Sharply Higher Rooftop Solar Potential Increases Potential For Energy Self-Reliance

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Earlier this year, the National Renewable Energy Laboratory released a new estimate of rooftop solar potential, an update to 2008 figures we used in our landmark state-by-state energy atlas, Energy Self-Reliant States. The bottom line: there’s much more potential to generate our electricity from solar on nearby buildings than we previously thought.

The irony is that this comes at a time of increasing tension between distribution power generation and a legacy of centralized power generation.

Rising Solar Potential

The following map shows the changes, attributable to more accurate roof surveys. The percentage represents the additional portion of electricity sales that could be met with rooftop solar electricity. 13 states saw an increase of at least 20%, a further 16 saw an increase of 10 to 20%. Estimates for just 4 states fell or remained the same.

rooftop solar potential usa by state ilsr change 2008-16

The following chart shows the 2008 data, with most states able get 20% or more of their annual electricity sales from rooftop solar alone (maximizing use of available roofs).

Local rooftop solar potential ILSR 2008 data

Estimates for rooftop potential are sharply higher in 2016, based on more accurate roof surveys. Nearly two-thirds of states could tap rooftop solar for one-third of their electricity.

Local rooftop solar potential ILSR 2016 data

High Tension Power

States may be growing their local power potential, but a recent New York Times editorial suggests that local should “make way” for transmission lines to send wind power long distances to fulfill a desire for inexpensive clean power across the country. That call comes not just in the context of rising opportunity to supply a state’s power needs on its own rooftops, but also plenty of wind power potential. The following map, based on data from the National Renewable Energy Laboratory, shows that 35 states have sufficient on-shore wind power resources at 110-meter turbine hub heights (taller than most existing turbines) to meet 100% of their electricity consumption on an annual basis. This is in addition to the rooftop solar potential above and does not include substantial and as yet untapped offshore resources off the Eastern Seaboard.

wind power potential usa 110m by state ilsr 2016

The tension between the NY Times editorial and the opportunity of self-reliance lies in a simple question. Would I rather spend $100 for 100% renewable electricity or $105 for 100% renewable electricity within my state, or $110 for 100% renewable electricity generated mostly within my own community?

In other words, is the goal of maximizing renewable energy one of minimizing the cost or maximizing the economic benefit?

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John Farrell

John 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 (, and articles are regularly syndicated on Grist and Renewable Energy World.   John Farrell can also be found on Twitter @johnffarrell, or at

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