The size and capacity of the next generation of wind turbines has the potential to increase the efficiency of the industry, reducing unit numbers and maintenance costs. But wind farms already have to clear a huge number of obstacles, from land-use laws to airspace regulations and, as the scale of engineering grows, an array of fresh legal considerations will come into play.
Siting and land use laws
The legal framework for siting and permitting wind energy facilities in the US varies from state to state. In some jurisdictions, siting authority rests with local branches of government, such as county commissions or planning and zoning boards. These authorities adopt mandatory siting rules, typically called “zoning ordinances”, or publish voluntary guidelines. Other states retain their siting authority at the state level through siting boards, councils authorised by statute or other state agencies.
Federal agencies can also be a factor. The Department of the Interior’s Bureau of Land Management, for example, has siting jurisdiction over US public land. The Minerals Management Service has authority to regulate offshore wind energy development, while the Federal Aviation Administration (FAA) regulates aspects of wind energy facilities that affect airspace.
Check local limitations
It is unlikely that there will be a pre-emptive federal regulatory regime for siting wind turbines, so the US wind energy industry will continue to work with a combination of federal laws and a patchwork of highly localised siting regulations to address height restrictions, setbacks, noise and other land-management, safety and aesthetic concerns.
When developing a wind farm with larger turbines, project developers and equipment vendors should first check local and regional land-use regulations for limitations. Look for restrictions on overall machine height, rotor diameter and electrical output.
For example, regulations in Massachusetts limit large machine height to 450 feet (137 metres), unless the applicant can prove that industry standards or manufacturer’s recommendations support a taller structure. On the other hand, Kern County, California, allows turbines up to 600 feet (183 metres) tall. For setbacks, which regulate the distance turbines must be located from other structures, Massachusetts requires only 1.2 times the machine height. Kern County, however, has specific setbacks for different structures, roads or rights of way.
Where federal, state or local rules have not anticipated the scale of today’s wind turbines and may prove to be too restrictive, developers, manufacturers and industry associations will need to work with permitting authorities to update the rules – lest those jurisdictions miss out on the efficiency, lower energy prices and increased local tax base that large turbines can offer. This involves manufacturers or developers invoking the legislative process and lobbying the relevant legislature to make the changes needed to accommodate larger turbines.
The FAA regulates airspace in the US above the minimum altitude of flight and must be notified whenever construction or alteration of an object in excess of 200 feet (61 metres) tall is proposed so an obstruction evaluation study can be done. This does not usually create problems for wind farms unless they are within a few miles of an airport.
But as larger wind turbines enter the US market, FAA regulations will play a more prominent role. Part 77 of the regulations contains standards for determining obstructions to air navigation, including any object that exceeds 500 feet (152 metres) in height. Therefore, a wind turbine exceeding this will be presumed to be a hazard to air navigation unless the obstruction evaluation study determines otherwise. An FAA “notice of presumed hazard” signals an uphill battle, and reducing overall machine height to 500 feet (152 metres) or less may be an important part of finding a workable solution.
FAA guidelines also require lights to be installed on wind turbines along the periphery of a wind farm if they are 200 feet (61 metres) or taller. And, in any turbine configuration, there must not be any unlit gap of more than half a mile (800 metres) between turbines. In unidirectional wind environments, where in-row spacing of three or four rotor diameters is possible, wind turbines with rotor diameters over 100 or even 125 metres could still meet this requirement by lighting every other turbine in each row.
With multi-directional winds, however, in-row spacing can typically be five to seven rotor diameters or more, and the use of very large turbines will mean that engineers, lawyers and the FAA will now need to consider for the first time whether it becomes necessary under the half-mile rule to light every turbine in each row of an array, or whether the guidelines need to be clarified.
Environmental legislation and environmental review processes, like those required under the National Environmental Protection Act (NEPA), and similar laws enacted at the state level, have long been used by opponents to delay development, including wind farms, because of concerns about potential harm to wildlife or natural resources, or aesthetic issues.
For example, in Washington state, a wind energy developer sought to build a 65-turbine wind farm near the town of Ellensburg. Local townspeople objected, saying the wind turbines would have negative environmental and visual impacts. In Oregon, plans for wind farms with turbines of 520 feet (158 metres) have met resistance due to their proximity to an historic wilderness town.
Wind energy projects have encountered opposition from bird conservationists, who fear that rotating turbine blades harm bird populations. The federal Endangered Species Act, the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act have all been invoked, with mixed results.
But at least two reports from consulting biologists predict that replacing small, early-model turbines with larger machines with blades further above ground and towers further apart, among other mitigation measures, would reduce harm to birds. Best-practice guidelines in countries such as Australia and the UK expressly recognise that widening the space between turbines allows birds to move safely around and between turbines, and that larger turbines may provide greater visibility for birds. A 2005 guidance document from conservation body Environment Canada and the Canadian Wildlife Service concurs.
However, a representative survey recently published by the National Wind Coordinating Collaborative indicates that the use of fewer and larger turbines with more spacing between them is not yet expressly recommended in the guidelines issued by many federal, state and local permitting agencies and environmental groups in the US.
While the science of predicting and measuring impacts on wildlife from the wind energy industry is beyond the scope of this article, we believe that broader official recognition of the benefits for wildlife from larger turbine design characteristics would help expedite the environmental review process, accelerate public acceptance and minimise controversy and litigation.
In theory, at least, larger wind turbines could reduce environmental challenges by producing the same amount of energy with fewer units. So, depending on local characteristics and community values, larger turbines may face less resistance and fewer NEPA or state NEPA-type challenges. The industry will need to continue addressing these issues on a project-by-project basis.
Larger wind turbines may raise other challenges for project developers. For example, weight limitations on roads may restrict transportation of longer and heavier wind turbine components. In such cases, rules will need to be modified, or an exemption obtained, to stop transportation laws from becoming a constraint to optimal turbine or tower design.
With the proper guidance, plenty of patience, and a healthy dose of creativity, larger wind systems can negotiate the regulatory arena and help propel the US towards the next level of growth and efficiency.