| Carbon capture and storage


Figure 8. James M. Barry site, with combined cycle units in the distance. (Photo: Alabama Power)


if not the majority, of the lost net power production. The upgrading required for a gas turbine differs depending on the gas turbine frame and configuration and must be assessed individually for each specific scenario. An advanced gas path (AGP) is a highly effective modification for gas turbines that can increase their power output. An advanced control system is necessary to enable the effective operation of the combined cycle power plant and capture plant under various operating conditions, including base load, part load, start up, shutdown, and upset scenarios.


Barry feed study


The US Department of Energy’s Office of Fossil Energy and Carbon Management has released the official findings of a GE Vernova


led front-end engineering design (FEED) study Retrofittable advanced combined cycle integration for flexible decarbonized generation. The study focused on retrofitting Southern Company subsidiary Alabama Power’s James M. Barry unit 6 combined cycle plant (located in Bucks, Alabama) with technology capable


of capturing up to 95% of the plant’s CO2 emissions. See Figures 7 and 8. In the study, measures and technologies considered demonstrated the use of NGCC power plant steam in the carbon capture system, implementation of gas turbine upgrades, installation of NGCC and carbon capture control systems, and employment of GE Vernova’s EGR system. Taken together, these steps would help reduce the size and the costs of the carbon capture system by


potentially halving the number of absorber towers, improving the efficiency and flexibility of the plant and increasing its power output. The EGR resulted in improved total installed cost ($43 million), reduced operations and maintenance costs ($21 million) driven by the reduced CCS oxidation driven solvent degradation and improved net plant output and heat rate ($18 million) due to the reduced steam extraction for CCS reboiler because of the increased CCS inlet CO2


concentration. See Figure 9.


The capture concept considered in the FEED study was Linde’s Gen 2 technology, based on BASF’s OASE® blue gas treatment system. The study was carried out by GE Vernova in collaboration with Southern Company, Linde, BASF and Kiewit.


Figure 9. Findings of USDOE sponsored EGR assessment/FEED study for carbon capture installed on two units at Southern Company (SoCo) subsidiary Alabama Power’s James M. Barry combined cycle plant. The EGR assessment showed a net NPV improvement of $82 million when exhaust gas recirculation is applied (Image: GE Vernova)


SoCo DOE FEED: 2x1 7F, 95% capture, 40% EGR Total plant cost (TPC), $million 1339 106 GEV + Kiewit 142 Linde + Kiewit TPC,


without EGR


EGR adder


CCS ISBL reduction


CCS OSBL reduction


CCS  TPC, with EGR ISBL = inside battery limit


EGR delivers $43 million TPC savings (~3.3% of the TPC) OSBL = outside battery limit


21 43 5 2 1295 $82 million improvement to NPV from EGR 18 +$82 million


CCS NPV (w/o EGR) (TPC)


CCS NPV with and without EGR


EGR net capex


EGR O&M


Net plant output


CCS NPV (w/ EGR) (TPC)


www.modernpowersystems.com | November/December 2024 | 17


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