Harnessed by solar collection methods such as solar cells
Converted into usable energy such as electricity
Originates with the thermonuclear fusion reactions occurring in the sun
What is Solar Energy?
All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth.
Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planet’s fossil fuels, both used and unused!
Advantages and Disadvantages
Sun does not shine consistently.
Solar energy is a diffuse source. To harness it, we must concentrate it into an amount and form that we can use, such as heat and electricity.
Addressed by approaching the problem through:
1) collection, 2) conversion, 3) storage.
Using Solar Energy to Provide Heat collector
Passive solar heating
Active solar heating
Solar energy collectors
passive (no moving parts) and active (pumps).
In both, a flat-plate collector is used to absorb the sun’s energy to heat the water.
Passive method used sand and rocks and bricks
Active methodd used water or air as medium
Photovoltaic Solar Cells
Photovoltaic Solar Cells
The potential difference produced by single PV cell of 4 cm2 Size is about 0.4-0.5 volts and produced 60 mille amperes of current.
Because they work best under direct sunlight, parabolic dishes and troughs must be steered throughout the day in the direction of the sun. Parabolic Dishes and Troughs
Direct Conversion into Electricity
Photovoltaic cells are capable of directly converting sunlight into electricity.
A simple wafer of silicon with wires attached to the layers. Current is produced based on types of silicon (n- and p-types) used for the layers. Each cell=0.5 volts.
Battery needed as storage
No moving parts do no wear out, but because they are exposed to the weather, their lifespan is about 20 years.
Solar cooker is work through reflect light with mirror.
Concave or parabolic reflectors works more efficiency
Solar cooker food have more nutrients due to slow heating
Solar water Heater Solar Furnace
Power Towers Power tower in Barstow, California.
Wind - electricity
No Greenhouse Gas Emissions Insurance Against Conventional Fossil-based Price Risk No Sulfur Dioxide (SO2), Nitrous Oxide (NOx), or Mercury Emissions
Why Wind Energy?
Wind, for now, is the renewable energy resource/technology of choice
“ Free” resource
A “clean” resource due to:
Replacement of a “dirty” energy source (coal) and,
No emissions associated with its use
Can be utilized on underutilized land or on lands currently in commodity crop production (“harvest” on the surface and “harvest” above the surface)
Energy Production and the Environment
Energy use in power plants accounts for:
67% of air emissions of SO 2 , the primary cause of acid rain. SO 2 causes acidification of lakes and damages forests and other habitats.
25% of NO x , which causes smog and respiratory ailments.
33% of Hg (mercury), a persistent, bio-accumulative toxin which increases in concentration as it moves up the food chain, e.g. from fish to birds, causing serious deformities and nerve disorders.
SOURCES: Union of Concerned Scientists (UCS)
Wind Energy Benefits
No air emissions
No fuel to mine, transport, or store
No cooling water
No water pollution
Wind Resources in the United States
Wind resources are characterized by wind-power density classes, ranging from class 1 (the lowest) to class 7 (the highest).
Good wind resources (class 3 and above) which have an average annual wind speed of at least 13 miles per hour, are found along the east coast, the Appalachian Mountain chain, the Great Plains, the Pacific Northwest, and some other locations.
Kansas Wind Potential
Kansas is one of the three best wind states in the country
Total “windy” land equals more than 108,000 square kilometers (about 1/2 of state)
Total Energy Potential = 1.07 trillion kWh or 121,900 MWa
Most of that potential probably won’t be developed . . .
Turbines: Different Sizes and Applications
Small ( 10 kW)
(e.g. battery changing, water pumping, telecom sites)
Large (500 kW – 5 MW)
Central Station Wind Farms
Wind Turbine Schematic
Wind - Natural Gas Comparison
Low Operating Cost
High Capital Cost
No Fuel Supply/Cost Risk
High Operating Costs
Low Capital Cost
Fuel Supply/Cost Risk
Smog, Greenhouse Gas Emissions
Wind Power Isn’t Perfect
Wind Power output varies over time; it isn’t dispatchable
Wind Power is location-dependent (rural vs. urban where it is needed most)
Wind Power is transmission-dependent for tie-in to the grid
Wind Power has environmental impacts
Wind Power can only meet part of the electrical load
Wind turbines are only generating electricity about one third of the time.
Wind turbines generate electricity essentially all the time, but only at their rated capacity about 30-40% of the time
Water flowing energy convert to electric energy
The minimum height of the waterfalls should be 10 m
The hydropower potential in India has 4x10 11 KW /hours. But we are utilize 11% in that only
Hydro power does not cause any pollution.
Ocean tides produces by gravitational forces of sun and moon
High tide enters the sea water into reservoir and rotate the turbine generate energy.
Low tides return the reservoir water into ocean and once again rotate the turbine
Only few sites are suitable for tidal energy in the world.
Ocean Thermal energy The energy is available due to the difference in temperature of water at surface of the ocean and at deeper levels is called “ ocean thermal energy(OTE)”
The difference temperate required 20 degrees
The warm surface water of ocean is used to boil liquid ammonia and it passed with high pressure through the turbine.
Later cooled the gas ammonia with use of deeper water
The process continuously takes place.
Geo Thermal energy
The energy getting from the hot rocks
Present inside of the earth is called “ Geo Thermal Energy ”
The heat comes from the fission of radio active naturally present in the rocks.
We can drill a hole up to rocks and get steam and pass through the turbine and generate electricity.
USA and New Zealand has several Geo thermal plants