The US Air Force is ready to switch to biofuels to help power its warplanes but the price of alternative fuels remains too high, military officials said.
Anxious to reduce its reliance on oil, the Air Force has approved the use of synthetic fuels for nearly all its aircraft and expects to get the green light for biofuels by the end of 2012, Undersecretary Erin Conaton said.
�The big thing we�re trying to do is to send a clear message to industry that the Air Force wants to be in a position to purchase biofuels and to use that operationally for our fleet,� Conaton said.
�But in order to do that,we need industry to be able to produce in the quantities we need at a cost-competitive price.�
Biofuels cost a prohibitive $35 a gallon (3.8l), about 10 times the price of conventional jet fuel, or JP-8.
Performance
�The biofuels that are available now are just nowhere near the cost of what we can buy JP-8 for,� Conaton said.
With the biofuels industry still in need of more private investment, the US military has joined forces with commercial airlines �to try to send the right message�to the alternative fuels industry, she said.
�We�re ready whenever they�re ready to produce it.�
Tests have shown fighter aircraft and cargo planes can fly on a blend of biofuels and traditional jet fuel with no sacrifice in speed or performance, she said.
Conaton spoke as biofuels industry representatives and military officials gathered for an energy conference on Tuesday in Washington where alternative fuels will feature high on the agenda.
US officials see the country�s dependence on foreign oil as a national security risk and an increasing financial burden.
To promote energy �security�, the Air Force has set a goal to have half of its domestic fuel needs drawn from alternative sources by 2016.
The biofuels tested on military aircraft, known as hydro processed renewable jet fuel, are derived from the camelina plant, animal fat and various waste oils.
The military and commercial airlines are also testing �alcohol-to-jet�fuel produced from cellulosic feedstock,including switch grass,grains and sugar.
Conaton said the Air Force had plans to test the ATJ fuel on A-10 ground attack aircraft.
Following the Air Force�s lead, the Navy and Army are also working to promote the use of alternative fuels in ships, ground vehicles and bases, with Navy Secretary Ray Mabus arguing that the military can help generate enough demand to lower the price of biofuels.
Mabus told NPR earlier this month that �if we establish the market, the price is going to begin to come down�.
The Air Force�s consumption of fuel is equivalent to a major commercial airline, or about 10 billion litres a year.
Source : http://www.eco-h2o.co.za/2011/07/20/biofuel-for-the-us-air-force/
Introduction
In just a few short decades wind energy has matured dramatically, making wind one of the fastest growing sources of electricity in the world today. Due to technological advancements, policy initiatives, and economic drivers, wind energy is now able to make a cost-competitive contribution to our growing energy needs.
Wind Turbine Technology
Turbines today are sleek and slender machines, a far cry from their wooden ancestors. Around the world, wind turbines of all sizes have become a familiar sight; ranging from home or farm-scale machines of 1 kilowatt (kW), all the way up to arrays of large 7 megawatt (MW) machines for off-shore use.
Modern wind turbines are up to the task of producing serious amounts of electricity. A popular sized machine in the U.S. today is a state-of-the-art 2 MW turbine that stands as tall as a 30-story building and costs roughly $2 million to $5 million installed. With a good wind resource, this size turbine can produce 5 million kWh of electricity each year, or enough energy to run 500 average American households.
Wind Energy Around the Globe
Turbines are sprouting up around the globe in record numbers. By the end of 2010, there were over 197,000 MW of wind installed around the world, which is more than three-times the 59,000 MW installed in 2005. The pace of growth is now greatest in China, where installed wind energy capacity grew by 18,928 MW in 2010, over half of their total 25,805 MW installed capacity. Yet the United States leads the world in total installation, with 35,086 MWby year end 2010. The growth in the Chinese market put China second in total installed wind capacity with 25,805 MW edging out Germany (25,777 MW).
China's recent boom can be attributed to the passage of a Renewable Energy Standard in 2007 and the introduction in 2009 of requirements for grid owners to buy electricity from renewables, as well as a 20-year feed-in-tariff for wind projects. While nearly half of the world's new installed capacity in 2010 came from China, other countries are also growing their wind resources. (Source: Global Energy Council's Global Wind Report 2010).
Spain continues to be a leader in wind power, with India, France, Italy and the UK rising in the market. The recent boom in renewable energy investment, including wind energy generation, is being aided through progressive policies and widespread public support. Legislation such as the UK's Renewables Obligation, the 29 US states and 2 territories with Renewable Portfolio Standards, and the EU's target for 20% renewable energy by 2020 is aiding the development of wind energy across the globe.
Wind Energy in the United States
Total wind capacity in the United States reached 46,919 MW by the end of 2011, with commercial-scale wind turbines operating in 38 states. Wind power accounted for 35% of the country's new power-production capacity from 2007 to 2011, second only to natural gas. According to the American Wind Energy Association (AWEA), Texas leads the country as the state with the most installed wind power with 10,135 MW. Iowa remains a leader in wind generation with 3,675 MW installed; while California and Minnesota continue to harvest significant amounts of wind with 3,179 MW and 2,432 MW respectively.
Although this is significant growth for wind energy, it still only accounts for a small percentage of the U.S. electricity supply. The U.S. Department of Energy recently released a report that laid out a plan to reach 20% wind energy power by 2030 to fuel the U.S. electricity grid. This would provide a major increase in jobs, benefits to rural landowners, and lead the Country to increased energy independence. Factors pushing for growth in U.S. wind energy include the high cost of fossil fuels and concern over national energy security. As a result, policy makers are actively considering a wide range of legislation that would support and enhance wind energy growth.
Progressive public policy has usually been a key ingredient both for encouraging wind energy expansion and helping to determine what forms that growth will take. Future growth will likely come from commercial-scale wind farms, which are typically vast arrays of turbines owned and operated by large corporations. Yet experience in Minnesota has shown that, with an encouraging policy environment, small clusters of turbines or even single turbines can make significant contirbutions, operated by local landowners, small businesses, and community wind projects.
The Future of Wind Energy
Technological advancements and supportive policy measures have the ability to dramatically increase the future of wind energy development in our nation and our world. Wind power has the unique ability to provide even greater sources of distributed energy production, which means less risk and a stronger energy portfolio. America�s ingenuity and drive for independence are well suited to increased wind energy development in the future. Stay tuned to advancements at industry and policy levels as wind energy continues to grow.
Source : http://www.windustry.org/wind-basics/introduction
It is time that we all face the truth that our oil resources will be depleted in less than a decade and all the benefits that we have reaped from this oil since date will vanish in a wisp of smoke. With fuel prices rising every year due to the decrease in natural oil resources one day will come when fuel will be costlier than diamond and we will be left with nothing. But this fate can be stopped if we become aware and start using biodiesel fuels to preserve mineral oil for functions that are extremely necessary for human kind and cannot do without mineral oil.
Biodiesel fuel is therefore the alternative fuel that we should use. You may say, but I know nothing about it, and so we are here to give you more information on biodiesel fuel so that you can cheaply and effectively run your car and other machines without damaging the environment at all.
Benefits Of Biodiesel Fuels:
A biodiesel fuel is essentially a non-petroleum fuel that has a long chain of alkyl esters. This fuel is produced from vegetable oil by its transesterification and can be used in most engine vehicles even if they are unmodified ones. There are vehicles that are designed to run only on biodiesel fuel but it can be used even if the vehicle is not made to run on it. It is a clean fuel that is an excellent alternative to petroleum.
In fact a biodiesel fuel is made from matter that is one hundred percent renewable. Moreover this fuel can actually be used in combination with petroleum if say your car doesnot support running entirely on it and needs some amount of petroleum. However pure biodiesel can only be used in diesel cars while petrol run cars will require blending like B20 or B50 etc.
