Wind Power Renewable Energy *

Wind Power Renewable Energy *

The facts about residential wind power
Is there a future for wind power?
Wind power advantages
The disadvantages of wind power
Dispelling 5 wind power myths

The main renewable energy resources that you know about are sunlight (solar energy) and wind energy and perhaps to a lesser extent tidal energy systems and geothermal energy systems. All of these are in some way or another connected to the sun, which is the ultimate life giver on this planet.

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.

The IEA explains it like this:  "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."

* Let's first examine wind power as a source of green alternative energy.

A wind turbine needs air, lots of it. A modern wind turbine ranges from 600 KW to 5 MW of rated power, although for commercial use the output range is typically 1.5-3 MW.

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 0.35x24x365 = 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 dioxide and methane.

Wind Power Market

At the end of 2008, worldwide wind farm capacity was 120,791 megawatts (MW), representing an increase of 28.8 percent during the year, and wind power produced some 1.3% of global electricity consumption. Wind power accounts for approximately 19% of electricity use in Denmark, 9% in Spain and Portugal, and 6% in Germany and the Republic of Ireland. The United States is an important growth area and installed U.S. wind power capacity reached 25,170 MW at the end of 2008.

Horse Hollow Wind Energy Center, in Texas, is the world's largest wind farm at 735.5 MW capacity. It consists of 291 GE Energy 1.5 MW wind turbines and 130 Siemens 2.3 MW wind turbines. A proposed 4,000 MW facility, called the Pampa Wind Project, is to be located near Pampa, Texas.

In the UK, a licence to build the world's largest offshore windfarm, in the Thames estuary, has been granted. The London Array Windfarm, 20 km off Kent and Essex, should eventually consist of 341 turbines, occupying an area of 230 km². This is a £1.5 billion, 1,000 megawatt project, which will power one-third of London homes. The windfarm will produce an amount of energy that, if generated by conventional means, would result in 1.9 million tonnes of carbon dioxide emissions every year. It could also make up to 10% of the Government's 2010 renewables target.

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 low 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.

What is wind power and how does it work?
The facts about residential wind power
Is there a future for wind power?
Wind power advantages
The disadvantages of wind power
Dispelling 5 wind power myths

Solar Energy

What is Solar Power?

Pros and cons of solar energy
How Costly is a Solar Power System
Top 5 Reasons to Use Solar Power
Does solar power have a future?
Solar Energy News

What is Solar Power?

The sun is the focal point of our solar system, and provides heat and light to all the planets revolving around it in the form of radiation. The infra red heat rays of the sun are incident on the earth’s surface during the day time. There is a high potential in these incident rays. This potential is harnessed by man in the form of power called the solar power.

Solar power is being used by us in two different forms

1. thermal energy
2. solar electric energy

The thermal energy of the sun is directly used for heating purposes. The application of this can be seen in heating water of swimming pools, either directly during sunny days or indirectly using heat conducting fluids in pipes and transferring the heat to the water in the swimming pool during cloudy days. Thermal energy is also used directly in drying clothes, drying seeds and other food products to keep them from pest attack and improve their shelf life. We also use thermal power for plant growth. Direct heat is also used in cooking food, as in solar cookers. Here a series of heat absorbing black coloured panel is used to absorb rays falling on it. This is reflected on the cooking vessel by a mirror there by  maximising the effect of heat falling on it, solar water heaters also work in a similar fashion but do not have mirrors attached to them.

The energy got from the sun can also be used to produce electricity. This is called the solar electric energy. This energy is harness by using solar panels which in turn are connected to grids that carry the electricity. The electricity producing power of solar energy is called Photovoltis.

Solar electricity can be produced in three different ways.

1. Stand alone system – here panels are set up to absorb the incident solar radiation. This is then converted to electricity. The electricity is not being stored and is rather used directly without the help of a grid. Such systems are useful in situations like that of a lone forest guest house where difficulty may be faced in laying electricity lines. Here the cost of installing solar power panel might work out to be cheaper than laying power lines.

2. Grid connected system – such system is commonly used in houses for use in various small household electrical appliances. Here the produced energy is saved in a grid which can be used later. This helps in a continuous supply of power and can be reliable, and regular use is possible in such a system.

3. Back up system – in situations where the power grid may be unreliable a back up is used. The reason to use backup may be due to frequent power failures. In such conditions, most of the household appliances are connected to the backup system, if there is a power failure they take up energy from the solar batteries. This can also be used in community lighting and other larger power requirement can be fulfilled.

Pros and cons of solar energy
Pros and cons of solar energy

As all other energy sources solar energy also has its own pros and cons. The various pros of solar energy are as given below:

• Pollution free – The most important advantage is that it does not produce any harmful gases or effluents during power production. This is important in current context of growing importance of ozone layer depletion and global warming etc.
• Renewable source of energy – solar energy is the harnessing of energy received from the sun, thus it is renewable, and does not get over when used, unlike other fossil fuels which become lesser and lesser over time and becomes extinct completely.
• Energy can be harnessed in remote areas – The best feature of solar energy is that it can be harnessed in very remote areas, where every other form of energy production is risky or not possible at all. An example of this is the production of electricity in satellites.
• Does not require special area/place to install – Installation of solar panels does not require special or large areas, the panels can be installed in the roof tops of buildings.
• Free source to produce energy – Solar energy need not be bought, it is free of cost. The installation process is the only stage where money is spent.
• Dependence on fossil fuel is reduced – the emergence of solar energy has reduced the high dependence on the fossil fuels which is becoming very costly.
• Reduces health costs – increased use of solar energy reduces the cost spent on health indirectly because there is no emissions like carbon, sulphur di oxide, etc and also acid rains.
• Independent working – once installed the solar panels work on their own and do not require any manual operation.
• Low to no maintenance – maintenance cost of solar panels is meagre. Sometimes no maintenance is required.

Pros and cons of solar energy
How Costly is a Solar Power System
Top 5 Reasons to Use Solar Power
Does solar power have a future?
Solar Energy News