Gasification technologies can reduce the emissions from coal used for electrical power generation. Emerson’s Alan Novak, Director of the Mining and Power industry teams, provides an update on some projects coming online.
Duke Energy recently announced commercial operation of its 618MW Edwardsport, Indiana Integrated Gasification Combined Cycle (IGCC) Power Plant. Edwardsport, as well as Southern Company’s Kemper County IGCC project (still under construction), have faced numerous schedule and budget challenges over the course of their development. Both of these facilities utilize a technology, coal gasification, which has not previously been deployed at this scale for power generation.
What is IGCC?
An Integrated Gasification Combined Cycle power plant first converts coal to a synthesis gas, or syngas, through a gasification process (high temperature and pressure) and then burns the syngas in a Combined Cycle Power Plant to produce electricity.
The gasification step allows for the removal of both Sulfur and Mercury from the gasified coal while at the same time producing a concentrated stream of carbon dioxide suitable for capture (Duke Edwardsport does not include CO2 capture while the Kemper County plant will capture 65% of its CO2 for use in enhanced oil recovery). An additional benefit is reduced solid waste since the remaining solids leave the gasifier as a vitrified, inert slag.Source: United States Department of Energy, the Energy lab, Integrated Gasification Combined Cycle (IGCC), https://jimc.me/12Lc4dk
Given the added complexity of the gasification step, it is expected that these plants will be more expensive than a conventional pulverized coal plant, which burns coal directly to produce steam.
The US Energy Information Administration provides a comparison of the expected costs of various generating technologies (partial list):
So how do the actual costs of the Duke Edwardsport and Kemper County IGCC plants compare with the above estimates from the US Energy Information Agency?Source: U.S. Energy Information Administration | Assumptions to the Annual Energy Outlook 2013, p5, https://jimc.me/1bDCkoa
- Duke Edwardsport: $3.4B actual (vs. original estimate of $2B) for 618MW output = $5500/KW (no CO2 capture)
- Kemper County: $4.3B actual to date (vs. original estimate of $2.4B) for 582MW output = $7388/KW (65% CO2 capture)
This means the actual cost of building the plants were respectively 48% and 99% greater than the EIA estimate (and significantly more than their original budgets).
New technologies generally face some degree of cost uncertainty during the first commercial-scale deployment and these plants are no exception. The Edwardsport facility is the largest IGCC in both the US and the world, while the Kemper County plant utilizes a new gasification process, the KBR/Southern Transport Integrated Gasifier, in its first commercial application. Kemper County is also the first plant in the US to include large-scale CO2 capture (for enhanced oil recovery).
It is interesting to note that other countries are using coal gasification for a very different purpose. China is currently implementing coal gasification plants across in multiple regions to produce chemicals, liquids and natural gas.
Do IGCC plants represent the future of coal-based power generation in the US or will their costs prove unsupportable? Only time will tell.
