Could U.S. Get 20% of Electricity from Solar under Power Lines?

October 17th, 2011 by John Farrell

What if the U.S. could get 20 percent of its power from solar, near transmission lines, and without covering virgin desert?

It could. Transmission right-of-way corridors, vast swaths of vegetation-free landscape to protect high-voltage power lines, could provide enough space for over 600,000 megawatts of solar PV. These arrays could provide enough electricity to meet 20% of the country’s electric needs. (Note: there may not be good interconnection opportunities for solar under these huge towers, so this should be read as a land use discussion rather than technical analysis of interconnection to the grid).

It starts with the federal Government Accountability Office, which estimates there are 155,000 miles of high-voltage transmission lines in the United States (defined as lines 230 kilovolts and higher). According to at least two major utilities (Duke Energy and the Tennessee Valley Authority), such power lines require a minimum of 150 feet of right-of-way, land generally cleared of all significant vegetation that might come in contact with the power lines.

That’s 4,400 square miles of already developed (or denuded) land for solar power, right under existing grid infrastructure.

Of course, the power lines themselves cause some shading, as may nearby trees (although, the New York Public Service Commission, and likely other PSCs, has height limits on nearby trees that would minimize shading on the actual right-of-way). To be conservative, we’ll assume that half of transmission line right-of-way is unsuitable for solar.

That leaves 2,200 square miles of available land for solar. With approximately 275 megawatts (MW) able to be installed per square mile, over 600,000 MW of solar could occupy the available right-of-way, providing enough electricity (over 720 billion kilowatt-hours) to supply 20 percent of U.S. power demands. (Note: we used the average annual solar insolation in Cincinnati as a proxy for the U.S. as a whole).

Making big strides toward a renewable energy future doesn’t require massive, remote solar projects. We can use existing infrastructure or land to generate significant portions of our electricity demand. Transmission right-of-way, providing 20% of U.S. electricity from solar, is just one piece of the puzzle, with another 20% possible using existing rooftops and a solar potential of nearly 100% from solar on highway right-of-way. Solar can help achieve a 100% clean – and local – energy future.

This post originally appeared on Energy Self-Reliant States, a resource of the Institute for Local Self-Reliance’s New Rules Project.

Top Photo Credit: Some rights reserved by William J. Gibson, the Canuckshutterer
Bottom Photo Credit: Some rights reserved by John Farrel

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Tags: distributed energy, distributed renewable energy, Distributed Solar, land use, power lines, power transmission lines, transmission lines, US

About the Author

John Farrell directs the Democratic Energy program at ILSR and he focuses on energy policy developments that best expand the benefits of local ownership and dispersed generation of renewable energy. His seminal paper, Democratizing the Electricity System, describes how to blast the roadblocks to distributed renewable energy generation, and how such small-scale renewable energy projects are the key to the biggest strides in renewable energy development. Farrell also authored the landmark report Energy Self-Reliant States, which serves as the definitive energy atlas for the United States, detailing the state-by-state renewable electricity generation potential. Farrell regularly provides discussion and analysis of distributed renewable energy policy on his blog, Energy Self-Reliant States (energyselfreliantstates.org), and articles are regularly syndicated on Grist and Renewable Energy World. John Farrell can also be found on Twitter @johnffarrell, or at jfarrell@ilsr.org.

Matthew Peffly

Power lines don’t buy the land. The get a right of way easement. The lines pass over homes, backyards, and farmer fields. So the only thing this post should have said is that there is land under the wires were for sure all the trees have been cut down. NOT that any of it can be used for solar. The only land they buy is right under the tower itself. So I guess you could hang panels on those. But you calculation should have been based on number of towers not the amount of land with a easement on it. That is like take all the roads in the US and say hey all home developments have a 15 ft setback easement on them. Put panels in them and we get all the energy we need. Oh wait that puts them in your front yard, and the white house front yard, and in everyone’s yard and parking lot.

Why not go easier, keep the 30% tax credit. Drop the $80Billion a year to oil/coal (see earlier post on support to oil/coal version wind/solar), Add a 10% cash payment to anyone who adds a roof top, or parking lot top PV system. Require all US power company to provide Net metering hook in one month or pay 5% of PV system cost/month until hook up is approved or 20 months which ever comes first.
Anonymous

Great idea. It’s land that’s cleared anyway.
Anonymous

A couple of issues. 1) Shade. As the sun moves through the sky panels under transmission lines are going to be shaded by lines and towers. 2) Transmission distance. Much of the high voltage line system runs through quite remote areas.

Don’t we have enough existing rooftops and parking lots close to where the power would be used?
- John Farrell
  
  Bob,
  
  Good point about rooftops. You can see a map of the potential for rooftop solar to serve U.S. electric demand by state here: http://energyselfreliantstates.org/content/graphics-report-democratizing-electricity-system