Energy Information

Wind Energy

Wind energy is a converted form of solar energy. The sun’s radiation heats different parts of the earth at different rates?most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth’s surface, and cooler air is drawn in to replace it. The result is wind.

Air has mass, and when it is in motion, it contains the energy of that motion ? “kinetic energy.” Some portion of that energy can converted into other forms ? mechanical force or electricity ? that we can use to perform work.

How does wind energy work?

A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use. Wind flows through turbines which create energy that can be used for electricity.

There are two basic designs of wind electric turbines: vertical-axis, or “egg-beater” style, and horizontal-axis (propeller-style) machines. Horizontal-axis wind turbines are most common today, constituting nearly all of the “utility-scale” (100 kilowatts, kW, capacity and larger) turbines in the global market.

The Future of Wind Energy

The U.S. wind energy industry turned in a solid performance in 2004, adding 389 megawatts (MW) of new generating equipment to the nationwide fleet, or enough to serve more than 100,000 average homes, according to AWEA.

How many homes can one megawatt of wind energy supply?

An average U.S. household uses about 10,000 kilowatt-hours (kWh) of electricity each year. One megawatt of wind energy can generate between 2.4 million and 3 million kWh annually. Therefore, a megawatt of wind generates about as much electricity as 240 to 300 households use. It is important to note that since the wind does not blow all of the time, it cannot be the only power source for that many households without some form of storage system. The “number of homes served” is just a convenient way to translate a quantity of electricity into a familiar term that people can understand. (Typically, storage is not needed, because wind generators are only part of the power plants on a utility system, and other fuel sources are used when the wind is not blowing.)

How much energy can wind realistically supply to the U.S.?

Wind energy could supply about 20% of the nation’s electricity, according to Battelle Pacific Northwest Laboratory, a federal research lab. Wind energy resources useful for generating electricity can be found in nearly every state.

U.S. wind resources are even greater, however. North Dakota alone is theoretically capable (if there were enough transmission capacity) of producing enough wind-generated power to meet more than one-third of U.S. electricity demand.

What is needed for wind to reach its full potential in the U.S.?

Consistent policy support

Over the past five years (1999-2003), the federal production tax credit has been extended twice, but each time Congress allowed the credit to expire before acting, and then only approved short durations. The PTC expired again December 31, 2003, and as of March 2004 had still not been renewed. These expiration-and-extension cycles inflict a high cost on the industry, cause large lay-offs, and hold up investments. Long-term, consistent policy support would help unleash the industry’s pent-up potential.

Nondiscriminatory access to transmission lines

Transmission line operators typically charge generators large penalty fees if they fail to deliver electricity when it is scheduled to be transmitted. The purpose of these penalty fees is to punish generators and deter them from using transmission scheduling as a “gaming” technique to gain advantage against competitors, and the fees are therefore not related to whether the system operator actually loses money as a result of the generator’s action. But because the wind is variable, wind plant owners cannot guarantee delivery of electricity for transmission at a scheduled time. Wind energy needs a new penalty system that recognizes the different nature of wind plants and allows them to compete on a fair basis.

New transmission lines

The entire transmission system of the wind-rich High Plains, which cover the central one-third of the U.S., needs to be extensively redesigned and redeveloped. At present, this system consists mostly of small distribution lines?instead, a series of new high-voltage transmission lines is needed to transmit electricity from wind plants to population centers. Such a redevelopment will be expensive, but it will also benefit consumers and national security, by making the electrical transmission system more reliable and by reducing shortages and price volatility of natural gas.

Transmission will be a key issue for the wind industry’s future development over the next two decades.

The REAL Cost Of Wind Energy

It is safe to say that wind energy is essentially free energy. It comes from the heating effect of the earth’s surface by the sun. This heating effect is irregular because of the uneven surface of the earth. It therefore gives rise to airstreams that move between the cooler zones and the hotter zones. This is the wind that blows and that makes the blades on the wind turbines move and thus generate electricity.

Wind energy business model: financing of wind energy

In the nineteen eighties the wind energy generators that were installed typically showed a cost of 30 cents per kilowatt-hour period. This in itself was not a very attractive price compared to the conventional power generators that existed already. However over the last twenty years fossil fuel prices have gone up, and wind generation prices have come down. Today we see a reduction of almost 80 percent in the cost per kilowatt-hour thanks to these factors and the latest high technology wind turbine generators. 5 cents per kilowatt-hour is a common phenomenon now. This is clearly an extremely advantageous rate at which to pay for one’s electricity.

Further advantages favor wind energy compared to fossil fuels. Wind energy is easily harvested on farms and ranches, which have an abundant supply of this free energy source. Wind energy is available to anyone who lives in an area where the wind blows. There are no imports necessary or even possible from foreign countries. This is a great difference compared to fossil fuels where importing large quantities of such fuels is a normal if unfortunate occurrence. Fossil fuels of course also are highly polluting and not a renewable source of energy.

To make sure that the wind energy generation can be done in a profitable and effective manner, it is necessary to select a site with certain minimum criteria. Wind speed, for example, which is directly correlated to the amounts of electricity that can be generated, must be at least 5m per second in this case.

