In modern western world the demand for energy has increased dramatically in the past century and it will grow even further and harder in the near future than ever before. The need for energy rises with upcoming markets that also need more energy. Energy is needed for cars, buses, and other means of transportation, but also to run our appliances and provides us light. Energy is also important for our safety. At night or in the dark a lot can be stolen without proper lightning. Energy is therefore needed for our development and safety.

The way we use energy today comes from knowledge that has it’s foundations in the past century and before. Great men like Newton and Philips have set the path for us today to make proper use of energy. The sources which we use for our energy demand are known as non-renewable energy resources. These sources will be discussed here in the article.

Definition of Non-Renewable Energy Resources

The name really explains it very well. Non-renewable energy resources are natural resources that cannot be recycled or re-grown. These natural resources are fossil fuels like coal, petroleum, and natural gas. It also includes mined resources such as the elements used in the production of electricity (uranium and plutonium, for instance). These resources replenish itself in a quicker rate.

Fossil fuels are very versatile. One of their functions is to generate electricity. In order to generate electricity, fossil fuels are burned through the process of combustion. The energy produced from the combustion process is used to power a turbine. The turbine is responsible for the conversion of energy produced from combusted fossil fuels into electricity.

Coal

Coal is one the most used fossil fuels. It is consider too be the most important energy source to produce electricity. The U.S. produces 50% of its energy supply through the combustion of coal. The coal itself is a brownish-black sedimentary rock which contains carbon and other assorted elements. It is extracted from the ground through underground mining or open-pit mining.

Natural Gas

Natural gas is also used to produce electricity. The electricity is produced through steam turbines and gas turbines. Because the gas contains methane the combustion emits less harmful gasses that have a negative effect on global warming. Thus natural gasses are better for the environment compared to petroleum and coal.

There is also another use for it and that is as fuel for cars. It is much cheaper that gasoline and produces less harmful gasses. The disadvantage of running your car on natural gas is that you need more fuel compared to gasoline and the car needs more maintenance. In countries like Argentina, Brazil, Pakistan, Italy, The Netherlands and India it is used as a fuel for cars.

Crude oil

This fuel is the most talk about for the past year(s). The prices for crude oil have gone through the roof and will be rising even more. The demand is increasing while there is less crude oil available. The term black gold is now more applicable than ever before.
The oil itself is very think in consistency and has a dark brown or greenish colour characteristic. It is a complex mixture of different hydrocarbons.
Crude oil or petroleum has various uses. It can be used as fuel or cars and different industrial machines. It is also used as a raw material for products like plastics, solvents, fertilizers and pesticides.
Although the need for crude oil is high and the demand is rising the available crude oil is decreasing. That leaves us no other option than to look for alternatives.

Non-renewable energy plays a very important role in our daily lives. Non-renewable energy will be needed today and in the future. Because this energy source cannot be recycled or re-grown the reserves are limited. The consequences of the shortages of fossil fuels are experienced today and tomorrow. We will need to use these fossil fuels wisely and will need to shift our focus to other renewable energy source. These are the sources that we need to focus on today and years to come.

Bryan Wong
http://www.articlesbase.com/environment-articles/renewable-energy-resources-versus-fossil-fuels-50132.html

It is no secret that the sun can be harnessed to provide a source of energy for homes and businesses.

The sun is a powerful star. It supplies us with energy, through a process called nuclear fusion, and sustains life on our planet Earth. Solar energy, or energy from the sun, has existed since prehistoric times when men would magnify the sun’s energy in efforts to start fires.

The sun is a valuable resource that radiates enough energy on the United States in one day to meet the nation’s needs for one and a half years. Since it is a free, clean and renewable source of energy, it is an energy source that will play a vital role in our future.

Using the sun’s energy for our energy source seems like an easy solution to having an energy supply forever. Harnessing the suns energy is where the problem lies. The sun’s rays shine all over the world and not in just one spot. Although it takes only 8 minutes for sunlight to travel to the earth, trying to catch the rays over such a wide area can prove to be tricky. Also, the energy in any one given place will vary due to factors, such as, clouds and weather conditions.

The history of using solar energy began in 1890’s when solar water heaters were used in the United States. Solar water heating requires a storage collector and a storage tank. Flat plate solar collectors are mounted on rooftops. Pipes carrying water are pumped through these collectors. The tubes are painted black so they will get hot quicker. As the heat is collected the fluid in the tubes get heated. A storage tank holds the hot liquid. This helps with central heating and cutting fuel costs. Solar heaters became popular when natural gas was expensive and burning wood and coals were burdensome. It’s popularity diminished with the discovery of an abundance of natural gas and oil deposits. Now they are making a comeback to replace the depleting fossil fuels that had taken its place.

Solar energy can be in the form of heat energy or light energy. The technology of photovoltaic, or PV as it is commonly called, converts the suns energy into electric currents through the use of solar cells. These electric currents can be used instantaneously or stored for later use. The PV cells consist of pieces of silicon under a thin piece of glass. They have both a positive and negative charge. Simple examples of this are the solar powered calculators that are common today. More complex examples are solar panels placed on roofs. This consists of using thin film solar cells as rooftop shingles, roof tiles, and even glazing for skylights. Unfortunately, the cells generate only about one sixth of the sun’s energy into electricity. This means bigger arrays are needed and along with this come larger costs.

Solar thermal power plants use the sun to heat fluid, which in turn, is transferred into steam similar to fossil fuel burning plants. The steam is transformed into mechanical energy in a turbine and electrical energy from a generator. The downfall is solar plants cannot produce energy on cloudy days.

It is expected the next few years will see millions of households using solar energy. As research continues and processes improve, using our sun as a renewable energy source will produce efficiency and cost savings. So, let the sun shine in and take full advantage of this warm energy source where you live.