You may feel that this fuel is actually like any vegetable oil fuel that has come up in recent years as an alternative fuel. It is not so and actually it is much different and more efficient a fuel than vegetable oil fuel. The former can only be used in combustion-ignition type engines while biodiesel fuel can be used in any engine, in pure form or blended form. This fuel is also very good for human health. For example it has cleared all the health effecting tests that any fuel has to clear; it meets the standards of non-polluting or rather polluting the environment to a bare minimum and has been literally termed environment friendly.
All these issues kept in mind; a biodiesel fuel is actually the best alternative fuel available and can be got anywhere. However, the price is a tad more than normal conventional fuel since the demand for the fuel is not much. But with the way in which things are going it is sure that the demand for the fuel will increase making it the fuel of the future.
Sumber : http://biodieselprocessor.org/
Tidal energy, also referred to as tidal power,is a process that harnesses the energy of the tides and converts it into power. Tidal energy is far more predictable than other forms of clean, green, renewable energy such as solar, wind and wave energy. In fact, tidal energy is far from being a new concept and has been used throughout history as a source of energy. The earliest account of tidal energy use dates back through the Middle Ages to Roman times!
How do the tides work? Basically, the relationship between the Earth and moon causes the tide to change. As the moon rotates around Earth and the Earth rotates around the sun, it has a gravitational push and pull on the ocean. This fluctuation takes energy, and that is the energy that can be harnessed! Because this process of fluctuating tides occurs at fairly predictable intervals of time, and because it is likely that the tidal fluctuations will continue to occur indefinitely, tidal energy is viewed as an inexhaustible resource.
There are several tidal energy farms throughout the world. Two farms are currently being built in Wales and both are expected to be operational in 2010. In Canada, the British Columbia Tidal Energy Corporation is currently building three turbines in Campbell River and should be completed by the end of 2009. Nova Scotia is also building a tidal energy farm.
Tidal energy power, like solar power, has a high initial investment and a very low maintenance cost. This poses a challenge, however, because many investors aren�t willing to provide the initial investment, especially when returns come back over an extended period of time. However, tidal energy has the potential to replace fossil fuel power plants. For example, a proposal for a tidal energy plant for the Severn Barrage in the United Kingdom would prevent eighteen-million tons of coal each year from being used.
There are many additional benefits to investing in tidal energy. To start, tidal energy farms can be located in any body of water that is affected by tidal fluctuation�oceans and rivers connected to the ocean. It is also very consistent, which is a problem that other sources of clean, sustainable energy sources face.
Harnessing tidal energy is a very interesting idea. Tidal energy advocates are highly optimistic and see the potential for tidal energy to provide a large amount of the energy. Opponents to the idea of tidal energy mainly point out its initial investment, which like solar power, is very high. However, many people are able to see beyond this challenge. After all, most environmentalists easily understand the concept of investing in compact fluorescent light (CFL) bulbs, even though they are more expensive than incandescent bulbs.
We need to keep in mind that when the use of fossil fuels began, it was extremely expensive to build the power plants and create the energy grids necessary to transfer that energy. More than one hundred years later, the process of obtaining energy from fossil fuels has been streamlined. EnviroCitizen.org acknowledges that it may be more expensive to invest in tidal energy now, but notes that in the not-too-distant-future we will be able to enjoy a low-cost, highly renewable, very green, clean energy source that with further preserve the Earth! An upfront investment is certainly worth the long-term benefits the Earth with experience.
Source : http://www.envirocitizen.org/article/how-does-tidal-energy-work/1087.html
Welcome to Extreme Biodiesel, home of the "Extractor", our standard water-wash processor, and the "Extreme Extractors", with our exclusive 2 and 5 hour waterless filtration systems.
Our new "Extreme Mini-Refineries" produce at least 600 gallons of biodiesel per day! We can also custom-build larger processors to accommodate your biodiesel needs.
After years of research and development, Extreme Biodiesel offers the finest constructed and most user-friendly processors in the biofuel industry. We are the cutting edge leaders in new technology and will continue to achieve technological advances in biodiesel production in our on-site laboratory.
At Extreme Biodiesel, we use only the finest components in constructing biodiesel processors. By using polyethylene and polypropylene materials, all of our fittings and hoses are biodiesel compatible. Unlike many biodiesel product manufacturers, we do not use white PVC, galvanized pipe or rubber hoses/tubing in our construction as these materials will eventually degrade, swell, crack and leak. The Apollo brass valves we use are made of the finest materials: including stainless steel inserts and Teflon seals.
Our custom biodiesel tanks are made with double-thick polyethylene. These tanks allow for production of 20 to 100 gallons of biodiesel in a single batch! You cannot find these biodiesel tanks anywhere but through Extreme Biodiesel.
With our exclusive "Methoxide Mixing System" you will never come into contact with both the methanol and lye together. These two chemicals are highly toxic to breathe in and will burn upon contact. Thus, we have added a separate, totally enclosed motorized methanol pump for your safety.
Our exclusive "Extreme Extractor" is a unique waterless system that completely eliminates the time consuming steps of water-washing and drying that is found in most biodiesel processors. It can produce up to 100 gallons of biodiesel in as little as 5.5 hours! And, with the "Extreme Extractor," wastewater disposal is eliminated!
If you already own a processor and are tired of water-washing, you can also purchase the "Extreme Purification System" separately. You will find all of these waterless systems well worth the price!
Biodiesel will have your engine run cooler, quieter, and eliminate up to 90% of emissions. Biodiesel will also reduce up to 90% of exhaust smoke, and most importantly, it's friendly to our environment!
Making biodiesel is simple. All you need to make biodiesel is vegetable oil (waste or virgin), methanol and lye. The vegetable oil-to-biodiesel-ratio is approximately 1:1. On average, you can produce biodiesel for as little as $0.80/Gallon!
Considering today's outrageous diesel prices, just think of the savings you will enjoy with your own biodiesel processing system from Extreme Biodiesel!
Source : http://www.extremebiodiesel.com/
A method developed at Aalto University in Finland makes it possible to use microbes to produce butanol suitable for biofuel and other industrial chemicals from wood biomass.
Butanol is particularly suited as a transport fuel because it is not water soluble and has higher energy content than ethanol.
Most commonly used raw materials in butanol production have so far been starch and cane sugar. In contrast to this, the starting point in the Aalto University study was to use only lignocellulose, otherwise known as wood biomass, which does not compete with food production.
Another new breakthrough in the study is to successfully combine modern pulp -- and biotechnology. Finland's advanced forest industry provides particularly good opportunities to develop this type of bioprocesses.
Wood biomass is made up of three primary substances: cellulose, hemicelluloses and lignin. Of these three, cellulose and hemicellulose can be used as a source of nutrition for microbes in bioprocesses. Along with cellulose, the Kraft process that is currently used in pulping produces black liquor, which can already be used as a source of energy. It is not, however, suitable for microbes. In the study, the pulping process was altered so that, in addition to cellulose, the other sugars remain unharmed and can therefore be used as raw material for microbes.
When wood biomass is boiled in a mixture of water, alcohol and sulphur dioxide, all parts of the wood -- cellulose, hemicellulose and lignin -- are separated into clean fractions. The cellulose can be used to make paper, nanocellulose or other products, while the hemicellulose is efficient microbe raw material for chemical production. Thus, the advantage of this new process is that no parts of the wood sugar are wasted.
