Concentrated+Solar

Use lenses or mirrors to concentrate a large area of sunlight into a small beam that heats a working fluid. The concentrated heat is then used as a heat source for a conventional power plant. Uses optics to concentrate a large amount of sunlight onto a small area of solar photovoltaic materials to generate electricity. Cogeneration technology used in concentrated photovoltaics that produces both electricity and heat in the same module.
 * ===Concentrated Solar Power (CSP)===
 * ===Concentrated PV (CPV)===
 * ===**Concentrated Photovoltaics and Thermal (CPVT)** or **Combined Heat and Power Solar (CHAPS)**===


 * ~ ==Type== ||~  ||~ ==Description== ||~ ==Comparison== ||
 * < **Parabolic trough (CSP)** ||< [[image:Solar_Array.jpg width="118" height="90" align="center"]] ||< Long, curved mirrors pivot to concentrate sunlight onto tubes filled with a heat transfer fluid, generally oil or water, whose steam moves a power‐generating turbine. ||< * One axis tracking
 * The most mature CSP technology - commercially proven investment and operating costs
 * Commercially available – over 12 billion kWh of operational experience
 * Highest single unit solar capacity to date: 80 MWe
 * Grid-connected plants
 * Commercially proven annual net plant efficiency of 14% (solar radiation to net electric output)
 * Operating temperature potential up to 500°C (400°C commercially proven)
 * Modularity
 * Thermal storage capability
 * Best land-use factor, lowest materials demand, and highest (proven) efficiency of all CSP technologies
 * The use of oil-based heat transfer media restricts operating temperatures today to 400°C, resulting in only moderate steam qualities ||
 * < **Power tower/ Central tower/ Heliostat** **(CSP)** ||< [[image:http://www.solar-thermal.com/images/image_players.jpg width="113" height="110" align="center"]] ||< Fields of flat mirrors (heliostats) focus sunlight onto a central receiver filled with a heat‐transfer fluid, most often molten salt, which can trap thermal energy for long periods. These systems concentrate heat at higher temperatures than other CSP systems, improving their conversion efficiency. ||< * Dual-axis tracking
 * Potential to be more cost effective, offer higher efficiency and better energy storage capability than other CSP technologies
 * Performance values, investment and operating costs still need to be proven in commercial operation
 * Highest single unit solar capacity to date: 10 MWe
 * Grid-connected plants
 * Operating temperature potential beyond 1,000°C (565°C proven at 10 MW scale)
 * Good mid-term prospects for high conversion efficiencies ||
 * < **Dish** **(CSP)** ||< [[image:http://thefraserdomain.typepad.com/photos/uncategorized/sterling_solar_dish.jpg width="118" height="110" align="center"]] ||< Mirrored dishes (resembling those for satellite television) track the sun and concentrate its heat onto a power‐generating unit that has an engine powered by a heat‐responsive fluid. Stirling engines, the most common type of engine for this system, do not require the extensive water cooling system needed for steam engines because its engine is powered by the expansion‐contraction of hydrogen gas as it is heated and cooled. ||< * Dual-axis tracking
 * Potential lies primarily in decentralised power supply and remote, stand-alone power systems.
 * Highest single unit solar capacity to date: 25 kWe
 * Stand-alone, small off-grid power systems or clustered to larger gridconnected dish parks
 * The (heavy) engine is part of the moving structure, which requires a rigid frame and strong tracking system
 * The newest systems have a 31.5% sun‐to‐grid energy conversion efficiency, the highest among CSP plants.
 * Modularity
 * Reliability needs to be improved
 * Projected cost goals of mass production still need to be achieved ||
 * < **Linear Fresnel Reflectors** **(CSP)** ||< [[image:http://news.cnet.com/i/ne/p/2007/910Ausra1_550x367.jpg width="122" height="80" align="center"]] ||< LFR systems function like parabolic trough systems but use flat mirror strips instead of curved mirrors. ||< * One axis tracking
 * Lower-cost alternative to trough technology
 * When suitable aiming strategies are used (mirrors aimed at different receivers at different times of day), this can allow a denser packing of mirrors on available land area.
 * Where higher steam temperatures are needed, LFR must still prove its cost effectiveness and system reliability.
 * Although less efficient than other CSP systems, the cheaper expense of flat mirrors lowers initial investment cost. ||
 * **Concentrated PV (CPV)** || [[image:http://news.cnet.com/i/bto/20080115/ISFOC-SolFocus-array.jpg width="126" height="68"]] || Concentrating photovoltaic systems use lenses or mirrors to concentrate sunlight onto high-efficiency solar cells. These solar cells are typically more expensive than conventional cells used for flat-plate photovoltaic systems. However, the concentration decreases the required cell area while also increasing the cell efficiency. || * Potential for solar cell efficiencies greater than 40%
 * No moving parts
 * No thermal mass; fast response
 * Reduction in costs of cells relative to optics
 * Scalable to a range of sizes. ||
 * **Combined Heat and Power Solar (CHAPS)** || [[image:http://www.renewableenergyworld.com/assets/images/story/2008/11/3/1332-researchers-explore-using-hybrid-concentrated-solar-energy-system-for-electricity-and-hot-water.jpg width="122" height="55" align="left"]] || The CHAPS collectors combine hot water and electricity generation into a single unit. Parabolic mirrors track the sun on a single axis and reflect light onto a strip of high efficiency solar cells at about 35 times the normal solar intensity.The solar cells convert about 20% of the sunlight into electricity. The balance of the solar energy is converted into heat, which is removed by water flowing in a channel behind the solar cells. || * Total solar conversion efficiencies above 60% are being achieved.
 * Performance depends very much on the location in question. A 24 m long trough in Alice Springs is 80% better than the same trough in Melbourne.
 * The efficiency of the collectors is equivalent to the best commercial PV and solar hot water collectors available – occupying half the space.
 * Because of the dual nature of the energy usage the overall conversion efficiency is higher than solar electric and solar thermal systems separately. ||