Matthew Hick
http://www.articlesbase.com/environment-articles/solar-renewable-energy-sun-power-103549.html

The heat of the Earth makes up what is known as geothermal energy. When dust and gasses from Earth mixed together 4 billion years ago, geothermal energy resulted.

Inside the Earth at its core, some 4, 000 miles deep, the temperature is estimated at about 9,000 degrees Fahrenheit. Geothermal energy has been used throughout history for bathing, relaxing, cooking and heating. It was thought by some to have healing effects and was used to treat eye and skin diseases. The first geothermal generator that produced energy was built in Lardarello, Italy in 1904. The United States followed with their first attempt at geothermal power in 1912 at The Geysers in California. Today it is produced in twenty-one countries around the world.

Geothermal energy is located deep in the ground. The heat at the core of the Earth has an outward flow. As it moves, it is transferred to surrounding rock layers called the mantle. As temperatures and pressure increase, the rock melts and becomes magma. The magma moves toward the surface of the earth carrying the heat with it. If the magma reaches the Earth’s surface, it becomes lava. However, most of it stays below the Earth’s crust and heats rocks and water that surround it. These temperatures can reach up to 700 degrees Fahrenheit. When the water travels to the Earth’s surface, it becomes hot springs or geysers. Mostly it stays trapped in fractured, porous rocks called geothermal reservoirs. This heat near the Earth’s surface becomes a form of energy.

Hot water or steam from the reservoir exerts a force that can spin a turbine connected to a generator and produces electricity. The cooled water is then returned to the reservoir in order for it to reheat. Much exploration and testing needs to be done to determine where the geothermal underground waters are. When ideal spots are located, drilling is done to create production wells that bring the water to the Earth’s surface for power generation in geothermal power plants.

Although the costs to construct geothermal plants and geothermal wells are high, the cost of producing electricity is lower over time. The fuel is reliable, stable and does not need to be transported. The white smoke you will see over geothermal power plants is not smoke but rather steam. During the process of operations it may, however, bring some hazardous gases from underground.

The United States stands as the biggest producer of geothermal energy. Unfortunately, interest in it is low and it only accounts for about 1% of this country’s energy supply. Through research and experience new methods and technologies for accessing geothermal energy will improve. Tapping into the heat under the Earth’s surface can produce much more of the nations energy. We are at a point where renewable energy sources must make their way to the forefront of the energy picture. Not only are fossil fuels being depleted, but also they are ruining our air quality. In time, geothermal energy may become an appealing alternative. Competitive pricing and minimal environmental impact could produce a hot future for this renewable energy source.

Matthew Hick
http://www.articlesbase.com/environment-articles/geothermal-renewable-energy-the-earth-109677.html

As a homeowner, you may be using renewable energy sources. Let’s look at a few of these important, powerful sources.

If you use solar powered lights to brighten your walkway, a solar cover on your swimming pool or hang your clothes out to dry, you are already making use of the sun’s renewable energy. There are many other renewable energy home options you can take advantage of, and by doing so, help preserve our environment.

The most practical of renewable energy options for the home consist of space heating and domestic hot water. This is over 50% of a household’s energy usage. In using renewable energy we can experience cost saving benefits.

Perhaps the best way to take advantage of renewable energy home options is when designing a new house. A southern wall taking advantage of an appropriate amount of windows can take full use of the low sun in the winter. Adding a roof overhang over these windows allow the higher summer sun to be blocked. Also, on a cool day you can open your windows to let a breeze cool off the house and make use of wind energy. You have achieved adding heat in the winter and coolness in the summer, thereby lowering your heating and cooling costs naturally. This is called passive solar heating since it is integrated with no extra costs. You can also do day lighting by taking full advantage of the sunlight during the day to take care of your daytime lighting needs.

Wood stoves can also be advantageous, if using only dead wood, diseased wood or small pellets made from wood chips, crop waste and other organic material for burning. This is a renewable source of heat through the use of space heating. Modern wood burning stoves are highly efficient, making it a more practical option.

A homeowner can also utilize active solar heating. A solar water heater can use renewable solar energy to heat water for a house. This would use solar collector panels placed on a roof. Water runs through pipes under these panels and is heated by the sun. The water travels to a water tank in your home for your use. Electricity can also be produced for a home using the photovoltaic technology. This runs on the same idea as a solar calculator. Solar electricity is ideal for rural homes where it would be difficult to run an electric line to.

Geothermal heat pumps use the heat from the Earth to move heat from one area to another. This system uses a series of underground pipes to move a heat exchange fluid. The heat pump moves this fluid, heated from the earth and transfers it to buildings for use. Initial installation costs are much the same as traditional heating systems, but operational costs are lower.

If you live in a windy part of the country and have quite a bit of land, wind can power a wind turbine to produce electricity for your household. But your location must be ideal to catch wind and you must be able to capture a certain amount for this to work.

These are some home options for renewable energy sources. By trying to utilize some of them we are preparing for our future by using clean energy that does not affect air quality or harm the environment.

Matthew Hick
http://www.articlesbase.com/environment-articles/renewable-energy-practical-home-options-107249.html

Ken Daniel, of Security Advisors Worldwide, or SAW, a renewable energy security advisory company contracted by Jetstream Wind, Inc. recently returned from the island of Haiti.    

I understand that you and Security Advisors Worldwide had a very successful trip to Haiti.  There doesn’t seem to be a great deal of media coming from this nation as to the daily lives of Haitians, the environmental issues they face, or the energy issues they’re looking at.

So that we can have a better picture, can you begin by talking about what it’s like for average citizens in Haiti on any given day?

