things to generate electricity. • Kinetic Harvesting electricity. • Geothermal Energy o Using heat from the earth and resulting steam to generate electricity. o Burning plant and wast material to generate o Harvesting movement of people, automobiles, waves, and other moving • Biomass o Harnessing wind currents to generate electricity. • Hydropower o Harnessing water movement to generate electricity. • Wind Power • Solar Energy o Gathering energy from the sun to generate electricity. Renewable Energy
http://www.alternative-energy-news.info But a specifjcally focused upon aspect of picture courtesy of: http://www.solarelectricpower.org/power/what_are_pvs.cfm photovoltaic effect. current using semiconductors exhibiting a converting solar radiation into electrical technology that generate electricity by Photovoltaics, or PV cells, are pieces of o • What are Photovoltaics (PV cells)? solar power is PV systems. o • What is solar power? altitudes creating rivers to spin turbines. water followed by condensation at higher power turbines, and even evaporation of temperature differences to drive wind and and turn to oil, uneven heating creating photosynthesis, or allowing it to break down to release the energy stored through of power are solar; burning plants as biomass Power from the sun. Broadly, most forms o Solar Power
How PV Cells This movement is blocked by an electric photovoltaic effect. current using semiconductors exhibiting a converting solar radiation into electrical technology that generate electricity by Photovoltaics, or PV cells, are pieces of o process. the circuit, creating electrical energy in the path for the electrons to follow and complete Wires coming from the layers provide a o P-N junction. surface between the 2 layers known as the fjeld created by electron movement on the o Work with phosphorus, creating a negative (N) • What they are made of o Bottom layer of silicon crystal combined with boron, creating a positive (P) charge. o Top layer of silicon crystal combined charge. want to move from N layer to Player. • How this makes enegy o Energy from the sun releases electrons from both layers. o Opposite layer charges make electrons http://www.mrsolar.com
Types of Cells Medium expense, medium efficiency. Single-crystal cell Polycrystalline cell Only makes up about 9% of PV cells. o Least expensive, and least efficient. o single step. surface in thin fjlm making the module in a Silicon is applied to glass or metal o • Amorphous Silicon Makes up roughly 62% of PV cells. o o • Single-crystal Cells and sliced into squares. Molton silicon cast or drawn into sheets o • Polycrystalline Cells Makes up roughly 29% of PV cells. o Most expensive, and most efficient. o round or hexagonal wafers. Made in long cylinders and sliced into o • Silicon Application Type • Silicon crystal Type Amorphous Silicon cell
Systems o Power from PV cells can either go directly www.fsec.ucf.ed www.fsec.ucf.ed Grid Connected system Battery Storage system Direct-Coupled system can power both AC and DC. while cells are not recieving power, and o Provides backup system, can opperate then to an AC load. o Battery can send power to inverter and to DC load or go to a battery. o Battery Storage, AC and DC loads • Stand-Alone System- not connected to grid. recieve power. o No backup system, only works while cells load. o Power from PV cells runs directly to a DC for profjt. electricity as backup and sale of extra power o Connection to grid allows the use of grid panel, connecting system and grid to loads. o Panel system connects to a distibution o Direct-Coupled • Grid Connected System www.fsec.ucf.ed
System Tilt o Higher efficiency, but harder and more complicated to maintain over time. o Highly efficient, but very costly and the greatest system efficiency. • Fixed System o Sensors and motors allow the system to • Tracking System costly to maintain. always face the sun at optimal angle and offer provides higher efficiency. the year to refmect the suns changin altitude o The ability to change the angle throughout • Adjustable System cheaper to maintain. o Least efficient, but signifjcantly easier and not move throughout the year. o System is located at a fjxed angle that does Fixed Adj. 2 seasons Adj. 4 seasons 2-axis tracking % of optimum 71.1% 75.2% 75.7% 100%
