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This paper will examine the performance enhancement and cost benefits of inlet air conditioning applied to a modern combined cycle plant at high ambients, resulting in lower electricity production costs. Site specific cases are presented to demonstrate a broad range of application and cost benefits. The successful project in today’s aggressive competitive power marketplace is most typically defined as “lowest $/kW”. Traditional combined cycle plants have been driven to higher levels of efficiency by increasing gas turbine heat recovery using large, multiple pressure level heat recovery steam generators and improving heat sink technologies with aggressive cooling towers or air cooled condensers. This methodology rapidly produced less competitive results as the price of new generation was reduced. The driving technology behind this change was the development of high output, high efficiency advanced gas turbines. Improved metallurgy, cooling schemes and blade coating systems permitted each GT manufacturer to offer improved output and efficiencies. These improvements, coupled with industry uncertainty due to the threat of deregulation and consequential reduction in new generation opportunities, has allowed new performance standards to be realized for equal or lower unit prices, leading to an unparalleled reduction of installed cost for new power plants.

There is a significant emphasis on peaking power, particularly recognized in the US power generation market. Orders for gas turbines are at their peaks, with OEMs taking orders for delivery in the year 2002, or later. Though a simple cycle GT is the recognized power plant of choice for daily cycle and peak power supply, it still has the highest fuel consumption rate per kWh produced (heat rate, Btu/kWh or Btu/kWh) with associated high emissions. The massive additions of GT power plants for primarily peak/cycling applications should generate needs for better utilization of installed capacities. The Compressed Air Energy Storage (CAES) plant is demonstrated as the best and cost-effective plant for storing significant amounts of the off-peak energy and releasing the peak energy as needed. This paper presents an innovative power plant concept, which is based on the integration of a conventional GT with the unfired CAES, air-bottoming cycle — denoted as GT-CAES. This concept is analyzed and compared to a conventional CAES cycle. Also, the paper presents characteristics of this concept based on ABB’s GT24/26 combustion turbine, the characteristics produced for a number of GT-CAES projects which are in various stages of development.

The Cambalache Power Station, engineered from 1993 to 1995, and constructed from 1996 to 1997, provides the island grid of Puerto Rico with 240 MW of flexible gas turbine power. The plant, now in commercial operation, has demonstrated the capability of a steam enhanced gas turbine to provide highly efficient simple cycle base load power and spinning reserve power to an island network which cannot rely on outside power generators to supplement demand in the event of forced outages and emergencies in other power stations. The plant also demonstrates the first application of a high temperature selective catalytic reactor for NOx reduction to less than 10 ppm (No. 2 fuel oil) on a volume basis corrected to 15% O2. Finally, the installation demonstrated the benefits to the owner, the Puerto Rico Electric Power Authority (PREPA), of a turnkey contract with the entire plant, including offsite oil barge delivery facilities, water wells, and 230 kV substation, designed, supplied and installed by one contractor. The power station was engineered, constructed and started by a limited partnership led by ABB Power Generation Inc. with Metric Constructors. Civil, structural and balance of plant engineering was performed by Lockwood Greene Scott and Associates., Cambalache Limited Partnership (CLP).

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