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