A new benchmark for gas engine CHP flexibility

It is located on the eastern shore of the Kieler Fo¨rde inlet in northern Germany. Representatives of Stadtwerke Kiel, Kraftanlagen Mu¨nchen GmbH (KAM) and INNIO attended the inauguration ceremony in January 2020 marking the culmination of the five-year project.

The 20 Jenbacher J920 FleXtra gas engines in the plant provide a total electrical output of 190 MW and a thermal output of 192 MW. Heat from the CHP plant feeds into the district heating network operated by Stadtwerke Kiel and the power is fed into the grid, “helping maintain grid stability across North Germany.”

Two critical pillars of the German government’s plan for cleaner electricity include increasing the adoption of renewables and eliminating coal, but the proliferation of renewables has led to significant electricity supply variability, and natural gas fired power generation has become pivotal to renewable energy development, contributing to grid stability and reliability.

In 2015, Stadtwerke Kiel made plans to shutter its 323 MW coal-fired power station and signed a contract to acquire 20 Jenbacher J920 FleXtra gas engines, the largest ever order for Jenbacher machines.

During the successful completion of a 20-day trial run of the Kiel plant in November 2019, culminating in the signing of acceptance documentation on 28 November, the facility “exceeded 92% overall efficiency”, says INNIO.

Stadtwerke Kiel’s coal fired plant was decommissioned in March 2019.

With a high proportion of wind on the grid, a major focus for Stadtwerke Kiel was achieving the greatest possible operational flexibility, a “primary requirement of the plant”, which includes a 60 m high, 30 000 m3, hot water storage tank and a 35 MW electrode boiler.

The Jenbacher J920 FleXtra gas engines have recorded “proven results in excellently compensating for renewable energy fluctuations”, able to “achieve full capacity in less than five minutes”, says INNIO.

INNIO and KAM engineered and implemented the new plant. While INNIO (owned by Advent International, previously by GE) provided the gas engines and engineering expertise, KAM (previously an Alpiq subsidiary, now part of Bouygues), acted as the general contractor responsible for engineering, procurement, construction and commissioning on a turnkey basis, with a scope including the auxiliary buildings and integrating the heat storage and electrode boiler.

The power generation part of the plant is arranged as four units, each with five generating sets, with the flexibility advantage of being “operable in slices”, says INNIO.

“This construction project was the largest investment in the history of Stadtwerke Kiel. It challenged us all and required a lot of strength, time and energy. Now the energy supply of the future is a reality in Kiel, and we look with a lot of pride at our coastal power plant,” said Frank Meier, chief executive officer of Stadtwerke Kiel.

The plant supplies district heating to some 73 000 households and facilities in Kiel, while the electric power generated feeds into Kiel’s 110 kV grid, with any surplus power “passed on to the upstream power grid.”

Carlos Lange, president and CEO of INNIO, said that as renewables continue to grow across Germany, the company plans to put increasing effort into the development of power generation technology based on “renewable gases – specifically, hydrogen and hydrogen carrier gases – to help build out 100% carbon neutral and carbon free power plants.”