By Christof Korner

Renewable energy sources are coming more and more into the spotlight. Wind power and Photovoltaics (PV) are especially gaining ground. The advantages of this form of power generation are obvious: the sun is (at least by human yardsticks) an infinite source of clean energy and tapping into it generates environmentally friendly, clean electricity. In addition, photovoltaics can be exploited in highly diverse regions of the world and in principle in a number of different ways─from free-standing panels to extensive solar farms, from roof-mounted to building integrated installations, from grid-connected to island solutions. Therefore, experts are expecting a rapid expansion in photovoltaics, the global revenue from which is predicted to rise to over 32 billion dollars by 2012, along with continuing above-average growth in the following years. This is according to forecasts given by the market researchers at BBC Research (Wellesley, MA, the U.S.A.).

Large-scale PV installations, in particular, are thought to have very good prospects, with forecast growth rates of between 17 and 20%. The progress made by solar power in Germany, for instance, is illustrated by the fact that 8 GW of output is produced even on cold sunny days. Against this background, Siemens has further intensified its activities in this field and reinforced its position as the world’s only provider of a complete energy infrastructure from a single source.

For example, several large projects have been implemented under Siemens’ leadership in recent years, including the Rende solar power plant in Calabria, the sun-blessed ‘toe’ of the ‘boot’ of Italy. Rende is the first PV installation in Calabria to achieve the size of one MWp. Siemens constructed it under contract to the Gruppo Falck, which also operates a number of biomass-power plants in the same region. One of these, which is fueled with residues from olive presses, is located in Rende, in the immediate vicinity of the solar installation. The project was developed in 2005 and 2006 by the renewable energy company Actelios, which was responsible for the preliminary planning, the licensing procedure, and the choice of suppliers. Siemens was chosen as general contractor. The project involved the Italian subsidiary Siemens S.p.A. Milano and the Center of Competence (CoC) in the Netherlands, at that time part of the former Power Transmission and Distribution (PTD), with a focus mainly on the solutions business. Restructuring in 2008 made this CoC the cornerstone of today’s Photovoltaics Business Segment.

In a way, the biomass power plant in Rende also paved the way for the solar installation to follow. The ash from the combustion process was used for landfilling directly on site, and it was on this area that the solar installation was later installed. Actelios originally thought that the available area would be adequate for the intended rated capacity of one MWp, but a recalculation by CoC showed that, if constructed erected using conventional methods, the surface area would only be enough for 600 kWp. As the customer insisted on an output of one MWp, an adapted solution had to be found. This consists of four rows of frames in the standard array, in which up to five modules are mounted one above the other on one frame, and an oversize assembly consisting of up to 17 modules one above the other directly beneath the biomass power plant. That was the only way to accommodate the desired capacity of one MWp in the available space of less than 10,000 square meters. The five frames were designed in the CoC in the Netherlands, and Falck themselves took charge of the one-off production.

The installation, which went into commercial operation in 2007, consists of a total of 5,486 modules, each comprising 48 cells of monocrystalline silicon. These exhibit a long service life with sustainable output performance. The modules are aligned to the south at an angle of 20° for maximum power yield. The annual output of 1,400,000 kWh is sufficient to supply 350 households with solar power at a carbon dioxide saving of about 750 tons per year.

The Rende solar power plant is a turnkey solution in which Siemens was responsible for the engineering and was in charge of project management and commissioning and supplied the inverters, transformers, and switchgear. Siemens is also responsible for care and maintenance of the plant. This installation, which is one of the biggest of its kind in all of Italy, served as a reference project for Siemens for further successes in that country. It was followed in 2008 by Canosa Puglia, another power plant with a rated capacity of one MWp, which was built for the Marseglia Group. One year later, Casale went on line for Statkraft AS, featuring a capacity of 3.3 MWp. With these projects, Siemens was also able to demonstrate its short project implementation times and excellent performance. The electricals and power corporation was also able to put a large-scale project on line in San Donaci, in the Italian province of Puglia, the peak output of which is 15 MWp, enough to supply 5,500 households. The customer for this project was Ital Green Energy, a subsidiary of the Marseglia Group.

Just recently, Siemens’ Energy booked a follow-on order from Italy for the turnkey construction of eight photovoltaic-installations. The solar power plants will be constructed in the regions Le Marche and Abruzzo, which lie between the Adriatic Sea and the Apennine mountains. The customer is Viridis Energia, a joint venture between Echidna S.p.A. and La.G.I. S.r.l., headquartered in Ancona. The PV-installations with a peak output of 14 MWp are scheduled for completion in the first half of 2011 and will then supply over 5,000 Italian households with ecofriendly power. Since the fall of 2010, Siemens has been installed solar power plants with a peak output totaling three MWp in the Le Marche region for the same customer. “Italy is one of the biggest markets for large-area photovoltaic installations in Europe,” sums up Rene Umlauft, CEO of Siemens’ Renewable Energy Division. “In the past year, we have booked orders from Italy in the PV sector for a peak capacity of more than 30 megawatts. This year, the market will continue to show strong growth, and we want to share in it.”

This encouraging trend was sparked off by the Rende solar power plant.

Christof Korner started with Siemens in 1982 as Commissioning Engineer and has been with Siemens Solar GmbH (www.siemenssolar.com). He has worked for the PV group of Siemens Energy as Sales Manager Engineering since 2009.