Since colonial times, windpower has been utilized in Virginia for transportation, pumping water, and powering equipment. In the future, high-tech windmills may be assembled in wind farms on Virgiginia's mopuntains and offshore to generate electricity, helping utilities meet Renewable Portfolio Standards goals. The capacity of wind to generate electricity is now forcing local, state, and Federal officials to define what places are appropriate vs. "off-limits" for modern wind turbines.
For 400 years, from the 1500's into the 1900's, the Spanish, French, English, and other Europeans used the kinetic energy in wind to sail from Virginia back and forth to the Caribbean, Africa, or Europe. Since the English settled Virginia successfully in 1607, rural Virginians also have used windpower to draw water up from wells and to power manufacturing facilities, such as mills that ground wheat into flour.
Pumping and powering grist mills required that the windmill be located directly next to the facility - gears and belts could not transmit the mechanical energy more than about 100 feet. In Tidewater, windmills located on bluffs next to the river, as in Yorktown, could maximize the opportunity to catch a steady breeze.
windmill at Yorktown, shown on French map in 1781
Source: Library of Congress, map by Sebastian Bauman, 1781
"The old windmill tower at Yorktown much in disrepair prior to 1840"
Source: National Park Service, Yorktown's Main Street - Illustrations
Today, almost all labor-saving devices in the home, office, or manufacturing plants use electricity that is generated far away from the site where the power is used. A handful of existing wind turbines convert wind energy to electrical energy, including one 10kW turbine at the Smith Mountain Lake Visitor Center.
traditional farm windmill, good for pumping water up from a well
Source: National Renewable Energy Laboratory Photographic Information eXchange
wind turbine designed to generate electricity
Source: National Renewable Energy Laboratory Photographic Information eXchange
More wind-powered turbines are planned in the mountainous regions of Virginia, and in the Atlantic Ocean east of the shoreline. Demand for more electricity is expected to increase along with the state's population. As more people are born in or move to Virginia, total demand for electricity in Virginia will climb - even if conservation efforts ultimately reduce demand/person.
The one-time infrastructure costs of building turbines and electrical transmission lines in remote areas is high, but the annual cost for fuel (wind...) is free. Even though electricity generated by wind costs more than electricity generated from coal, hydropwer, or nuclear facilities, there are still customers for wind-generated electricity.
In addition to Federal tax advantages, some states are adopting Renewable Portfolio Standards that mandate a certain percentage of electricity generated or purchased within the state come from renewable sources. Urban regions not in "attainment" with Clean Air Act standards (such as Metropolitan Washington) seek credit for purchasing "green power" to meet pollution standards.
Virginia has defined voluntary (but not mandatory) Renewable Portfolio Standards in the 2010 Virginia Energy Plan. The state's Renewable Portfolio Standard is limited to investor-owned utilities, so it excludes electric cooperatives, municipal utilities, and industrial co-generation plants. The standard also excludes nuclear energy from the baseline. The optional target is to obtain 15% of the remaining sources of electricity from renewable sources by the year 2025.1
Ridgetops in the Blue Ridge, Ridge and Valley, and Appalachian Plateau physiographic provinces - and the open water region off the Outer Continental Shelf - are clearly the areas with Class 3 and higher winds that could power a modern turbine. The Piedmont and the Coastal Plain have few locations with high wind potential. The greatest potential for generating electricity from wind energy in Virginia is to locate turbines in the mountains (a proposed wind farm in Highland County received the first zoning approval in Virginia) and offshore (east of the Eastern Shore/Virginia Beach).
Utilities seeking to generate electricity for sale look for at least Class 3 or higher zones, where wind speeds exceed 12.5 mph. (Wind power maps often show speeds measuring "wind density," where Class 3 speeds are about 15 mph. Wind density accounts for the decline in atmospheric density at higher elevation; thinner air generates less power when pushing against a turbine blade.)
The energy potential of a wind turbine increases dramatically as wind speed increases. The maximum energy output of a turbine at full speed is far greater than the likely production at average speeds... and the wind does not blow 24 hours/day, either.
