utorak, 23. ožujka 2010.

SOLAR serdar - RENEWABLE ENERGY

SOLAR serdar - RENEWABLE ENERGY

SOLAR serdar
About Renewable Energy
Content
Key Descriptors
What is Renewable Energy?
Hydro Energy
Bioenergy
Wind Energy
Solar Energy
Geothermal Energy
Ocean Energy
Key Descriptors
Canada, with its large landmass and diversified geography, has substantial renewable resources that can be used to produce energy; these resources include moving water, biomass, and wind, solar, geothermal and ocean energy.
Canada is a world leader in the production and use of energy from renewable resources. Renewable energy sources currently provide about 16% of Canada’s total primary energy supply.
Moving water is the most important renewable energy source in Canada, providing about 59 percent of Canada’s electricity. In fact, Canada is the second largest producer of hydroelectricity in the world.
Biomass is the second most important renewable energy source in Canada. The primary types of bioenergy include electricity and industrial heat from wood waste, space heating from firewood, and biofuels from agricultural crops.
While they are emerging sources, wind and solar energy are experiencing high growth rates.

What is Renewable Energy?
Renewable energy is energy obtained from natural resources that can be naturally replenished or renewed within a human lifespan, that is, the resource is a sustainable source of energy. Some natural resources, such as moving water, wind and sunshine, are not at risk of depletion from their use for energy production. Biomass, however, is a renewable resource only if its rate of consumption does not exceed its rate of regeneration.
A wide range of energy-producing technologies and equipment have been developed over time to take advantage of these natural resources. As a result, usable energy can be produced in the form of electricity, industrial heat, thermal energy for space and water conditioning, and transportation fuels.
With its large landmass and diversified geography, Canada has an abundance of renewable resources that can be used to produce energy. Canada is a world leader in the production and use of energy from renewable resources. Renewable energy resources currently provide about 16% of Canada’s total primary energy supply.
Hydroelectricity is by far the most important form of renewable energy produced in Canada. Bioenergy also makes an important contribution to Canada’s energy mix. Several emerging resources, such as wind and solar power, are making much smaller contributions but are experiencing high growth rates.

Hydroelectricity
The natural flow of water in rivers offers kinetic power that can be transformed into usable energy. Early usages included mechanical power for transformation activities, such as milling and sawing, and for irrigation. As well, rivers have been used for transportation purposes, such as moving logs from forests to industrial centers.
Currently, hydroelectricity is the major form of usable energy produced from flowing water. To produce hydroelectricity, the water flow is directed at the blades of a turbine, making it spin, which causes an electrical generator connected to the turbine to spin as well and thus generate electricity.
The amount of energy extracted from flowing water depends on the volume of water and its speed. Usually, a hydroelectric station is built at a sharp incline or waterfall to take advantage of the speed gained by the water as a result of gravity. Dams are built at some locations to help regulate the flow of water and, therefore, the electricity generation.
Canada has many rivers flowing from mountainous areas toward its three bordering oceans. In 2006, Canada had 499 hydroelectric stations together capable of producing about 73 thousand megawatts (or million kilowatts). These stations include 360 small hydroelectric facilities, that is, facilities with a nameplate capacity of 50 megawatts or less, and they together are capable of producing 3.4 thousand megawatts, which is about 5% of Canada’s total hydroelectric production capacity.
All the hydroelectric stations in Canada generated about 350 million megawatt-hours in 2006. This accounted for 59% of Canada’s total electricity production. Canada is the second largest producer of hydroelectricity in the world. In fact, hydroelectricity represents about 11% of Canada’s total primary energy supply.
Hydroelectric stations have been developed in Canada where the geography and hydrography were favourable, particularly in Quebec. Other areas producing large quantities of hydroelectricity include British Columbia, Ontario, Labrador and Manitoba. There still are significant untapped moving-water resources in Canada, for large-scale hydroelectric projects are currently under consideration in British Columbia, Manitoba, Labrador, Alberta, and Quebec. As well, there is potential for small- and medium-scale developments, particularly in British Columbia, Ontario and Quebec.

Bioenergy
Bioenergy comprises different forms of usable energy obtained from materials referred to as biomass. A biomass is a biological material in solid, liquid or gaseous form that has stored sunlight in the form of chemical energy. Excluded from this definition is organic material that has been transformed over long periods of time by geological processes into substances such as coal or petroleum.
Several types of biomass can be used, with the proper technology and equipment, to produce energy. The most commonly used type of biomass is wood, either round wood or wood waste from industrial activities. Wood and wood waste can be combusted to produce heat used for industrial purposes, for space and water heating, or to produce steam for electricity generation. Through anaerobic digestion, methane can be produced from solid landfill waste or other biomass materials such as sewage, manure and agricultural waste. Sugars can be extracted from agricultural crops and, through distillation, alcohols can be produced for use as transportation fuels. As well, numerous other technologies exist or are being developed to take advantage of other biomass feedstock.
With its large landmass and active forest and agricultural industries, Canada has access to large and diversified biomass resources that can be used for energy production. Currently, bioenergy is the second most important form of renewable energy in Canada. In fact, bioenergy represents about 5 percent of Canada’s total primary energy.
Historically, the use of wood has been very important in Canada for space and water heating, as well as for cooking. It is still important today, as almost 10% of households use wood as a primary or secondary source for space heating. Every year, over 100 petajoules of energy from wood are consumed in the residential sector, representing about 8 percent of residential energy use.
The most important type of biomass in Canada is industrial wood waste, especially waste from the pulp and paper industry, which is used to produce electricity and steam. Every year, nearly 500 petajoules of bioenergy are used in the industrial sector. The pulp and paper industry is by far the largest industrial user of bioenergy, which accounts for more than half of the energy used in this industry.
At the end of 2006, Canada had 62 bioenergy power plants with a total electricity generating capacity of 1,652 megawatts, and most of this capacity was built around the use of wood biomass and spent pulping liquor, as well as landfill gas. In 2006, 7 million megawatt-hours of electricity were generated using wood and spent pulping liquor. Most of the biomass-fired capacity was found in provinces with significant forestry activities: British Columbia, Ontario, Quebec, Alberta and New Brunswick.
Biofuels – or fuels from renewable sources — are a growing form of bioenergy in Canada. The principal agriculture feedstock for producing ethanol, a gasoline substitute, includes corn, wheat and barley. Canada is a major world producer and exporter of these grains. As well, vegetable oils and animal fats can be used to produce biodiesel, a diesel substitute.
In 2006, the domestic production capacity of biofuels in Canada was approximately 600 million litres of ethanol and 100 million litres of biodiesel. The federal and provincial governments have announced several measures that should lead to the increased production and use of biofuels in the coming years.

