Solar energy: the loophole out of the energy and climate crisis

Reserves of fossil fuels cannot cover our energy needs in the long term. Furthermore, price increases must be expected. It will be increasingly necessary to exploit deposits that are more difficult to mine, or that must be transported over longer distances. A worst-case scenario shows an increase in the number of political or even violent conflicts over control of remaining resources. A world that uses solar energy solves important, central questions for mankind: less air pollution, less climate-changing CO2, fewer political and violent conflicts over fossil fuels and a multitude of new, permanent work places.

City Solar is making great strides in delivering cost-effective power to the masses through their ambitious and aggressive power-plant building projects. To date, City Solar has connected to the grid projects with capacity of more than 81MW, including a 20MW installation in Beneixama (Spain), one of the world’s largest photovoltaic power plants.

City Solar develops and constructs solar power plants independent of any manufacturer. With a proven track record of 21 installations in Germany and Spain using modern, top quality technology from producers of renown, they are able to achieve optimum operational availability for their power plants. This is vital to create high and continuous electricity yields with low operating costs and attractive returns for owners.

Large-scale energy providers jumping head-first into the market

Without the financial support of government tariffs and the move by large utilities into the solar space, it is clear that the solar power plant market would not be growing at the triple digit growth it has enjoyed over the past five years. The recent Southern California Edison rooftops project is a great example of a large-scale energy provider jumping head-first into the solar energy market. In March 2008, Southern California Edison (SCE) announced an ambitious project designed to generate 250MWp upon completion in five years. Funded partially by national and state government grants, this project will introduce a new scale for power generation projects.

City Solar’s track record and expertise is uniquely placed to greatly influence the solar power landscape now and in the future. I caught up with Stephan Brust of City Solar, and asked him a few questions regarding the company’s technology and plans for the future.

Who supplies you with the volume of modules required for your projects?

"We use multiple suppliers like Q-Cells, aleo solar, SOLON, Canadian Solar, EPV, and Suntech. They were selected based on long-term experience in the market, high quality, reliability, large capacities, price-performance ratio and, of course, the strength of their warranties. Quality is paramount to everything we do and so we cannot afford any risks when putting together a 20MWp installation."

What are the key criteria for selecting different brands of modules?

"We focus on characteristics such as efficiency rates, durability, ease of installation and how the modules work with different inverters. The modules need a max voltage of 1,000V. We only work together with manufacturers who are able to ensure warranty. Furthermore, the modules must fit to our mounting system. The most important advantages of our patented system are its simple and quick assembly and its uncomplicated installation. This means a significant saving on material and time – savings of up to 50 percent. Particularly in the case of large-scale projects, these savings play an important role."

What are the characteristics of industrial strength inverters for solar power installations and how important are they to the running of a plant?

"They are very important for the running of a solar power plant. We work together with Siemens - in 2003, when our first power plant was built up at the Saarbrücken airport, Siemens was permanently involved in the construction. Siemens supplies invertors, transformers, substations, and takes care of the engineering as well as the electrical fittings. The example of our transformers demonstrates our strategy: we use dry-type transformers (Geafol), as, even though they are more expensive to buy than oil transformers, they do not need servicing, operate more efficiently and are environmentally friendly."

Are thin-film modules an obvious choice over Si modules?

"Absolutely. Recently, we entered into a long-term solar module supply agreement with EPV Solar, Inc., a leading thin-film solar module manufacturer and photovoltaic systems provider headquartered in New Jersey, USA. The framework agreement allows us to purchase 250MW of amorphous silicon modules over a period of five years. We use EPV modules to further execute our profitable growth strategy in Europe. A first 2MW project with EPV modules will be realized in Germany by the end of 2008."

What is next for City Solar?

"At the moment we are in the final phase of the big 15MWp Tracker project in Mahora (Spain), which will be finished in July. Moreover, we realized another two big ground-level power plants in Spain (7.5MWp in Yecla and 10MWp in Alconchel). So currently, City Solar has connected to the grid projects with capacity of more than 81MWp. Further markets are Italy and Greece: in Italy, we will build two projects by the end of this year; Greece will start in 2009."