Wind energy is often measured at 50 meters (164 feet) above the ground, but turbines on towers may be placed higher. Wind speed next to the ground is reduced by friction with vegetation and the surface of the ground. In engineering terms, "there is often a layer of high wind shear between 10 and 50 m height above ground due to the influence of trees."2
To maximize wind speed that turns blades, windmills involve tall towers. If a turbine blade can be extended on a tower as much as 400 feet above the ground, the wind currents will be faster and steadier. The vertical distribution of wind speeds is not a simple "higher is always better" equation, but typically a tall windmill has greater potential to convert more wind energy into electrical energy, and produce more electricity at a lower cost.
However, a tall windmill will also be more visible from a distance; wind energy projects create scenic impacts. Raising turbine blades far above trees on towers 150-400 feet tall increases the potential windpower that could be captured... but makes the turbines very obvious intrusions on top of forested mountain ridges. In addition, new transmission lines will require cutting new swaths through the forests, creating visual scars.
Classification schemes to evaluate potential wind energy vary. A "Class 3" location by one organization might be categorized as "Class 6" by another scheme. The Virginia Wind Resource Map summarizes the wind potential of the state at 50 meters above the ground, in simple language:3
Offshore locations are atttractive locations physically because there are no forests, no trees to slow down the breeze. Wind energy projects can be located according to financial and political reasons, as well as by simple physical geography. From a venture capitalist point of view, the ownership and permitting issues are also significant. Turbines are not cheap, and "time is money," so investors look for places where the delays in getting authorization to build will be minimized. Offshore, companies can negotiate with just state/Federal governments to get rights to build towers with turbines.
There are no private landowners offshore, no land to lease or buy. Instead, Federal permits must be obtained from the Department of the Interior - Bureau of Ocean Energy Management (formerly known as the Minerals Management Service). Previously the Corps of Engineers issued the permits, in order to manage the creation of new obstructions to navigation. Now the Bureau of Ocean Energy Management has the responsibility, reflecting their offshore responsibilities for oil and gas drilling and mining from the ocean seafloor. The Federal government will lease 20 blocks in a 140,000 acre area designated for offshore wind turbines.
Federal permits require an environmental analysis and a public comment process. The request for a Federal permit for the Cape Wind project near Nantucket Island in Massachusetts was delayed a decade by political dispute. That delay rippled throughout the wind industry (especially affecting the willingness of lenders to finance other projects), until the willingness of the Federal government to approve offshore wind farms was made more clear.
Siting a wind farm off the Virginia coast is a complex challenge. All proposals for wind farms in ocean waters create potential conflicts with shipping along the coast. In addition, military radars on the coastline may be affected by wind turbine blades, though some companies are developing "stealth" turbines that would not block radar signals. An offshore wind farm near Virginia Beach/Norfolk would be closer to the market for the electricity than one located off Chincoteague, reducing costs for underwater transmission lines - but would have more conflicts with shipping going in/out of the Chesapeake Bay.
Geographic Information System (GIS) technology can be used to identify environmentally-sensitive locations that would stimulate objections to a proposed wind energy "farm" of multiple turbines:
On land, the taller mountain ridges in Virginia are the most attractive locations for electricity-producing wind tubines. Wind speed on the ridges is usually higher than in the valleys. Because the jet stream typically flows north of Virginia, windmills are feasible on low ridges in the northern part of the state. The closer to the North Carolina border, the higher the Virginia ridge must be to intercept strong and steady winds in all four seasons of the year:4
Most wind energy projects in the mountains are located on private lands. Energy companies would rather pay a private landowner and go through a county planning process than request a permit from the USDA-Forest Service to place turbines on National Forest lands. (Wind energy projects intended to generate power for sale must also get a certificate from the State Corporation Commission.) Those Federal forests have existing stakeholders and land use plans that defined primary uses for specific areas, and changing the designated uses to include wind turbines is a difficult process.
In November, 2002, Winergy LLC proposed to build 271 wind turbines in the Atlantic Ocean, east of Accomack County at a site called Porpoise Banks 2. The company proposed to build enough turbines to generate 975 megawatts/hour, equivalent to the output from a nuclear power plant. When the Army Corps of Engineers advised that the location was sensitive to the military, Winergy shifted its area of interest to the ocean east of Smith Island, at the southern tip of the Eastern Shore.
Locating turbines out of sight, offshore of the Atlantic coastline of Virginia, does not eliminate siting conflicts. All proposals for wind farms off the Virginia coast remain just proposals, with no operating turbines.
