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How Dirty Is Your State’s Electricity?

Photo By Walter, From Https://

I’ve been working on my presentation for the 10th anniversary of the North American Passive House Conference. It’s on the global warming impact of insulation, a followup to my latest article about Alex Wilson’s work on that subject. One of the things I wanted to do was to see what difference it made when a home used “dirty electricity,” with a high carbon intensity, versus a home using “clean electricity.” The Emissions & Generation Resource Integrated Database (eGRID) from the US Environmental Protection Agency, has the data I was looking for.

When you scroll to the bottom of the eGRID page, you’ll see a link for eGRID2012 Data File (XLS). That gets you their full data set. It includes far more than I was looking for: It’s got SOx and NOx and mercury and all kinds of good data, split up various ways. It’s a really nice spreadsheet!

What I wanted was carbon intensity of electricity in the 50 states of the US, and that was in there. They gave it in units of pounds per megawatt-hour and I wanted kilograms per kilowatt-hour, but that was an easy calculation.

Once I had kg CO2 emissions per kWh of electricity produced in a single column, I could see which states were best and which were worst. This morning I created a column chart of those data so you can see easily where your state fits in.

Here in Georgia, I’m in the middle of the pack at about 0.5 kg/kWh. The worst states are Wyoming, Kentucky, and West Virginia. Know what they have in common? The best is Vermont, which is so low you can’t even see the column on this chart. Their number is 0.002 kg/kWh.

One important fact to note about this chart is that the numbers here are for electricity generated in each state, not the electricity used. Because the electric grid crosses state, and country, lines, there’s a lot of export and import of electricity across state lines. A look at the regional carbon intensity would give a better idea of what you’re using. Best would be to have the data for your electric utility.

How much carbon is in your state’s electricity?


N.B. The North American Passive House Conference is coming up in three weeks. I think I’ve got some really good analysis on the global warming impact of insulation, so sign up and show up for my presentation in Philadelphia!


Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and writes the Energy Vanguard Blog. He is also writing a book on building science. You can follow him on Twitter at @EnergyVanguard.


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This Post Has 22 Comments

  1. Allison, you are a treasure
    Allison, you are a treasure for digging up these marvelously geeky sources. 🙂
    I’ll dig into this a bit myself, but is this electricity generated within a state or used within a state? The interstate transmission of electricity makes these data a little less absolute, although still extremely valuable.
    As for my Vermont neighbors, now that the Vermont Yankee Nuclear plant has closed I’m guessing that their carbon load has risen slightly.
    All in all good stuff. It shows us where we need to work to improve things.

  2. Thanks, Bill. Great question
    Thanks, Bill. Great question about used vs. generated in a state. I’ll have to see what I can find out.

  3. At the moment our power in
    At the moment our power in North Florida is cleaner than normal, mostly because so much of it is out!

  4. Interesting article.
    Interesting article. Politics and geography play a huge part in the feasibility of alternative power generation. Here in UT, we have abundant sunshine and great potential for PV, but our provider is Pacificorp, owned by Warren Buffet’s Berkshire Hathaway and he only like PV which he controls. BH lobbied the NV legislature to effectively prohibit PV in that state. He is working hard to do the same in UT.

    Obviously, the ‘cleanest’ power on a CO2 scale is nuclear, PV and wind. I have to wonder if the data on VT is correct considering that VT Yankee was decommissioned in 2014

  5. I got the answer from my
    I got the answer from my friend Skylar Swinford. He lives in Idaho and said their number, 0.05 kg/kWh, is misleading because they export their hydroelectricity and import coal and natural gas. I’ve added another paragraph near the bottom of the article to explain that.

  6. North Dakota sits near the
    North Dakota sits near the top of this list yet we have among some of the cleanest air in the world. Beautiful blue skies and abundant wildlife…tell me again why we need to dump coal?

  7. Very interesting graph. It
    Very interesting graph. It is odd to look at my state, MT, and see the fairly high carbon intensity and think about the clean power plan requirement for us that is quite high. Yet, on the west side of the state, where we are, our power comes almost completely from hydro with no coal which is what is driving the high number. As you said, interstate electric transport makes state levels of carbon in their electricity so mis-leading. I think looking at insulation value based on carbon emissions from the electricity source is fascinating but unless you know the historical numbers from the actual electric provider you could be way off using a state level number. Thanks for sharing though.

  8. Allison, Yes you are “stacked
    Allison, Yes you are “stacked” with energy information thanks again for sharing and caring. We are learning and improving here in Colorado, still have a way to go, but working on it.

  9. Mercury (HG). Coal contains
    Mercury (HG). Coal contains trace amounts of mercury that, when burned, enter the environment and human bodies, effecting intellectual development.

  10. My home state of Oregon is
    My home state of Oregon is near the bottom on this chart due to the high percentage of hydroelectric power generated from our dammed rivers. Hydro serves most of the “old load” from our buildings and industry, but any new load is served by coal and gas-fired generation, so it’s fair to place new construction in Oregon up there with North Dakota. I seriously doubt we’ll ever dam another river in the Northwest and gradually the existing dams are coming down.

    Insulating and air sealing our new homes and buildings is important to reduce the increase in energy use and emissions, but to reduce the existing load we must retrofit our built environment with responsible energy efficiency measures.

    Build Tight and Ventilate Right. “Right” Ventilation is balanced, filtered, and distributed with energy recovery if it makes economic and environmental sense.