In accordance with EU requirements, all fuel must contain 10 per cent biofuel by 2020. A clear benefit of butanol is that a significantly large percentage -- more than 20 per cent of butanol, can be added to fuel without having to make any changes to existing combustion engines. The nitrogen and carbon emissions from a fuel mix including more than 20 per cent butanol are significantly lower than with fossil fuels. For example, the incomplete combustion of ethanol in an engine produces volatile compounds that increase odour nuisances in the environment. Estimates indicate that combining a butanol and pulp plant into a modern biorefinery would provide significant synergy benefits in terms of energy use and biofuel production.
The project run by Aalto University is part of the Tekes' BioRefine programme. Tekes is the Finnish Funding Agency for Technology and Innovation.
The Biorefine programme is developing new competence based on national strengths and related to the refining of biomass. The overall aim of the project is to increase the refining value of forest residues that cannot be utilised in, for example, the pulp process. The research has been developed by Professor Aadrian van Heiningen and Tom Granstr�m and a group of researchers at Aalto University.
Results of findings have been published in scientific journals such as Bioresource Technology. The developed technology has been patented.
Source : http://www.sciencedaily.com/
A Portuguese energy company called Enersis is funding a commercial wave energy project in Northern Portugal. Construction of Pelamis Offshore Wave Energy Project will begin at the end of October 2006. The project will use Pelamis wave generator technology (manufactured by Ocean Power Delivery) to harness energy from the ocean. After two decades of research and testing at the Lisbon Technical Institute, the first stage of this ocean energy project is intended to produce 2.25 megawatts and power homes through the nation�s state-run electrical grid system. Ocean Power Delivery is considered to be the world�s leading ocean energy company.
�This project, begun in 2003, is now in the world vanguard,� said Rui Barros, Enersis director of new projects. �Of all the varieties of renewable energy, perhaps harnessing the waves is the only one where Portugal might have a real future,� he said. With its geographical position and extensive coastline giving access to the larger and more powerful Atlantic waves, official estimates from Portugal�s State Secretariat for Industry and Innovation have predicted wave power could account for up to 30 percent of the country�s gross domestic product by 2050. Renewable energy experts have determined wave farms in Portugal could yield as much as three times as much energy as that produced by a wind turbine park for the same investment cost.
A report published by the Portuguese Wave Energy Center has confirmed the long-term economic benefits of wave energy for the country and calls on the government to put in place a strategy to attract foreign investment into Portuguese wave power ventures. �The utilization of wave energy may have a significant socio-economic impact on Portugal, namely regarding renewables, creation of job opportunities, opportunity of exportation of equipment and services, innovation and development of technology, as well as companies dedicated to the exploitation of other oceanic resources,� the report says.
Relatively new in development, modern research into wave power had its beginnings in response to the 1973 oil crisis. Professor Stephen Salter of the University of Edinburgh pioneered research into wave energy with his prototype machine �Salter�s Duck.� Though the duck remains a laboratory prototype, the machine remains the standard for wave energy. The experimental device converted around 90 percent of the wave power by bobbing up and down on the surface of the water � like a duck. Despite its early promise though, setbacks and a general lack of government support saw the project shelved.
However, with the Portuguese system set to be the world�s first commercial wave energy venture, the exploitation of wave power has found itself back on the renewable energy agenda.
Following the Enersis announcement, other countries naturally suited to the development of wave power have expressed their interest in introducing the technology. Following his recent visit to Aguadoura, Scottish Executive Enterprise Minister Nicol Stephen announced that a portion of the 8 million pounds already set aside for renewable marine energy in Scotland would now be directed towards installing the Pelamis wave devices at the European Marine Energy Center in Orkney.
�I am committed to supporting Scotland�s huge wave and tidal energy resource. Scotland has a real opportunity to be a world leader in this field,� said the minister shortly after his visit to view the wave energy project in northern Portugal. �The opportunity now exists to create a multi-million pound industry based in Scotland, employing thousands of highly skilled people,� he said.
However, environmental group Friends of the Earth, while supporting the minister�s announcement, sounded a warning that any delays in introducing the wave power technology could lead to an exodus of Scottish expertise.
�Wave and tidal power could supply a fifth of U.K. energy needs and Scotland is ideally placed to generate significant amounts of this pollution-free energy,� said Friends of the Earth chief executive Duncan McLaren. �However, there is a danger that unless we see full-scale devices in our waters soon that the world-leading expertise Scotland has built up will rapidly depart these shores,� he said.
As part of the government supported alternative energy plan, another 28 wave power devices will be installed in Portugal within a year, reaching a target of 22.5 megawatts of electricity produced using wave energy. The project is supported by state run power company Energias de Portugal.
Source : http://wavepowerplant.blogspot.com/
More than a dozen advanced reactor designs are in various stages of development. Some are evolutionary from the PWR, BWR and PHWR designs above, some are more radical departures. The former include the Advanced Boiling Water Reactor (ABWR), two of which are now operating with others under construction, and the planned passively safe ESBWR and AP1000 units (see Nuclear Power 2010 Program).
The Integral Fast Reactor (IFR) was built, tested and evaluated during the 1980s and then retired under the Clinton administration in the 1990s due to nuclear non-proliferation policies of the administration. Recycling spent fuel is the core of its design and it therefore produces only a fraction of the waste of current reactors.
The Pebble Bed Reactor, a High Temperature Gas Cooled Reactor (HTGCR), is designed so high temperatures reduce power output by doppler broadening of the fuel's neutron cross-section. It uses ceramic fuels so its safe operating temperatures exceed the power-reduction temperature range. Most designs are cooled by inert helium. Helium is not subject to steam explosions, resists neutron absorption leading to radioactivity, and does not dissolve contaminants that can become radioactive.
Typical designs have more layers (up to 7) of passive containment than light water reactors (usually 3). A unique feature that may aid safety is that the fuel-balls actually form the core's mechanism, and are replaced one-by-one as they age. The design of the fuel makes fuel reprocessing expensive.
The Small Sealed Transportable Autonomous Reactor (SSTAR) is being primarily researched and developed in the US, intended as a fast breeder reactor that is passively safe and could be remotely shut down in case the suspicion arises that it is being tampered with.
The Clean And Environmentally Safe Advanced Reactor (CAESAR) is a nuclear reactor concept that uses steam as a moderator � this design is still in development.
The Hydrogen Moderated Self-regulating Nuclear Power Module (HPM) is a reactor design emanating from the Los Alamos National Laboratory that uses uranium hydride as fuel.
Subcritical reactors are designed to be safer and more stable, but pose a number of engineering and economic difficulties. One example is the Energy amplifier.
Thorium based reactors. It is possible to convert Thorium-232 into U-233 in reactors specially designed for the purpose. In this way, thorium, which is more plentiful than uranium, can be used to breed U-233 nuclear fuel. U-233 is also believed to have favourable nuclear properties as compared to traditionally used U-235, including better neutron economy and lower production of long lived transuranic waste.
Advanced Heavy Water Reactor (AHWR)� A proposed heavy water moderated nuclear power reactor that will be the next generation design of the PHWR type. Under development in the Bhabha Atomic Research Centre (BARC), India.
KAMINI � A unique reactor using Uranium-233 isotope for fuel. Built in India by BARC and Indira Gandhi Center for Atomic Research (IGCAR).
India is also planning to build fast breeder reactors using the thorium � Uranium-233 fuel cycle. The FBTR (Fast Breeder Test Reactor) in operation at Kalpakkam (India) uses Plutonium as a fuel and liquid sodium as a coolant.
Source : http://nuclear-powerplants.blogspot.com/
Just as many conventional thermal power stations generate electricity by harnessing the thermal energy released from burning fossil fuels, nuclear power plants convert the energy released from the nucleus of an atom, typically via nuclear fission.
