Why renewables need strong gas-fired backup

As intermittent renewable energies continue to increase their contribution to the global energy mix, the efficient operation and maintenance of combined-cycle gas turbine (CCGT) plants will be vital.

Since wind and solar-powered plants reach peak production at different hours of the day, gas-fired plants are increasingly required to stop and start multiple times per day in order to provide necessary stabilizing energy to the system, said performance consultant James Nyenhuis of US manufacturing and technology firm Emerson at the BNamericas 5th Latam Power Generation Summit in Lima, Peru.

Nyenhuis said that Emerson clients are increasingly asking for ways to improve efficiency and minimize the fuel wastage and increased costs that occur as a result of these stop-and-start processes, which can take one to three hours to complete.

Efficiency is improved by real-time monitoring of the different working elements of a CCGT plant – namely the gas turbine and the heat input – so that the plant produces just the right amount of heat necessary to re-start after it has been shut down. Otherwise, Nyenhuis said, that excess heat and the fuel used to produce it are wasted.

Since CCGT plants have a life cycle of 20 years or more, it can be hard for developers to plan ahead for increased wind and solar generation, Nyenhuis said, requiring more flexibility from new and existing CCGT plants.

CCGT and renewables account for the majority of generation projects planned for Latin America in the coming years.