Map shows when solar will be cheaper than grid electricity in North American areas

Existing grid-supplied electricity is becoming more expensive. Electricity from solar panels is getting cheaper. Here's an animated map of North America that shows when the rising-grid-cost and falling-solar-cost curves will intersect for different metropolitan areas.

We used the following assumptions in the construction of this animated map:

The cost of solar in 2011 is $4.00 per Watt installed.

Grid electricity price is the average residential retail rate reported by PVWatts for the core city of the metropolitan area.

The cost of solar decreases by 7% per year.

The grid electricity price increases by 2% per year.

According to John Farrell who created the animated map, San Diego will be the first solar grid parity city, in 2013.


  1. $4/watt installed for unsubsidized solar seems low. That would mean a 2.5Kw system installed (unsubsidized) for $10,000 and I think the real numbers right now are roughly twice that, at least in major cities (where labor is more expensive.) The *subsidized* cost per installed watt is probably around $4/watt (that is, after tax incentives, etc.)

    1. According to the chart, it’s not the subsidized price.  Cheaper solar is being driven by a lot of factors including:

      Increasing efficiency of solar cells
      (ratio of electrical energy produced to sunshine energy)

      • Dramatic manufacturing technology improvements

      • Economies of scale.
      (The PV solar industry has been growing globally about 25% per year even during the recession)

  2. Does the map account for climate variance?  I suspect there would likely be some significant differences, bang-for-the-buck-wise, between solar panels installed in, say, Phoenix and those installed in Seattle.

  3. While interesting in concept, this map is largely useless, as it appears to completely fail to take into account variation in efficiency due to climate factors as well as the effect of latitude.  I can guarantee you that you will get much less electricity out of your solar panels here in Portland than you will in San Diego, which is way further south & gets a lot more sunshine!.

    1. The map DOES take into account the differences in ‘sunniness’ for different localities. Take a look at the following article from the same website to get an idea of how they figure grid parity:

      As a side note it is very possible to run a pure solar house in Seattle, my grandfather has done it for at least the last 15 years. Granted it gets less sun so needs more panels / costs more to implement than San Diego, but that is why Seattle doesn’t achieve parity until DEAD LAST at 2027.

  4. Let me preface this by saying that I like solar very much, and once solar panel production is entirely solar powered it comes close to free energy. Assuming that solar costs go down 7% a year assumes no physical limits on electron recovery, however, and that seems like something that at the very least demands reasoning to support this assumption over the next 5-10 years.

    1. In what way?  If solar panels were to achieve 100.0% efficiency and thus they could not get more efficient even in theory, the price of manufacturing them can still go down.

  5. I guess I still don’t understand why San Diego will be the first solar grid parity city  in 2013.  Is it because San Diego’s demographics tend to be mostly the wealthy class [conservative/Republican/WASP’s] who can afford to get off of the grid sooner than other less wealthy locales?

  6. No, its highly likely that we have already passed the point where we can save ourselves from the proverbial dangerous 2 degrees of warming, unless we invent something to start sucking carbon out of the atmosphere in great quantities.

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