Wind energy is clean, sustainable, renewable and domestic, and it is one of the fastest growing energy sources in the world. With declining costs and improvements in technology, wind is quickly becoming cost-competitive with other generation resources, but harnessing it comes with challenges.
How It Works
Large utility-scale wind applications are often called “wind farms.” Wind farms tie together multiple individual wind turbines to create a source of energy that is connected to the electric grid.
Wind farms can either be onshore (land-based) or offshore (off the coast in ocean or lake waters). The latter takes advantage of the higher and more consistent wind speeds offshore than on land, with turbine structures seated on the seabed or installed on floating platforms when in deeper waters. Figures 1-3 provide an overview of the basic components of an offshore wind project.
Whether on land or offshore, wind turbines capture kinetic energy from the wind and spin a shaft to generate electricity. Power from the generators inside each turbine’s nacelle is transferred to cables buried throughout the footprint of the wind farm. In an offshore wind farm, these cables direct the energy to an offshore substation where the voltage is stepped up, transmitted to the shore and tied into the grid, as shown in Figure 1. Many offshore wind facilities utilize direct drive turbines, which simplify the nacelle system and can increase efficiency and reliability by avoiding gearbox issues. They work by connecting the rotor directly to the generator.
Global Offshore Wind
The first offshore wind farm, Vindeby, was installed off the coast of Denmark in 1991. This offshore wind farm consisted of 11 450-kilowatt turbines with a total nameplate capacity of 4.95 megawatts (MW). Decommissioned in 2017, the Vindeby wind farm served as an important test bed for offshore wind development.
Today, four of the top five countries by installed offshore wind capacity are in Europe. The United Kingdom leads the way with just over 10 gigawatts (GW). As a whole, Europe has 25 GW of offshore wind capacity from 5,402 grid-connected offshore wind turbines across 12 countries. It added 2.9 GW in 2020. China is second in offshore wind capacity with just under 10 GW. In 2020, China led the world in offshore wind installations for the third consecutive year, adding over 3 GW. Rounding out the top five are Germany, the Netherlands and Belgium. Worldwide, installed offshore wind capacity was 35.5 GW at the end of 2020.
Offshore Wind in the U.S.
Despite ranking second globally in total wind capacity (including both onshore and offshore installations), the U.S. currently sits 13th in offshore wind capacity, with only 42 MW installed.
The first U.S. offshore wind farm was completed in December 2016. The Block Island Wind Farm, developed by Deepwater Wind off the coast of New Shoreham, Rhode Island, consists of five 6-MW turbines with an installed capacity of 30 MW.
In January 2021, two 6-MW turbines commenced operation at the Coastal Virginia Offshore Wind (CVOW) pilot project, 27 miles off Virginia Beach, Virginia. CVOW, developed by Dominion Energy, is the first U.S. offshore wind project installed in federal waters and the only project to date built and owned by an electric utility. The CVOW commercial project is ultimately proposed to be a 2,640-MW offshore wind farm. It is scheduled to begin construction in 2024 and be completed in 2026, when it will be the largest offshore wind project in the country.
Vineyard Wind, an 800-MW project off the coast of Martha’s Vineyard, is slated to initiate construction later this year and start generating electricity by 2023. The project will feature the most powerful wind turbines currently available, the GE Haliade-X with a capacity of 13 MW each.
In addition to the above efforts, there are 28 GW of planned offshore wind projects in issued federal leases. Furthermore, two offshore wind demonstration projects are planned for state waters off Ohio and Maine. Developers expect 14 projects totaling over 9 GW to be operational by 2026, and the industry estimates total state level plans to procure nearly 30 GW of offshore wind capacity by 2035. The U.S. Department of Energy found that with stable policies, there is an offshore potential of 86 GW by 2050.
In some areas, the wind energy potential just offshore from population centers in the coastal and Great Lakes states — which account for nearly 80% of total electricity demand — is twice the entire nation’s electricity use. Utilizing this resource effectively can play a significant role in meeting carbon reduction and renewable energy goals.
Environmental, Maritime Shipping and Military Operation Impacts
Environmental, shipping and military operation concerns are considered throughout the life of a wind facility, from its construction and long-term operation to its decommissioning.
Wind energy production, both onshore and offshore, must go through extensive environmental impact assessments before projects can be built. The National Environmental Policy Act (NEPA) is the principal law dictating the environmental permitting and review process. This process is public and often leads to project delays.
An Environmental Assessment (EA) is conducted to determine the need for the proposed project. Based on the EA results, the federal Bureau of Ocean Energy Management (BOEM) may prepare a more rigorous assessment allowing for public review and comment. BOEM acts as the lead and coordinates with other federal, state and local agencies throughout the process. Environmental matters that must be addressed include possible impacts to:
- Birds and bats
- Marine mammals and other marine species
BOEM also evaluates the impact of wind facilities on shipping lanes. Detailed surveys, warning beacons and buffer zones must be established to avoid conflict with commercial shipping, fishing and private boating activities.
