| Wind energy is a converted form of solar | | | | nation's electricity, according to Battelle |
| energy. The sun's radiation heats different | | | | Pacific Northwest Laboratory, a federal |
| parts of the earth at different rates-most | | | | research lab. Wind energy resources useful |
| notably during the day and night, but also | | | | for generating electricity can be found in |
| when different surfaces (for example, water | | | | nearly every state. |
| and land) absorb or reflect at different | | | | |
| rates. This in turn causes portions of the | | | | U.S. wind resources are even greater, |
| atmosphere to warm differently. Hot air | | | | however. North Dakota alone is theoretically |
| rises, reducing the atmospheric pressure at | | | | capable (if there were enough transmission |
| the earth's surface, and cooler air is drawn | | | | capacity) of producing enough wind-generated |
| in to replace it. The result is wind. | | | | power to meet more than one-third of U.S. |
| | | | electricity demand. |
| Air has mass, and when it is in motion, it | | | | |
| contains the energy of that motion - "kinetic | | | | What is needed for wind to reach its full |
| energy." Some portion of that energy can | | | | potential in the U.S.? |
| converted into other forms - mechanical force | | | | |
| or electricity - that we can use to perform | | | | Consistent policy support |
| work. | | | | |
| | | | Over the past five years (1999-2003), the |
| How does wind energy work? | | | | federal production tax credit has been |
| | | | extended twice, but each time Congress |
| A wind energy system transforms the kinetic | | | | allowed the credit to expire before acting, |
| energy of the wind into mechanical or | | | | and then only approved short durations. The |
| electrical energy that can be harnessed for | | | | PTC expired again December 31, 2003, and as |
| practical use. Wind flows through turbines | | | | of March 2004 had still not been renewed. |
| which create energy that can be used for | | | | These expiration-and-extension cycles inflict |
| electricity. | | | | a high cost on the industry, cause large |
| | | | lay-offs, and hold up investments. Long-term, |
| There are two basic designs of wind electric | | | | consistent policy support would help unleash |
| turbines: vertical-axis, or "egg-beater" | | | | the industry's pent-up potential. |
| style, and horizontal-axis (propeller-style) | | | | |
| machines. Horizontal-axis wind turbines are | | | | Nondiscriminatory access to transmission |
| most common today, constituting nearly all of | | | | lines |
| the "utility-scale" (100 kilowatts, kW, | | | | |
| capacity and larger) turbines in the global | | | | Transmission line operators typically charge |
| market. | | | | generators large penalty fees if they fail to |
| | | | deliver electricity when it is scheduled to |
| The Future of Wind Energy | | | | be transmitted. The purpose of these penalty |
| | | | fees is to punish generators and deter them |
| The U.S. wind energy industry turned in a | | | | from using transmission scheduling as a |
| solid performance in 2004, adding 389 | | | | "gaming" technique to gain advantage against |
| megawatts (MW) of new generating equipment to | | | | competitors, and the fees are therefore not |
| the nationwide fleet, or enough to serve more | | | | related to whether the system operator |
| than 100,000 average homes, according to | | | | actually loses money as a result of the |
| AWEA. | | | | generator's action. But because the wind is |
| | | | variable, wind plant owners cannot guarantee |
| How many homes can one megawatt of wind | | | | delivery of electricity for transmission at a |
| energy supply? | | | | scheduled time. Wind energy needs a new |
| | | | penalty system that recognizes the different |
| An average U.S. household uses about 10,000 | | | | nature of wind plants and allows them to |
| kilowatt-hours (kWh) of electricity each | | | | compete on a fair basis. |
| year. One megawatt of wind energy can | | | | |
| generate between 2.4 million and 3 million | | | | New transmission lines |
| kWh annually. Therefore, a megawatt of wind | | | | |
| generates about as much electricity as 240 to | | | | The entire transmission system of the |
| 300 households use. It is important to note | | | | wind-rich High Plains, which cover the |
| that since the wind does not blow all of the | | | | central one-third of the U.S., needs to be |
| time, it cannot be the only power source for | | | | extensively redesigned and redeveloped. At |
| that many households without some form of | | | | present, this system consists mostly of small |
| storage system. The "number of homes served" | | | | distribution lines-instead, a series of new |
| is just a convenient way to translate a | | | | high-voltage transmission lines is needed to |
| quantity of electricity into a familiar term | | | | transmit electricity from wind plants to |
| that people can understand. (Typically, | | | | population centers. Such a redevelopment will |
| storage is not needed, because wind | | | | be expensive, but it will also benefit |
| generators are only part of the power plants | | | | consumers and national security, by making |
| on a utility system, and other fuel sources | | | | the electrical transmission system more |
| are used when the wind is not blowing.) | | | | reliable and by reducing shortages and price |
| | | | volatility of natural gas. |
| How much energy can wind realistically supply | | | | |
| to the U.S.? | | | | Transmission will be a key issue for the wind |
| | | | industry's future development over the next |
| Wind energy could supply about 20% of the | | | | two decades. |