Alstom optimizes operational concept of the KA26 combined cycle power plant for fast start-up

Alstom has optimized the operation concept of the KA26 combined cycle power plant for fast start-up as the French gas turbine manufacturer is focusing on the operational flexibility of its gas turbines.

“Operational flexibility is not just having a high ramp rate, rather it’s a combination of start-up and shut down times, ramp rates and efficiency at part load operations,” Michael Ladwig, Director of Marketing and Product Management for Alstom's Global Gas Business told ‘Gas-to-Power Journal’ in an interview.

Sequential combustion is a unique feature of the GT26 gas turbine. It makes it possible to ‘park’ the entire KA26 combined cycle power plant at very low load (below 20%) with only one of the two GT26 combustors in operation, fully complying with regulatory emission lim-its. “This provides reliable and rapid reserve power of more than 350 MW within less than 15 minutes,” Lawdig said.

Flexibility is paramount for operating a gas plant economically viable to provide backstop electricity to balance the intermittent electricity supply from renewable energy sources.

Alstom has optimized the operation concept of the KA26 combined cycle power plant for fast start-up. “Thermal and mechanical stress in the steam turbine and in the heat recovery steam generator have been carefully analyzed and included in the simulation of the dynamic behavior of the plant to achieve an optimum balance between fast start and minimum life time impact of the equipment,” he said.

To increase the efficiency of gas turbines, Alstom is focusing on improving the efficiency of its components through aerodynamic improvements and reduction of cooling air and minimization of leakages. The French turbine manufacturer is also investing in R&D efforts in the field of materials and coatings.

The fuel efficiency of a plant can be improved by increasing the combustion temperature. “Increasing the firing temperatures helps to increase the efficiency not only of the gas turbine but also of the entire plant,” Lawdig explained. Hereby the efficiency of the steam turbine, the heat recovery steam generator (HRSG) and the turbo-generator contribute to an overall gas plant efficiency increase.

“As Alstom develops all these components in-house,” Ladwig stressed; “It focuses on not only the GT efficiency but rather all these components in order to maximize the overall plant efficiency.