 * ~ ==Strength== ||~ ==Weakness== ||~ ==Opportunity== ||~ ==Threats (risks)== ||
 * Compared to conventional flat panel systems CPV systems are less expensive to produce || High capital installation cost || Together, advanced technologies, mass production, economies of scale and improved operation will enable a reduction in the cost of solar electricity to a level competitive with conventional, fossil-fueled peak and mid-load power stations within the next ten years. || Competing technologies ||
 * Little adverse environmental impact, with none of the polluting emissions or safety concerns associated with conventional generation technologies. || Diffuse light (cloudy and overcast conditions) cannot be concentrated || Thermal storage (cheaper and more efficient than electric storage) can deal with intermittency of the sun in CSP plants || Must be located in areas that receive plentiful direct sunlight to achieve maximum efficiency. Suitable sites should receive at least 2,000 kilowatt hours (kWh) of sunlight radiation per m2 annually, whilst best site locations receive more than 2,800 kWh/m2/year. ||
 * < Renewable resource ||< Tracking system necessary ||< Bulk power transmission from high-insolation sites, such as in northern Africa ||< Because CSP functions best in sunny desert climates, water scarcity is often an issue. CSP plants with a steam engine require a cooling system to recirculate the water used. ||
 * < CSP plants similar to conventional power plant ||<  ||< Combined generation of heat and power by CSP has particularly promising potential, as the high-value solar energy input is used to the best possible efficiency, exceeding 85%. ||<   ||
 * ||  || A number of countries have introduced legislation which offers attractive tariffs for project developers or forces power suppliers to source a rising percentage of their supply from renewable fuels. ||   ||

Sources:
Aringhoff, R., Brakmann, Geyer, M., Teske, S., 2005, //Concentrated Solar Thermal Power - Now//, Greenpeace International Concentrated photovoltaics, 2011, In //Wikipedia, The Free Encyclopedia//. Retrieved April 11, 2011, from [] Concentrated solar power, 2011, In //Wikipedia, The Free Encyclopedia//. Retrieved April 11, 2011, from [] Jennings, T., Parsons, L., 2009, //Concentrated Solar Power//, Environmental and Energy Study Institute, Washington, DC MacKay, D., 2009, //Sustainable Energy - Without the hot air//, UIT, Cambridge NREL, 2009, //Concentrating Photovoltaic Technology//, U.S. Department of Energy, Retrieved April 11, 2011, from [] Solar thermal energy, 2011, In //Wikipedia, The Free Encyclopedia//.c [|http://en.wikipedia.org/w/index.php?title=Solar_thermal_energy&oldid=42285365] UNENERGY, 2006, 'Cost comparisons of Energy supply technologies', weblog, Retrieved April 18, 2011, from []