(209a) Life Cycle Analysis of Carbon Capture Retrofit Using the Petra Nova Model

The Petra Nova Project near Houston, TX captures 90 percent of a slipstream of flue gas from W.A. Parish Unit 8 equivalent to 240 MWe [1]. Petra Nova utilizes an amine based capture process (Kansai Mitsubishi Carbon Dioxide Recovery Process [KM CDR Process]) and began commercial operation on January 11, 2017 [2, 3]. This installation marks the world’s largest implementation of post-combustion capture at a power plant. One of the unique attributes about the Petra Nova Project is that the steam and power required to run the capture process are not provided by Unit 8, but rather a separate 75 MW cogen natural gas plant. That 75 MW facility previously operated as a peaker unit, but was converted to cogeneration service specifically for the Petra Nova Project [4]. Approximately 60% of the output from the cogen plant will be used to operate the capture equipment and the remainder will be sold onto the grid [5]. Because of this configuration, the total power output from Unit 8 was not affected by addition of carbon capture. This configuration or similar approaches avoids the use of steam and/or power from the base coal-fired power plant and is anticipated to be used for future deployments of carbon capture of both first-generation solvents and other advanced cogen concepts like the Fuel Cell Energy Combined Electric Power and Carbon-dioxide Separation (CEPACS).

Cogen systems provide unique challenges in evaluating both the cost and environmental performance due to multiple fuel streams and accounting of trade-offs between the different services provided by the system. As technology concepts, such as carbon capture, move from design to demonstration, understanding how technology developers, investors, and the public perceive the environmental strengths and weaknesses of disparate technology choices is critical to making fair and accurate comparisons. Understanding and communicating the environmental performance of technology options can identify R&D improvement opportunities during the design and demonstration phase as well as improve the acceptance of new technology for commercialization.

This analysis compares the life cycle environmental impacts for an amine-based capture retrofit with an external co-gen source providing the utility inputs for capture compared to a more traditional retrofit in which the plant/unit output is de-rated with the utility inputs for operating the capture system coming directly from the plant. One of the major differences between the designs is that in the case of the external cogen unit, the combustion emissions associated with operating the capture unit are not part of the flue gas stream that is directed to the capture unit. Another unique consideration in this analysis is the inclusion of the upstream natural gas life cycle in the boundaries of the cogen retrofit. This analysis compares the life cycle environmental impacts for an amine-based capture retrofit with an external co-gen source providing the utility inputs for capture compared to a more traditional retrofit in which the plant/unit output is de-rated with the utility inputs for operating the capture system coming directly from the plant. To our knowledge this comparative analysis has not been performed to-date and offers an opportunity to fully understand the environmental impacts of the Petra Nova Project and offer insight into how this type of project compares to more conventional carbon capture technologies.

References

1. PETRA NOVA PARISH HOLDINGS W.A. Parish Post-Combustion CO2 Capture and Sequestration Project. 2017; Available from: https://www.netl.doe.gov/research/coal/project-information/fe0003311-ppp.
2. Capturing Carbon and Seizing Innovation: Petra Nova Is POWER’s Plant of the Year. 2017; Available from: http://www.powermag.com/capturing-carbon-and-seizing-innovation-petra-n….
3. DOE Office of Fossil Energy. Petra Nova, World’s Largest Post-Combustion Carbon-Capture Project, Begins Commercial Operation. 2017; Available from: https://energy.gov/fe/articles/petra-nova-world-s-largest-post-combusti….
4. S&P Global Platts. NRG to return Petra Nova peaker plant in Texas to operations in mid-July. 2016; Available from: https://www.platts.com/latest-news/electric-power/houston/nrg-to-return….
5. Wang, U. NRG's $1B Bet To Show How Carbon Capture Could Be Feasible For Coal Power Plants. 2014; Available from: https://www.forbes.com/sites/uciliawang/2014/07/15/nrgs-1b-bet-to-show-….

DISCLAIMER

"This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof."

Attribution

KeyLogic Systems, Inc.’s contributions to this work were funded by the National Energy Technology Laboratory under the Mission Execution and Strategic Analysis contract (DE-FE0025912) for support services.