The turning point for the Concentrated Photovoltaic (CPV) segment of the solar industry occurred in 2008. That year, multiple companies installed one MW, or more, of CPV systems for a total 6 to 6.5 MW. In 2009, some CPV firms moved from the development phase into manufacturing; the year saw a slight increase in the deployment of CPV technology. The recent “European Photovoltaic Industry Association's (EPIA) Global Outlook for Photovoltaics Until 2015” report states, PV installation capacity grew by 15 GW in 2010; CPV accounts for about 20 MW of that amount.
At the end of 2010, CPV’s installed capacity made up 28 MW of the total 40 GW of photovoltaic capacity installed worldwide. While the CPV figure is paltry, compared to overall PV capacity, the amount represents a significant figure for the CPV segment of the market.
Late last year, EPIA predicted concentrated photovoltaic installation would exceed one GW annually by 2015. A sentiment echoed recently by a reputable research firm. However, some industry analysts believe 500 MW to be more realistic. To reach a global installation capacity of 500 to 1000 MW by 2015, like their PV modules and thin film competitors, the challenge for CPV manufacturers and developers center on generating electricity at cost parity to conventional power generation plants.
CPV Technology: How It Works
CPV technology has been around since the 70s. Recent technological advancements have enabled CPV to reach viability and compete with traditional fossil fuel plants, such as coal, natural gas, and oil, when installed in regions of the world with sunny and dry climates.
Concentrating photovoltaic systems work by converting solar light into electricity. Traditional rooftop solar modules rely on the same basic concept to generate electricity. So, what is the key difference between conventional PV and CPV systems?
CPV systems have an optical component, which “concentrates” significant amounts of sunlight onto “multi-junction” solar cells. Sometimes called “III-V”cells, NASA researchers developed multi-junction solar cells for use in space. These special cells have higher energy conversion efficiency than high-efficiency silicon solar cells.
The system's optical unit functions like a telescope. It concentrates sunlight on solar modules mounted on a tracking system. CVP systems automatically track the position of the sun -- from sunrise to sunset.
Semiconductor materials account for 50 percent of the cost of photovoltaic systems. Despite a lower efficiency rating for some applications, thin film has a competitive advantage over conventional crystalline silicone PV. Thin film requires one percent of the semiconductor material used for silicone cells. CPV has a competitive edge over both technologies. It requires just one-tenth of one percent of the semiconductor materials consumed in the silicone manufacturing process.
CPV requires less semiconductor materials because a significant portion of the system draws on inexpensive and abundant resources, such as aluminum and glass, commonly employed in the automobile and disk drive sectors. Less reliance on silicon materials or thin film elements make CPV less vulnerable to market restraints and fluctuations. In addition, components, such as coatings, seals, and other items used in CPV construction, have proven performance and reliability standards as verified by testing and certification in well- established industries.
Because optical lenses cost less than using more semiconductor materials in the manufacturing and installation process, concentrated photovoltaic generates a kilowatt- hour output for less compared to thin-film and silicon modules. CVP also requires less capital investment than CSP systems.
In April 2011, Solar Junction, a solar cell manufacturer located in San Jose, California, recorded a world-record efficiency of 43.5% for CPV solar cells, as verified by the U.S. National Energy Research Laboratory. High-efficiency silicon has an efficiency of 22%; thin film's efficiency is 13%. In terms of the overall system efficiency, CPV - 29%, high-efficiency silicon - 15-16%, thin film - 7-8%, and CSP - 13-15%. Late last year, JDS Uniphase (JDSU), which specializes in optical networking, lasers and coatings made its entrance into the concentrated photovoltaic market as a chip vendor. The director of the firm’s CPV group, Jan Gustav-Werthen states that the efficiency of III/V semiconductors would soon achieve 50 percent.
Currently, CPV technology works best in regions of the world with an abundance of sunny and clear skies or “Direct- Normal Irradiance” (DNI) -- sunlight emitted directly from the sun. The best locations for CVP systems are the Middle East, Southern Africa, Saharan Africa, Australia and Southwestern United States.
The higher the DNI, the lower the levelized cost of energy (LOCE) per kWh. For CPV systems installed in the United States, Mountain View, California’s Skyline Solar claims, for DNI of 7.0, its CPV system generates electricity at 9.5 cents/kWh compared to 13.5 cents/kWh for fix-tilt PV, and 12.5 cents/kWh for thin film technologies. The company’s systems installed on piers, instead of posts set in concrete, the LOCE drop to 8.0 cents/kWh.
Amonix, a global leader in CPV installations and development, sums up the benefits of CPV technology with the following statement: “CPV has higher efficiencies, higher energy yields and lower overall system costs than traditional PV in sunny and dry climates, requires no water in operation, less land, and is less disruptive to the land than Concentrated Solar Power (CSP).
Compared to CSP or ground-mounted PV, CPV systems offer the easiest, most flexible field installation. From the permitting process to installation, the entire CVP process takes as little as six months. Contrast this time frame to CSP, which in some cases can take years to complete.
According to California-based Solfocus, CPV systems require 6 to 8 acres of land for each megawatt of solar modules installed. The solar panels mount on tracking systems; therefore, the land serves a dual use, such as grazing livestock or growing shade crops. The flexibility of CPV systems also reduces the environmental impact on the installation area. In addition, CVP does not require water for power generation – only a small amount for cleaning panels.
Concentrated photovoltaic does not have as long a record of accomplishment as other, more mature solar technologies. For many years, CPV technology struggle with the image of being unproven and a high risk venture. However, its lower cost per kilowatt-hour, scalability, and less dependence on semiconductor materials have solar developers, utilities and investors taking a fresh look at the feasibility of the technology.
CPV developers must do some work to overcome CPV’s image of a “lack of bankability,” as stated in a recent industry report. The three companies that control over 95% of the operations , construction and development of concentrated PV systems -- Amonix, Concentrix Solar, and SolFocus, have taken steps to overcome this obstacle. Each firm has developed strategic partnerships with recognized names in the world of commerce and R&D, such as Goldman Sachs, Johnson Controls, IBM, and UC Berkeley.
Another development that may signal a change in how developers and investors view CPV ‘s profitability potential, a few weeks ago, Diamond Generating Corporation, Competitive Power Ventures, Inc., and GE Energy Financial Services closed on a deal to build the largest CPV power plant in the world. The Sentinel CPV plant will be located in Riverside, California; construction on the 800-megawatt CPV power station starts immediately. Scheduled to go online in 2013; the plant costs $900 million.
The CPV market must also make progress towards overcoming its deployment restriction to high DNI regions and expand into other locations. A recent National Research Energy Laboratory report cites promising research that demonstrates feasibility in possibly installing CPV technology in low DNI areas like Boston, Massachusetts. Boston has a DNI of 3.58 kWh/m2/day.
At the end of the day, like other solar technologies, reducing cost continues to be the driving force behind CPV really taking off. The industry has a goal of reducing the cost of CPV systems by another 30% by 2015. If realized, this factor alone could significantly boost the demand for CPV systems.