Mapping Solar Grid Parity

March 6th, 2012 by John Farrell

Within a decade, 100 million Americans could get cheaper electricity from rooftop solar — without subsidies — than is provided by their utility. This finding from a new report from the Institute for Local Self-Reliance — Rooftop Revolution: Changing Everything with Cost-Effective Local Solar — inspired our popular animated map, showing when major metropolitan areas reached this crucial solar crossroads.

The only complaint was, “what about the 30% federal tax credit?” I think the former argument – without subsidies – is stronger, but for those who really wanted to see the solar future based on the existing tax incentive (and assuming it is extended, as is, after 2016), this map’s for you (click here or on the map to the animated version):

You can also view the original solar grid parity map, or look at a still image (also from 2024):

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Tags: Electricity, grid parity, 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.

Ross

So will the utilities encourage people to covert to electric vehicles and sell them grid power to charge the vehicles? I’m assuming most of the roof panel installations won’t be powerful enough for that?
- Bob_Wallace
  
  Why not? EVs on the grid is additional business for utilities and an excellent market for their late night time wind power. If late night use increases then utilities can afford to install more turbines in order to have increased access to cheaper peak hour wind.
  
  A dispatchable load like EV charging is a major asset for grid management. EVs can eat up supply peaks and drop out when supply tightens. The average EV (32 miles per day) needs only about 1.5 hours of charge time per day using a 240 volt outlet.
  
  —
  
  Solar on your roof.
  
  There are lots of days that solar panels are going to produce more power than the home can use, especially during the sunny hours. Sell that power to utilities for other peak hour demand and buy back cheaper off-peak power.
  
  I’m running my house on 1.2kW of solar panels. This time of year my batteries are full by 10am. That gives me about 7.2kWh of electricity that I’m not using and could be fed into an EV. About 20 miles of cost free driving per day. If I were on the grid I could sell that power to the utility company and buy it back at a cheaper price at night.
  
  (Come on car manufacturers. Give me an affordable 4wd EV. I got teh power going to waste….)
  
  —
  
  Average US driver piles up 12,000 miles per year, 32.9 miles per day.
  
  Typical EV uses 0.35kWh/mile or 11.5kWh per day.
  
  Almost all of the lower 48 gets 4.5 or more solar hours per day. In a 4.5 solar hour location you can produce that 11.5kWh with 2, 600 watts of solar panels. Panel prices have dropped below $1/watt, installation prices need to come down.
  
  If we could get installation at what German homeowners pay 2.6kW of panels would cost a little under $10k. That would give one 40 or more years of driving for about $21/month.
  
  Wind is a lot cheaper than solar. Currently 4-5 times cheaper.