U.S. wind power has been one of the energy sector's great success stories of the past decade. From small beginnings, wind capacity has grown fourfold over the past ten years and now supplies roughly 6 percent of U.S. electricity.

That success is thanks, in no small part, to what have been large federal tax credits. With wind energy's current credit of 2.3 cents per kilowatt-hour potentially under threat of a more rapid phase-out under Congress' tax reform plan, the industry is understandably keeping a close eye on Capitol Hill. But even more threatening to the future growth of wind power are state-level legislative initiatives in which opponents of renewable energy are invoking some rather specious national security arguments.

In states like Texas, Oklahoma, New York and North Carolina, wind's opponents now claim that large wind farms threaten military operations. Chief among their arguments is that a windmill’s spinning turbine creates a reflective signal that can be picked up by radar, which in turn complicates a flight controller’s job of safely guiding aircraft to landing.

While the Pentagon itself does not agree with this technical assessment, laws have been passed in several states blocking construction of wind farms. A Texas law passed in June 2017 making wind farms within 25 nautical miles of a military base with fixed wing aviation ineligible for a property tax abatement. In North Carolina, a partial moratorium on future windmill construction is in place until 2021. A more dramatic anti-wind bill in New York would have banned all wind energy within 40 miles of military aviation facilities, excluding up to 5,000 square miles of the state from possible development. The measure did not pass the New York State Legislature.

The reality is that the U.S. Department of Defense (DoD) and the Federal Aviation Administration (FAA) have jurisdiction over utility-scale turbines near military bases that exceed 200 feet in height. The Pentagon has established a clearinghouse that effectively alerts developers to military concerns before any construction begins. Since 2010, at least 12 wind farms have entered mitigation agreements with DoD covering turbine siting and operational issues, with no known problems to military operations or the proper functioning of radar. In many instances, the mitigation plan calls for the wind farm to stop and lock the wind turbines whenever a military service says it needs to reserve the airspace.

But these solutions have not stopped state-level politicians from finding problems where none exist. In North Carolina, some of the fears are based on the possibility that wind farms would detract from the value of military bases if Congress were to establish a new Base Realignment and Closure Commission (BRAC). During legislative hearings in Raleigh, retired military officers dubbed such fears "over-regulation." Since the late 1980s, BRACs have closed more than 350 U.S. military facilities. The most recent BRAC completed its work in 2005, and none are expected in the current session of Congress.

Research by the Massachusetts Institute of Technology shows simple upgrades to military radars with mid-20th century technology can solve many of the air-traffic control, weather radar and aircraft navigation concerns at DoD sites. As far back as 2010, the Air Force used the MIT research as the basis for several wind projects near the border of Oregon and Washington State.

The federal wind tax credit is already scheduled to fall to zero by 2020, and the wind industry believes it is prepared to battle other energy sources on an even playing field. Let’s hope reason will prevail at the state level, where wind power's opponents still hold significant influence. It would be a shame to see narrow interests with poorly supported arguments undermine an industry that is finally on a path to operate without government support.

William Murray is federal energy policy manager for the R Street Institute, a Washington D.C.-based nonprofit group aimed at promoting limited government and free markets.