SOURCES and USAGE of ALTERNATIVE ENERGY Introduction Solar Power Wind Power Biomass  Algae as microscopic power plants Ethanol fuel Geothermal   Hydropower Hydropower combined with other renewable energy resources Hydroelectric Power Plants HYDROPOWER summary

 

SOURCES and USAGE of ALTERNATIVE ENERGY

 

Introduction

 

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Alternative energy resources are inexhaustible in duration and their potential ibiomass s enormous as they can, in principle, meet many times the world’s energy demand. Renewable energy sources include solar power (solar thermal and photovoltaic); wind power; (wood, wood waste, municipal solid waste, landfill gas and other biomass); ethanol fuel; biofuels and geothermal.

 

It’s becoming clear that developing market opportunity in the renewable energy sector will be of fundamental importance in the near future: renewable energy sources currently supply something between 15% and 20% of world’s total energy demand.

 

 

Solar Power

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 (Photo source)

 

The use of solar panels is one of the most common examples of renewable energy. A photovoltaic panel converts solar energy into electricity: solar cells produce direct current electricity from sun rays and it can be used to power equipment or to recharge batteries but only sunlight of certain energy will work efficiently to create electricity.

 

In a typical commercial photovoltaic panel only 15% of the sunlight striking the cell transforms it into electricity. The performance of a photovoltaic panel is measured in terms of its efficiency in converting sunlight to electricity. When more power is required than a single cell can deliver, cells are generally put together to form “PV modules”, or the so called solar panels, that may be arranged in arrays.

 

Solar energy incentive programs may help the widespread of photovoltaic systems in the States. On January 12, 2006, the California Public Utilities Commission approved the California Solar Initiative (CSI), investing $3.2 billion to promote the use of solar power over the next 11 years. The rest of the United States should adopt similar measures to begin the transition away from fossil fuel dependence.

 

 

Wind Power

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According to the U.S.A. Department of Energy, wind power is the fastest growing renewable resource of energy and it's cleaner than fossil fuels. It doesn’t produce neither air pollution nor waste and it creates jobs and income especially in rural areas.

 

Wind turbines are fixed on a tower to catch the most energy, they can be used as stand-alone applications but they can be even combined with a photovoltaic system. Wind turbines can generate enough energy if they’re built close together to form a wind plant and there must be a large amount of wind year-round to utilize kinetic energy. Wind farms can be built offshore and wind turbines are widely spaced, lands with windmills can have several employments.

 

AWEA (the American Wind Energy Association) promotes wind energy as an alternative and clean energy resource for people all around the world; it provides up-to-date information about domestic and international wind energy industry too.

 

Wind power is the leader in wholesale renewable electricity production in the United States. According to the American Wind Energy Association, total installed U.S. wind power capacity was 9,149 megawatts at the beginning of 2006. A large part of that (2,420 megawatts) was installed in 2005 and an estimated 3,000 megawatts is planned for installation in 2006. Thanks to recent technological advances, the price competitiveness of wind generation versus natural gas has been improving. Furthermore, the U.S. federal government offers companies a production tax credit for wind power equal to about 1.9 cents per watt-hour. This has been a powerful incentive to attract tax-oriented investors, such as utility companies, into wind farm ownership.

 

The original market for wind power was Denmark in the late 1990s, followed by Germany. Today hot markets are Spain, Italy, France, the United Kingdom and India; but wind power is available almost everywhere.

 

According to AWEA market research wind power generating capacity increased by 27% in 2006: it's produced nearly 31 billion kilowatt-hours per year which is enough energy to serve 2.9 million household American need [1].

 

In America wind power is also widely supported by the state itself and by each federal government legislatures: their aim is to increase the number of wind farms throughout the U.S. Thanks to a federal production tax credit (PTC), wind plants productivity and that of other alternative energy technologies are rewarded; the Government has recently extended this incentive through 2008.

 

 

Biomass 

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Biomass energy is derived from plants; the most used type of biomass energy comes from burning wood. However, other technologies have been developed to replace carbon-emitting fuels with cleaner and more acceptable fuels.

 

One of the potential fuels is biodiesel.