Mr. Ken Daniel: 

On an average morning in Haiti, people there don’t wake up to the possibility of electricity like we do here. They pretty much use coal to warm themselves in the morning. There also aren’t the refrigeration capabilities like here in the states, so they walk to the market everyday to get whatever food they can prepare and eat that given day.

As far as the issue of water goes, in the capitol of Port-au-Prince there was some running water, and I would see people on the exteriors of buildings filling up their water containers. But out in the rural areas, it’s more difficult and being pumped out of wells.

Along the roadways are fifty-five gallon plastic drums filled with water. Haitian citizens basically walk some distances to these to get their daily water since there aren’t many vehicles owned by private citizens.

There’s obviously not a large availability of electricity in Haiti, which seems odd in this day and age. Where does this issue stem from?

Ken: 

There’s a hydro-plant that rests in-between Port-au-Prince and Hesh. It was actually built by Americans in the early part of the last century and has been around for a very long time. Put simply, it’s just old and doesn’t kick out enough power.

All of the power lines that we take for granted here in the US, actually have cobwebs growing on them in Haiti. And then, with the bad weather, hurricanes and such, there were numerous poles leaning at 45 degree angles with wires coming out of them.

The only real power was in the capitol of Port-au-Prince and it goes off regularly. Mostly though, what I saw were people with candles and bags of coal to cook their food. Really, unless you are a person with a little bit of money and can afford to be affluent, you can’t rely on the comfort of being able to depend on electricity.

With the hurricane situation, the lack of food and good shelter, renewable energy quite possibly could be the key to bringing in some the needed electricity to help with the situation.

This would be the first renewable energy technology being developed on an island, which is monumental. Would it be more difficult creating wind, solar, or hydrogen power on an island in the middle of the ocean as opposed to it being developed on a mainland?

Ken: 

In this particular place, almost everything that is needed can literally be brought to the land. With hydrogen technology for example, an area of land is cleared where it won’t require much manipulation as this technology is easily able to be placed. An added benefit to that is there won’t be any deforestation.

With solar technology, another small piece of land within a vast spread of land is cleared and the technology placed upon it. Lines won’t have to be ran over long expanses of land for fuels, diesel, or natural gas. There won’t ever be an oil spill or pipes in the ground that corrode.

So it doesn’t seem to be too difficult. Exporting equipment out of the United States and importing to an island would be the main issue to be dealt with. Jetstream Wind would have to look at building an airstrip so that they can cargo fly equipment in. Most building materials would have to be imported from the U.S., which is 300 miles off the coast of Miami, and would either come in by cargo plane or shipped in by sea.

It would be a benefit to take the time and see if there was anything available on the island that can readily be used, salvaged and recycled.

The terrain in Haiti (being an island) is more than acceptable. There are mountains, which means the wind is constantly blowing across them. There’s plenty of sunshine shining on the hills that are vast, rounded and able to be navigated. Even the new hydrogen technology can easily be implemented there.

If Haiti were to bring renewable energy in, it could be put anywhere. It wouldn’t have to be placed in a major metropolitan area, and the power from the renewable energy plant(s) could run to the pre-existing grid. The hope would be, however that Haiti itself would help to re-build the infrastructure so that all of this power could get to the homes, schools, hospitals, businesses and other places where electricity is vitally needed.

The truth is that they would have to wait far longer to get any other type of an energy program in, such as coal for example. There are also some pretty severe issues with deforestation happening at present, and so I would think that renewable energy is really the only way to go for Haiti right now.

Looking at the environmental impact of renewable energy on Haiti, would you say that there would be any, at all, created from this technology?

Ken: 

As compared to a coal-fired plant here in the United States, no, other than having to clear small pieces of land to put things on.

There are many countries that simply have to have energy right now, and this is by far the cleanest way to get it. Nuclear is not the answer. It leaves a long-standing residue as a result of that power. Natural gas and coal also lead to numerous environmental concerns.

The fact is that we can’t rely on oil for our needs any longer and I don’t want to see any more damaging changes in the land. This won’t. And the residue from this technology won’t be a bigger burden for the Earth. What’s cleaner than water?

But it really doesn’t matter what country it’s in as far as getting the renewables to work for people. It’s the technology that Jetstream Wind has that hits the central point of this whole thing. In other words, if the technology can get there and the transmission lines can get ran, then this can work almost anywhere.

Working through the issues of basic infrastructure, transmission, politics, and environment, a company like Jetstream Wind is the right answer for those people.

Did the Haitian government welcome you and the possibility of a Jetstream Wind collaboration?

Ken: 

Yes. I was treated very well. I was able to meet with the US Ambassador to Haiti, the advisor to the President of Haiti, several Prime Ministers, and the necessary others that would become involved should we all come together and build a renewable plant there.

Other than simple barriers with the French-Creole language, it was a very successful meeting and everyone was excited. It went from one meeting to five or six, with them wanting me to speak with as many leaders as possible in my short time there.

This is a major project of which Jetstream Wind would probably want to share some sort of responsibility. How deeply would the country of Haiti be involved and responsible in re-powering their nation?

Ken: 

The United States created a bailout for the auto industry. The country of Haiti will possibly need to create a financial bailout for their energy problem. They’re probably going to have to put some money into the system to start readying themselves for this type of project.

Having the years of experience in large military operations, I’ve learned to back-plan for anything. In other words, I can see the end result, but before I can get there I have to first go all the way back to where it begins. It begins by asking questions…a lot of them.

In order for renewable energy to be a reality in Haiti, the Haitian government has to ask themselves some questions so that Jetstream Wind and Security Advisors Worldwide can do our jobs.

How will they find the necessary people needed for this large of a project? How will they train these people? Where are the people located and where is the transportation going to come from to move these people? How will they communicate?