Tilt • Fixed System Basics o If your latitude is below 25°, use the latitude times 0.87. o If your latitude is between 25° and 50°, use the latitude, times 0.76, plus 3.1 degrees. o From initial angle, plus 15° in winter and minus 15° in summer. • Adjustable System Basics Recomendations Full year Avg. insolation on % of Northern hemisphere Southern hemisphere Latitude angle panel optimum Adjust to summer angle on March 30 September 29 0° (Quito) 0.0 6.5 72% Adjust to winter angle on September 12 March 14 5° (Bogotá) 4.4 6.5 72% 10° (Caracas) 8.7 6.5 72% Avg. Summer Winter % of Latitude insolation on 15° (Dakar) 13.1 6.4 72% angle angle optimum panel 20° (Mérida) 17.4 6.3 72% 25° 2.3 41.1 6.6 76% 25° (Key West, Taipei) 22.1 6.2 72% 30° 6.9 45.5 6.4 76% 30° (Houston, Cairo) 25.9 6.1 71% 35° 11.6 49.8 6.2 76% 35° (Albuquerque, 29.7 6.0 71% 40° 16.2 54.2 6.0 75% Tokyo) 45° 20.9 58.6 5.7 75% 40° (Denver, Madrid) 33.5 5.7 71% 50° 25.5 63.0 5.3 74% 45° (Minneapolis, 37.3 5.4 71% Milano) 50° (Winnipeg, Prague) 41.1 5.1 70%
Application to Site http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/US/code/pvwattsv1.cgi Fixed Angle Results Input Adjustable Angle Results Solar AC Energy City: Solar AC Energy Month Radiation Energy Value Month Radiation Energy Value State: (kWh/m 2 /day) (kWh) ($) (kWh/m 2 /day) (kWh) ($) Latitude: 32.48° N 1 4.82 435 73.32 1 5.74 521 87.82 Longitude: -116.57° W 2 5.34 433 72.99 2 6.52 530 89.34 Elevation: 9 m 3 5.91 529 89.17 3 7.40 670 112.94 PV System Specifications 4 6.53 559 94.23 4 8.40 727 122.54 DC Rating: 4.0 kW 5 6.06 538 90.69 5 7.44 669 112.77 DC to AC Derate Factor: 0.770 6 5.99 508 85.63 6 7.47 644 108.55 AC Rating: 3.1 kW 7 6.27 542 91.36 7 7.97 701 118.16 Array Type: Fixed Tilt 8 6.62 567 95.57 8 8.49 738 124.40 Array Tilt: 32.5° 9 6.02 504 84.95 9 7.41 623 105.01 Array Azimuth: 180.0° 10 5.88 519 87.48 10 7.21 641 108.05 Energy Specifications 11 5.15 446 75.18 11 6.20 543 91.53 Cost of Electricity: 16.9 ¢/kWh 12 4.67 415 69.95 12 5.56 499 84.11 Year 5.77 5994 1010.35 Year 7.15 7506 1265.21
WIND POWER Is the conversion of wind energy into a useful form of energy, such as using: wind turbines to make electricity or windmills for mechanical power. A large wind farm may consist of several hun- dred individual wind turbines which are con- nected to the electric power transmission net- work. Offshore wind farms can harness more fre- quent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to pro- vide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines
BENEFITS Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions dur- ing operation and uses little land. As of 2011, 83 countries around the world are using wind power on a commercial basis. As of 2010 wind energy was over 2.5% of total world- wide electricity usage, growing at more than 25% per annum. The monetary cost per unit of energy produced is similar to the cost for new coal and natural gas installations. Wind energy is local . Wind projects keep more energy dollars in the communities where proj- ects are located and provide a steady income through lease payments to the landowners.
CONSIDERATIONS Although very consistent from year to year, wind power has signifjcant variation over shorter timescales. The intermittency of wind seldom creates problems when used to supply up to 20% of total electricity demand, but as the proportion increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur. Power management techniques such as having excess capacity storage, dispatch- able backing supplies (usually natural gas), exporting and importing power to neigh- boring areas or reducing demand when wind production is low, can greatly miti- gate these problems.
HIGH ALTITUDE WIND POWER (HAWP) HAWP has been imagined as a source of useful energy since 1833 with John Etzler’s vision of capturing the power of winds high in the sky by use of tether and cable technology. Various mechanisms are proposed for capturing the kinetic energy of winds such as: - kites - kytoons - aerostats - gliders - gliders with turbines for regenerative soaring - sailplanes with turbines - other airfoils - including multiple-point building - or terrain-enabled holdings
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