Biodiesel is a domestic, renewable fuel for diesel engines derived from natural oils like soybean oil. The toxic emissions of biodiesel have lower levels than those of petroleum. This kind of energy has the potential to play a role in reducing carbon emissions in conjunction with other changes; nevertheless, planting enough soybeans to fuel all of the United States on biodiesel alone would take about one-sixth of the world's cropland.

 

Hydrogen fuel cells have enormous potential too as a substitute for gasoline in combustion engines; its only emission is water vapour.

Although the technology for hydrogen fuel cells has existed for years, it does not exist any purified and efficient methods of isolating and transporting the hydrogen. Nearly the total hydrogen production today is powered by steam reformation of natural gas; the most encouraging method of producing hydrogen is from electrolysis where water is electrochemically split into hydrogen and oxygen. The advantage of this renewable process is that it uses a reasonable source of electricity. Even if hydrogen produces a small amount of energy compared to its volume, new technology should be developed in order to transport and store it.

 

 

 

 

 

Algae as microscopic power plants

 

 

How can the world wean off of oil?

Since fossil fuels are mainly used for transport, finding out and developing alternative methods of powering cars, buses and trucks are the two main challenges to be faced. While the first one has already been achieved, the second one is still at an initial stage; however several researchers from all over the world are working to refine both theories and technologies in order to achieve more concrete results.

These researchers agree with the fact that, at present, the best alternative to petroleum is biodiesel, a fuel that is made out of vegetable oils and animal fats and that can be produced by micro-algae, in particular the so-called “pond scum” (Chlamydomonas reinhardtii):

 

 

The discovery of this microscopic green alga dates back to the 30s. Hans Gaffron, a German researcher who was attending the University of Chicago in those years, was the first to become aware of the power potential of these algae, which have an high oil and protein content used by the Mayas and the Aztecs as a dietary supplement.

 

In 1999 Professor Tasios Melis (University of California) together with a team of researchers from the National Renewable Energy Laboratory (NREL) discovered that if algae are deprived of sulphur and oxygen, they produce hydrogen for a certain period of time. Two years later, Melis founded the “Melis Energy” company in order to commercialize a technique that harnessed algae’s potential to turn sunlight into hydrogen. In autumn 2001, the company built a bioreactor containing 500 litres of water and algae that can produce up to 1 litre of hydrogen per hour. This hydrogen is extracted by a siphoning system and stored in its gaseous state.

 

 

Thus far, only a small percentage of algae production potential has been achieved. This means that nowadays biofuel energy can’t be cost-competitive with fossil fuel. Up to the present time micro-algae technologies may be only a small industry but they are at the core of recent studies and projects in the context of greenhouse gas mitigation.

    

Applications of micro-algae technologies in greenhouse gas mitigation

production of energy saving products (fertilizers, bioplastics)

wastewater treatment

aquaculture

 

 

Micro-algae mass cultures use solar energy for the biofixation of power plant flue gas and other concentrated CO₂ sources into biomass. This biomass can be used to produce renewable fuels, such as methane, ethanol, biodiesel, oils and hydrogen, thus reducing CH₄ and N₂O emissions. Consequently, this process helps mitigating the effects of greenhouse gases.

 

According to a research made by a University of New Hampshire on biofuel production from algae, wastewater treatment plants may be redesigned to use raceway algae ponds as the primary treatment phase, with the twofold aim of treating the waste and growing algae for biofuel extraction. Furthermore, it is possible to use the algae mush (that kind of soft paste which remains after the extraction of oil) as a fertilizer.

 

In 2001 EniTecnologie (the U.S. Department of Energy and the IEA Greenhouse Gas R&D Programme) organised a Workshop in Monterotondo (Rome), in order to discuss on micro-algae technologies in the context of greenhouse gas mitigation.

 

 

 

 

Ethanol fuel

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(Photo source)

 

Ethanol is a colorless, chemical compound which is often simply called alcohol[1]. There are two different types of ethanol: synthetic ethanol, which is produced in a chemical process, and bio-ethanol, which is obtained from plants such as sugar canes, sugar beets, potatoes, sunflowers, etc. In the United States, the principal supplier for the production of ethanol is corn.

