Renewable Energy Sources

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Renewable Energy

Sources

AUTHOR:

K.KARTHIKEYAN

Assistant Professor/EEE

PANNAI COLLEGE OF

ENGINEERING

&TECHNOLOGY

SIVAGANGAI-630 561.

Mobile No:9942361131.

Abstract: The electricity requirements of the world including India are increasing at alarming rate and the power demand has been running ahead of supply. It is also now widely recognized that the fossil fuels (i.e., coal, petroleum and natural gas) and other conventional resources, presently being used for generation of electrical energy, may not be either sufficient or suitable to keep pace with ever increasing demand of the electrical energy of the world. Also generation of electrical power by cold based steam power plant or nuclear power plants causes pollution, which is likely to be more accurate in future due to large generating capacity on one side and greater awareness of the people in this respect.This paper describes about different Renewable Energy Sources such as Hydro power Energy,Wind Energy,Solar Energy,Bio-mass Energy,Geo-thermal Energy,Ocean Energy,Hydrogen Energy.

Renewable Energy Overview :

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(EEG 2012) entered into force on 1 January 2012.According to (the unchanged) Section 1 para. 1 EEG 2012, the purpose of the law is to facilitate the sustainable development of energy supply, particularly for the sake of protecting the climate and the environment, to reduce the costs of energy supply to the national economy (also by incorporating external long-term effects), to conserve fossil fuels and to promote the further development of technologies for the generation of electricity from renewable energy sources. To this end, the Act aims to increase the share of renewable energy sources in the German electricity supply. According to Section 1 para. 2 EEG 2012, renewable energy shall account for 35% of the electricity production by 2020, for 50% by 2030, for 65% by 2040 and for 80% by 2050.

Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, waves and geothermal heat, which are renewable (naturally replenished). About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from hydroelectricity. New renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels) accounted for another 3% and are growing very rapidly. The share of renewables in electricity generation is around 19%, with 16% of global electricity coming from hydroelectricity and 3% from new renewables.

Renewable Energy Sources :

Both direct investments and purchasing credits are popular ways of obtaining renewable energy companies can obtain their renewable electricity directly in a number of different ways. However, such avenues are not always obvious to companies, which may be unaware of, or confused by, the variety of options available

to them and by the lack of transparency in the market. Given this, it is perhaps unsurprising that a popular way for many companies to procure renewable energy is by purchasing certificates. However, this method accounts for only 38% of global renewable energy purchasing by companies. The most popular in terms of the amount of energ procured is direct investment, with 40% of the total in 2011. A small number of large energy users such as pulp and paper or car manufacturers accounts for the majority of direct investments, with a greater number of smaller users preferring RECs.

% Renewable Energy Information Resources :

One hundred percent of the world‘s energy can be obtained via renewable energy. There are no technical, financial, space, nor resource barriers.Political will is the only thing preventing a 100% renewable world from happening.

There are numerous academics, consultants, nations, and other groups that have put forth various 100% renewable energy scenarios. Though there are so many scenarios, I‘ve found it difficult to find them at times due to the vagaries of search engine optimization. I also have a feeling that certain vested interests such as the nuclear and fossil fuel industries would prefer you not read them. So I decided to write this post to make it easier to find these resources.Here is a list of various 100% renewable energy research papers, presentations, scenarios, and other interesting information:

Transnational Renewables: Low Cost but Totally Renewable Electricity Supply

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also done major works on the creation of ‗supergrids‘ to allow for efficient transmission of energy over long distances. One of the unfortunate problems the English speaking world faces is that experts such as Dr. Czisch and many others do not publish all their studies in our language and therefore leading countries such as Germany‘s vast and pioneering know-how is effectively limited in distribution.

 IEER & NPRI: Carbon-Free and Nuclear-Free: A Roadmap for U.S. Energy Policy (2007) The landmark work by Dr. Arjun Makihijani is available as a free downloadable PDF book. Written in 2007, the scenario shows that the USA could eliminate carbon emissions and nuclear power within 30 to 50 years – the barriers are not technical nor economic, only political will is a barrier.

 Scientific American: A Path to Sustainable Energy by 2030 by Mark Z. Jacobson & Mark A. Delucchi (2009, PDF) This was the cover article in Scientific American for the November 2009 issue. The article is a good overview of Delucchi & Jacobson‘s landmark work. The plan calls for all energy to be supplied via wind, water, and solar power, hence it is often called the WWS (Wind Water Solar) scenario. Water in WWS includes geothermal as well as hydro power. Energy efficiency also plays an important part. Various low emissions energy sources were evaluated and prioritized. Cost of renewable energy is less than providing energy via nuclear or fossils. There are also a number of great video presentations by Dr. Jacobson online. Here is one from Stanford:

 Greenpeace: The Energy [R]evolution (2010) Greenpeace has put together a scenario for 95% or more of energy worldwide by 2050 to be created via renewable energy and energy efficiency gains. According to

the scenario there are enormous

economic benefits including the

creation of millions of jobs to be gained. Like in other scenarios, there

are no technology revolutions

necessary to make this happen – all the technology has already been developed and is proven in the real world.