There is a lot of work to be done from taking out old transmission lines and putting in new ones, to breaking ground on the energy plant itself. Power poles will be placed on every block. New construction companies will be built, taking into account everything that goes with that including the huge amount of labor needed.

We can also take into account the education necessary to work with a project of this type, creating a national boost in knowledge. Anything from taking down a power line to managing a company with the large workforce will have to be covered.

It’s not only about the end result of the plant supplying renewable energy to the people. It also includes the entire scope of the process beginning with Haiti’s choice and ability to prepare for it.

In seeing the potential, meeting the representatives, and observing the culture, what is the one thing that you come back with?

Ken: 

I come back with the insight that the country of Haiti is only a two and half hour flight from Miami. It’s not so far away that we can’t touch it with our assistance.

Little kids are walking distances, carrying the water they needed for the day. You have to remember we as a human race have also been to the moon. We’re building a space station. How is it possible that an island, so close to the United States is in the situation it is?

This has the capacity of creating and developing a whole new job infrastructure and economy. It is a prime example of renewable energy quickly effecting the situation for the better.

The capability is there to get it done. The land is there, the people are motivated, and the technology is ready to go. With the help of the Haitians in getting the infrastructure ready, a whole new way of life can arise from this for the people of Haiti, and also the same possibility for other people and nations all over the world.

What strikes me the most from our conversation about renewable energy is its ability to cross borders, boundaries, cultures, political policies, and even world religions without leaving heavy footprints of various unwanted agendas.  

Thank you once again, Ken, for sharing this information showing how people and technology can come together to create a clean, economically stable world for our future and our children’s futures. 

Click here if you would like more information about Security Advisors Worldwide (SAW).

Ornesha  De Paoli

Green Ascension ~ Evolving People on an Evolving Planet

Ornesha De Paoli
http://www.articlesbase.com/news-and-society-articles/can-renewable-energy-power-islands-like-haiti-705671.html

Renewable energy

Renewable energy sources worldwide at the end of 2006.

Renewable energy is energy generated from natural resources—such as sunlight, wind, rain, tides, and geothermal heat — which are renewable (naturally replenished). In 2006, about 18% of global final energy consumption came from renewables, with 13% coming from traditional biomass, such as wood-burning.Hydroelectricity was the next largest renewable source, providing 3% (15% of global electricity generaiton), followed by solar hot water /heating, which contributed 1.3%. Modern technologies, such as geothermal energy, wind power, solar power and ocean energy together provided some 0.8% of final energy consumption.

Climate change concerns coupled with high oil prices, peak oil and increasing government support are driving increasing renewable energy legislation, incentives and commercialization.European Union leaders reached an agreement in principle in March 2007 that 20 percent of their nations’ energy should be produced from renewable fuels by 2020, as part of its drive to cut emissions of carbon dioxide, blamed in part for global warming. Investment capital flowing into renewable energy climbed from $80 billion in 2005 to a record $100 billion in 2006.

In responce to the G8’s call on the IEA for “guidance on how to achieve a clean, clever and competitive energy future”, the IEA reported that the replacement of current technology with renewable energy could help reduce CO2 emmisions by 50% by 2050, which they claim is of crucial importance because current policies are not sustainable.

Wind power is growing at the rate of 30 percent annually, with a worldwide installed capacity of over 100 GW, and is widely used in several European countries and the United States. The manufacturing output of the photovoltaics industry reached more than 2,000 MW in 2006, and photovoltaic (PV) power stations are particularly popular in Germany. Solar thermal power stations operate in the USA and Spain, and the largest of these is the 354 MW SEGS power plant in the Mojave Desert. The world’s largest geothermal power installation is The Gevsers in California, with a rated capacity of 750 MW. Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18 percent of the country’s automotive fuel. Ethanol fuel is also widely available in the USA.

While there are many large-scale renewable energy projects and production, renewable technologies are also suited to small off-grid applications, sometimes in rural and remote areas, where energy is often crucial in human development. Kenya has the world’s highest household solar ownership rate with roughly 30,000 small (20–100 watt) solar power systems sold per year.

Some renewable energy technologies are criticised for being intermittent or unsightly, yet the market is growing for many forms of renewable energy.

Main renewable energy technologies

Three energy sources

The majority of renewable energy technologies are directly or indirectly powered by the sun. The Earth-Atmosphere system is in equilibrium such that heat radiation into space is equal to incoming solar radiation, the resulting level of energy within the Earth-Atmosphere system can roughly be described as the Earth’s “climate.” The hydrosphere (water) absorbs a major fraction of the incoming radiation. Most radiation is absorbed at low latitudes around the equator, but this energy is dissipated around the globe in the form of winds and ocean currents. Wave motion may play a role in the process of transferring mechanical energy between the atmosphere and the ocean through wind stress. Solar energy is also responsible for the distribution of precipitation which is tapped by hydroelectric projects, and for the growth of plants used to create biofuels.

Renewable energy flows involve natural phenomena such as sunlight, wind, tides and geothermal heat, as the International Energy Agency explains:

“Renewable energy is derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources.”

Each of these sources has unique characteristics which influence how and where they are used.

Wind power

 Vestas V80 wind turbines

Airflows can be used to run wind turbines. Modern wind turbines range from around 600 kW to 5 MW of rated power, although turbines with rated output of 1.5–3 MW have become the most common for commercial use; the power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases dramatically. Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms.

Since wind speed is not constant, a wind farm’s annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. Typical capacity factors are 20-40%, with values at the upper end of the range in particularly favourable sites. For example, a 1 megawatt turbine with a capacity factor of 35% will not produce 8,760 megawatt-hours in a year, but only 0.35×24x365 = 3,066 MWh, averaging to 0.35 MW. Online data is available for some locations and the capacity factor can be calculated from the yearly output.

Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand. This could require large amounts of land to be used for wind turbines, particularly in areas of higher wind resources. Offshore resources experience mean wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more energy. This number could also increase with higher altitude ground-based or airborne wind turbines.

Wind power is renewable and produces no greenhouse gases during operation, such as carbon dioxdie and methane.

Water power

Energy in water (in the form of kinetic energy, temperature differences or salinity gradients) can be harnessed and used. Since water is about 800 times denser than air, even a slow flowing stream of water, or moderate sea swell, can yield considerable amounts of energy.

One of 3 PELAMIS P-750 Ocean Wave Power engines in the harbour of Peniche/ Portugal.

There are many forms of water energy:

·         Hydroelectric energy is a term usually reserved for large-scale hydroelectric dams. Examples are the Grand Coulee Dam in Washington State and the Akosombo Dam in Ghana.

·         Micro hydro systems are hydroelectric power installations that typically produce up to 100 kW of power. They are often used in water rich areas as a Remote Area Power Supply (RAPS). There are many of these installations around the world, including several delivering around 50 kW in the Solomon Islands.

·         Damless hydro systems derive kinetic energy from rivers and oceans without using a dam.

·         Ocean energy  describes all the technologies to harness energy from the ocean and the sea:

o   Marine current power. Similar to tidal stream power, uses the kinetic energy of marine currents

o   Ocean thermal energy  conversion (OTEC) uses the temperature difference between the warmer surface of the ocean and the colder lower recesses. To this end, it employs a cyclic heat engine. OTEC has not been field-tested on a large scale.

o   Tidal power captures energy from the tides. Two different principles for generating energy from the tides are used at the moment:

o   Tidal motion in the vertical direction — Tides come in, raise water levels in a basin, and tides roll out. Around low tide, the water in the basin is discharged through a turbine, exploiting the stored potential energy.

o   Tidal motion in the horizontal direction — Or tidal stream power. Using tidal stream generators, like wind turbines but then in a tidal stream. Due to the high density of water, about eight-hundred times the density of air, tidal currents can have a lot of kinetic energy. Several commercial prototypes have been build, and more are in development.

·         Wave power  uses the energy in waves. Wave power machines usually take the form of floating or neutrally buoyant structures which move relative to one another or to a fixed point. Wave power has now reached commercialization.

·         Saline gradient power,  or osmotic power, is the energy retrieved from the difference in the salt concentration between seawater and river water. Reverse electrodialysis (RED), and Pressure retarded osmosis (PRO) is in research and testing phase.

·         Deep lake water cooling,  although not technically an energy generation method, can save a lot of energy in summer. It uses submerged pipes as a heat sink for climate control systems. Lake-bottom water is a year-round local constant of about 4 °C.

Solar energy use

Monocrystalline solar cell

In this context, “solar energy” refers to energy that is collected from sunlight. Solar energy can be applied in many ways, including to:

•           Generate electricity by heating trapped air which rotates turbines in a Solar updraft tower.

•           Generate electricity in geosynchronous orbit using solar power satellites.

•           Generate electricity using photovoltaic solar cells.

•           Generate electricity using concentrated solar power.

•           Generate hydrogen using photoelectrochemical cells.

•           Heat and cool air through use of solar chimneys.

•           Heat buildings, directly, through passive solar building design.

•           Heat foodstuffs, through solar ovens.

•           Heat water or air for domestic hot water and space heating needs using solar-thermal panels.

•           Solar air conditioning

Biofuel

Plants use photosynthesis to grow and produce biomass. Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel, ethanol and bagasse (often a by-product of sugar cane cultivation) can be burned in internal combustion engines or boilers. Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work.

Liquid biofuel

Information on pump, California.

Liquid biofuel is usually either a bioalcohol such as ethanol fuel or a bio-oil such as biodiesel and straight vegetable oil. Biodiesel can be used in modern diesel vehicles with little or no modification to the engine and can be made from waste and virgin vegetable and animal oil and fats (lipids). Virgin vegetable oils can be used in modified diesel engines. In fact the Diesel engine was originally designed to run on vegetable oil rather than fossil fuel. A major benefit of biodiesel is lower emissions. The use of biodiesel reduces emission of carbon monoxide and other hydrocarbons by 20 to 40%.

In some areas corn, cornstalks, sugarbeets, sugar cane, and switchgrasses are grown specifically to produce ethanol (also known as grain alcohol) a liquid which can be used in internal combustion engines and fuel cells. Ethanol is being phased into the current energy infrastructure. E85 is a fuel composed of 85% ethanol and 15% gasoline that is sold to consumers. Biobutanol is being developed as an alternative to bioethanol. There is growing international criticism about biofuels from food crops with respect to issues such as food security, environmental impacts (deforestation) and energy balance.

Solid biomass

Sugar cane  residue can be used as a biofuel

Solid biomass is mostly commonly usually used directly as a combustible fuel, producing 10-20 MJ/kg of heat.

Its forms and sources include wood fuel,  the biogenic portion of municipal solid waste, or the unused portion of field crops. Field crops may or may not be grown intentionally as an energy crop,  and the remaining plant byproduct used as a fuel. Most types of biomass contain energy. Even cow manure still contains two-thirds of the original energy consumed by the cow. Energy harvesting via a bioreactor is a cost-effective solution to the waste disposal issues faced by the dairy farmer, and can produce enough biogas to run a farm.

With current technology, it is not ideally suited for use as a transportation fuel. Most transportation vehicles require power sources with high power density, such as that provided by internal combustion engines. These engines generally require clean burning fuels, which are generally in liquid form, and to a lesser extent, compressed gaseous phase. Liquids are more portable because they have high energy density, and they can be pumped, which makes handling easier. This is why most transportation fuels are liquids.

