Saturday, January 09, 2010

DOE/NETL Defines
Technology Pathways

to Lower IGCC Costs

Final report on benefits of advanced IGCC technologies now available

Back in early October this site reported on a study by the DOE/NETL Office of Analysis and Planning of the potential of advanced technologies currently under development to lower the cost of coal-based IGCC power plants with high levels of carbon capture.

Study results, presented at the 2009 Gasification Technologies Council (GTC) conference held Oct. 4-7 in Colorado Springs
, predict that significant improvements are indeed possible. Now the final study report dated, November 2009, is available for downloading at the DOE/NETL website.

Severe economic impact of CCS
A number of studies supported by EPRI and the DOE/NETL (see Jan-Feb 2009 Gas Turbine World), have focused on the severity of the economic impacts of carbon capture and sequestration (CCS) for all forms of coal-based power generation.

For example, the impact of 90% CO2 capture on typical current-technology IGCC plants is to increase HHV heat rate by more than 16 percent (i.e. reducing plant efficiency from around 38% to below 32%).
And the additional parasitic plant loads associated with CO2 processing and compression reduce net plant output by more than15 percent.

The combined overall 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).

R&D aims at recouping CCS losses
In a drive to recoup losses in IGCC plant efficiency, and mitigate increases in plant capital costs due to adding CCS, the DOE has several advanced technologies under development with a well defined technology pathway for both near term and longer term improvements.

The NETL report
"Current and Future Technologies for Gasification-Based Power Generation" (DOE/NETL- 2009/1384) provides estimates of the benefits of each element of DOE's broad portfolio of advanced power systems technology programs.

Presented roughly in order of expected commercial deployment, these programs are shown to significantly improve process efficiency, cut capital costs and substantially lower the COE for coal-based IGCC plants operating with 90% CCS.

Largest returns are expected of the following R&D efforts which are targeted at specific advances in design and performance:

  • Advanced hydrogen turbine. Increases in efficiency and power rating will lower emissions and reduce $/kW total plant cost.
  • Warm gas cleanup. Eliminates thermal penalty of conventional cold cleanup and reduces capital cost. Included is application of high temperature hydrogen transport membranes for CO2 separation.
  • Ion transport membrane oxygen. "ITM" oxygen production greatly reduces power penalty and cost of cryogenic air separation.
  • Gasifier technology. Improved gasifier materials, instrumentation and controls improves plant reliability and availability. Increasing plant time on-line goes directly toward lowering energy production cost per kWh.
Starting with a nominal 600 MW current-technology FA-Class IGCC plant with slurry-fed gasification, cold gas cleanup, and 90% CO2 capture and compression, progressive application of these advanced technologies is shown to more than restore plant efficiency to pre-CCS levels (to better than 40%), and to reduce capital cost ($/kW) and COE ($/MWh) by 32% or more.

The Nov-Dec issue of Gas Turbine World magazine features a summary abstract of the DOE/NETL study, highlighting the benefits of the various advanced programs being supported by the DOE.

Additional savings on horizon
Additional savings are on the horizon with progress being made in the development of other advanced IGCC technologies outside of the DOE R&D program.

One example is the revolutionary Pratt & Whitney Rocketdyne (PWR) compact gasification process, which involves the innovative application of rocket-based technology for the production of coal-derived syngas at high pressure and temperature.

Operating conditions result in improved process efficiency and greatly reduced pressure vessel volume (by 90%), leading to an estimated 50% reduction in gasification system cost. This would clearly have a major positive impact on IGCC economics.

In another presentation at the 2009 GTC conference, PWR reported on the status of their program, including their partnership with ExxonMobil and the Alberta Energy Research Institute. As scheduled, the 18 tpd compact gasification pilot test unit started operations at the Gas Technology Institute research facility near Chicago on November 5. Hot-gas testing is now underway, and initial results have reportedly been very satisfactory.

With their process pilot plan now in operation, PWR is said to be close to announcing plans for a commercial-scale demonstration project.

Gas Turbine World is looking forward to presenting an update of the progress of this very promising advanced gasification technology program, including initial test results and design performance data, in our upcoming 2010 IGCC Reference Guide.

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