Map Monday: Rooftop Solar Grid Parity

Here’s a map that crossed my desk this morning all about how affordable rooftop solar is becoming in many places around the US. (This comes from a big infographic out of the Union of Concerned Scientists…)

rooftop solar map

It doesn’t take a rocket scientist to figure out why Minnesota might be a bit slow with this particular technology. This time of year, the sun can’t shine its way out of a paper bag. I’d bet it also depends on the regional cost of energy.

How might a greater reliance on rooftop solar affect urban development patterns, both here and elsewhere?

13 thoughts on “Map Monday: Rooftop Solar Grid Parity

  1. Steven Prince

    Wow, if this was mapped by population of the states instead of by area, it looks like the now + near-term states represent the majority of the U.S. population.

  2. Thomas Mercier

    What do they have against Alaska that they aren’t willing to do the analysis for them?

      1. Thomas Mercier

        They actually say in the small, blurry text that Hawaii and Washington D.C. are in the now category but just say they ignored Alaska.

        1. Nathanael

          Alaska is also in the “now” category, largely because it has the 5th highest grid electricity prices in the nation. (Hawaii has the highest.)

          These numbers *do* disguise variations within each state; different regions have wildly different grid prices.

          Long Island and New York City have expensive grid electricity; Buffalo and Niagara Falls have cheap grid electricity (thank you Niagara Falls), so solar usually isn’t cheaper than grid out in Western NY. Of course with the grid being hydro, this is not an environmental problem.

          Alaska’s even more extreme. In the more rural areas, going completely off-grid with battery backup is far cheaper than buying electricity off the grid.

          1. Nathanael

            I should also point out that in Washington State and Oregon, just like in upstate NY, the areas with cheap grid electricity are largely hydropowered. So it isn’t terribly important environmentally that solar doesn’t have grid parity in those areas. It’s more of an issue in the Midwest and Southeast where coal is still used.

  3. Alex

    The Wisconsin Public Service Commission just allowed WE Energy (provider basically all of SE Wisconsin) to restructure their rates in a way that is both unfavorable to consumer solar and to energy conservation. Basically they’re jacking up their base fee, so that there is less incentive for reducing usage. Probably someone in the Walker administration saw this map as a challenge.

  4. David MarkleDavid Markle

    Solar heating (and systems that involve subsoil plumbing) also remain underutilized here, and could offer attractive long-term savings for those building new homes in this climate.

  5. Dan Thiede

    Hi Bill–thanks for the post! You actually might be surprised to know that Minnesota is a great place for solar energy, even in the winter. Much of Minnesota, for instance, is just as sunny as places like Tallahassee, FL and Austin, TX, and we’re 23% more sunny than Germany, the global solar leader.

    When you’re talking about grid parity it’s a little harder in MN because the electricity costs are so much lower than places like HI ($0.38), NY ($0.21), and CA ($0.17) where solar is really taking off. In MN we’re at $0.12, but that’s still high in the Upper Midwest. Despite this, in Minnesota a suite of commercial-scale solar installations recently beat out natural gas in proposals for new generation to Xcel Energy. In part this is because solar module prices are down 75% since 2008.

    High electricity costs, pro-solar policies, incentives, and financing are key drivers. A new suite of solar-boosting policies was passed by the Minnesota legislature in 2013. One of them requires that 1.5% of electricity be generated from solar by 2020. This will have a dramatic impact on the growth of solar in the state, with a rise to 400 MW of solar in 2020 from the current 14 MW. This is a 28-fold increase over today’s installed capacity, and it is estimated that 28 MW will be from consumer residential systems, an increase from the current 1,000 systems to 4,000. This level of growth represents a boom from the relatively slow growth of solar adoption in previous decades. There are also federal, state, and utility incentives that can currently take care of a large share of the price of solar. Given this mix, the time could not be better for those who want to go solar.

    If you’re wondering about the solar potential of any place in Minnesota, the Clean Energy Resource Teams where I work has partnered with U-Spatial at the University of Minnesota to create a Minnesota Solar Suitability App that lets you explore every square meter of the state. You can check it out at

    And if you don’t live in a particularly sunny spot or you can’t install solar for some other reason, a new program in Minnesota called Community Solar Gardens now allows you to subscribe to large solar projects and directly benefit from the solar they produce–you actually get a credit on your utility bill. More about that at

    Dan Thiede
    CERTs Communications Manager or 612.626.0556

  6. Sam RockwellSam

    Rooftop solar is a great carbon-free source of energy. However, in the urban development pattern context, solar can potentially lead to unexpected negative results.

    Solar panels are only as good as the sunlight they receive. Therefore, advocates of solar often advocate for laws that protect sunlight access to panels to guarantee a return on investment for the panels. These laws can take the form of “solar easements” that prevent owners of adjoining property from letting trees grow too tall or building structures that block sunlight.

    These solar easements could prevent construction or a multifamily or apartment building if that building might block sun. The irony is that multifamily units usually decrease energy consumption because of shared internal walls (heat leaks from one unit to another instead of out of the building) and because of the potential for car-lite or free living in dense neighborhoods.

    The last thing Minnesota needs is another tool to block dense development….

    1. Dan Thiede

      Hi Sam, I think that you will find very few situations in which solar is competing with dense development. In fact, much of the large, commercial-scale projects that will be going in are in much less developed areas where there are not a lot of competing land uses.

      It would be perfect for multi-family buildings to put solar on their rooves, just like Hope Community’s Wellstone building on Franklin in Minneapolis (MPR story on that here: They have large rooves and lots of people using hot water and electricity–a natural fit.

      If you know of specific situations where solar is competing with good, dense development I’d love to know about them. Otherwise I have to think that local governments are carefully weighing costs and benefits when they make these sorts of development decisions.

      We think that tools like the Minnesota Solar Suitability App ( will be groundbreaking for helping solar development in the state, reducing soft costs for installers, and providing consumer protection.

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