energy: cogeneration for the Tor di Valle District Heating Plant
To replace its 30 year old plant at Tor di Valle, Rome’s largest multi-utility Acea entrusted a consortium made up of General Electric and Cefla Engineering with the revamping in order to ensure quality and continuity for the 40,000 residential customers and significantly improve efficiency in order to tackle the pricing issues in today’s wholesale energy market. Key objectives were: efficiency, flexibility and respect for the environment.
Type of intervention
Excluding the complex design phase which saw the implementation of 3D simulations to enable smooth construction work and installation on site, this challenging turnkey assignment was accomplished in a record-breaking 360 days and involved the following tasks:
- Plant engineering and civil works
- Mechanical plant engineering and its relevance to the engines
- CE certification of the entire plant including anti-seismic compliance
The major benefits
Apart from completion ahead of schedule, the new Tor di Valle plant has greatly improved air quality for the local community, reducing CO2 emissions by 16,000 tons annually. The Jenbacher gensets achieve approx. 80% efficiency generating just 19 MW electrical energy compared to the previous plant’s 120 MW. Furthermore Acea is now totally self-sufficient in terms of energy to power its huge sewage treatment plant serving over 2,000,000 inhabitants of the metropolitan area.
Today, the efficiency of the plant means that no more than the precise amount of fuel required is ever consumed to maintain the requested supply of heating, hot water and sewage treatment to the local population. Designed to address seasonal needs, the plant relies on six 220 m3 storage tanks to cushion peak demand. The engines can be started up or shut down in less than 5 minutes, providing Acea with the flexibility required to respond in real time to network needs. Environmentally speaking, the new CHP plant contributes significantly to favouring the quality of life in the Tor di Valle district.
Overall network length: 50 km
Residential customers: 40,000
Fuel: natural gas
Generator sets: two 50 Hz Jenbacher J920 FleXtra units (GE)
Electrical power (both engines together): 19 MW
Thermal power (both engines together): 15 MW
Thermal power from 3 auxiliary gas boilers: 70 MW
Storage capacity for superheated water: six 220m3 tanks