When a relatively large fissile atomic nucleus (usually uranium-235 or plutonium-239) absorbs a neutron, a fission of the atom often results. Fission splits the atom into two or more smaller nuclei with kinetic energy (known as fission products) and also releases gamma radiation and free neutrons. A portion of these neutrons may later be absorbed by other fissile atoms and create more fissions, which release more neutrons, and so on.
This nuclear chain reaction can be controlled by using neutron poisons and neutron moderators to change the portion of neutrons that will go on to cause more fissions. Nuclear reactors generally have automatic and manual systems to shut the fission reaction down if unsafe conditions are detected.
A cooling system removes heat from the reactor core and transports it to another area of the plant, where the thermal energy can be harnessed to produce electricity or to do other useful work. Typically the hot coolant will be used as a heat source for a boiler, and the pressurized steam from that boiler will power one or more steam turbine driven electrical generators.
There are many different reactor designs, utilizing different fuels and coolants and incorporating different control schemes. Some of these designs have been engineered to meet a specific need. Reactors for nuclear submarines and large naval ships, for example, commonly use highly enriched uranium as a fuel. This fuel choice increases the reactor's power density and extends the usable life of the nuclear fuel load, but is more expensive and a greater risk to nuclear proliferation than some of the other nuclear fuels.
A number of new designs for nuclear power generation, collectively known as the Generation IV reactors, are the subject of active research and may be used for practical power generation in the future. Many of these new designs specifically attempt to make fission reactors cleaner, safer and/or less of a risk to the proliferation of nuclear weapons. Passively safe plants (such as the ESBWR) are available to be built and other designs that are believed to be nearly fool-proof are being pursued. Fusion reactors, which may be viable in the future, diminish or eliminate many of the risks associated with nuclear fission.
There are two types of nuclear power in current use:
* The Radioisotope thermoelectric generator produces heat through passive radioactive decay. Some radioisotope thermoelectric generators have been created to power space probes (for example, the Cassini probe), some lighthouses in the former Soviet Union, and some pacemakers. The heat output of these generators diminishes with time; the heat is converted to electricity utilising the thermoelectric effect.
* Nuclear fission reactors produce heat through a controlled nuclear chain reaction in a critical mass of fissile material. All current nuclear power plants are critical fission reactors, which are the focus of this article. The output of fission reactors is controllable. There are several subtypes of critical fission reactors, which can be classified as Generation I, Generation II and Generation III. All reactors will be compared to the Pressurized Water Reactor (PWR), as that is the standard modern reactor design.
Pressurized Water Reactors (PWR)
These reactors use a pressure vessel to contain the nuclear fuel, control rods, moderator, and coolant. They are cooled and moderated by high pressure liquid water. The hot radioactive water that leaves the pressure vessel is looped through a steam generator, which in turn heats a secondary (non-radioactive) loop of water to steam that can run turbines. They are the majority of current reactors, and are generally considered the safest and most reliable technology currently in large scale deployment. This is a thermal neutron reactor design, the newest of which are the VVER-1200, Advanced Pressurized Water Reactor and the European Pressurized Reactor. United States Naval reactors are of this type.
Boiling Water Reactors (BWR)
A BWR is like a PWR without the steam generator. A boiling water reactor is cooled and moderated by water like a PWR, but at a lower pressure, which allows the water to boil inside the pressure vessel producing the steam that runs the turbines. Unlike a PWR, there is no primary and secondary loop. The thermal efficiency of these reactors can be higher, and they can be simpler, and even potentially more stable and safe. This is a thermal neutron reactor design, the newest of which are the Advanced Boiling Water Reactor and the Economic Simplified Boiling Water Reactor.
Pressurized Heavy Water Reactor (PHWR)
A Canadian design (known as CANDU), these reactors are heavy-water-cooled and -moderated Pressurized-Water reactors. Instead of using a single large pressure vessel as in a PWR, the fuel is contained in hundreds of pressure tubes. These reactors are fueled with natural uranium and are thermal neutron reactor designs. PHWRs can be refueled while at full power, which makes them very efficient in their use of uranium (it allows for precise flux control in the core). CANDU PHWRs have been built in Canada, Argentina, China, India (pre-NPT), Pakistan (pre-NPT), Romania, and South Korea. India also operates a number of PHWRs, often termed 'CANDU-derivatives', built after the Government of Canada halted nuclear dealings with India following the 1974 Smiling Buddha nuclear weapon test.
Reaktor Bolshoy Moschnosti Kanalniy (High Power Channel Reactor) (RBMK)
A Soviet design, built to produce plutonium as well as power. RBMKs are water cooled with a graphite moderator. RBMKs are in some respects similar to CANDU in that they are refuelable during power operation and employ a pressure tube design instead of a PWR-style pressure vessel. However, unlike CANDU they are very unstable and large, making containment buildings for them expensive. A series of critical safety flaws have also been identified with the RBMK design, though some of these were corrected following the Chernobyl accident. Their main attraction is their use of light water and un-enriched uranium. As of 2010, 11 remain open, mostly due to safety improvements and help from international safety agencies such as the DOE. Despite these safety improvements, RBMK reactors are still considered one of the most dangerous reactor designs in use. RBMK reactors were deployed only in the former Soviet Union.
Gas Cooled Reactor (GCR) and Advanced Gas Cooled Reactor (AGR)
These are generally graphite moderated and CO2 cooled. They can have a high thermal efficiency compared with PWRs due to higher operating temperatures. There are a number of operating reactors of this design, mostly in the United Kingdom, where the concept was developed. Older designs (i.e. Magnox stations) are either shut down or will be in the near future. However, the AGCRs have an anticipated life of a further 10 to 20 years. This is a thermal neutron reactor design. Decommissioning costs can be high due to large volume of reactor core.
Liquid Metal Fast Breeder Reactor (LMFBR)
This is a reactor design that is cooled by liquid metal, totally unmoderated, and produces more fuel than it consumes. They are said to "breed" fuel, because they produce fissionable fuel during operation because of neutron capture. These reactors can function much like a PWR in terms of efficiency, and do not require much high pressure containment, as the liquid metal does not need to be kept at high pressure, even at very high temperatures. BN-350 and BN-600 in USSR and Superph�nix in France were a reactor of this type, as was Fermi-I in the United States. The Monju reactor in Japan suffered a sodium leak in 1995 and is pending restart earliest in February 2010. All of them use/used liquid sodium. These reactors are fast neutron, not thermal neutron designs. These reactors come in two types:
Lead cooled
Using lead as the liquid metal provides excellent radiation shielding, and allows for operation at very high temperatures. Also, lead is (mostly) transparent to neutrons, so fewer neutrons are lost in the coolant, and the coolant does not become radioactive. Unlike sodium, lead is mostly inert, so there is less risk of explosion or accident, but such large quantities of lead may be problematic from toxicology and disposal points of view. Often a reactor of this type would use a lead-bismuth eutectic mixture. In this case, the bismuth would present some minor radiation problems, as it is not quite as transparent to neutrons, and can be transmuted to a radioactive isotope more readily than lead. The Russian Alfa class submarine uses a lead-bismuth-cooled fast reactor as its main power plant.
Sodium cooled
Most LMFBRs are of this type. The sodium is relatively easy to obtain and work with, and it also manages to actually prevent corrosion on the various reactor parts immersed in it. However, sodium explodes violently when exposed to water, so care must be taken, but such explosions wouldn't be vastly more violent than (for example) a leak of superheated fluid from a SCWR or PWR. EBR-I, the first reactor to have a core meltdown, was of this type.
Pebble Bed Reactors (PBR)
These use fuel molded into ceramic balls, and then circulate gas through the balls. The result is an efficient, low-maintenance, very safe reactor with inexpensive, standardized fuel. The prototype was the AVR.