Canada’s Bioenergy Installed Generating Capacity, by Province (2006, in megawatts)
Provinces
Total biomass
Prince Edward Island
2
Nova Scotia
66
New Brunswick
129
Quebec
303
Ontario
313
Manitoba
22
Saskatchewan
-
Alberta
144
British Columbia
673
Canada
1,652

Wind Power
The kinetic energy in wind can be converted into useful forms of energy such as mechanical energy or electricity. Wind energy has been harnessed for centuries to propel sailing vessels and turn grist mills and water pumps. Today, wind is used increasingly to generate electricity. Turbines with large propellers are erected on ‘wind farms’ located in strategic areas that have good wind regimes and that are in proximity to existing electrical grids. Wind energy is captured only when the wind speed is sufficient to move the turbine blades, but not in high winds when the turbine might be damaged if operated.
Canada has large areas with excellent wind resources and therefore a significant potential for the expansion of wind-generated power. Some of the highest quality areas are offshore and along coastlines. No offshore wind farms have been built in Canada yet, and the development of coastal wind farms is limited because most of Canada’s coastline is in remote regions, away from the existing electrical grid. There are also high quality areas inland at different locations across Canada, including the southern Prairies and along the Gulf of St. Lawrence.
Installed wind power capacity in Canada has expanded rapidly in recent years and is forecasted to continue to grow at a rapid pace due to increased interest from electricity producers and governmental initiatives. As of December 31, 2007, Canada had 1,400 wind turbines operating on 85 wind farms for a total installed capacity of 1,846 megawatts, compared with only 60 wind turbines, 8 wind farms and 23 megawatts a decade earlier. The provincial leaders in wind power capacity are Alberta, Ontario and Quebec.

Solar Energy
Solar energy is energy from the sun in the form of radiated heat and light. The sun’s radiant energy can be used to provide lighting and heat for buildings and to produce electricity. Historically, solar energy has been harnessed through passive solar technologies. Typically, these involve the strategic location of buildings and various elements of these buildings, such as windows, overhangs and thermal masses. Such practices take advantage of the sun for lighting and space heating to significantly reduce the use of electrical or mechanical equipment. Solar energy can be harnessed only during the day and only if the sunlight is not blocked by clouds, buildings or other obstacles.
Today, two active solar technologies that involve electrical or mechanical equipment are becoming more common. First, solar collectors or panels are used to heat water or ventilation air for use in buildings. Second, solar photovoltaic technology uses solar cells to convert sunlight directly into electricity.
The potential for solar energy varies across Canada. The potential is lower in coastal areas, due to increased cloud coverage, and is higher in the central regions. The solar potential varies even more around the globe. In general, many Canadian cities have a solar potential that is comparable internationally with that of many major cities. For instance, about half of Canada’s residential electricity requirements could be met by installing solar panels on the roofs of residential buildings.
Canada’s use of solar energy has increased in recent years, although it remains relatively small in terms of market penetration. Installed capacity for solar thermal power has seen average annual growth of 17 percent since 1998, reaching 290 megawatts of thermal power in 2005. Installed capacity for solar photovoltaic power has grown by 27 percent annually since 1993, reaching 25.8 megawatts in 2007, of which 89% are in off-grid applications.

Geothermal Energy
Geothermal energy can be captured from the heat stored beneath the earth’s surface or from the absorbed heat in the atmosphere and oceans. In the first instance, geothermal energy can be captured from naturally occurring underground steam and be used to produce electricity. In the second instance, heating and cooling can be achieved by taking advantage of the temperature differential between outside air and the ground or groundwater.
Canada’s known geothermal steam resource is limited, but electricity generation projects are being considered. Furthermore, approximately 3,150 ground-source heat pump units were installed in residential, commercial and institutional buildings across Canada in 2006.

Ocean Energy
The ocean is a vast source of energy that can be harnessed to produce different forms of usable energy. For instance, technologies have been developed to convert the energy of ocean waves and tides into electricity or other useful forms of power. However, a number of technical, economic and environmental barriers remain and, as a result, ocean energy is currently not a widely exploited energy source.
Being landlocked only along its southern border, much of Canada is surrounded by oceans, meaning it has access to a significant energy potential. Currently, Canada has a tidal power plant in Nova Scotia with a generating capacity of 20 megawatts of electricity. Recently, a technology demonstration project using a Canadian designed tidal current turbine with a generating capacity of 0.065 megawatts was installed in British Columbia’s offshore. Additional tidal current demonstration projects are being considered.
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