 PWC: 100% renewable electricity – A roadmap to 2050 for Europe and North Africa (2010, PDF) Experts at Price-Waterhouse found that a 100% renewable electricity system for all of Europe and North Africa would not only be possible, it is also cheaper than a the ‗business as usual‘ scenario that we currently face. The PWC scenario focuses on an intercontinental ‗SuperSmart Grid‘ with a scale up of all forms of renewable energy.

 EREC: RE-thinking 2050 – A 100% Renewable Energy Vision for the European Union (2010, PDF) The European Renewable Energy Council created a 100% renewable energy scenario for the EU which also confirms that there are vast economic benefits to switching to a carbon free future. The report states that millions of jobs would be created by the new renewable energy industries as well as enormous environmental and other social benefits.

 BZE: Zero Carbon Australia 2020

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 WWF: The Energy Report – 100% Renewable Energy by 2050 (2011) This study by the WWF also calls for a 100% renewable energy world, but with a slower rollout schedule. Calls for 4 trillion dollars per year in savings!.

Renewable Energy Sources in India :

Due to the prohibitive price, solar will remain on the back foot in India in the near future.There are efforts from industries to reduce the cost and make it cheaper than the present situation. Solar has a great potential and will be utilized by individuals or someinstitutions for their captive needs. However, large installations will take at least around 5 to 10 years in India to make its presence felt.

Other forms of renewable energy like biomass, bio-fuel and wastes will also require time in India. The technologies to convert jatropha, palm oil or algae into bio-fuels are not yet commercial and will take time to become economical. Algae, if pursued and successful, will be the answer to the worries of energy. It will not only engulf the huge amounts of carbon dioxide, but also give higher yields per unit area. Wind energy will be the biggest beneficiary and will grow from its present position. From over 7500 MW of installations to 45,000 MW potential, there is a long way to go. In a short span i.e. around next five years it will be wind energy which will grow.

Sources of renewable energy:

Hydro Power :

Water flowing downstream is a powerful force. Water is a renewable resource, constantly recharged by the global cycle of evaporation and precipitation. The heat of the sun causes water in lakes and oceans to evaporate and form clouds. The water then falls back to Earth as rain or snow, and drains into rivers and streams that flow back to the ocean. Flowing water can be used to power water wheels that drive mechanical processes. And captured by turbines and generators, like those housed at many dams around the world, the energy of flowing water can be used to generate electricity.

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watermills, sawmills, textile mills, dock cranes, domestic lifts and paint making.

Since the early 20th century, the term is used almost exclusively in conjunction with the modern development of hydro-electric power, which allowed use of distant energy sources. Another method used to transmit energy used a trompe, which produces compressed air from falling water. Compressed air could then be piped to power other machinery at a distance from the waterfall.The power available from falling water can be calculated from the flow rate and density of water, the height of fall, and the local acceleration due to gravity. In SI units, the power is:

where

 P is power in watts

 η is the dimensionless efficiency of the turbine

 ρ is the density of water in kilograms per cubic metre

 Q is the flow in cubic metres per second

 g is the acceleration due to gravity

 h is the height difference between inlet and outlet

Wind Energy :

Wind is the movement of air that occurs when warm air rises and cooler air rushes in to replace it. The energy of the wind has been used for centuries to sail ships and drive windmills that grind grain. Today, wind energy is captured by wind turbines and used to generate electricity.

Wind power is the conversion of wind energy into a useful form of energy, such as using: wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships.A large wind farm may consist of several hundred individual wind turbines which are connected to the electric power transmission network. Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines.

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Solar Energy :

The sun is our most powerful source of energy. Sunlight, or solar energy, can be used for heating, lighting and cooling homes and other buildings, generating electricity, water heating, and a variety of industrial processes. Most forms of renewable energy come either directly or indirectly from the sun. For example, heat from the sun causes the wind to blow, contributes to the growth of trees and other plants that are used for biomass energy, and plays an essential role in the cycle of evaporation and precipitation that makes hydropower possible.

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric current using the photoelectric effect.

Commercial concentrated solar power plants were first developed in the 1980s. The 354 MW SEGS CSP installation is the largest solar power plant in the world, located in the Mojave Desert of California. Other large CSP plants include the Solnova Solar Power Station (150 MW) and the Andasol solar

power station (150 MW), both in Spain. The over 200 MW Agua Caliente Solar Project in the United States, and the 214 MW Charanka Solar Park in India, are the world‘s largest photovoltaic plants. Average insolation showing land area (small black dots) required to replace the world primary energy supply with solar electricity. 18 TW is 568 Exajoule (EJ) per year. Insolation for most people is from 150 to 300 W/m2 or 3.5 to 7.0 kWh/(m2day).

Biomass energy :

Biomass has been an important source of energy ever since people first began burning wood to cook food and warm themselves against the winter chill. Wood is still the most common source of biomass energy, but other sources of biomass energy include food crops, grasses and other plants, agricultural and forestry waste and residue, organic components from municipal and industrial wastes, even methane gas harvested from community landfills. Biomass can be used to produce electricity and as fuel for transportation, or to manufacture products that would otherwise require the use of non-renewable fossil fuels.