Molten Salt Reactors
These dissolve the fuels in fluoride salts, or use fluoride salts for coolant. These have many safety features, high efficiency and a high power density suitable for vehicles. Notably, they have no high pressures or flammable components in the core. The prototype was the MSRE, which also used Thorium's fuel cycle to produce 0.1% of the radioactive waste of standard reactors.
Aqueous Homogeneous Reactor (AHR)
These reactors use soluble nuclear salts dissolved in water and mixed with a coolant and a neutron moderator.
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What are Geothermal Power Plants?
There are three geothermal power plant technologies being used to convert hydrothermal fluids to electricity. The conversion technologies are dry steam, flash, and binary cycle. The type of conversion used depends on the state of the fluid (whether steam or water) and its temperature. Dry steam power plants systems were the first type of geothermal power generation plants built. They use the steam from the geothermal reservoir as it comes from wells, and route it directly through turbine/generator units to produce electricity. Flash steam plants are the most common type of geothermal power generation plants in operation today. They use water at temperatures greater than 360�F (182�C) that is pumped under high pressure to the generation equipment at the surface. Binary cycle geothermal power generation plants differ from Dry Steam and Flash Steam systems in that the water or steam from the geothermal reservoir never comes in contact with the turbine/generator units.
Types of Geothermal Power Plants
Dry Steam Power Plants
This is the earliest form of geothermal power plant, which directs steam into turbines to produce electricity. Excess heat from the production well is channeled back into the reservoir via an injection well. This type of generator was first used in 1904, to generate electricity in Lardarello, Italy, where it still stands today, fully operational. The United States have also built dry steam power plants, including those in Northern California geysers.
Steam plants use hydrothermal fluids that are primarily steam. The steam goes directly to a turbine, which drives a generator that produces electricity. The steam eliminates the need to burn fossil fuels to run the turbine. (Also eliminating the need to transport and store fuels!) This is the oldest type of geothermal power plant. It was first used at Lardarello in Italy in 1904, and is still very effective. Steam technology is used today at The Geysers in northern California, the world's largest single source of geothermal power. These plants emit only excess steam and very minor amounts of gases.
Flash Steam Power Plants
Hot springs above 1750�C may is used to power Flash Steam Power Plants. These hot fluids are channeled to a low pressure flash tank, magnifying its steam formation. This flash steam is then used to power turbines, activating the generator to produce electricity. Excess heat is returned to the reservoir by means of an injector well. One example of a flash steam power plant is the Cal-Energy Navy I, located in Coso Geothermal Field, California.
Hydrothermal fluids above 360�F (182�C) can be used in flash plants to make electricity. Fluid is sprayed into a tank held at a much lower pressure than the fluid, causing some of the fluid to rapidly vaporize, or "flash." The vapor then drives a turbine, which drives a generator. If any liquid remains in the tank, it can be flashed again in a second tank to extract even more energy.
Binary-Cycle Power Plants
This type of power plant use a completely different method compared with the above systems, where the steam from production wells does not directly come into contact with the turbines. Steam is used to heat working fluids in the heat exchanger, which then generates flash steam. This steam is then used to power the turbines and generator to produce electricity. Steam from the heat exchanger is what�s called Binary / Secondary Fluid. This is a closed loop system, where no excess heat is released into the air.
BCPP is able to be operated in low temperatures, between 90-1750�C. One example of this technology is the Mammoth Pacific Binary Geo-Thermal Power Plants in Casa Diablo geothermal field. This technology is a glimpse of future geothermal technology, one that will be used in the future.
The Agency For the Assessment and Application Technology (BPPT) has built a prototype 2KW binary cycle power plant with hydrocarbon as its primary fluid. BPPT has also planned to develop small scale power plants between 2010-2014 which includes a 1 MW binary cycle power plant (targeted for 2014) through a 2 KW prototype (2008) and 100 KW pilot project (2012), and the development of condensing turbine power plant technology with a capacity of 2-5 MW (2011 and 2013).
Most geothermal areas contain moderate-temperature water (below 400�F). Energy is extracted from these fluids in binary-cycle power plants. Hot geothermal fluid and a secondary (hence, "binary") fluid with a much lower boiling point than water pass through a heat exchanger. Heat from the geothermal fluid causes the secondary fluid to flash to vapor, which then drives the turbines. Because this is a closed-loop system, virtually nothing is emitted to the atmosphere. Moderate-temperature water is by far the more common geothermal resource, and most geothermal power plants in the future will be binary-cycle plants.
The Future of Geothermal Electricity
Steam and hot water reservoirs are just a small part of the geothermal resource. The Earth's magma and hot dry rock will provide cheap, clean, and almost unlimited energy as soon as we develop the technology to use them. In the meantime, because they're so abundant, moderate-temperature sites running binary-cycle power plants will be the most common electricity producers.
Before geothermal electricity can be considered a key element of the U.S. energy infrastructure, it must become cost-competitive with traditional forms of energy. The U.S. Department of Energy is working with the geothermal industry to achieve $0.03 to $0.05 per kilowatt-hour. We believe the result will be about 15,000 megawatts of new capacity within the next decade.
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There are many advantages and disadvantages of nuclear power. There are also ethical concerns as well as political concerns. The following article addresses many of the major advantages and disadvantages to nuclear power.
There are many advantages and disadvantages of nuclear power. There are also ethical concerns as well as political concerns. The following article addresses many of the major advantages and disadvantages to nuclear power.
Advantages of Nuclear Power:
* Nuclear power plants don't take up much space. This allows them to be placed in already developed areas and the power does not have to be transferred over long distances.
* It doesn't pollute in a very direct way. It is cleaner than many other forms of energy production. This is in reference to greenhouse gas emissions which are released into the atmosphere. There is a waste product as described below.
* Another advantage of nuclear power is that nuclear energy is by far the most concentrated form of energy, so it can be produced in large quantities over short periods of time.
* The possibility for long term production is great since new reactors, where costly can be made when the old ones wear out. Oil reserves and other fossil type fuels are likely to run out at some point.
Disadvantages of Nuclear Power:
* Nuclear Power generates radiation, which can be harmful or even fatal to infected people.
* A nuclear meltdown can often occur which will release massive amounts of radiation into the community.
* Extremely radioactive nuclear waste is produced by nuclear power plants. This stuff can�t be just thrown out. The US plans to move all its nuclear was to an underground dump by the year 2010. Currently it is stored in the plants.
* Nuclear waste dumps can spontaneously combust without warning.
* Nuclear reactors only last for about forty to fifty years, so where they are extremely productive, they break down and are costly to replace.
* There are international dangers too. Some reactors produce plutonium which can be used to make nuclear weapons. If the whole world were to use these, they would have unlimited access to nuclear weapons.
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Geothermal energy is the energy obtained from the earth(geo) from the hot rocks present inside the earth. It is produced due to the fission of radioactive materials in the earth�s core and some places inside the earth become very hot. These are called hot spots. They cause water deep inside the earth to form steam. As more steam is formed, it gets compressed at high pressure and comes out in the form of hot springs which produces geothermal power.
To harness this geothermal energy, two holes are dug deep into the earth and cold water is pumped through the first one and steam comes out through the second long pipe which helps in generating electricity. The holes dug for harnessing geothermal energy result in lesser emission of greenhouse gases than due to burning of fossil fuels. Thus if used at a larger scale and more efficiently, it gives a hope to reduce global warming.
Geo-thermal energy is one of the rare forms of energy which is not directly or indirectly from solar energy. In areas where hot springs are found, hot springs baths are very common and enjoyable form of recreation. However, they need to be in a controlled environment since they cannot be accessed without proper supervision. We have earlier seen how it is harnessed, the process involved is a long and expensive one and not feasible in some areas.
