2 Solar Thermal Power Plants STPs work somewhat like a magnifying glass. They concentrate rays of sun, in order to obtain a high temp of around 300 degrees Celsius.Can only be operated economically between the 35th southern latitudes and 35th northern latitudes.
3 Solar Thermal Power Plants The concentrated heat received is used as a heat source for a conventional power plant.A wide range of concentrating technologies exists; the most developed are the parabolic trough, the concentrating linear fresnel reflector, the Stirling dish and the solar power tower.Various techniques are used to track the Sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.
4 Solar Thermal Power Plants Feed around 500 GWh per year into the power grids.Many northern countries such as Germany and Austria are far too north to operate solar thermal power plants economically.
5 Structural Shapes for Collectors 1. Dish Concentrator2. Central Receiver System3. Parabolic Trough Concentrator
6 Dish Concentrators Follows the motion of the sun across two axes. Parabolic silver dishes that focus the radiation of the sun onto a single point.Size limited to 100m2 which also limits the electric power output to around 10 kW.
7 Central Receiver Systems Divides up the oversized concentrator into a set of smaller, individually movable concentrator mirrors. (Heliostats)The heliostats are directed towards a common point or tower which collects heat.Can collect up to sever hundred MW of solar radiation power.
8 Parabolic Trough Concentrators Linear concentrator moved along only one axis.Can be joined up into lines many hundred meters in length.Can collect hundreds of MW of thermal power.
9 Cost EffectivenessIn the 1980’s the cost was approx. $0.70-$1.45 per kWhSEGS power plants lowered that to around $0.30 per kWhEventually lowered to around $0.17-$0.22 per KWh. (In comparison: Photovoltaic power runs about $0.22-$0.44 per kWh)Location greatly effects profitability (Example: SEGS sites generate 2.5 times more solar power than Germany)
10 Cost EffectivenessPower from STP plants is around twice as expensive as wind powered plants, and half as expensive as photovoltaic.
11 Photovoltaic Solar Cells Transforms energy of sunlight directly into electrical energy.Silicon dominates the solar modules with over a 90% share.In 2006, 2831 MWp was installed in Germany. All together these systems generated 2000 GWh of electrical energy. (0.4% of Germany’s electrical consumption)
12 General Photovoltaic Info 30% annual growth rate for photovoltaic systems the past few years.Solar Cells have a very low efficiency rating in comparison to other renewable energies. (2.5% to around 39%, but the average is around 14-15%)
13 General Overview of how PV Cells Work When a PV cell absorbs a light quantum (photon) from sunlight, this photon can raise an electron out of the bound states (“valence band”) in the solid. The electron leaves an empty hole, and this hole can hop from atom to atom and contribute to an electric current.
14 Large Thin Film Solar Installations On the roof of the Stillwell Avenue subway terminal in Brooklyn there is a module area of 7060 m2 which produces 210 kWh.The world’s largest thin film solar power plant “Rote Jahne” (Germany) consits of over 90,000 modules and has a total capactiy of 6MWp (provides enough electricity to power 1900 homes).
15 Largest Solar Power Plants (PV/STP) Parque Fotovoltaico Puertollano (50 MW)Moura photovoltaic (46 MW)Solarpark Lieberose (45 MW)Solarpark Finsterwalde (41 MW)Solarpark Waldpolenz (40 MW)Planta Solar Arnedo (34 MW)
16 ReferencesRenewable Energy: Sustainable Energy concepts for the future (2008)The Wall Street Journal: “Solar Power: Finally, A Reason to Invest Says HSBC”Martin and Goswami (2005), p. 45PVPower (2009)