The four technologies employed to make use of solar energy are: Daylighting- the use of natural sunlight to brighten the building’s interior. Passive Solar Heating- takes advantage of Sun’s warmth and materials that absorb that warmth during the day/release it at night when heat is needed. Active Solar Heating- solar collectors concentrate the sun’s power on dark color plates that absorb heat. Air or liquid flows through tubes and warmed by the plates. Concentrating Solar Thermal- mirrors direct sunlight on one point. Water is turned into steam with this heat. The steam turns a turbine to create electricity. Photovoltaic(PV)- converts sunlight directly to electricity.
Langston High School in Arlington, VA and Caywood Elementary in Kentucky use daylighting to keep energy costs down.
These homes in Montana and California with a passive solar design heats the home in the winter and cools the home in the winter.
Indirect Water Heater : The most common collector is called a flat-plate collector . Mounted on the roof, it consists of a thin, flat, rectangular box with a transparent cover that faces the sun. Small tubes run through the box and carry the fluid — either water or other fluid, such as an antifreeze solution — to be heated. The tubes are attached to an absorber plate, which is painted black to absorb the heat. As heat builds up in the collector, it heats the fluid passing through the tubes. Evacuated-tube collectors can achieve extremely high temperatures (170°F to 350°F), making them more appropriate for commercial and industrial application. However, evacuated-tube collectors are more expensive than flat-plate collectors, with unit area costs about twice that of flat-plate collectors. Evacuated tube collectors are usually made of parallel rows of transparent glass tubes. Each tube contains a glass outer tube and metal absorber tube attached to a fin. The fin is covered with a coating that absorbs solar energy well, but which inhibits radiative heat loss. Air is removed, or evacuated, from the space between the two glass tubes to form a vacuum, which eliminates conductive and convective heat loss. The storage tank then holds the hot liquid. It can be just a modified water heater, but it is usually larger and very well-insulated. Systems that use fluids other than water usually heat the water by passing it through a coil of tubing in the tank, which is full of hot fluid. Solar water heating systems can be either active or passive, but the most common are active systems. Active systems rely on pumps to move the liquid between the collector and the storage tank, while passive systems rely on gravity and the tendency for water to naturally circulate as it is heated. More information available at http://www1.eere.energy.gov/solar/sh_basics_water.html
A clean, large-scale solar thermal technology known as concentrating solar power is used in special power plants (Concentrating Solar Power or CSP plants) that use different kinds of mirror configurations to convert the sun's energy into high-temperature heat. The heat energy is then used to generate electricity in a steam generator.
Photovoltaic systems convert sunlight directly into electricity, and are potentially one of the most useful of the renewable energy technologies. Also known as solar cells, PV systems are already an important part of our lives. The simplest systems power many of the small calculators and wrist watches we use everyday.
Dec 6 renewable nonrenewable energy
Renewable and Non-renewable Energies Prepared by: Ms. Llupo
Non-Renewable vs. Renewable• Non-renewable – resources that cannot regenerate quickly, takes thousands or millions of years.• Renewable – resources that regenerate quickly within decades.
Energy Efficiency and Energy ConservationEnergy efficiency – the amount of useful energy produced compared to the amount wasted as heat (2nd Law of Thermodynamics); built into the device or system, unavoidable wasteExamples of levels of energy efficiency: human body: 20-25% incandescent light bulb: 5% internal combustion engine: 20-25% steam turbine: 45%Energy conservation – the effort to reduce the amount of energy used, some waste can be avoided
Energy conservation and energy efficiency are presently the mostpowerful tools in transition to a clean energy future.As shown in the Energy Pyramid, renewable energy is an importantpiece of our future energy, but the largest opportunities are currentlyin energy conservation and efficiency.
Where does the electricity come from?Renewables•Wind•Solar•Hydropower•Geothermal•Tidal•Biomass•Wave
Wind PowerAdvantages•No fossil fuels are generated•Take up less space than the average power station. Windmillsonly have to occupy a few square meters for the base, this allowsthe land around the turbine to be used for many purposes, forexample agriculture.•Extraction of wind energy is much more efficient. The wind is free•Represents a great energy source when combined with solarpanels•45%–55% efficiency
Disadvantages:• Less electricity than the average fossil fuels• Construction can be very expensive and costly too Rotating blades are a danger to birds• Wind turbines can spoil the view and the rotating blades are noisy• It is unreliable, since wind speed can change at any time
Solar PowerDisadvantages:•Electricity cannot be produced when the Sun is notshining•Solar cells are only about 33 percent efficient.
Solar PowerThe four technologies employed to make use ofsolar energy are:•Daylighting•Passive Solar Heating•Active Solar Heating•Concentrating Solar Thermal•Photovoltaic(PV)
Solar Technologies• Daylighting• Passive Solar Heating• Active Solar Heating• Concentrating Solar Thermal• Photovoltaics (PV)
Daylighting: the use of natural sunlight tobrighten the building’s interior.
Passive Solar Heating: takes advantage of Sun’swarmth and materials that absorb that warmth during theday/release it at night when heat is needed.