 

Nowadays, ethanol is becoming an important alternative to gasoline; it is a clean burning fuel and is increasingly used to power cars. However, it is not really a substitute of gasoline yet, (100% ethanol is not used as a fuel) but it can be combined with different percentages of gasoline in order to reduce the consumption and the prices of the latter. [2] According to the Energy Policy Act (1992), E85 (85% ethanol and 15% gasoline) and blends with higher concentrations are considered alternative fuels. [3] Ethanol is a sustainable energy resource which may become economically important in future; it costs less than gasoline and is not a limited resource (in the sense that it will not run out), but is produced from renewable resources. However, for its production water, sunlight and soil are necessary.

 

A disadvantage of the use of ethanol as fuel is the fact that it contains less energy than gasoline and therefore, it is necessary to refuel the vehicles more often. Moreover, in order to be able to use ethanol as a fuel, the fuel system of the cars must be modified. An additional disadvantage is that ethanol cannot be very easily transported in pipelines because the production levels are not high enough and it would be too expensive to create pipelines from the Midwestern United states, where the corn is produced, to the coasts.

In the United States, the government allows up to 10% combinations of ethanol with gasoline and all the vehicles are compatible with this mixture without modifications of the engine. As the pollution using ethanol fuel is minimal, in some of the States and cities the mixture is compulsory, above all during the winter, when the level of air pollution is particularly high. Pollution can, however, be caused in the production of ethanol if a large amount of fertilizers and pesticides are used. In 2004, in the United States, about one third of the gasoline was combined with ethanol.

 

The United States and Europe need much more petroleum and natural gas than they produce in their territory. This means that these states are dependent on the petroleum resources of other countries. To reduce this dependence and increase the production of ethanol the government of the United States has developed bio-ethanol fuel programs and researchers are working to improve the efficiency of ethanol fuel.

 

  

 

Geothermal

 

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Geothermal energy results from exploiting heat that comes from the earth’s core (for further information about geothermal energy in general please visit Alternative Energy Sources in Italy).  Being deeply underground you may not see the most geothermal energy sources apart from volcanoes, hot springs, geysers and fumaroles that are its only visible signs.

 

For finding geothermal resources geologists analyze e.g. the chemical composition of the soil and water, magnetic fields and gravity, maps and photographs of the territory, etc. but drilling wells is  the only way of knowing for certain if in that site there are geothermal sources because it allows experts to measure underground temperatures.

 

Geothermal resources are divided into four groups:

 

• hydrothermic;
• geopressured;
• hot dry rock;
• magma.

 

 

However only hydrothermal ones are exploited for producing electricity and e.g. for heating buildings and greenhouses today, whereas the other three categories have to be more developed in order to be used.

In the world geothermal resources are concentrated in the so-called “Ring of Fire” an area that edges the Pacific Ocean, Japan, the Philippines, the Aleutian Islands, North America, Central America, and South America.

 

 

photo taken from Enchantedlearning.com

 

 

 

The USA is the greatest producer of electricity generated from geothermal energy in the world. The most important geothermal resources are in western states and Hawaii, while other moderately hot ones are located in the Dakotas, along the Atlantic coast, in Arkansas and Texas.

In 2004 there were 43 power plants producing electricity from geothermal energy in the US. The most of them are located in California and Nevada, whereas Utah has two power plants and Hawaii, an archipelago of volcanic origin, has one. California, Nevada, Utah and Hawaii are, indeed, the four states that produce the most quantity of geothermal energy as shows the picture below.

 

 

 

 

photo taken from Utah Geological Survey

 

 

Exploiting geothermal energy for getting electricity is possible only in few specific sites that have some particular geologist conditions. One of them is The Geysers, north of San Francisco California, that produces electricity equivalent of what all the other geothermal sites combined do. In California, indeed, 6% of the electricity comes from geothermal energy.

In Utah the most important geothermal sources, Roosevelt Hot Spring and the Cove Fort-Sulphurdale, are located in the southwestern part of the country, while in Hawaii the geothermal area is Puna Geothermal Venture which is in the south of Hilo on the Big Island of Hawaii and produces 20% of electricity that the population needs.

Today American geothermal power plants produce about 3,200 megawatts (MW) that corresponds to what three nuclear power plants do.

