CO₂ from energy consumption is a primary greenhouse gas. In 2001, 274 electrical generation plants produced ~2.33x10­⁸ short tons (tons) or 55% of the total CO₂ emitted in the Texas. Nearly 1/3 of this CO₂ was emitted by the top 5 power plants. Thus, sequestering CO₂ from a few plants could significantly reduce emissions. Moreover, sequestration of CO₂ in coal beds may have the added benefit of enhanced coalbed methane (CBM) recovery.

To evaluate the feasibility and the environmental and economic impacts of CO₂ sequestration in Texas low-rank coals, we assessed the (1) technical feasibility and volume of CO₂ that could be sequestered, (2) locations and quantity of CO₂ sources near coal injection sites, and (3) potential for enhanced CBM recovery.

Three CO₂ emission sources were identified near potential injection sites in low-rank coals less than 4,500 ft deep. Protected waters in major aquifers were mapped to establish the limits of potential injection projects. Based on CO₂ emissions, coal characteristics, and water quality, we selected Gibbons Creek, Sam K. Seymour, and Martin Lake power plants for sequestration evaluation. In 2001, these plants emitted 3.5x10­⁶, 12.2x10­⁶, and 18.4x10­⁶ tons of CO₂, respectively.

Computer simulation models of the 3 sites will be run to model injection of different mixes of CO₂, nitrogen and other gases. Thus, we will determine volumes of CO₂ that can be sequestered, the impact on CBM production, and potential water production volumes to be handled. This technology may be transferable to other low-rank coals in many parts of the USA.