Non-transportation applications can usually tolerate the low power-density of external combustion engines, that can run directly on less-expensive solid biomass fuel, for combined heat and power. One type of biomass is wood, which has been used for millennia in varying quantities, and more recently is finding increased use. Two billion people currently cook every day, and heat their homes in the winter by burning biomass, which is a major contributor to man-made climate change global warming. The black soot that is being carried from Asia to polar ice caps is causing them to melt faster in the summer. In the 19th century, wood-fired steam engines were common, contributing significantly to industrial revolution unhealthy air pollution. Coal is a form of biomass that has been compressed over millennia to produce a non-renewable, highly-polluting fossil fuel.

Wood and its byproducts can now be converted through process such as gasification into biofuels such as woodgas, biogas,  methanol or ethanol fuel; although further development may be required to make these methods affordable and practical. Sugar cane residue, wheat chaff, com cobs and other plant matter can be, and are, burned quite successfully. The net carbon dioxide emissions that are added to the atmosphere by this process are only from the fossil fuel that was consumed to plant, fertilize, harvest and transport the biomass.

Processes to harvest biomass from short-rotation poplars and willows, and perennial grasses such as switchgrass, phalaris, and miscanthus, require less frequent cultivation and less nitrogen than from typical annual crops. Pelletizing miscanthus and burning it to generate electricity is being studied and may be economically viable.

Biogas

Biogas can easily be produced from current waste streams, such as: paper production, sugar production, sewage, animal waste and so forth. These various waste streams have to be slurried together and allowed to naturally ferment, producing methane gas. This can be done by converting current sewage plants into biogas plants. When a biogas plant has extracted all the methane it can, the remains are sometimes better suitable as fertilizer than the original biomass.

Alternatively biogas can be produced via advanced waste processing systems such as mechanical biological treatment. These systems recover the recyclable elements of household waste and process the biodegradable fraction in anaerobic digesters.

Renewable natural gas is a biogas which has been upgraded to a quality similar to natural gas. By upgrading the quality to that of natural gas, it becomes possible to distribute the gas to the mass market via gas grid.

Geothermal energy

Krafla Geothermal Station in northeast Iceland

Geothermal energy is energy obtained by tapping the heat of the earth itself, usually from kilometers deep into the Earth’s crust. It is expensive to build a power station but operating costs are low resulting in low energy costs for suitable sites. Ultimately, this energy derives from heat in the Earth’s core. The government of Iceland states: “It should be stressed that the geothermal resource is not strictly renewable in the same sense as the hydro resource.” It estimates that Iceland’s geothermal energy could provide 1700 MW for over 100 years, compared to the current production of 140 MW. Radioactive elements in the earth’s crust continuously decay, replenishing the heat. The International Energy Agency classifies geothermal power as renewable.

Three types of power plants are used to generate power from geothermal energy: dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine that spins a generator. Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then separates the steam phase in steam/water separators and then runs the steam through a turbine. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine. The condensed steam and remaining geothermal fluid from all three types of plants are injected back into the hot rock to pick up more heat.

The geothermal energy from the core of the Earth is closer to the surface in some areas than in others. Where hot underground steam or water can be tapped and brought to the surface it may be used to generate electricity. Such geothermal power sources exist in certain geologically unstable parts of the world such as Chile, Iceland, New Zealand, United States, the Philippines and Italy. The two most prominent areas for this in the United States are in the Yellowstone basin and in northern California. Iceland produced 170 MW geothermal power and heated 86% of all houses in the year 2000 through geothermal energy. Some 8000 MW of capacity is operational in total.

There is also the potential to generate geothermal energy from hot dry rocks. Holes at least 3 km deep are drilled into the earth. Some of these holes pump water into the earth, while other holes pump hot water out. The heat resource consists of hot underground radiogenic granite rocks, which heat up when there is enough sediment between the rock and the earths surface. Several companies in Australia are exploring this technology.

Renewable energy commercialization

Costs

Source                         2001 energy costs                              Potential future energy cost

Electricity

Wind                           4–8 ¢/kWh                                                      3–10 ¢/kWh

Solar photovoltaic       25–160 ¢/kWh                                                            5–25 ¢/kWh

Solar thermal               12–34 ¢/kWh                                                  4–20 ¢/kWh

Large hydropower      2–10 ¢/kWh                                                    2–10 ¢/kWh

Small hydropower       2–12 ¢/kWh                                                    2–10 ¢/kWh

Geothermal                 2–10 ¢/kWh                                                    1–8 ¢/kWh

Biomass                       3–12 ¢/kWh                                                    4–10 ¢/kWh

Coal (comparison)       4 ¢/kWh         

Heat

Geothermal Heat         0.5–5 ¢/kWh                                                   0.5–5 ¢/kWh

Biomass — heat          1–6 ¢/kWh                                                      1–5 ¢/kWh

Low Temp Solar Heat 2–25 ¢/kWh                                                    2–10 ¢/kWh

All costs are in 2001 US$-cent per kilowatt-hour.

New generation of solar thermal plants

The 11 megawatt PS10 solar power tower in Spain produces electricity from the sun using 624 large movable mirrors called heliostats.

Aerial view of one of the SEGS plants.

Since 2004 there has been renewed interest in solar thermal power stations and two plants were completed during 2006/2007: the 64 MW Nevada Solar One and the 11 MW PS10 solar power tower in Spain. Three 50 MW trough plants were under construction in Spain at the end of 2007 with 10 additional 50 MW plants planned. In the United States, utilities in California and Florida have announced plans (or contracted for) at least eight new projects totaling more than 2,000 MW.

