Sources Of Energy1

SOURCES OF ENERGY HYDRO POWER PLANT

Hydro energy is derived from flowing water in rivers, water streams in mountains or from manmade installations where water flows from a high level reservoir down through a tunnel and away from the dam. Energy from flowing water (or kinetic energy) has been used for centuries to turn water wheels attached to grinding wheels for grinding corn or flour or other machinery in mills

and factories. Hydro energy is now mostly used to generate electrical energy on large scale by collecting water in large reservoirs or dams called hydroelectric power.

ADVANTAGES • Hydropower is a fueled by water, so it's a clean fuel source. Hydropower doesn't pollute the air like power plants. • Hydropower is a domestic source of energy. •

Hydropower relies on the water cycle, which is driven by the sun, thus it's a renewable power source.

• Engineers can control the flow of water through the turbines to produce electricity on demand. • Hydropower plants provide benefits in addition to clean electricity.

• Impoundment hydropower creates reservoirs that offer a variety of recreational opportunities.

DISADVANTAGES

• Dams can be built only in few places.

• Large areas of agricultural land and human habitation are to be sacrificed as they get submerged. • The vegetation that is submerged rots under anaerobic condition and give rise to methane. • It creates problem of satisfactory rehabilitation.

WIND ENERGY

A wind turbine is a rotating machine which converts the kinetic energy in wind into mechanical energy. If the mechanical energy is used directly by machinery, such as a pump or grinding stones, the machine is usually called a windmill. If the mechanical energy is then converted to electricity, the machine is called a wind generator, wind turbine, wind power unit (WPU), wind energy converter (WEC), or aero generator.

ADVANTAGES • Wind energy is fueled by the wind, so it's a clean fuel source. • Wind turbines don't produce atmospheric emissions that cause acid rain or greenhouse gasses. • Wind energy is a domestic source of energy. The nation's wind supply is abundant. • Wind energy is one of the lowest-priced renewable energy technologies available today. DISADVANTAGES • Wind energy farms can be established in places where wind blows greater part of the year. The wind speed should be higher than 15 km/h to maintain the required speed of the turbine. • There should be more back-up facilities to take care of the energy needs during a period when there is no wind. • Establishment of farms needs large area of land and cost of establishment is high. • Since the tower and blades are made up of iron they might corrode in the presence of moisture and air.

SOLAR ENERGY

SOLAR COOKER

Sunlight is the “fuel”. A solar cooker needs an outdoor spot that is sunny for several hours and protected from strong wind, and where food will be safe. Dark surfaces get very hot in sunlight, whereas light surface don’t. Food cooks best in dark, shallow, thin metal pots with dark, tight-fitting lids to hold in heat and moisture.

A transparent heat trap around the dark pot lets in sunlight, but keeps in the heat. This is a clear, heat-resistant plastic bag or large inverted glass bowl (in panel cookers) or an insulated box with a glass or plastic window (in box cookers). Curved concentrator cookers typically don’t need a heat trap. SOLAR CELL PANEL

Solar Panels are a form of active solar power, a term that describes how solar panels make use of the sun's energy: solar panels harvest sunlight and actively convert it to electricity. Solar Cells, or photovoltaic cells, are arranged in a grid-like pattern on

the surface of the solar panel. These solar voltaic cells collect sunlight during the daylight hours and covert it into electricity.

TIDAL ENERGY

Due to the gravitational pull of mainly the moon on the spinning earth, the level of water in the sea rises and falls. This phenomenon is called high and low tides and the difference in sea levels gives us tidal energy.

ADVANTAGES • The most important advantage of tidal energy is its economical benefits, as tidal energy does not require any fuel. • Tides rise and fall every day in a very consistent pattern. • The economic life of a tidal plant is very high. A plant is expected to be in production for 75 to 100 years, • Tidal energy is clean and renewable, unlike fossil fuels. • A very important feature of tidal energy is that it is non-polluting. DISADVANTAGES • The altering of the ecosystem at the bay is the biggest drawback of tidal power. • Damages like reduced flushing, winter icing and erosion can change the vegetation of the area and disrupt the balance. • The alteration of tidal currents affects the habitat of the seabirds and the fish. • For a tidal power plant to produce electricity effectively (about 85% efficiency), it requires

• a basin or a gulf that has a mean tidal amplitude of 7 meters or above. • When planning the location major consideration has to be given to see whether the tides are high enough and if there is a suitable place for building the site

WAVE ENERGY

Waves are caused by the wind blowing over the surface of the ocean. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves. There is

tremendous energy in the ocean waves. Wave Power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface

ADVANTAGES

• The energy is free – no fuel needed, no waste produced. • Not expensive to operate and maintain. • Can produce a great deal of energy. DISADVANTAGES

• Depends on the waves – sometimes you’ll get loads of energy, sometimes almost nothing. • Needs a suitable site, where waves are consistently strong. • Some designs are noisy. But then again, so any waves, so any noise is unlikely to be a problem. • Must be able to withstand very rough weather.

OCEAN THERMAL ENERGY

The water at the surface of the sea or ocean is heated by the sun while the water in deeper sections is relatively cold. This difference in temperature is exploited to obtain energy in ocean-thermal-energy conversion plants. These plants can operate if the temperature difference between the water at depths up to 2km is 293K or more.

GEOTHERMAL ENERGY

The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generates electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. ADVANTAGES • The heat source requires no purchase of fuel.

• From an environmental standpoint, emissions of undesirable substances are small.

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It is also nearly sustainable because the heat extraction is small compared to the size of the heat reservoir. In addition, geothermal power plants are unaffected by changing weather conditions. From an economic view, geothermal energy is extremely price competitive in some areas and reduces reliance on fossil fuels and their inherent price unpredictability. It also offers a degree of scalability: a large geothermal plant can power entire cities while smaller power plants can supply more remote sites such as rural villages. DISADVANTAGES

From an engineering perspective, the geothermal fluid is corrosive. • Much of the heat energy is lost, unless there is also a local use for low-temperature heat; greenhouses, timber mills, district heating, etc. • Construction of the power plants can adversely affect land stability in the surrounding region. This is mainly a concern with Enhanced •

Geothermal Systems, where water is injected into hot dry rock where no water was before.

Dry steam and flash steam power plants also emit low levels of carbon dioxide, nitric oxide, and sulphur. Hot water from geothermal sources will contain trace amounts of dangerous elements which if disposed of into rivers can render their water unsafe to drink. • Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down. • Along with biomass, geothermal energy is one of the only two renewable energy sources which require careful management in order to avoid depletion. •

NUCLEAR ENERGY

Power derived from fission or fusion nuclear reactions. Nuclear power is interpreted as the -utilization of the fission reactions in a nuclear power reactor to produce steam for electric power production. Fission reactions involve the breakup of the nucleus of high-mass atoms and yield an energy release which is more than a million fold greater than that obtained from chemical reactions involving the burning of a fuel. ADVANTAGES • Nuclear power costs about the same as coal, so it’s not expensive to make. • Does not produce smoke or carbon dioxide, so it does not contribute to the green house effect.

• Produces huge amounts of energy from small amounts of energy from small amount of fuel. • Produces small amounts of waste • Nuclear power is reliable. DISADVANTAGES • Although not much waste is produced, it is very, very dangerous.

• It must be sealed up and buried for many thousands of years to allow the radioactivity to die away. • For all that time it must be kept safe from earthquakes, flooding, terrorists and everything else. This is difficult. •

Nuclear power is reliable, but a lot of money has to be spent on safety - if it does go wrong, a nuclear accident can be a major disaster.