Solar and Wind Power Lecture 11 2018 PDF

Solar and Wind Power IM 115 Does solar and wind power pay? Is it always just about money?  Some people:  Prefer using green energy Less environmental impact Peace of mind  Have no choice (off th...

Solar and Wind Power IM 115 Does solar and wind power pay? Is it always just about money?  Some people:  Prefer using green energy Less environmental impact Peace of mind  Have no choice (off the grid)  Like to tinker If money is of concern:  A company selling power to a utility or a third party  A small business wanting to offset electrical energy costs  A homeowner wanting to offset electrical energy costs  Payback Potential  The bigger the better  Medium – less cost effective  Small – least cost effective  High initial cost  Plan on long term payback  Most turbines and/or solar panels will run 20+ years Payback Considerations  Homeowner  Okto size the system to less than expected monthly electric costs  Buy pack price may be low  Don’t have to be concerned with buyback at all  Operate loads that are low priority only off the turbine  Can be operated directly to eliminate need for inverter  Either AC or DC  Is net-metering available? Payback Considerations & Net metering  Netmetering is setting up a system to sell electrical energy back to the utility  Sizethe system up  No need for batteries  Bank kWh in the utility system  Design system around one main source  Wind  Solar  As of March 2005, Michigan has net-metering U.S. Dept. of Energy: Wind Costs Less Than Bulk Power 12 COE (¢/kWh [constant 2000 $]) 10 8 Low wind speed sites 6 Bulk Power Competitive High wind Price Band speed sites 4 2 0 1990 1995 2000 2005 2010 2015 2020 Solar Energy – online February 2014 Basic Solar Cell Taken from Floyd, 2003 PV Cell Types  The cells are then cut into squares to increase efficiency of the panel  16 – 20% efficient  Each cell produces about.5 volts  Wiring these cells in series increases the voltage  Parallel increases the current availability as does cells area  A solar module is basically a “panel” and an array is a “collection of solar panels” Cell, Module and Array Taken from Patel, 2006 PORTLAND, Ore. - A 62,500 square foot solar array on top of the IKEA store in Northeast Portland is in operation. A total of 2,072 solar panels generate electricity for the store at 10280 N.E. Cascades Parkway. The panels output 568,900 kWh per year - enough to power 48 homes. (March 2012) Soft Solar Cells Insolation  Maximumsolar energy reaching the earth is 1000 W/m2  Items affecting this value:  Atmosphere impurities that scatter light  Atmosphere impurities that absorb light Intensity of Sunlight Taken from Photovoltaics Design and Installation Manual, 2004 Cell Temperature  Heat is a form of electrical resistance  Asthe cell heats up, the voltage output decreases  Ifthe voltage output matches battery level, charge current will not flow  Approximately.5% loss of efficiency per °C of increase in temperature  Shading  Can have an extreme effect on crystalline cells Taken from Photovoltaics Design and Installation Manual, 2004 Shading Taken from Photovoltaics Design and Installation Manual, 2004 Periodic Cleaning Panels and Arrays are wired in Parallel Power of an array Mounting Types Taken from Patel, 2006 Mounting Considerations  Shading at the site  Weather conditions  Roof materials  Soil or load bearing capacity  System applications Angle of the Earth  Ourhemisphere is angled away during winter  Size system for the winter months  ThePV array needs to be aligned perpendicular to the sun at midday or zero degrees azimuth Angle for Maximum Insolation  Best tilt angle equals latitude at spring and fall equinox  Winter: best tilt angle equals latitude plus 15°  Summer: best tilt angle equals latitude minus 15° Taken from Photovoltaics Design and Installation Manual, 2004 Solar Site Analysis Taken from Photovoltaics Design and Installation Manual, 2004 Final Analysis  Compare costs to:  Raise array  Remove obstructions  Increase array size  Choose a new array location Wind Machines  Windmill  Turbines  Systems  Main parts  Rotor  Nacelle  Tower Wind Machines  Windmill  Turbines  Systems  Main parts  Rotor  Nacelle  Tower  Small Turbines Operate at variable speed Need batteries and/or inverter to provide a usable AC signal Slow speed, low power high speeds, more power 1. Nose cone 2. Rotor blades 3. Alternator 4. Mainframe 5. Yaw assembly 6. Slip rings & brushes 7. Tail vane 8. Nacelle cover 9. Furling winch  Medium Turbines  Operate at a standard speed to maintain frequency  As wind speed increases, field strength is increased to output more electrical power  Approximately 200 feet to the nose cone Large Turbines  About 3 MW (megawatts)  300 feet to the nose cone  Rotor diameter of 300 feet ± Wind Power Applications  Before large grid systems in U.S.  Still used in undeveloped countries and locations that are not cost effective  Water pumping still in use today  Green initiatives  Electric fences, cathode protection for pipelines  Heat Utility Connection  60 Hertz (cycles per second)  Voltage magnitude  Phase relationship  Natural sine wave  Synthetic sine wave Wind Farms  The best states are the Great Plains states  Michigan Ranks 14 behind these states  Utilities are building their own wind farms  Price per kilowatt from 35 to 5 cents in the last three decades Recent Technological Improvements  High strength composites (blades)  Lower cost power electronics  Allow varying speeds on large turbines  Lower required wind speed  Economies of scale (go big)  Learning curve Wind Energy Potential Wind  What is wind energy?  Fluid power  Air is a fluid  What causes wind movement?  Sun and heat  Thermal currents  Changes in pressure Wind Patterns  Increased wind speed at the upper 1/3rd of the slope Source: Wind Power, Paul Gipe, 2004 Power in the Wind  Power is directly related to:  Air Density  Area (Swept Area of the blades)  Wind Speed  Measured in Watts/meters2 Power in the Wind  Air Density  Decreases with temperature  Up to 15% from season to season  Worse for us? -20°F to 90°F  Decreases at higher elevations  More of an effect than temperature  Accordingto Gipe, can mostly be ignored in the U.S. east of the Rocky Mountains and in Europe Power in the Wind  Swept Area  Twice the area, twice the power  Increases exponentially due to A = πr2  Twice the diameter however, equals four times the original swept area Power in the Wind  Wind Speed  The primary factor in determining power available to operate a generator  Small differences in speed can account for large increases in output  At a given density and area, doubling wind speed, provides an eight-fold increase in power Anemometers  A measuring device that measures pulses or frequency of a small generator  Should log data on short intervals  Data loggers  Best when done at the anticipated turbine height, not too expensive  Use a small turbine as the anemometer, upgrade when can Historical Data  May be suspect  Citiesin protected areas  Airports placed in favorable areas  Improperly placed equipment  Not a true annual measurement  The importance of wind data is proportional to the reason you want to incorporate wind power Basic Siting of a wind turbine  Ask people who have turbines  Is your site comparable?  Do you have a year to test?  Let the turbine be the test  Look at the trees Basic Siting I 7-9 mph II 9-11 mph III 11-13 mph IV 13-16 mph V 15-18 mph VI 16-21 mph VII 22+ mph