In developing countries, three world bank projects for integrated CSP/combined-cycle gas-turbine power plants in Egypt, Mexico, and Morocco were approved during 2006/2007.

There are several solar thermal power plant in the Mojave Desert which supply power to the electricity grid. Solar Energy Generating Systems (SEGS) is the name given to nine solar power plants in the Mojave Desert which were built in the 1980s. These plants have a combined capacity of 354 MW making them the largest solar power installation in the world.

World’s largest photovoltaic power plants

Several large photovoltaic power plants have been completed in Spain in 2008: the Parque Fotovoltaico Olmedilla de Alarcon (60 MW), Parque Solar Merida/Don Alvaro (30 MW), Planta solar Fuente Alamo (26 MW), Planta fotovoltaica de Lucainena de las Torres (23.2 MW), Parque Fotovoltaico Abertura Solar (23.1 MW), Parque Solar Hoya de Los Vincentes (23 MW), the Solarpark Calveron (21 MW), and the Planta Solar La Magascona (20 MW).

First Solar 40 MW PV Array installed by JUWI Group in Waldpolenz, Germany

Waldpolenz Solar Park, which will be the world’s largest thin-flim photovoltaic (PV) power system, is being built at a former military air base to the east of Leipzig in Germany. The power plant will be a 40-megawatt solar power system using state-of-the-art thin film technology, and should be finished by the end of 2009. 550,000 First Solar thin-film modules will be used, which will supply 40,000 MWh of electricity per year.

Topaz Solar Farm is a proposed 550 MW solar photovoltaic power plant which is to be built northwest of California Valley in the USA at a cost of over $1 billion. Built on 9.5 square miles (25 km2) of ranchland, the project would utilize thin-film PV panels designed and manufactured by OptiSolar in Hayward and Sacramento. The project would deliver approximately 1,100 gigawatt-hours (GWh) annually of renewable energy. The project is expected to begin construction in 2010, begin power delivery in 2011, and be fully operational by 2013.

High Plains Ranch  is a proposed 250 MW solar photovoltaic power plant which is to be built by Sun Power in the Carrizo Plain, northwest of California Valley.

However, when it comes to renewable energy systems and PV, it is not just large systems that matter. Building-Integrated Photovoltaics or “onsite” PV systems have the advantage of being matched to end use energy needs in terms of scale. So the energy is supplied close to where it is needed.

Environmental and social considerations

While most renewable energy sources do not produce pollution directly, the materials, industrial processes, and construction equipment used to create them may generate waste and pollution. Some renewable energy systems actually create environmental problems. For instance, older wind turbines can be hazardous to flying birds.

Land area required

Another environmental issue, particularly with biomass and biofuels, is the large amount of land required to harvest energy, which otherwise could be used for other purposes or left as undeveloped land. However, it should be pointed out that these fuels may reduce the need for harvesting non-renewable energy sources, such as vast strip-mined areas and slag mountains for coal, safety zones around nuclear plants, and hundreds of square miles being strip-mined for oil sands. These responses, however, do not account for the extremely high biodiversity and endemism of land used for ethanol crops, particularly sugar cane.

In the U.S., crops grown for biofuels are the most land- and water-intensive of the renewable energy sources. In 2005, about 12% of the nation’s corn crop (covering 11 million acres (45,000 km²) of farmland) was used to produce four billion gallons of ethanol—which equates to about 2% of annual U.S. gasoline consumption. For biofuels to make a much larger contribution to the energy economy, the industry will have to accelerate the development of new feedstocks, agricultural practices, and technologies that are more land and water efficient. Already, the efficiency of biofuels production has increased significantly and there are new methods to boost biofuel production.

Hydroelectric dams

The major advantage of hydroelectric systems is the elimination of the cost of fuel. Other advantages include longer life than fuel-fired generation, low operating costs, and the provision of facilities for water sports. Operation of pumped-storage plants improves the daily load factor of the generation system. Overall, hydroelectric power can be far less expensive than electricity generated from fossil fuels or nuclear energy, and areas with abundant hydroelectric power attract industry.

However, there are several major disadvantages of hydroelectric systems. These include: dislocation of people living where the reservoirs are planned, release of significant amounts of carbon dioxide at construction and flooding of the reservoir, disruption of aquatic ecosystems and birdlife, adverse impacts on the river environment, potential risks of sabotage and terrorism, and in rare cases catastrophic failure of the dam wall.

Hydroelectric power is now more difficult to site in developed nations because most major sites within these nations are either already being exploited or may be unavailable for other reasons such as environmental considerations.

Wind farms

Wind power  is one of the most environmentally friendly sources of renewable energy

A wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources:

•           It occupies less land area per kilowatt-hour (kWh) of electricity generated than any other energy conversion system, apart from rooftop solar energy, and is compatible with grazing and crops.

•           It generates the energy used in its construction in just 3 months of operation, yet its operational lifetime is 20–25 years.

•           Greenhouse gas emissions and air pollution produced by its construction are tiny and declining. There are no emissions or pollution produced by its operation.

•           In substituting for base-load coal power, wind power produces a net decrease in greenhouse gas emissions and air pollution, and a net increase in biodiversity.

•           Modern wind turbines are almost silent and rotate so slowly (in terms of revolutions per minute) that they are rarely a hazard to birds.

Studies of birds and offshore wind farms in Europe have found that there are very few bird collisions. Several offshore wind sites in Europe have been in areas heavily used by seabirds. Improvements in wind turbine design, including a much slower rate of rotation of the blades and a smooth tower base instead of perchable lattice towers, have helped reduce bird mortality at wind farms around the world. However older smaller wind turbines may be hazardous to flying birds. Birds are severely impacted by fossil fuel energy; examples include birds dying from exposure to oil spills, habitat loss from acid rain and mountaintop removal coal mining, and mercury poisoning.