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lignocellulosic biomass (second generation biofuels) as fuel. This is either using harvested wood directly as a fuel, or collecting from wood waste streams. The largest source of energy from wood is pulping liquor or ―black liquor,‖ a waste product from processes of the pulp, paper and paperboard industry. Waste energy is the second-largest source of biomass energy. The main contributors of waste energy are municipal solid waste (MSW), manufacturing waste, and landfill gas. Sugars and oils (first generation biofuels), such as sugarcane and corn, are used to produce bioethanol, an alcohol fuel. Alcohol fuels can be used directly, like other fuels, or as an additive to gasoline. Second generation biofuels are less simple to extract or process while first generation biofuels are more prone to escalating the Food vs. Fuel dilemma.

Geothermal Energy :

The heat inside the Earth produces steam and hot water that can be used to power generators and produce electricity, or for other applications such as home heating and power generation for industry. Geothermal energy can be drawn from deep underground reservoirs by drilling, or from other geothermal reservoirs closer to the surface.

Geothermal power is cost effective, reliable, sustainable, and environmentally friendly but has historically been limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for applications such as home heating, opening a potential for widespread exploitation. Geothermal wells release greenhouse gases trapped deep within the earth, but these emissions are much lower per energy unit than those of fossil fuels. As a result, geothermal power has the potential to help mitigate global warming if widely deployed in place of fossil fuels.

Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The Geothermal energy of the Earth's crust originates from the original formation of the planet (20%) and from radioactive decay of minerals (80%). The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface.

Ocean Energy :

The ocean provides several forms of renewable energy, and each one is driven by different forces. Energy from ocean waves and tides can be harnessed to generate electricity, and ocean thermal energy—from the heat stored in sea water—can also be converted to electricity. Using current technologies, most ocean energy is not cost-effective compared to other renewable energy sources, but the ocean remains and important potential energy source for the future.

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waves.Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors.

Ocean thermal energy is used for many applications, including electricity generation. There are three types of electricity conversion systems: closed-cycle, open-cycle, and hybrid. Closed-cycle systems use the ocean's warm surface water to vaporize a working fluid, which has a low-boiling point, such as ammonia. The vapor expands and turns a turbine. The turbinethen activates a generator to produce electricity. Open-cycle systems actually boil the seawater by operating at low pressures. This produces steam that passes through a turbine/generator. And hybrid systems combine both closed-cycle and open-cycle systems.

Ocean mechanical energy is quite different from ocean thermal energy. Even though the

sun affects all ocean activity, tides are driven primarily by the gravitational pull of the moon, and waves are driven primarily by the winds. As a result, tides and waves are intermittent sources of energy, while ocean thermal energy is fairly constant. Also, unlike thermal energy, the electricity conversion of both tidal and wave energy usually involves mechanical devices.

Hydrogen :

Hydrogen has tremendous potential as a fuel and energy source, but the technology needed to realize that potential is still in the early stages. Hydrogen is the most common element on Earth—for example, water is two-thirds hydrogen—but in nature it is always found in combination with other elements. Once separated from other elements, hydrogen can be used to power vehicles, replace natural gas for heating and cooking, and to generate electricity.

Hydrogen is the simplest element. An atom of hydrogen consists of only one proton and one electron. It's also the most plentiful element in the universe. Despite its simplicity and abundance, hydrogen doesn't occur naturally as a gas on the Earth - it's always combine with other elements. Water, for example, is a combination of hydrogen and oxygen (H2O).

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natural gas, methanol, and propane. Hydrogen can be separated from hydrocarbons through the application of heat - a process known as reforming. Currently, most hydrogen is made this way from natural gas. An electrical current can also be used to separate water into its components of oxygen and hydrogen. This process is known as electrolysis. Some algae and bacteria, using sunlight as their energy source, even give off hydrogen under certain conditions.

Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. NASA has used liquid hydrogen since the 1970s to propel the space shuttle and other rockets into orbit. Hydrogen fuel cells power the shuttle's electrical systems, producing a clean byproduct - pure water, which the crew drinks.

Conclusion :

Renewable energy technologies in the context of energy access have proven to be reliable and with the appropriate business model affordable for poor households. They can support the UN goal of reaching full energy access by 2030 and have the potential to create almost 4 million direct jobs in the off-grid electricity sector alone. Successful initiatives have some elements in common, including building qualified skills, setting quality standards for equipment and providing financial support to entrepreneurs. Therefore, in designing and implementing policies to increase sustainable jobs when introducing Renewable Energy Technologies for access, policy makers may want to consider the following aspects such as Job Creation,improving skills,Gender,

Standards and Quality Assurance, Improving Primary Data.

References :

 http://sciencenetlinks.com/lessons/re newable-energy-sources

 http://www.geni.org

 http://www.renewableenergyfocus.

com

 http://indianpowersector.com/

 http://www.washingtonpost.com/

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