 

Hydropower

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Hydropower offers benefits like the possibility of producing power with low costs and reducing air pollution and greenhouse effect. However, producing energy thanks to the water flow has some negative aspects as well e.g. high capital costs and regulatory burden for hydropower that obstructs new investments. In order to develop the usage of this renewable energy the Us government should quantify and underline hydropower benefits for attracting new investments and starting new projects.

 

Hydropower provides 80,000 megawatts of electricity; as a consequence it is the largest renewable electricity source in the USA.

 

Thanks to the so-called DOE program, 49 out of 50 states (Delaware is the only state not analyzed because of scarce resources) have been assessed: researchers found out that there are other 5,677 sites in the United States with a further capacity of 30,000 MW to be used. According to the U.S. Department of Energy website “The aim of the DOE Program for Ecosystem Research (PER) is to produce scientific knowledge about potential effects of climatic change on ecosystems so that decision makers (including the public) can determine if fossil-based energy production is ‘safe’”. 

 

There are about 180 federal projects and other 2,000 projects regulated by the Federal Energy Regulatory Commission (FERC) which controls the production of hydropower energy. This Regulatory Commission works in all 50 states and in Puerto Rico as well.

 

 

Hydropower combined with other renewable energy resources

 

 

Given that some alternative energy sources are wind and solar ones they might not produce energy every time, while hydropower plants can store energy by stopping part of the water and releasing it when it is needed. This is the reason why combining it with other alternative energy sources - e.g. with wind energy i.e. intermittent in nature - is very useful for providing energy non-stop; however it is not always possible because it depends on e.g. the flows and ramp rates.

 

Irrigation, navigation, flood control, energy demand and need and the presence of wildlife are elements that have to be considered for choosing which flows might be exploited.

 

For producing hydropower energy combined with other alternative sources you have to respect some factors imposed by intermittent reneweable resources rather than power needs. These factors are described in the following list.

 

• Technical.

• Institutional. It is important for wind and hydropower energy production because it allows them to operate in an integrate fashion.

• Economic.  Economic analysis is associated with market prices and differences in seasonal and daily power demands co-occur on making prices vary.

• Political.  Some political parties want to combine the use of hydropower with the use of wind energy for developing areas in which energy is produced by wind, while other Associations see wind energy as a threat to their interests because they invest in fuel production or have other electric plants.

• Engineering.  It refers to geographical locations of the facilities and seasonal variability of flows.

 

Hydroelectric Power Plants

 

The second point against hydroelectric power plants is the fact that the dam, which is essential to the plant, destroys many habitats and alters the landscape. A dam needs to hold a huge quantity of water and floods out surrounding forests, deserts, towns and anything else in its way. Just think that the amount of water of Lake Mead, which supplies the Hoover Dam, could flood the entire state of Pennsylvania to a depth of 1 foot! Hydroelectric power has many benefits that outweigh the downsides, but improvements are still needed.

 

 

 

HYDROPOWER summary

 

• Today hydropower, including pumped storage, supplies over 10 percent of the electrical generating capacity of the United States compared to coal-fired steam generation which is the number one source.

• Hydropower is the primary contributor of renewable energy in the United States.

• The costs of generating hydropower are the lowest of all sources of electricity.

• Hydroelectricity currently produced in the United States each year is equivalent to nearly 500 million barrels of oil.

• Hydropower generation doesn't contribute to atmospheric emissions, which are a growing problem on both national and global levels.

• Hydropower is nowadays the most efficient way of producing energy with each kilowatt-hour of hydroelectricity being produced at an efficiency more than twice that of any competing energy resource.

• Only 3 percent of the around 80,000 existing dams in the United States have hydropower facilities.

• Potential sites for all types of hydropower exist and would double the U.S. hydroelectric production if developed. However, a variety of restraints exists on this development, some are natural and some are imposed by our society. The natural restraints include such things as occasional unfavourable terrains for dams. Other restraints include disagreements about the institution which should develop the resource or deal with the changes in environmental conditions. Often, other developments already exist at sites otherwise suitable for hydropower generation. Finding solutions to the problems imposed by natural restraints demands extensive engineering efforts. Sometimes no solution is possible, or is so expensive that the entire project becomes impractical. Solutions to the social issues are frequently much more difficult to resolve and the costs are far greater than those imposed by nature.

• Developing the full potential of hydropower will require consideration and coordination of many varied factors. 5