This paper focuses on the use of ultra-light combined cycle (ULCC) power plants in offshore oil and gas applications. The paper will discuss the advantages ULCC plants can provide when compared to gas turbines (GTs) operating in simple/open cycle configurations, which have traditionally dominated the offshore market.
The majority of floating, storage, production, and offloading (FPSO) vessels and fixed offshore platforms in operation today utilize gas turbines in simple cycle configuration. Thermal efficiency of these plants typically ranges from 30 - 45%. Combined cycle plants offer much higher efficiencies, however, their use in offshore oil and gas applications has been limited mainly due to weight and space constraints. In recent years, Siemens has made numerous design enhancements which have reduced weight and footprint of combined cycle designs by up to 50%. ULCC is now a concept based on proven technologies that can deliver substantial reductions in CO2 emissions, helping offshore operators meet increasingly strict environmental regulations.
When compared to two open cycle GTs, ULCC canreduceCO2 emissions by 80,000-110,000 t/annum. In some offshore regions, this equates more than $5 million in annual savings from carbon taxes and licenses. This excludes savings that can be captured from reduced fuel consumption, especially when the GT is run in feedstock. The entire ULCC package can be provided as a pre-installed module (i.e., plug and play) and is applicable to both new builds and brownfields. The concept has been designed for ease of installation and been optimized to solve typical offshore challenges, with a focus on constructability, maintainability, motions, footprint and weight.