Other issues

Sustainability

Renewable energy sources are generally sustainable in the sense that they cannot “run out” as well as in the sense that their environmental and social impacts are generally more benign than those of fossil. However, both biomass and geothermal energy require wise management if they are to be used in a sustainable manner. For all of the other renewables, almost any realistic rate of use would be unlikely to approach their rate of replenishment by nature.

Transmission

If renewable and distribution generation were to become widespread, electric power transmission and electricity distribution systems might no longer be the main distributors of electrical energy but would operate to balance the electricity needs of local communities. Those with surplus energy would sell to areas needing “top ups”. That is, network operation would require a shift from ‘passive management’ — where generators are hooked up and the system is operated to get electricity ‘downstream’ to the consumer — to ‘active management’, wherein generators are spread across a network and inputs and outputs need to be constantly monitored to ensure proper balancing occurs within the system. Some governments and regulators are moving to address this, though much remains to be done. One potential solution is the increased use of active management of electricity transmission and distribution networks. This will require significant changes in the way that such networks are operated.

However, on a smaller scale, use of renewable energy produced on site reduces burdens on electricity distribution systems. Current systems, while rarely economically efficient, have shown that an average household with an appropriately-sized solar panel array and energy storage system needs electricity from outside sources for only a few hours per week. By matching electricity supply to end-use needs, advocates of renewable energy and the soft energy path believe electricity systems will become smaller and easier to manage, rather than the opposite.

Controversy over nuclear power as a renewable energy source

In 1983, physicist Bernard Cohen proposed that uranium is effectively inexhaustible, and could therefore be considered a renewable source of energy. He claims that fast breeder reactors, fueled by uranium extracted from seawater, could supply energy at least as long as the sun’s expected remaining lifespan of five billion years. Nuclear energy has also been referred to as “renewable” by the politicians George W. Bush, Charlie Crist,  and David Sainsbury.

Inclusion under the “renewable energy” classification could render nuclear power projects eligible for development aid under various jurisdictions. However, it has not been established that nuclear energy is inexhaustible, and issues such as peak uranium and uranium depletion are ongoing debates. No legislative body has yet included nuclear energy under any legal definition of “renewable energy sources” for provision of development support. Similarly, statutory and scientific definitions of renewable energies usually exclude nuclear energy. Commonly sourced definitions of renewable energy sources often omit or explicitly exclude nuclear energy sources as examples.Nuclear fission is not regarded as renewable by the U.S. DOE on the website “What is Energy?”

There are also environmental concerns over nuclear power, including the dangerous environmental hazards of nuclear waste and concerns that development of new plants cannot happen quickly enough to reduce CO2 emissions, such that nuclear energy is neither efficient nor effective in cutting CO2 emissions.

ADVANTAGES AND DISADVANTAGES OF RENEWABLE ENERGY:

There are many energy sources today that are extremely limited in supply. Some of these sources include oil, natural gas, and coal. It is a matter of time before they will be exhausted.

Estimates are that they can only meet our energy demands for another fifty to seventy years. So in an effort to find alternative forms of energy, the world has turned to renewable energy sources as the solution. There are many advantages and disadvantages to this.

Renewable energy sources consist of solar, hydro, wind, geothermal, ocean and biomass. The most common advantage of each is that they are renewable and cannot be depleted. They are a clean energy, as they don’t pollute the air, and they don’t contribute to global warming or greenhouse effects. Since their sources are natural the cost of operations is reduced and they also require less maintenance on their plants. A common disadvantage to all is that it is difficult to produce the large quantities of electricity their counterpart the fossil fuels are able to. Since they are also new technologies, the cost of initiating them is high.

Solar energy makes use of the sun’s energy. It is advantageous because the systems can fit into existing buildings and it does not affect land use. But since the area of the collectors is large, more materials are required. Solar radiation is also controlled by geography. And it is limited to daytime hours and non-cloudy days.

wind energy uses the power of the wind to produce electricity. Although it is the largest job producer, it is reliant on strong winds. Wind turbines are large and, although you can use the area under them for farming, many consider them unattractive looking. They are also very noisy to operate. In addition, they threaten the wild bird population.

Hydroelectric energy uses water to produce power. This is the most reliable of all the renewable energy sources. On the down side, it affects ecology and causes downstream problems. The decay of vegetation along the riverbed can cause the buildup of methane. Methane is a contributing gas to greenhouse effect. Dams can also alter the natural river flow and affect wildlife. Colder, oxygen poor water can be released into the river, killing fish. And the release of water from the dam can cause flooding.

Geothermal energy uses steam from the Earth’s ground to generate power. It uses smaller land areas than other power plants. They can run 24 hours per day, every day of the year. Disadvantages are that it is very site specific and, along with the heat from the Earth, it can also bring up toxic chemicals when obtaining the steam. Drilling geothermal reservoirs and finding them can be an expensive task.

Biomass electricity is produced through the energies from wood, agricultural and municipal waste. It helps save on landfill waste but transportation can be expensive and ecological diversity of land may be affected. In addition, its process needs to be made simpler.

Ocean energy is a clean and abundant energy form. It does, however, have high costs. Ocean thermal energy also requires close to a forty degree Fahrenheit difference in water temperature year round. In addition, construction and laying pipes can cause damage to the ecosystem.

There are many advantages to the use of renewable energy sources. There are also some disadvantages. The fact is energy demands will continue to increase. Through research and development, as well as, new technologies, the hope is many of the disadvantages of renewable sources of energy can be eliminated and we can successfully incorporate it into our power supplies.

N.Sankari
http://www.articlesbase.com/electronics-articles/renewable-energy-707358.html