy Balance

Conclusions

Four process schemes were evaluated in this study of coal gasification for hydrogen production: 1) a reference case where CO₂ sequestration and coalbed methane recovery are not incorporated, 2) a CO₂ sequestration case, 3) maximum hydrogen production incorporating steam methane reforming of recovered coalbed methane, and 4) hydrogen/power coproduction with the hydrogen being produced from the syngas and the power from the recovered methane. The economics favor sequestering CO₂, recovering coalbed methane, and making hydrogen or power (Cases 3 and 4). However, due to the CO₂ emissions generated from the steam methane reformer, additional hydrogen production via recovered natural gas (Case 3) is not necessarily the most environmentally friendly option from a CO₂ standpoint. Coal fired power plants emit large quantities of CO₂, therefore optimizing hydrogen production with electricity generation, as in Case 4, is a means of lowering the CO₂ emissions from power generation in the U.S. Because of the high temperatures and low CH₄ content in the resulting syngas, coal gasification for hydrogen production does not require a steam methane reforming step, and adding CO₂ sequestration (Case 2), results in almost no CO₂ being emitted to the atmosphere, for minimal additional cost. Mandating a carbon tax would make sequestering the CO₂ economically viable. However, for all of the cases examined in the analysis, it should be noted that there is much debate about the fate of the sequestered CO₂ and its long term environmental effects.