In addition to the constraints of finding a location in Virginia with sufficient energy to power turbines, two environmental constraints limit the potential location of new wind energy farms - the visual impacts of the towers and blades, and tendency of the blades to kill birds and bats migrating through the area. Turbines could be "bird Cuisinarts," when a flock migrates through a wind farm. The Eastern Shore is a major stopping point on the Atlantic Flyway, and the Federal government must consider the potential impact on migratory birds before granting a permit for an offshore wind farm.
Birds and bats are threatened by onshore wind farms as well. A proposal in 2005 to build turbines on a ridge in Highland County exposed the conflicts between tourism-based businesses and the those who support wind farms. Multiple lawsuits were finally resolved in 2007 in favor of Highland County's rezoning. The wind farm, which would be the highest in the United States at over 4,200 feet, could have 20 towers as much as 400 feet tall... but after the approvals were finalized, nothing was built.6
Even within states with the climate and topography to generate a lot of wind energy, the locations for windmills are often in rural areas - requiring unsightly power lines to the urban areas creating the demand for power. As discussed in the Congressional debate:7
In early 2006, Community Energy, Inc. revealed its interest in building a wind farm in Patrick County. The immediate result was a decision by the local officials to tighten zoning restrictions, to ensure a special review process would be required and a wind farm could not be constructed without clear approval from the county:8
A proposal by Invenergy Wind Development to build 135-meter high towers (443 feet) on Poor Mountain in Roanoke County has generated conflict regarding the noise and visual impacts vs. economic and environmental benefits of wind-generated electricity. The Roanoke Group of the Sierra Club conditionally endorsed the project, acknowledging that the benefits of generating renewable energy at the site outweighted the predicted environmental impacts.9
In 2010, Governor Bob McDonnell articulated a goal of making Virginia the "energy capital of the East Coast," and included windpower in his plans. Research and planning for offshore wind projects are starting to be followed by investment, with the expectation that wind-generated electricity can compete with traditional sources (especially if coal prices climb, as international customers such as China increase demand for coal faster than mines can increase supply).
The Virginia Coastal Energy Research Consortium calculated that offshore wind farms could generate electricity at a rate competitive with coal-fired power plants, if the facilities using fossil fuel were required to implement carbon capture and sequestration to offset the global warming impacts of carbon dioxide.
Working from the shoreline near Cape Henry, NASA's Langley Research Center in Hampton has used Doppler LIDAR to map the wind speeds in the 20 different blocks in the area to be leased by the Federal government.
In March 2011, the Virginia Marine Resources Commission approved a site in state waters three miles west of Cape Carles (centered on N 37º14'55.00", W 76º04'35.6") for a 5MW offshore wind turbine prototype, a month after the same Spanish energy company (Gamesa) opened an offshore turbine factory in Norfolk. A competing firm, Poseidon Atlantic, also announced plans to build 10 test pads on the Eastern Shore to test and certify wind turbines on towers as much as 750' high, which is the maximum height authorized in Northampton County.12
In 2012, the intergovernmental Virginia Renewable Energy Task Force identified 112,799 acres off the Virginia coast, defined in 32 specific blocks of ocean between 23.5-35.5 nautical miles east of Virginia Beach, as the prime area for future wind farm leases. The initial Federal review started with 70 square blocks, 3 miles on each side. After excluding areas with potential conflicts with Department of Defense activities (including dredge disposal regulated by the U.S. Army Corps of Engineers), NASA operations from Wallops Island, and shipping paths (including the Coast Guard's Atlantic Coast Port Access Route Study) - but still including a fish haven/artificial reef - the Bureau of Ocean Energy Management narrowed the area of potential leasing to 19 complete blocks and 13 partial blocks.13
On May 7, 2012 the Spanish firm Gamesa abandoned its plans for Virginia's prototype offshore windmill. Instead of completing the first operating offshore wind project in U.S. waters by 2013, Gamesa chose instead to build in the Canary Islands. Though Virginia state agencies had green-lighted all permits quickly, the company may have been spooked by unclear Federal policy regarding subsidies for renewable energy and by the threat of competition from power plants fueled by low-cost natural gas.14
Poor Mountain southwest of Roanoke
showing planned locations of up to 18 turbines on ridgetops
Source: Invenergy Wind Development, Poor Mountain Site Map