Construction of geothermal energy plants can affect the seismic stability to a large extent. Even though there are lesser emissions, digging deep holes causes seismic disturbances which have led to earthquakes.
Now lets discuss advantages and disadvantages of Geothermal Energy.
Advantages of Geothermal Energy
1) It is a renewable source of energy.
2) By far, it is non-polluting and environment friendly.
3) There is no wastage or generation of by-products.
4) Geothermal energy can be used directly. In ancient times, people used this source of energy for heating homes, cooking, etc.
5) Maintenance cost of geothermal power plants is very less.
6) Geothermal power plants don't occupy too much space and thus help in protecting natural environment.
7) Unlike solar energy, it is not dependent on the weather conditions.
Disadvantages of Geothermal Energy
1) Only few sites have the potential of Geothermal Energy.
2) Most of the sites, where geothermal energy is produced, are far from markets or cities, where it needs to be consumed.
3) Total generation potential of this source is too small.
4) There is always a danger of eruption of volcano.
5) Installation cost of steam power plant is very high.
6) There is no guarantee that the amount of energy which is produced will justify the capital expenditure and operations costs.
7) It may release some harmful, poisonous gases that can escape through the holes drilled during construction.
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Geothermal energy comes from within the earth. It may be the result of the decay of radioactive substances, chemical reactions, friction from the movement of the continents or heat present when the earth formed.
Most of this heat is at depths beyond the reach of current technology. One of the most famous examples of geothermal energy is the geyser Old Faithful in Yellowstone National Park in the United States.
The four basic forms of geothermal energy are dry steam, hot water (or wet steam), hot dry rock and geopressurized systems. Dry steam occurs only in a few places, but it is the only one of the forms that is in commercial use.
Dry steam
The Geysers plant north of San Francisco, California, uses dry steam to run turbine generators, producing more than 500 megawatts of electric power. Operators pipe dry steam from natural underground reservoirs through a conventional steam turbine generator to produce electricity. The system converts the steam to water in a condenser and returns the water to the earth.
Hot water
Hot rock far beneath the earth's surface heats underground water to temperatures up to 2,200 degrees Fahrenheit. Pressure keeps the water in liquid form. The hot water flows to the surface through wells. Deprived of its pressure, it becomes steam to drive a steam turbine directly or to heat another fluid to run a turbine. Hot water geothermal energy provides central heating for all the buildings in Reykjavik, Iceland.
Hot dry rock
Extracting energy from subterranean hot dry rock means introducing a heat exchange fluid (water) to carry the heat from the rock to the power plant. Scientists inject water deep into fractured hot rock. Then they use the heated water as geothermal water for conversion to useful energy.
Geopressurized systems
Reservoirs of hot water mixed with methane gas, trapped underground, offer the energy potentials of both pressure and burnable methane, as well as the heat energy available from any geothermal resource.
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Hydroelectric energy is the electrical energy derived from hydro (water) power. It is a non-conventional or alternate source of energy.
How hydroelectric energy is generated?
Before discussing advantages and disadvantages of Hydroelectric power, let�s first understand how a hydroelectric power plant works to understand its merits and demerits better. Flowing water possesses kinetic energy. Traditionally, this energy was used to drive water mills to grind pulses etc. Modern day methods have modified this use for a bigger purpose- generation of electricity. When rain falls on high grounds in hilly areas, it flows down in the form if rivers and reaches the sea level. This water is stopped in between and stored in large reservoirs or damns. The dams are at a height and thus water now contains potential energy. This water is then made to flow to large turbines. The water flows with high speed and pressure and rotates turbines, which in turn generates electricity. The water stream follows its natural course, once out of the generator. This is how a hydroelectric power plant can convert the potential energy of stored water in a reservoir of a tall dam into electric energy.
The main reason for using this form of energy for electricity generation is the fact that it is an alternate source of energy and can bring a relief to the use of conventional energy sources. Other advantages of hydro energy are discussed below.
Hydroelectric Power
Hydroelectric power uses the energy of moving water to make electricity. Fuel for a hydro plant is renewable and costs nothing. Another benefit is that hydro plants do not affect air quality.
Hydro plants generated 33 percent of the electricity in the US in the 1920s. Today they generate more electricity than 60 years ago, but account for only 13 percent of the US total. The percentage is smaller because total electric generation from other sources has increased over time.
In a hydropower system, dams on a river capture its power and direct the fast-flowing water through turbines and turning generators to produce electricity. The difference between the water levels above and below the turbine and the rate of water flow determine the amount of power generated.
Run-of-the-river plants use the natural flow of the stream. This greatly limits their potential to produce electricity in a controlled manner because the flow usually varies during the year. To avoid this, some dams store water upstream in a reservoir and then release it as needed.
Advantages of Hydroelectric Energy
1) It is a non-polluting source of energy.
2) It has lower operational cost compared to fossil fuel-based generation plants.
3) Can be easily transmitted through wires to long distances.
4) Dams made for generation of Hydroelectricity also help in irrigation projects.
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When it comes to the future, solar energy is looking strong. People are now realizing that in the long term, solar energy provides a financially viable option. The upfronts costs might be high, but in the long term, everyone can save money by using solar energy. Here are some of the major advantages of solar energy.
Saving money is something that everyone is looking to achieve when it comes to solar energy. The great advantage of solar energy is that it utilizes a free energy resource; the sun. By utilizing the power of the sun, solar energy systems can create electricity. In fact, even if extra energy is produced, this can actually be sold to utility providers at a profit. Solar energy does not just save people money, but it can also make them money too.
A lot more people these days are focused on doing what is right for the environment. This includes things like producing energy. Power plants use a lot of non-renewable energy resources to provide our homes with power. Solar energy systems do not damage the environment in any way, so are good for the future of the planet.
One of the major advantages of solar energy is the lack of maintenance that is required in the long term. The systems do need slight maintenance every now and then, but in the long term, the costs are minimal. This means that once the initial investment has been made, there is little that a owner of a solar energy system really needs to do.
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What is wind energy?
Wind, that is moving air, possesses some kinetic energy due to its high speed. Wind is a result of the solar energy, as heating of land results in movement of air. The most common application of wind could probably be kite flying! Or even paragliding, sail boats etc. Well these activities are definitely not possible without wind. Ever wondered what else it could be useful for?? Wind energy can be harnessed and used for generating electricity or for other smaller purposes by a windmill. In olden times, windmills were used to draw water out of wells or to grind flour etc. It is the rotatory motion of the shaft in a windmill that is used to rotate the turbine and convert it to the form of energy we need it in.
The main advantage of wind energy is that harnessing it doesn�t disrupt natural processes or harm the environment, unlike a lot of other energy sources. To generate electricity on a large scale, a number of windmills are set up over a large area, called a wind energy farm. Such areas need a wind speed of 15kmph.
Lets discuss advantages and disadvantages of Wind Energy.
Advantages Of Wind Energy
1) Wind Energy is an inexhaustible source of energy and is virtually a limitless resource.
2) Energy is generated without polluting environment.
3) This source of energy has tremendous potential to generate energy on large scale.
4) Like solar energy and hydropower, wind power taps a natural physical resource.
5) Windmill generators don�t emit any emissions that can lead to acid rain or greenhouse effect.
6) Wind Energy can be used directly as mechanical energy.
7) In remote areas, wind turbines can be used as great resource to generate energy.
8) In combination with Solar Energy they can be used to provide reliable as well as steady supply of electricity.
9) Land around wind turbines can be used for other uses, e.g. Farming.