With City Solar moving into thin-film modules and large players like juwi already using CdTe thin-film modules from First Solar, it seems clear that the future of the power generation segment of the solar industry will become increasingly about scale.

Competing Technologies

1. Crystalline silicon technology
   
   Crystalline silicon cells are made from thin slices cut from a single crystal of silicon (monocrystalline) or from a block of silicon crystals (polycrystalline); their efficiency ranges between 12% and 17%. This is the most common technology representing about 90% of the market today.

   Cost of running power plants with crystalline technology: 73% modules, 27% BOS (DC-Cables, engineering, substructure, installation, inverters).
   

   
   
   
2. Thin-film technology
   
   Thin-film modules are constructed by depositing extremely thin layers of photosensitive materials onto a low-cost backing such as glass, stainless steel or plastic. Thin-film manufacturing processes result in lower production costs compared to the more material-intensive crystalline technology, a price advantage that is currently counterbalanced by substantially lower efficiency rates (from 5% to 13%). Major developers such as juwi international and Phoenix Solar use the cadmium telluride (CdTe) technology of First Solar (efficiency rate about 10%).

   Cost of running power plants with thin-film technology: 52% modules, 48% BOS (DC-Cables, engineering, substructure, installation, inverters).
   

Photovoltaic power plants by City Solar

Nominal power:

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The contributions of Denis Lenardic of PV Resources, Stephan Brust of City Solar AG, and Paula Mints, Navigant Consulting Inc. PV Services Program are greatly appreciated. Photos courtesy of City Solar AG.

Further information:

• 2008 Photovoltaic trends: Innovative thin film technology and large-scale power plants; Gigawatt perspectives in the USA
  
• Large photovoltaic power plants: average growth by almost 100 % since 2005.

Footnotes

Additional Solar-Reports:

• The photovoltaics industry: against all odds, strong growth continues
• PV production: The dawn of the "gigawatt" fab
• Review Intersolar 2008: the largest solar fair of the world
• 2008 Photovoltaic trends: Innovative thin film technology and large-scale power plants
• Large photovoltaic power plants: average growth by almost 100 % since 2005
  
  
• Research Agenda provides a Vision for European Photovoltaic Solar Energy Technology
• Organic photovoltaics: solar power from extremely thin tinted films and polymer films
• Intersolar on its way to becoming the Solar World Fair
• Building integrated Photovoltaics (BIPV): Solar electric power systems conquer large roofs and façades
• Solar thermal in Europe: expanding markets, state-of-the-art technical solutions
• Photovoltaic investments outside Germany? Looking into the southern EU states
• Solar power from the desert rather than desert in Germany
  
  
• New Study: Renewable Energy can replace abandoned Nuclear Energy in Germany
• BBC Interview with Dr. Knies (TREC): The energy source of the future is solar
• Photovoltaic industry achieves record profits, discussion over high module prices continues
• Chinese solar modules penetrating the German market
• Solar Roof Tile Exhibition shows developments in photovoltaic roofing
• Intersolar 2006: Solar technology and demand at an all-time high
  
  
• New Photovoltaic Factories and Capacities in Germany
• Renewable Energy in Australia
• Cooling with Solar Heat: Growing Interest in Solar Air Conditioning
  
  
• Building Solar: The Prospects and Costs of Living with the Sun
• Fuel Cell Research and Development in Southern Germany
• The Photovoltaic Market in Japan: Unquestioned Leadership of World Market
• The National Energy Plan
• Trade Fair Intersolar 2001 Presents World Wide Solar Technology for the First Time
• Solar Thermal Technologies in the United States
• An Overview of Photovoltaics in the USA
• The Year 2000: Breakthrough for Solar Technology in Germany
  
  
• Fuel Cells and Solar Hydrogen-A Power Package for the Future?