Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Red Rocks Community College ENY 130 Grid-tied PV Fall 2009 Module 1
What is a Watt? • 1 watt = 1 amp x 1 volt
Energy vs. Power? “Watt” is Power “Watt Hour” is Energy Energy = Power x Time A Microwave uses 1000 watts while running, this is the Power it uses If this microwave runs for 1 hour, it uses 1000 watt hours of Energy = 1kWh
Watts up with Photovoltaics • A PV array is sized at 1000 watts (1kW), this is the Power of the array • If this array produces energy for 5 hours it produces 5000 Whr of Energy = 5kWh
Energy Terms • 1 kWh/m² = • 3.412 BTU/ft² = • 3.6 Mega Joules/m² = 3600 kJ/m² • 1 Langley x 0.0116 • 1 Peak Sun Hour • Solar Constant is at outer atmosphere at 1367 W/m²
kW/m2 • Surface Density of Radiant Energy
Electrical Vocabulary • Voltage • Amperage • Resistance • Watts • Watt Hours
Photovoltaic Electric Principles • Terminology: • Electricity-Flow of electrons through a circuit • Volt (V)- The unit of force (electrical pressure) that causes electrons to flow. • Ampere or Amp (I)- Unit of electrical current flowing through a wire. 1 amp for one hour is 1Ah • Watt – Unit of electrical power equal to a current of 1 ampere under the pressure of 1 volt.
Electricity is the flow of electrons: using a water analogy…. • Copper wire can be thought of as a pipe • Voltage can be thought of as the water Pressure • Amperage can be thought of as volume or gallons per minute (gpm)
Terms expanded… • Watt-hour: the electrical unit of Energy • Kilowatt hour-refers to 1000 watt-hours and abbreviated as 1 kWh • This could be 1 watt produced over 1000 hours or • 1000 watts produced (or used) over 1 hour • 1000 kW (Power) = 1megawatt = 1mW =778 households • 1000 mW = 1 gigawatt = 1gW = City of San Francisco • Or 750,000 homes (but you need the area of 2400 football fields) • It takes 1.21 gigawatts to go Back to the Future.
Some History • Evidence of solar architecture goes back 2500 years to ancient Greek and Roman Architecture • 214 B.C. Archimedes is written to have used bronze mirrors to focus sunlight on ships to set them on fire. In 1973 the US navy is to have recreated this experiment and set fire to a wooden boat 50 meters away.
Burning Mirrors Source: Renewable Energy Fair
Myth Busters/MIT experiment Source: MIT
1839 - Edmond Becquerel discovers photovoltaic effect, at the age of 19, but the discovery was not useful to anyone
1873 Willoughby Smith Discovered the effects of sunlight on selenium rods while working with telegraph cable
History continued…. • 1914: The existence of a barrier layer in a PV device was observed • 1918: Czochrolsky developed a way to grow single-crystal silicon • 1923: Albert Einstein won Nobel Peace Prize for describing theories of Photoelectric effect in 1904
Photovoltaic – The process of turning light into electricity
Solar irradiance • 1927: measuring sunlight to determine level of pollution. New York atmosphere was blocking almost ½ of the sunlight
(1931) Thomas Edison in conversation with Henry Ford and Harvey Firestone • “We are like tenant farmers chopping down the fence around our house for fuel when we should be using Natures inexhaustible sources of energy — sun, wind and tide. … I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that.”
40’s - Bell Labs PV technology Source: Bell Labs
50’s – Bell labs continued Battery systems Source: Bell Labs
Into the 60’s Solar Cells make advancements in space technologies
The 70’s • 1975: U.S. began Earthbound PV and research and development • 1977: Solar Energy Research Institute (SERI) later named National Renewable Energy Laboratory (NREL) opened in Golden Colorado.
70’ – 80’s • Popular opinion attributes PV system use predominantly in the Emerald Triangle region of Northern California. These residents were engaged in agricultural pursuits that spurred PV innovation while maintaining their independence from the grid.
Late 1970’s – Federal Tax incentives give boost to solar thermal Mid 1980’s (Reagan) end of Federal tax incentives. This greatly slows solar thermal progress as a heat source Because of the incentives many flash-in-the-pan companies installed systems of poor quality giving solar a poor reputation
1980’s – Concentrator Solar (thermal) power plants Kramer Junction, CA
80’s to 2000’s • Inverter technology progresses • Square Wave inverter • Modified square Wave • True Sine Wave
1990’s: the grid tied inverter…. Converts Direct Current produced by PV to usable Alternating Current
2000’s – Photovoltaic (PV) Technology becomes more available and affordable
2004 – Colorado Voters approve Amendment 37 to have Energy providers offer rebates for installation of PV systems Habitat for Humanity house in Wheat Ridge: 1200 sf $147,000 plus donated items 4kW PV 96 sf of collectors w/ 200 ga storage tank Designed heat load: 4.4 kWh Annual Energy Savings : 96 MBTU (128,130 kWh)
2007 – Nevada Solar 1 concentrator power plant comes online 64 megawatts capacity 300 acres 134 million kWh/year Cost 266 million
Fossil Fuel Elect. Generation Plants • Are only 30-35% efficient • Which does not include the mining and transport of fuel • And does not include dealing with the toxic wastes Solar, though seemingly expensive, is delivered freely, abundantly, has no waste byproducts AND is up to 20% Efficient
The Future?? • PV efficiencies of 20% now, can we get to 50% or even 100%? Silicon cells have a 29% theoretical maximum. • Storage of electricity…better batteries, Spinning storage? • Energy Saving lifestyles – Living Light ! • Buildings that produce energy instead of using energy.
Uses for Solar Energy • Heating • Air Conditioning • Electricity • Water Pumping • Remote Power/Heat • Grid Power/Heat • Desalination • Transportation • Food cooking/Processing • Space Applications • All Earth Applications
Hybrid Solar Lighting Sunlight direct