Disadvantages Of Wind Energy
1) Wind energy requires expensive storage during peak production time.
2) It is unreliable energy source as winds are uncertain and unpredictable.
3) There is visual and aesthetic impact on region.
4) Requires large open areas for setting up wind farms.
5) Noise pollution problem is usually associated with wind mills.
6) Wind energy can be harnessed only in those areas where wind is strong enough and weather is windy for most parts of the year.
7) Usually places, where wind power set-up is situated, are away from the places where demand of electricity is there. Transmission from such places increases cost of electricity.
8) The average efficiency of wind turbine is very less as compared to fossil fuel power plants. We might require many wind turbines to produce similar impact.
9) It can be a threat to wildlife. Birds do get killed or injured when they fly into turbines.
10) Maintenance cost of wind turbines is high as they have mechanical parts which undergo wear and tear over the time.
Even though there are advantages of wind energy, the limitations make it extremely difficult for it to be harnessed and prove to be a setback.
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Earlier in the discussion about advantages and disadvantages of nuclear energy we saw how nuclear energy is beneficial, if used in the right manner and its scope utilised to the fullest.
However, there is a great deal of radiation danger associated with Nuclear energy. It is capable of causing genetic disorders, thus once exposed, can affect generations to come adversely. Another drawback is the storage of nuclear wastes, as it too can lead to disastrous effects if not disposed or stored in the right manner.
A well known nuclear disaster was the attack on Hiroshima and Nagasaki by the United States during World War II. An experiment, as described by some, was a grave event in the history of nuclear energy and its effects. It was the first of its kind. Another infamous event is the Chernobyl disaster. Although an accident, it made the world realize that controlling such a potentially great power is not entirely in our hands. The accident happened during a test in a nuclear power plant. The extent of damage was controlled as the plant was shut down immediately, and the residents relocated. Even now, the city is in ruins, a pale picture of its past.
The most recent nuclear mishap was the Fukushima Accident in Japan. It was caused by an earthquake-generated tsunami. The nuclear reactor was seismically robust, however could not sustain the effect of the gallons of sea water that went inside the reactor, thus leading to power failure which in turn led to overheating. This ultimately resulted in a hydrogen explosion and subsequent events led to the discharge of radioactive materials into the atmosphere.
Disadvantages of Nuclear Energy
1) Radioactive minerals are unevenly distributed around the world and are found in limited quantities.
2) Supply of high quality uranium, one of the raw material, will last only for few decades.
3) Nuclear waste from nuclear power plant creates thermal(heat) pollution which may damage the environment.
4) A large amount of nuclear waste is also created and disposal of this waste is a major problem.
5) The danger of accidental discharge of radio activity also exists.
6) Starting a nuclear plant requires huge capital investment and advanced technology.
7) Nuclear plants are opposed on moral grounds, by many groups, because of their close linkage with development of nuclear weapons.
8) There are number of restrictions on the export or import of nuclear technology,fuels etc.
9) Nuclear power stations are always at the risk from terrorist attack.
10) Aftermaths of Chernobyl cannot be forgotten easily.
11) Safety issues associated with nuclear power are hard to be overlooked.
12) Proliferation of nuclear technology increases the risk of nuclear war too.
13) The waste produced remains 'active' over many years and disposing it safely is a an issue which needs to be addressed properly.
14) Nuclear power is not a renewable source of energy. Uranium is a metal that is mined from the ground in much the same way as coal is mined. It is a scarce metal and the supply of uranium will one day run out making all the nuclear power plants obsolete.
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What is nuclear energy?
Nuclear energy is a powerful source of energy, generated during a nuclear reaction, by change in the nucleus of an atom. The source of nuclear energy is the mass of the nucleus and energy generated during a nuclear reaction is due to conversion of mass into energy (Einstein's Theory)
There are two ways to obtain nuclear energy:
1) Nuclear fission and
2) Nuclear fusion.
In a nuclear fission reaction, the nucleus of a heavy radioactive element like uranium, plutonium or thorium splits up into smaller nuclei, when bombarded by low energy neutrons. A huge amount of heat is generated in this process, which is used in nuclear power plants to generate electricity.
Nuclear fusion reaction involves the combination or fusion of two light elements to form a heavier element and release uncontrollable energy. Thus it cannot be used to generate electricity, unlike fission reaction. Did you know that the sun�s energy is generated by nuclear fusion reaction? The heat and light that we get from Sun, is all due to the continuous reactions going on inside it. We can now imagine how much energy would be released in the nuclear fusion reaction, that it is the source of sun�s energy.
Let�s cut out the technical part behind nuclear power and discuss advantages and disadvantages of nuclear energy, starting with advantages.
Advantages of Nuclear Energy
1) As compared to other conventional energy sources, Nuclear power produces very less amount of pollution.
2) Very small amount of raw material is required to generate huge amount of nuclear energy. To put it into perspective, about 28gm of Uranium releases as much amount of energy as is generated by 100 metric tonnes of coal.
3) Since they are required in small quantities, atomic materials can be easily transported to far-off places even at a global scale. Thus transportation is easy unless you are considering security part of it.
4) If nuclear power stations are operated up to their full capacity they can produce cheap electricity and gain from other benefits of Nuclear energy.
5) The quantity of nuclear waste produced is also small. Cons of this advantage are discussed in Disadvantages of Nuclear Energy.
6) It is a very reliable source of energy. The average life span of a nuclear reactor is approx. 40 years which can be extended up to 60 years.
7) Nuclear power stations are usually very compact compared to thermal stations.
8) Although the initial capital cost of building a nuclear plant is high, the maintenance and running costs are relatively low.
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In our discussion about advantages and disadvantages of solar energy, we have already discussed advantages of solar energy. Now lets take a look at disadvantages of solar energy.
However, this seemingly free source of energy is not free of cost in literal terms, let�s see how.
Too much exposure to sun rays can be harmful for the skin and may lead to skin problems. But the atmosphere acts as a sieve and removes a major part of the unwanted harmful rays of the sun. However, due to the global warming (caused due to release harmful gases into the atmosphere), the ozone layer has a hole in it now. Nature has provided us with all solutions to keep us safe and cozy, but it too demands care, or at least doesn�t want its own destruction. Utilizing its resources in the right manner is the only thing we can do. Over utilization has led us to a stage where we need to change the way we live and that comes at a huge monetary cost.
So, the choice is up to us. Whether we want to this big ball of fire to spoil our future for the present or refrain from harming the soil we have grown on, for a sustainable life.
Disadvantages of Solar Energy
1) Solar energy is mostly available in tropical and sub-tropical areas. The region with maximum Solar energy potential is lying between 50 degrees north and south of equator. As we move towards poles, proportion of solar energy received by earth goes on decreasing.
2) It is seasonal in nature and cannot be utilized during monsoon or when weather is cloudy.
3) The solar power technology is still at infant stage and is quite expensive.
4) Cost of installation of solar energy plant is very high.
5) During night it is not possible to produce Solar Energy.
6) Storage of this form of energy is difficult.
7) At present heavy machines are not possible to operate on this source.
8) Solar panels consume land, as power generation per unit square is low.
9) Silicon, used in production of SPV (Solar Photo Voltaic), is a pollutant.
10) Return of Investment(ROI) on solar energy takes around 3-5 years.
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Solar energy is energy that people can obtain for free. The sun produces energy every single day that is completely wasted, but now it can be used. By using a solar system, people can make use of the energy that the sun produces on a day to day basis. One of the most popular ways is to use photovoltaic cells in solar panels, that eventually are converted using a converter, into electricity.