Active Solar Heating: solar collectorsconcentrate the sun’s power on dark color platesthat absorb heat. Air or liquid flows through tubesand warmed by the plates. Flat Plate Collector Evacuated Tube Collector 16
Concentrating Solar Thermal: mirrors direct sunlighton one point. Water is turned into steam with this heat.The steam turns a turbine to create electricity.
Hydro PowerAdvantages•There are no combustion emissions•Operating costs are low and it is about 90%efficient•95% efficiency
Disadvantages:•Flooding - large areas of land are flooded tocreate dams and reservoirs.•Consequent impacts on people, animals andvegetation. When submerged vegetationdecays, it produces methane and releasesmercury.•Impact stream flow•Traps sediments and nutrients•Decreases dissolved oxygen in water
Geothermal PowerAdvantages•Less costs•Consumes less electricity•More efficiency than gas and oil furnaces•A highly acceptable solution as greenhouse gases and airpollutants levels are less•Cools and operates quietly•15%–20% efficiency
Disadvantages•High installation costs•Requires lots of space•Needs a bedrock base•Installation is tricky
Tidal PowerTidal energy is hydropower which converts theenergy of tides into electricity or other forms ofpower. Tides are more predictable than wind energyand solar power.
Advantages• More predictable than wind energy and solar power• Doesn’t depend on whether• No pollution• Requires no fuel• Not expensive to maintain• 95% efficiency
Disadvantages• A barrage is expensive to build and affects a wide area• Environment is being affected• Provide power for only 10 hours a day• Cannot be installed everywhere
Biomass PowerAdvantages:•Using plant matter before it decomposes prevents•the release of methane gas•5% efficiency
Disadvantages:• Burning plant matter adds carbon dioxide to the atmosphere• A large supply of biomass fuels is not readily available
Fossil Fuels: Oil, Natural Gas, Coal• Fossil fuels originated from the decay of living organisms millions of years ago• 40% efficiency
Advantages• Ample supply for 35-84 years• Low cost• High net energy yield• Easily transported within and between countries
Disadvantages• Artificially low price encourages waste and discourages search for alternatives• Air pollution, releases CO2 when burned• Moderate water pollution
Natural Gas – another fossil fuelMixture of gases • 50–90% Methane (CH4) • Ethane (C2H6) • Propane (C3H8) • Butane (C4H10) • Hydrogen sulfide (H2S)
The use of Natural Gas• Produce electricity• Heat homes - inside homes, water heater• Industry - heat for warmth and producing things• Vehicles• Cooking
Advantages• High net energy yield• Low cost• Less air pollution than other fossil fuels• Lower CO2 emission than other fossil fuels• Moderate environmental impact• Good fuel for fuel cells and gas turbines
Disadvantages• Releases CO2 when burned• Leaks of methane – GHG• Shipped across ocean as highly explosive• Sometimes burned off and wasted at low price• Fractioning can cause groundwater contamination and earthquakes
Fossil Fuel Power - CoalAdvantage:Coal is inexpensive
Coal PowerDisadvantages:•High GHG Emissions - it produces carbon dioxide andother gases that contribute to acid rain.•Harmful extraction process•High water demand•Thermal discharge - the process is only 30 percentefficient. That is, about 70 percent of the energyproduced is lost as heat before it reaches theconsumer•Waste created
Acid Mine DrainageAcid mine drainage comes mainly from abandoned coal mines and active mining.
Nuclear Power - UraniumAdvantages•There are no greenhouse gas emissions.•A small amount of nuclear fuel will produce a great amount of energy•20%–50% efficiency
Nuclear power meets more than 50 per cent ofOntarios electricity needs. Energy Output by 2008
Ontario Power Generation owns and operates the Pickeringand Darlington Nuclear Power Stations. The two stations havea combined generating capacity of about 6,600 megawatts. Pickering Nuclear Power Stations is one of the worlds largest nuclear generating facilities. Capacity: 3,100 MW
Darlington Nuclear Power Stations sits on the shores of Lake Ontario,roughly 60-kilometres east of Toronto.Capacity: 3,500 MW
Disadvantages• Thermal Discharge - when cooling water is discharged into the lake, the temperature of water rises.• Radioactive Waste - power plants are very expensive and radioactive waste must be properly stored.
Three Mile Island• March 29, 1979, a reactor near Harrisburg, plant in Pennsylvania, lost coolant water because of mechanical and human errors and suffered a partial meltdown• 50,000 people evacuated & another 50,000 fled area• Unknown amounts of radioactive materials released• Partial cleanup & damages cost $1.2 billion• Released radiation increased cancer rates.
Chernobyl• April 26, 1986, reactor explosion, Ukraine flung radioactive debris into atmosphere• Health ministry reported 3,576 deaths• Green Peace estimates 32,000 deaths• About 400,000 people were forced to leave their homes• ~160,000 Km2 contaminated• > Half million people exposed to dangerous levels of radioactivity, causing cancer, tumors, eye cataract, and genetic mutations• Cost of incident > $358 billion