Saturday, October 03, 2009

Bringing down the cost of IGCC

plants with Carbon Capture

By now, industry observers and especially regular readers of Gas Turbine World Magazine and this blog well understand the negative impact on coal-based power plant performance and costs associated with the various technical and regulatory proposals aimed at lowering CO2 emissions and to dispose of the waste CO2.

Several recent studies, notably those supported by EPRI and the DOE/NETL (see Jan-Feb 2009 GTW), have been focused on the severity of the economic impacts of carbon capture and sequestration for all forms of coal-based power generation.

For example, the impact of 90% CO2 capture on typical current-technology slurry-fed IGCC plants is to reduce HHV efficiency by more than 15 percent (from around 38% to below 32%).

And the additional parasitic plant loads reduce net plant output of 15 percent. Combined, the net effect is to increase total plant capital cost ($ per net kW) by over 35 percent and add at least 35% to the 20-year levelized cost of electricity (COE).

IGCC has advantage
NETL estimates that the impact for pulverized coal plants with 90% CCS is even a larger penalty - a whopping 85% increase in COE -- emphasizing a true advantage of IGCC technology in a carbon constrained world.

In a drive to recoup losses in IGCC plant efficiency, and mitigate increases in costs, the DOE has several advanced technologies under development with a well defined technology pathway for both near term and longer term improvements.

Most recent studies published by NETL show that the cumulative impacts of advanced technology programs are expected to improve the efficiency of IGCC+CCS plants by 8 percentage points and reduce capital cost and COE by over 30 percent.

Progress reported
Progress being made on a broad portfolio of DOE/NETL advanced technology development programs promises to significantly improve process efficiency, cut capital costs and substantially lower the cost of energy produced by coal based IGCC plants operating with carbon capture and sequestration.

Largest returns are expected of the following projects which are targeted at specific advances in design and performance:
  • Warm gas cleanup. Eliminates the thermal penalty of cold cleanup and reduces capital cost of the process.
  • Ion transport membrane oxygen. "ITM" oxygen production reduces power penalty and cost of cryogenic air separation.
  • Advanced hydrogen turbine. Advanced gas turbine increases efficiency and power rating, lowers emissions and reduces $/kW total plant cost.
  • Gasifier technology. Improved gasifier materials, instrumentation and controls improves plant reliability and availability.

At the 9th Greenhouse Gas Technologies Conference held in Washington DC late last year, Julianne Klara, a senior analyst with NETL, Pittsburgh, discussed the potential for these technologies to reduce costs in future IGCC plants.

An updated presentation of study results will be made at the 2009 Gasification Technologies Council conference being held in Colorado Springs, next week Oct 4-7.

Natural gas as the "bridge fuel"
The focus of DOE’s Clean Coal R&D program is on restoring the economic viability of coal-based power generation with carbon capture and sequestration (CCS) by applying advanced technologies to a gasification-based configuration.

Because of the steep environmental challenges currently frustrating new coal-based projects in the US, she maintains, the situation has created a dilemma for coal. Almost all new generating capacity being added is based on using natural gas fuel.

Although the use of this “bridge fuel” by utilities and developers alike is seen as the only viable alternative for reducing CO2 emissions at this time, recent history tells us that this alternative is fraught with risk of fuel cost volatility relative to coal.

The long-term solution for coal, according to the NETL study, is the technology needed to achieve the cost reductions and performance improvements to make coal-based IGCC plants with CCS more competitive with natural gas fired combined cycle plants.

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