The new unit of the Ostiglia combined-cycle power plant will be a multi-shaft unit. Credit: Siemens Energy.
The new unit will feature Siemens’ HL-class gas turbine technology. Credit: Siemens Energy.
The SGT5-9000HL gas turbine has the capacity to generate up to 880MW of power. Credit: Siemens Energy.

The existing Ostiglia combined-cycle power plant (CCPP), located in Ostiglia, Lombardy, Italy, is being extended with the addition of a new 880MW combined-cycle unit.

Italy-based electricity generation company EP Produzione, a subsidiary of the EHP Group, is developing the power plant. The expansion was proposed in July 2020 and is expected to be operational by 2025.

The development of the new unit is in line with the objectives of Italy’s Integrated National Energy and Climate Plan, which is aimed at achieving decarbonisation while bolstering the security of the national electricity system. The new unit will supply clean energy to more than half a million households in Italy.

The project is part of Terna’s Capacity Market programme. A European grid operator, Terna designed the programme to procure energy by awarding long-term supply contracts through competitive bidding.


The new unit is being developed within the existing Ostiglia thermoelectric power plant site, which spans 51ha on the left bank of the River Po. The site is found in the Ostiglia municipality of the province of Mantua, located in Lombardy in northern Italy.

The existing power plant includes three combined-cycle gas turbine units with a total installed capacity of 1.13GW.

Ostiglia combined-cycle power plant make-up

The new Ostiglia CCPP unit will be a multi-shaft unit, consisting of gas and steam turbines that drive their own generators. The unit will also include state-of-the-art technology to facilitate optimum natural gas usage along with a high degree of flexibility.

The plant will comprise a Siemens SGT5-9000HL gas turbine, SGen5-3000W gas turbine generator, SST5-5000 steam turbine, SGen5-1200A steam turbine generator and heat-recovery steam generator.

It will also include Siemens’s T3000 control system, which helps to ensure reliable power plant operations by supporting power plant operators. The system implements the highest cybersecurity standards and has received the IEC 62443 certification, a leading standard for IT security for industrial communication networks, from American IT security company TÜD SÜD.

In the future, the natural gas-fired power plant will be able to operate with up to 30% hydrogen fuel.

Turbine details

The SGT5-9000HL gas turbine has the capacity to generate up to 880MW of power with more than 60% net efficiency.

The gas turbine weighs 497,000kg and measures 13m (42.6ft) long, 5.3m (17.4ft) wide and 5.5m (18.1ft) high. The turbine is capable of operating on fuels that include natural gas, liquified natural gas (LNG) and distillate oil.

Suitable for both 50Hz and 60Hz grids, the SST5-5000 steam turbine can generate between 120MW and 700MW of power. It is suitable for CCPP as well as steam power plants and offers an efficiency of more than 64% in combined-cycle mode.

The SGen5-3000W gas turbine generator weighs up to 425t and offers high operating flexibility. It incorporates a MICALASTIC® insulation system and Global Vacuum Pressure Impregnation (GVPI) technology, enabling optimum electrical endurance.


The new CCPP unit will feature Siemens Energy technology, which will substantially reduce carbon dioxide emissions due to its high efficiency in comparison to coal or older gas-fired power plants. It will also maintain nitrogen oxide emissions at less than 10mg/Nm³.

The air-cooled condenser in the plant will eliminate the need for water to be drawn from the nearby River Po for cooling purposes. It also features a flexible operating range, along with minimised fuel consumption.

Contractors involved

In February 2022, construction engineering company Fata, part of Danieli Group, signed an agreement to provide engineering, procurement and construction services for the project in a consortium with Siemens Energy, an energy company based in Germany, and Demont, a construction company.

Siemens Energy will supply the gas turbine, steam turbine, gas generator, steam generator, heat recovery steam generator and control system for the expansion. It will also provide long-term services for all the equipment and components.

Demont will be responsible for the mechanical erection of all plants, as well as the engineering, procurement and construction of the balance of plant piping.