Construction Challenges
Several technical solutions at Livorno Ferraris are unusual for a combined-cycle power plant but had to be adopted to comply with authorization granted by local authorities in charge of environment protection, Krüger explained.
"Because the soil at the site was full of water [and did not have the required compressive strength for standard concrete pad foundations], it was necessary to rest the foundations on piles," he said. "Standard concrete piles were not allowed because they would disturb the flow of underground waters. The piling was constructed according to the Vibro Column Technique by the Italian subsidiary of a German company (one of the two suppliers in Europe). A 1-meter-high concrete ‘head’ was plugged into the soil, followed by a column of compacted gravel, which allows water to go through it with minimum impact on the original water flow."
Although surface water is present in great quantities at the plant site, it could be not used to as cooling water due to the need to prevent any possible contamination of the water that could affect nearby rice cultivation. Because a standard water-cooled steam condenser was not allowed, Siemens had to install an air-cooled steam condenser. This was unusual, considering that air-cooled technology is widely used by power plants located in desert environments but is not commonly used when water is available because of the large size and high cost of such equipment.
The plant building, which contains all three turbogenerator sets, the two HRSGs, and offices, had to be no more than 32 meters (m) in height in order to meet environmental standards regarding visibility. This created a challenge, Krüger explained, as the typical height of HRSGs is approximately 38 m to 40 m. For this project, Siemens had to modify the design so that HRSG equipment could fit inside the main building.
The color of the building and the square stacks had to be such that they would have less impact on the environment under all weather conditions. Sample panels were exposed to different lighting conditions — from sunshine to fog — before permission was granted for installation.
Usually, passersby can detect a power plant site by the steel pylons supporting the high-tension cables that connect it to the grid. But the utility did not want this standard, high-visibility profile. Therefore, the contractor had to connect the plant to the grid by laying underground high-voltage (400 kV) cable for 1.5 km to link it to the national grid at the Terna substation (Figure 3).
3. Stepping up voltage. These are the medium-voltage transformers installed at the Livorno Ferraris power plant. During construction, Siemens had to lay 1.5 kilometers of underground 400-kV high-voltage cable from the plant to the Terna substation in order to connect the plant to the Italian national grid. Courtesy: E.ON
The entire plant is surrounded by a tree fence to shelter it. Although the recently planted trees haven’t reached their mature heights, the Livorno Ferraris power plant is more attractive than most and looks more like an office complex than an industrial plant (Figure 4). European engineering and design have perfectly balanced the need for reliable electricity, low environmental impact, and a scenic countryside.
4. Fashionably functional. In the land famous for Ferrari cars, Armani suits, and other symbols of sophisticated style, it is not surprising that the Livorno Ferraris power plant building is an example of attractive, yet functional architectural design. Courtesy: E.ON
—Angela Neville, JD is POWER’s senior editor.
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