Skip to main content
Skip to navigation

This site is archival. Please visit for up-to-date content.

EXPERT AVAILABLE: Current Renewable Energy Laws Undervalue Airspace, MU Expert Says

February 2nd, 2012

Story Contact: Nathan Hurst, 573-882-6217,

The views and opinions expressed in this “for expert comment” release are based on research and/or opinions of the researcher(s) and/or faculty member(s) and do not reflect the University’s official stance.

COLUMBIA, Mo. – In an era of volatile energy prices and continued concerns over climate change, the demand for renewable energy and sustainable development has never been greater.  Because green development often requires heavier use of the space immediately above our homes and neighborhoods, that airspace is more valuable than ever before.  Troy Rule, an associate professor at the University of Missouri School of Law and a renewable energy law expert, says that some laws improperly respond to the growing role of airspace in our increasingly green economy by weakening rather than strengthening landowners’ airspace rights.

Airspace is the volume of space directly above every parcel of land.  Landowners have historically held property rights to that space up to a certain height; however, Rule argues that some laws relating to wind and solar energy are unjustifiably eroding landowners’ airspace rights.  For example, the Federal Aviation Administration and U.S. Department of Defense have delayed several wind energy projects in recent years due to fears that the turbines might interfere with military radar signals traveling through private rural airspace.  And laws in some states prohibit landowners from adding second stories to their homes or growing large trees on their properties solely because such land uses might shade a particular neighbor’s solar panel.  Rule says that these well-intended laws can result in an inefficient use of airspace.

“A growing number of policies responding to the sustainability movement disregard landowners’ airspace rights in ways that can cause airspace to be underutilized,” Rule said. “Solar panels can be installed almost anywhere that there is sun, but a skyscraper generally makes sense only in a downtown area.  Building vertically is often a higher-valued use of city airspace than protecting a few solar panels from being blocked by the sun. The solar panels would be just as productive in a rural area, while a new office or residential tower would not.”

Rule argues that some airspace is most valuable to society as a conservation commons in which physically occupying the space is prohibited in order to protect non-physical airspace uses such as preserving scenic views or ensuring sunlight access for solar panels.  Other airspace, such as that above urban centers, is more valuable to society when filled with buildings. Rule’s research advocates incorporating options into laws regulating airspace is a useful way to promote wind and solar energy while still respecting landowners’ existing airspace rights.

In a paper published in the UCLA Law Review, Rule outlines several ways that policymakers can help clear the air regarding renewable energy and property law. He believes policymakers should acknowledge existing airspace rights but use options to add flexibility to help ensure that airspace rights are allocated to their highest valued use.

“Before acting on pressure to promote renewable energy by implementing a broad law aimed at promoting a particular use of airspace, policymakers should recognize and weigh the law’s likely effects on both rival and non-rival uses of the airspace at issue,” Rule said.

Troy Rule joined MU’s law faculty as an associate professor of law in 2009. Prior to entering law teaching, he was an attorney at K&L Gates LLP in Seattle, where his practice focused primarily on commercial real estate transactions and wind energy development. He graduated with honors from the University of Chicago Law School in 2005, where he served on the Chicago Journal of International Law.