Similarly, the U.S. Department of Defense (DOD) studies every project proposal in conjunction with affected military bases and branches. They follow an extensive vetting process, established in 2011, known as the Siting Clearinghouse. The Clearinghouse review begins with the federal identification of lease areas with BOEM and lasts through the regulatory process when a developer submits their construction and operations plan. This procedure prevents construction of any onshore or offshore wind project that could hinder military training or operations. If risks cannot be mitigated, the project is not approved.
Wind Energy in North Carolina
The first commercial wind farm in the Southeast, Amazon Wind Farm North Carolina — Desert Wind, lies in northeastern North Carolina near Elizabeth City and the Albemarle Sound. The Desert Wind Farm, operated and maintained by Avangrid Renewables, is an onshore project that began producing power in 2017. It consists of 104 turbines with a total capacity of 208 MW. All of the electricity generated at the facility is contracted to Amazon to power its data centers in the region.
In July 2017, the North Carolina General Assembly passed House Bill 589, which included provisions to develop more than 3,200 MW of solar energy in the state but also contained an 18-month moratorium on wind farm permits. The moratorium was intended to allow time to assess any potential interference additional wind turbines could have on military installations, even though the Desert Wind Farm went through the DOD’s Siting Clearinghouse process prior to development. The moratorium was allowed to expire as planned on December 31, 2018, but the uncertainty it sparked led to an indefinite delay in wind farm projects that were expected to generate 420 MW by 2019.
Offshore Wind Production
With steady winds and shallow waters (less than 60 meters) that extend a long distance from the shore, the seas off North Carolina’s coast are favorable for offshore wind energy production and represent a significant untapped source of clean, renewable energy (Figure 4). According to the National Renewable Energy Laboratory, North Carolina has among the highest offshore wind energy potential on the east coast; however, a lack of load centers and strong transmission ties across a large portion of our coast present a challenge to harnessing this potential economically.
Recognizing North Carolina’s offshore wind capabilities, Gov. Roy Cooper signed Executive Order 218, “Advancing North Carolina’s Economic and Clean Energy Future with Offshore Wind,” in June 2021. The order calls for the state to develop 2.8 GW of wind capacity off North Carolina’s coast by 2030, and 8 GW by 2040.
In addition, North Carolina entered into a Memorandum of Understanding with Virginia and Maryland that outlines a framework under which the three states will “…cooperatively promote, develop, and expand offshore wind energy generation and the accompanying industry supply chain and workforce.” Although the memorandum is not legally binding, the parties agreed to form a Smart Power Leadership team comprising representatives from each state.
Wind Energy Areas
BOEM works with federal, state, local and tribal partners to identify areas along the coast that appear most suitable for commercial wind energy activities while presenting the fewest apparent environmental and user conflicts. These areas are referred to as “Wind Energy Areas,” or WEAs. Through this process, BOEM identified three WEAs off North Carolina’s coast: Kitty Hawk, Wilmington West and Wilmington East (Figure 5).
In 2017, Avangrid Renewables was awarded a 122,405-acre lease in the Kitty Hawk WEA, which is expected to support up to 2,500 MW of generation capacity. The two Wilmington WEAs are not yet leased but, combined, represent about 1.5 times the acreage of Kitty Hawk, suggesting a capacity of 3 to 4 GW.
Economic Development Potential
According to the American Clean Power Association, there are currently about 114,000 jobs in the U.S. wind energy industry. By 2030, offshore wind alone is projected to provide as many as 83,000 jobs. Opportunities are generated throughout project development, including during on-site construction, turbine and component manufacturing, and ongoing operation and maintenance. Offshore wind construction taps into the skills of U.S. oil and gas workers, who have decades of experience with ocean energy infrastructure. Applying best practices and insight from Europe, the U.S. offshore industry is expected to create a $140 billion supply chain by 2035.
For North Carolina, a solid manufacturing base, established ports, strong rail and highway infrastructure, and positive economic conditions make the state a contender to capitalize on offshore projects both locally and nationally — particularly if there is a focused effort to develop a supply chain.
Estimated impacts during construction (one-time impacts that could last from three to six years per project) range from 14,000 to 28,000 jobs created with an economic output between $4 billion and $7+ billion. Annual operations are estimated to generate between 1,000 and 2,500 ongoing full-time jobs with an economic output between $257 million and $790 million. These impacts are estimated to occur throughout the life of a project, which is generally expected to be 30 years.
Offshore wind represents a significant opportunity for wind energy development in the U.S. If pursued aggressively, it can help ensure the country meets its carbon reduction and renewable energy goals. As with any energy production technology, though, there are financial and environmental considerations, including impacts to marine life, shipping and military operations.
Lessons learned from Europe, China and other parts of the world are driving development and operating costs to be competitive with coal and natural gas. The oil and gas sector has substantial experience constructing and operating offshore structures, and with the proper regulatory policies in place, offshore wind development can succeed. The economic impact potential for North Carolina is considerable, especially if the state utilizes its manufacturing base and transportation networks to develop a supply chain.