Solar energy capturing has been done for a number of years. Nowadays there are extremely effective ways to do this, although the best is using solar panels. The solar panels absorb the rays from the sun, which creates energy. This energy can be easily converted into electricity to power the home. The great thing is, if there is any left, the owner can sell the electricity units to a utility supplier.
The main advantage of using solar energy rather than conventional energy resources is that they produce free energy. Instead of spending hundreds every month, people can now produce their own electricity for free. In fact, they can actually make money if they have extra energy to sell to utility suppliers.
There are a few barriers that stop a lot of people using solar energy. One of the major disadvantages and barriers of using solar energy is the fact that the upfront cost is extremely high. In many cases, it will cost thousands to produce and install a solar energy producing system, which means that a lot of people simply can not afford it.
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What is Biomass Energy?
Biomass means all materials which come from living organisms. For instance, waste material of plants and animals, wood, agricultural wastes, dead parts of plants and animals. Since all living organisms contain carbon compounds, biomass has energy stored in the form of chemical compounds. The method of harnessing energy from each one of them could be different. Direct burning of these materials generally causes pollution but could be the cheapest form of energy. Eg. Using wood or dried cow dung cakes as fuel generates a lot of smoke. However, if cow dung is used in biogas plant, clean fuel can be generated. Mostly in villages, all types of biomass are traditionally burnt directly to produce heat. And if modern methods are used, they can be utilized properly.
Lets talk about advantages and disadvantages of biomass energy.
Advantages of Biomass Energy
1) It�s a renewable source of energy.
2) It�s a comparatively lesser pollution generating energy.
3) Biomass energy helps in cleanliness in villages and cities.
4) It provides manure for the agriculture and gardens.
5) There is tremendous potential to generate biogas energy.
6) Biomass energy is relatively cheaper and reliable.
7) It can be generated from everyday human and animal wastes, vegetable and agriculture left-over etc.
8) Recycling of waste reduces pollution and spread of diseases.
9) Heat energy that one gets from biogas is 3.5 times the heat from burning wood.
10) Because of more heat produced the time required for cooking is lesser.
11) Pressure on the surrounding forest and scrubs can be reduced when biogas is used as cooking fuel.
12) It is a more cost effective means of acquiring energy as compared to oil supplies. As oil supplies are getting depleted day by day, it is becoming a costly commodity.
13) Growing biomass crops use up carbon dioxide and produces oxygen.
Disadvantages of Biomass Energy
1) Cost of construction of biogas plant is high, so only rich people can use it.
2) Continuous supply of biomass is required to generate biomass energy.
3) Some people don�t like to cook food on biogas produced from sewage waste.
4) Biogas plant requires space and produces dirty smell.
5) Due to improper construction many biogas plants are working inefficiently.
6) It is difficult to store biogas in cylinders.
7) Transportation of biogas through pipe over long distances is difficult.
8) Many easily grown grains like corn, wheat are being used to make ethanol. This can have bad consequences if too much of food crop is diverted for use as fuel.
9) Crops which are used to produce biomass energy are seasonal and are not available over whole year.
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Tidal Energy : Introduction
Tides are the waves caused due to the gravitational pull of the moon and also sun(though its pull is very low). The rise is called high tide and fall is called low tide. This building up and receding of waves happens twice a day and causes enormous movement of water. It is so powerful that it has caused many mishaps and resulted in sinking of ships. Thus tidal energy forms a large source of energy and can be harnessed in some of the coastal areas of the world. Tidal dams are built near shores for this purpose. During high tide, the water flows into the dam and during low tide, water flows out which result in turning the turbine.
Lets now discuss the advantages and disadvantages of tidal energy.
Advantages of Tidal Energy
1) It is an inexhaustible source of energy.
2) Tidal energy is environment friendly energy and doesn�t produce greenhouse gases.
3) As 71% of Earth�s surface is covered by water, there is scope to generate this energy on large scale.
4) We can predict the rise and fall of tides as they follow cyclic fashion.
5) Efficiency of tidal power is far greater as compared to coal, solar or wind energy. Its efficiency is around 80%.
6) Although cost of construction of tidal power is high but maintenance costs are relatively low.
7) Tidal Energy doesn�t require any kind of fuel to run.
8) The life of tidal energy power plant is very long.
9) The energy density of tidal energy is relatively higher than other renewable energy sources.
Disadvantages of Tidal Energy
1) Cost of construction of tidal power plant is high.
2) There are very few ideal locations for construction of plant and they too are localized to coastal regions only.
3) Intensity of sea waves is unpredictable and there can be damage to power generation units.
4) Influences aquatic life adversely and can disrupt migration of fish.
5) The actual generation is for a short period of time. The tides only happen twice a day so electricity can be produced only for that time.
6) Frozen sea, low or weak tides, straight shorelines, low tidal rise or fall are some of the obstructions.
7) This technology is still not cost effective and more technological advancements are required to make it commercially viable.
8) Usually the places where tidal energy is produced are far away from the places where it is consumed. This transmission is expensive and difficult.
Tidal Energy is thus a clean source of energy and doesn�t require much land or other resources as in harnessing energy from other sources. However, the energy generated is not much as high and low tides occur only twice a day and continuous energy production is not possible.
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Ocean wave energy can be captured directly from surface waves. Blowing wind and pressure fluctuations below the surface are the main reasons for causing waves. But consistency of waves differs from one area of ocean to another. Some regions of oceans receive waves with enough uniformity and force. Ocean waves contain tremendous energy. Currently scientists and companies are considering exploiting the wave power of oceans to harness clean and green energy.
ANSYS Inc is a global trend setter of simulation software and technologies. Recently it has developed software that is assisting in converting the persistent forces of ocean waves into electricity. Green Ocean Energy Ltd is an Aberdeen based renewable energy company. Their mission is to create and innovate in the field of clean and green energy. They are developing mechanisms to harness energy from the Earth�s oceans. They are also focusing on other facts such as the economic viability and sustainability of their products.
Green Ocean Energy has produced two innovative devices � Ocean Treader and Wave Treader. These devices will move on the ocean surface in a manner as if someone is nodding, these up and down movements of the arms will help in generating power.
It is estimated that each machine will produce around 500KW of electrical power. This power can be transported to the shore with the aid of underwater cables. This amount of electricity can be utilized by about 125 homes. Wave power farms can be established to generate any required amount of power.
Ocean Treader is a floating device. It will be tied up 1 � 2 miles offshore in ocean wave systems. It will not pose any obstruction on the shoreline. The theory has been put to test in wave tank. Now the company is producing a full size machine for offshore testing.
Wave Treader has grown out of our work with Ocean Treader. Wave Treader uses its Sponsons and Arms and are mounted on the base of a static offshore structure. That structure can be a Wind Turbine or Tidal Turbine. By sharing the high infrastructure costs with another device, such as the foundation costs, cabling costs, etc., the economics of both devices are enhanced and the energy yield for a given sea area greatly improved.
Green Ocean Energy has receives a noteworthy boost to the development of its wave power technology after managing �100,000 of funding from the Scottish Enterprise Seed Fund. They have also secured �150,000 of private investment. Graeme Bell, Special Projects Director at Green Ocean Energy said: �We are delighted to receive this support from Scottish Enterprise. The funding will enable the company to take a major step forward and begin detailed engineering and design of a full scale Wave Treader. It�s been an exciting time for the company and we�re enjoying a fantastic level of interest in our activities.�
This financial support will enable the company to continue the engineering and testing of its ground breaking Wave Treader device. This device is affixed to the transition piece of an offshore wind turbine thereby providing combined wind and wave energy.
It is expected that manufacture of a full scale prototype will start next year once an appropriate site has been acknowledged with deployment in early 2011. Commercialization is expected to being in 2012.
Sumber : http://www.alternative-energy-news.info/
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