Solar Alone

In this post I talk about when, from a carbon footprint savings standpoint, it makes the most sense to just put some Solar Panels on your roof and forget about a Home Battery for now. The sources I used for this post are: and

If you've read some of the previous posts, you know that the argument I make is that if you're going to put Solar Panels on your roof, Home Batteries become essential if your area already gets above 10 to 13% of its electricity from Solar. Adding more Solar beyond this 10 - 13% results in fossil fuel power plant cycling (turning off then back on) which largely wastes the carbon savings you should be getting you Solar Panels. Check out the earlier posts to learn more! So... basically the flip side of this argument is that if your area is below 10 - 13% Solar generation then, from a carbon savings standpoint, it is better to forget about a Home Battery for now. And... the vast majority of the US is below 10%, which would mean the vast majority of the time it's best to forget about a Home Battery (for now). So here's the basic breakdown as of 2015 (I will update this with 2016 numbers when they come out):

  • Hawaii 18%
  • California 9% (a 46% increase from 2014!)
  • Vermont 5.7%
  • Nevada 4.5%
  • Massachusetts 4.2%
  • Arizona 3.5%
  • New Jersey 2.6%
  • New Mexico 2.4%
  • North Carolina 1.5%
  • Delaware 1.5%
  • Texas 1.3%
  • Colorado 1.3%
  • Maryland 1.1%
  • US total 0.86% (up from 0.6% in 2014, a 30% increase)

...and every other state is less than 1%. Note that in the map I referenced above they show Florida at 8% Solar which is an error (you have so much potential though, Florida!) These are the real actual generation numbers reported to the EIA for 2015, and even better the EIA totals the numbers from both large utility scale Solar PV plants and homeowner rooftop Solar. As far as I can tell these numbers are the best numbers out there. In 2016, 36% of new electric capacity added to the grid will be from Solar.

Ok so basically I'm saying that as of now (2017) other than Hawaii and California it's best to add Solar Panels but not a Home Battery.

But... a couple of little caveats. Currently about 70% of Solar electricity is generated from large utility scale Solar plants and about 30% from homeowner rooftops. As more homeowners add panels, that results in a steady upward trajectory for Solar. But when a large utility scale Solar plant opens, that results in a sudden jump for Solar. So if your state has a bunch of big Solar projects about to open, your state might be in for a big jump! Many big projects are planned in really sunny places (duh) -- see More specifically, a recent article by Jeff St John at GreenTechMedia quotes Greg Litra, of ScottMadden consulting who says: "Growing numbers of utility-scale installations could mean that 'the duck' could migrate to states like Arizona, Georgia, Nevada, North Carolina and Texas in the not-too-distant future." (source:

To unpack that quote a little bit, by "the duck" he is referring to "the duck curve" which is a term describing how Solar during the middle of the day lowers the demand on fossil fuel power plants, but then increases this demand on fossil fuel plants suddenly as the sun goes down. For those interested, the now famous original article on "the duck curve" is here:

So... if you live in a really sunny place with big Solar plants soon to come (like Arizona, Nevada, or Texas) then you might consider a Home Battery a little bit more than otherwise. North Carolina is only at 1.5% but that will be increasing pretty quickly. And Georgia is below 1% but is slated for some big projects too. And finally Vermont is already at 5.7%. 

In the next post I will discuss where you should consider Solar Panels plus a Home Battery:  California!