Acea Produzione SpA (ITA)

Background

Italian utility Acea Produzione SpA, asubsidiary of Acea SpA – one of Italy’sprincipal multi-utilities – supplies energy, water, and other environmental services in southwestern Rome. The utility recently modernized its largest district heating power plant – the 1990 Tor di Valle combined cycle heat and powerplant – to improve its operating flexibility and energy efficiency as well as reduce its environmental impact. The district heating power plant originally was constructed as a gas turbine combined cycle (GTCC) plant with heat extraction providing about 120 MW of power and70 MW of heat to the nearby Torrino areadistrict heating network.

Solution 

The existing district heating power plant modernization resulted into a new 19 MW combined heat and power (CHP) plant with two of INNIO’s 9.5 MW Jenbacher J920 FleXtra engines, plus three 23 MW auxiliary gas boilers, six 215 cubic meter(m³) heat storage tanks, and associated balance of plant systems to connect to the existing district heating system. Jenbacher engines, auxiliary gasboilers, and other balance of plant equipment were installed in the existing modernized engine hall. The engines are integrated with a thermal energy storage system consisting of six 215 m³ outdoor heat storage tanks. The storage system helps ensure a continuous supply of heat without the need to increase electric power generation in times of low power demand from gas engines. Acea’s two Jenbacher J920 FleXtra gas engines are connected to INNIO’s myPlant Asset Performance Management (APM) platform. The myPlant APM solution actively monitors all key engine parameters and supplies analytics that can predict component life, allowing operators to move from a proactive maintenance schedule to a condition-based maintenance approach.

Results

The modernized 19 MW Tor di Valle CHP plant began commercial operation near the end of 2017, supplying electricity to Acea’s nearby sewage treatment plant and Rome’s distribution grid. Heat is used for the local district heating network to supply about 40,000 residential customers in the Torrino area. The Jenbacher J920 FleXtra units – expected to run as much as 5,000 to 6,000 operating hours per year – support the plant’s ability to achieve a high fuelutilization and total efficiency above 80%, so it qualifies for white certificates from the Italian government. Compared to the older GTCC plant, the new engine CHP plant reduces the annual CO₂ emissions by about 16,000 tons per year.

Customer advantages

• Total efficiency higher than 80%
• Economical CHP from two 9.5 MW Jenbacher J920 FleXtra engines
• Less than 5-minute startup time ́ and quick shutdown capability
• Reduced CO₂ emissions – by approximately 16,000 tons annually