THE CHIVASSO THERMAL POWER PLANT Via Mezzano 10034 Chivasso (To) Phone 011/6004200 - Fax. 011/6004249 Email: centrale.chivasso@edipower.it

YESTERDAY

Under the management of Ing. Luigi Selmo, the design and erection of the Chivasso Power Plant started in June 1950, taking in consideration the possibility of future extension with the installation of other units.

The first unit was commissioned in 1953 and in the first years of operation, natural gas,  coal, and fuel oil were used as boiler fuels.

The second unit was commissioned in 1956 whereas the third and the fourth units, fuel oil fired only, came into operation in 1959. In 1962, also the 30 MW gas turbine section, located in a dedicated building, came into  operation.

We have to wait until 1966 to see the fifth unit (fuel oil fired) in operation, which represented, with its 250 MW, the largest section of the Chivasso Power Plant.

In 1975,  in order to use also natural gas as fuel, units 4 and 5 were transformed, thus following the diversification strategy in the procurement of fuel resources.

The maximum production period is recorded right between 1967 and 1980. Afterwards, with the commissioning of more advanced power plants having higher efficiency, the Chivasso Power Plant was used only in peak periods until 1992, when  the unit 3 (gas turbine) was officially shut down, and, on the same date, also the units 1 and 2 were  shutdown.

In 2002, to allow the construction of the modern combined cycle plant, currently in operation, also units 4 and 5 were shutdown.

TODAY

TECHNICAL OUTLOOK
The old power plant, located between the left side of Po River and the entrance of the Cavour Channel, in the area of Chivasso municipality, has been transformed into a modern gas turbine plant with combined cycle gas turbine  units.

The new plant, commissioned at the end of 2004, has a total capacity of approx. 1,170 MW (performance test).

The new power plant is located in an area  of approx. 400.000 m² and consists of two gas turbine combined cycle production units (defined Modules):

• one module (CH1) consisting of two production sections with gas turbine and of a production section with steam turbine, for a total capacity of 790 MW.
• one module (CH2) consisting of one production section with gas turbine and one production section with steam turbine, for a total capacity of 381 MW.

The plant is fed with natural gas only.

The power plant is equipped with:

• 3 gas turbines
• 3 heat recovery steam generators
• 2 steam turbines
• 2 steam condensers
• 5 generators
• 5 main transformers
• 3 stacks, 90 m high

TECHNICAL DESCRIPTION

GAS TURBINES
The gas turbines installed in the combined cycle have a single shaft, and are able to reach a power output of approximately 250 MW.

The multistage axial compressor is equipped with inlet guide vanes (IGV).

A withdrawal of compressed air is used for the cooling of the turbine and to avoid the pumping phenomenon during the start up.

Air exhausted by the axial compressor is sent to the combustion chamber.

The burner is of the dry low NOx type (Dry Low NOx, reverse flow DLN-2) with 18 combustors arranged in a circular array on the discharge section of the compressor.

The heat generated by the combustion is transformed into mechanical power in the gas turbine and then in electricity through the coupled generator. The flue gas coming out from the gas turbines is sent to the heat recovery steam generators (HRSG), where it releases heat for steam production, and then it is discharged from the stack.

STEAM TURBINES
The steam turbines of Module 1 and of Module 2 are of the impulse/reaction type and consist of three cylinders (high pressure, intermediate pressure and low pressure) installed on the same axis.

GENERATORS
Generators are of the three-phase type, with cooling in closed cycle hydrogen atmosphere. The generator of the steam turbine of  Module 2 is fit with an additional demineralised water cooling system of the stator winding (fixed winding).


MAIN TRANSFORMERS
The electricity  produced by the power plant is inlet in the transmission grid, partly at 230 kV voltage and partly at 400 kV voltage through the 5 main transformers.

HEAT RECOVERY STEAM GENERATORS
The Module 1 is equipped with two heat recovery steam generators (HRSG) whereas  Module 2  with one HRSG. These HRGs produce steam using the flue gas discharged by the relevant gas turbines.

CONDENSERS
Condensers are of the surface type with one-way horizontal pipes (Module 1) and two-way pipes (Module 2) and two independent half-casings on the river water side. The condensate, collected in the hot well of the condenser, is pumped out  by extraction pumps to be sent, after filtration and treatment, to the drums of the HRSGs.

The condenser cooling water is taken from the Po River, upstream the intake of the Cavour Channel and can be discharged in the same channel or through a  secondary discharge channel directly to the Po River.

FUELS
The fuel used in the Chivasso Power Plant is natural gas only. A gas pipeline connects directly the plant to the national gas grid and the gas pressure is reduced, through a pressure reduction station, to the correct  value for the operation of the gas turbines.

ENVIRONMENTAL PROTECTION

To minimize the emissions to the air the power plant is equipped with combustion systems enabling the dry (Dry Low NOx) reduction of nitrogen oxides (NOx).

The power plant is equipped with an Air Quality Monitoring Network (RRQA), consisting of two measurement workstations (located in the  municipalities of Chivasso and Castagneto Po), which measure the discharge of pollutants on the ground. Recently, new instruments have been installed on both stations. The data are periodically transmitted to ARPA Piemonte and Chivasso municipality.

The emissions to air of nitrogen oxides (NOx) and carbon monoxide (CO) are continuously monitored and recorded through an Emission Monitoring System (SME); the measured data is transmitted, in real time, to the Control Authority (ARPA).

The waste waters (acid/alkaline, oily, biological) are treated in a purposely designed plant (ITAR) and continuously tested before the discharge.

The management of the Thermal Power Plant has implemented an Environmental Management System that was certified according to the UNI EN ISO  Standard 14001 in December 2002..

To foster the ongoing improvement of the environmental performances and the information to the public the management of the power plant has voluntarily adopted the EU Ecomanagement and Audit Scheme (EMAS) and obtained the registration in December 19, 2003 with the number  I-000176.