Chapter One: Introduction
Chapter One: Introduction
Today, most1of the1energy we1used comes1from1fossil’fuels. /Oil, natural1gas, ’and/ coal’ are/ all/ fossil ’fuels .’While 1fossil1fuels are still/being1created/today1by underground heat1and pressure they are1being consumed more rapidly than are created. For that reason, fossil1fuels/are/considered non/renewable; that1is, they/are1not replaced1as soon1as we use/them. So1we could run1out of them1sometime in the1future, /or we1might someday1use so much fossil/fuel1that we won’t be able to1drill fast1enough to keep up with the1demand. In addition, because1there are so many people1on the earth1using fossil fuels, we1create a lot of1pollution. So, we should also1use energy sources1that produce as little pollution as1possible. Because1our world depends1so much on energy, we need to1find sources of1energy that last1a long time. But what if1there was1a type of1energy that never1ran out? 1There is. It is1called renewable1energy. While1most traditional energy1sources cause1some pollution1in their creation1or their consumption, 1renewable energy systems are1generally is none polluting. Over 15,000 billion1kWh of electricity/are/generated/annually/worldwide . Wind power along with solar energy, hydropower, and1tidal energy1are possible1solutions for an environmentally1friendly energy1production.
The use of wind for electricity generation has been expanding rapidly in recent years. Wind energy is used because it is renewable, economic, safe and good for the environment. Electricity generated from the wind if replaces generation from conventional power stations, could prevent the emission of several greenhouse gases, including carbon and sulfur dioxides. For example the Wind turbines in the UK currently prevent the emission of one and three-quarter million tons of carbon dioxide each year .
Wind power is being established in many countries by way of government-level policy. It is reported that by 2020, Europe will achieve 20% of power consumed in there supplying by large-scale wind farms. Besides, Europe is now planning for enlarging the capacity of the large-scale offshore wind farms to more than 30 GW power by 2015 . Other countries such as China and USA also have promising offshore wind power resources and similar plans for wind farm installation.
Wind energy can be generated locally and distributed directly to the local distribution network; this is known as embedded generation. This reduces the distance over which electricity has to travel, meaning less electrical losses in transmission and distribution, and therefore saving energy.
The benefits from local electricity generation are particularly valuable in areas remote from centralized systems and where the transmission or distribution grid is weak. Local energy generation will also be of great importance as the world fossil fuel sources start to run out.
The majority of renewable energy resources are directly or indirectly powered by the sun. The Earth-Atmosphere system is in equilibrium such that heat radiation into space is equal to incoming solar radiation. The resulting level of energy within the Earth-Atmosphere system can roughly be described as the Earth’s "climate." The hydrosphere (water) absorbs a major fraction of the incoming radiation. Most radiation is absorbed at low latitudes around the equator, but this energy is dissipated around the globe in the form of winds and ocean currents. Wave motion may play a role in the process of transferring mechanical energy between the atmosphere and the ocean through wind stress . Solar energy is also responsible for the distribution of precipitation which is tapped by hydroelectric projects, and for the growth of plants used to create bio-fuels.
Renewable energy flows involve natural phenomena such as sunlight, wind, tides and geothermal heat, as the International Energy Agency explains:
"Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition are electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and bio-fuels and hydrogen derived from renewable resources" . Each of these sources has unique characteristics which influence how and where they are used.
Energy in water (in the form of motive energy or temperature differences) can be harnessed and used. Since water is about 800 times denser than air, even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of energy.
There are many different forms of water energy :
• Hydroelectric energy is a term usually stands for large-scale hydroelectric dams. A famous example of this is the Akosombo Dam in Ghana, and high dam in Egypt.
• Micro-hydro systems/are hydroelectric power/installations that typically produce up to 100 kW of/power. They are/often used in water rich/areas as a Remote/Area Power/Supply. There are many of these installations around the world, including several delivering/around 50 kW in the Solomon Islands.
• Wave power uses/the energy in waves. The waves/will usually make large pontoons go up and down in the water, leaving an area with reduced wave height/in the "shadow". Wave power has now reached commercialization.
• Ocean thermal energy conversion uses/the temperature difference between the/warmer surface of the/ocean and the colder lower/recesses. To this/end, it/employs a cyclic/heat engine.
• Deep lake water cooling, although not technically an energy generation method can save a/lot of energy in summer. It uses submerged pipes/as a heat sink/for climate/control systems. Lake-bottom water/is a year-round local constant of about 4°C.
A photovoltaic (PV) module is that consists of multiple PV cells. Two or more interconnected PV modules create an array .
"Solar Energy" refers/to energy that is collected from sunlight. Solar energy can be applied in many ways, including to:
1- Generate electricity/using photovoltaic solar cells.
2- Generate electricity using concentrated solar power.
3- Heat buildings, directly, through passive solar design.
4- Heat water or air for domestic hot water and space heating needs using solar-thermal Panels.
5- Heat and cool air through the use of solar chimneys.