coal power generation options

Given the growing need for power generation, and the abundance of coal to meet this need, there is also considerable interest in finding ways to use coal and mitigate impacts on the environment — including the release of carbon dioxide (CO₂).

The schematic shown in the top section of the chart illustrates how coal is used in a conventional plant to produce electricity. In a very simplified form, coal is burned to create steam from a boiler. That steam drives a turbine, which makes electricity. CO₂ is vented as part of the resulting flue gas.

In comparison, the schematic shown in the bottom section illustrates an integrated gasification combined cycle (IGCC) plant with carbon capture and storage (CCS). The process begins with typical coal that is then partially combusted in a gasifier to produce carbon monoxide and hydrogen.

In this approach, about 10 percent of the original CO₂ is vented as flue gas. The remainder is captured downstream of the gasifier, then transported and stored underground. The hydrogen is used to power a combustion turbine, creating electricity and heat. The heat is used to drive a steam turbine, also producing electricity.

Clearly, there is more equipment and complexity in an IGCC-CCS process than exists in a conventional coal plant. That naturally equates to significantly higher costs. This factor, along with the need for additional research on CCS, indicates that widespread application of IGCC-CCS is not likely in the period to 2030.