Improving the financials for wind energy even further

A wind energy developer applying utility financing to wind energy power plants can already generate wind power for as low as 5 cents per kilowatt-hour from a standard 50 MW wind power plant. However this price for kilowatt-hour can drop to as little as 3,5 cents, which is a 30 percent reduction. Wind power generation in this sense is even more attractive compared to say gas power plants and it is clear that wind power generation costs will continue to decrease in the coming years.

Save money and save the environment at the same time!

The environmental question of course is a very important one concerning wind energy and any other renewable energy source. Wind energy is clean. This is in comparison to say coal emissions from coal fired energy plants, which release very small dust particles into the atmosphere. These dust particles can have a serious sometimes fatal effect on human beings because of the cardiovascular and respiratory diseases that can be provoked. They may also result in a higher infant mortality rates for the same reason. Coal plants of course are also responsible for the production of greenhouse gases and the phenomenon such as acid rain. Use of coal power plants can be clearly linked to both a worsening visibility in the earth’s atmosphere and global warming.

Wind power now needs to be set-up with the long-term power generation contracts to solidify and consolidates market acceptance of this new and renewable energy source. The advantages that should allow this to happen include the minimum cost of life cycle for wind energy plants, because they have minimum operating expenses and no fuel purchase is necessary. Wind energy can be used and reused, but will never contribute to any of the pollution that is generated by the conventional fossil fuel power plants.

Gas Hydrate Alternative Energy

http://EZGasSavers.com

Measuring Solar Power: What the Sun Has to Offer. (part 5)

This article explains the fundamental terms related to sunlight and residential solar energy systems. You will learn about units of measure, forms of solar radiation, spectral distribution, energy distribution, and solar position.

Germany and Japan are often cloudy or foggy but is where most solar panels now sold in the United States are produced. Because of the way solar modules produce power from direct, diffused and reflected light it works great in these conditions. A very high performing solar array can be found on a foggy beach in California.

Measuring Light and How Solar Panels Use It

The following terms related to different aspects of light and their characteristics as they come in contact with different physical formations on Earth. The definitions below will help explain how some residential solar energy systems seemingly in areas with poor sun quality can actually achieve respectable power output.

Irradiance – The rate of solar radiation falling on a given area at a moment in time. Irradiance is measured in units of kW/m2 (read kilowatts per square meter).

Irradiation – The amount of solar energy over time. Irradiation is measured in units of kWh/m2/day and read kilowatt-hours per square meter per day. Different locations through the United States (and the World) have different levels of irradiation. As in previous articles, you can find many maps on the Internet that will show the average annual solar irradiation throughout the United States.

Light Characteristics and Solar Fundamentals

Deflection – The amount of light lost when the solar panels aren’t facing the sun squarely as the sun moves across the sky. This loss of light is called deflection. Even though solar cells are etched on the surface into little pyramids to collect light from all angles, coated with a light diffusing coating, and protected with light diffusing glass, more light is deflected when the sun is not directly in front of the panels.

Spectral distribution – The bulk of the solar light spectrum which reaches the Earth’s surface is ideally suited for conversion by solar (PV) cells into electrical energy.

The Sun’s Position as It Relates to Solar Energy Systems

Two coordinates describe the position of the sun at any given time. The orientation provide the information to home solar installers to figure out and orientate the solar energy system to collect and convert as much sun energy as possible into residential electricity.

Azimuth – Describes the direction from east to west in degrees (?). North is 0 degrees. East is 90 degrees. South is 180 degrees. West is 270 degrees. The layout of this grid is not unlike the face of a compass. The markings are in degrees indicated on the face.

Altitude – Is the measurement in degrees, like on a compass, that the sun is from the horizon. Altitude is measured in degrees as well. Altitude is the point in the sky where it is located right over head often referred to it’s highest point in the sky. Just like a plane has an altitude that it travels at across the sky as it is measured above the horizon. So does the sun.

Irradiation Example for a Solar Energy System

In the coast area of California, residential solar energy systems are sized using an average of 5.5 sun hours per day. More often than not, most people think or comment that their house gets more like 8 to 15 hours of sunlight per day. This is true but sunlight is different than solar sun hours per day.

The sun hour numbers take into account things like fog, rain, night and, most importantly, deflection. The sun hour ratings listed for different places throughout the United States is the amount of solar irradiation available to be converted into electricity by a fixed mounted solar array facing true south at the optimal tilt angle. A solar module produces its full rated power only when in direct sunlight, so when the sun is to the East or the West of the module it is not at full production.

reThinking the Economics of Residential Solar Energy

Doing your part to choose green, solar power can be a bit confusing and complex at times. There are many terms, aspects of the installation, and details about your sun light hours per day that all influence decisions to upgrade your home to solar energy. A very interesting and attractive option currently development in the solar market is the option to rent a residential solar energy system versus having to pay out up to $40,000 for your own solar panels and related equipment.

The economics of residential solar power have changed. Every American homeowner can decide to upgrade to solar energy and avoid large purchase of a solar energy system. New rental programs are now available that give homeowners the chance to adopt residential solar energy without having to make a huge investment.