  11. Jonathan, I wasn’t aware that
    Jonathan, I wasn’t aware that Berkshire Hathaway was bad for solar. Regarding Vermont, the data shown here are from 2012.

  12. David, yes, having actual
    David, yes, having actual emissions data from the electric utility you use would be the best. If you wanted to know your actual carbon footprint, you’d have to get updates regularly to account for varying fuel mixes and import/export of electricity.

  13. Yeah, Dennis, the Rocky
    Yeah, Dennis, the Rocky Mountain region is the worst when you look at the regional data. But the solar age is just beginning.

  14. Jonathan is correct about BH
    Jonathan is correct about BH involvement in NV’s electric supply. They own NVEnergy and have suppressed rooftop solar, but are encouraging mega-solar installations. A ballot referendum to add rooftop solar options by legislation was denied by our Supreme Court for…reasons. Under great pressure, NVEnergy grandfathered in existing rooftop solar customers when a new rate structure decimated paybacks.

    One other item, we now have an option from NVEnergy to choose 50% or 100% (for an added fee) of our power from renewables:

  15. This video makes the point
    This video makes the point that when solar becomes cheaper than the cost of transmission, then centralized utilities become obsolete and all the “Dirt” is gone. We are closer than I thought: by 2022 solar collection will be cheaper than the transmission cost to say nothing of the cost to produce the power in the first place. This is the big disruption that will occur.

    My question is, how does energy conservation play into all this? I believe we can save energy cheaper than we can collect and store it but if we cannot, does that mean the end of our industry?
    interested in youall’s input.

  16. I don’t think so, Colin. But
    I don’t think so, Colin. But you raise a good point, which I’ve been concerned about for some time. The solar industry are making great progress, bless their hearts, but they won’t wait for efficiency. If they blaze past “price parity” in the next 5 years, as predicted, they will continue growing indefinitely, and they won’t wait for efficiency jobs to make money selling distributed power generation. So those of us who focus on efficiency will have to swim against that current. Plan on it. On the other hand, efficiency always improves (over the long run) in every industry. Plus, the benefits of high performance buildings far exceed the energy savings. Comfort. Health. Durability. Resilience. You can’t get these benefits reliably without getting control of your losses and flows. Efficiency will survive as a viable industry, but the inevitable growth of renewables will not make it easy. Fasten your seat belts. We’re about to experience some turbulence.

  17. Interesting contrast with SD.
    Interesting contrast with SD. Dump coal because your mercury is blowing down wind. MI mercury is blowing downwind getting into the great lakes where we need to limit the amount of fish we eat.

  18. Rooftop solar isn’t what will
    Rooftop solar isn’t what will kill EE. Both are becoming victims of their own success. Indeed, what will kill EE and rooftop solar is the utility industry as it shifts toward price structures that ensure recovery of its sunk infrastructure investments. The more efficient we make our buildings and move toward net zero with on-site generation, the more utilities will have to adopt new rate structures to cover sunk costs.

    This shift is already beginning to happen. Regulators, regardless of political stripe, won’t be able to stop this trend. The only question is how it gets addressed.

    In the residential sector, infrastructure costs are largely recovered through inflated kWh charges. Generally speaking, there are two pricing strategies that can protect a utility from under-recovery of sunk costs: (a) increase flat rates while reducing kWh charges, or (b) impose time-of-use (TOU) and/or demand (kW) charges.

    When a utility shifts from kWh to flat charges, this acts as a incentive to do nothing and flies in the face of the so-called smart grid. A giant step backward on several levels. Dumb.

    On the other hand, a shift toward mandatory TOU and/or demand charges depreciates EE, while incentivizing storage and advanced load management technologies. Installing high efficiency equipment, fixing leaky ducts, or adding more insulation only has a marginal impact on energy bills when the bulk of the bill is based on time-of-use or peak demand. That same investment focused on storage or load management tech will always yield greater savings. This is where our industry needs to go. Where we must go. Get ready.

  19. Excellent Post, David.
    Excellent Post, David.

    Witness the changes in the NV Energy billing for solar customers.

    NV Energy currently charges all ratepayers, including solar customers, a fixed service fee of $12.75. With the rates approved by the PUC going into effect Friday, solar customers will pay $17.90 starting Jan. 1. By Jan. 1, 2020, that fee will rise to $38.51.

    Under a policy known as net metering, NV Energy reimburses solar customers about 11 cents for per kilowatt-hour of excess energy they generate. The value of those credits will slip to about 9 cents Friday and eventually reach 2.6 cents in 2020.
    Buffet’s companies have PPA’s with CA at over $.05/kw, but he will be paying rooftop solar producers only $.026….

  20. Golden wrote an article
    Golden wrote an article showing EE is still one quarter the cost of solar. I can see where storage would be a good investment against TOU charges. If EE was high, then could selling your solar during peaks make enough to make that worthwhile? Clearly it depends on price being paid and since that is diminishing then maybe that is my answer.

    A house has only so much area to collect solar so if EE is high then they can store more also.

    What then is a winning strategy for EE? Can we sell it to the forward thinking utilities who have not overpaid for obsolete generation infrastructure? Can we get to a point where there is enough solar and storage that utilities simply can no longer be viable?

  21. @Colin, keep in mind that for
    @Colin, keep in mind that for now, TOU (and kW demand) tariffs are optional for nearly all residential customers. In that context, it makes no sense for most folks to sign up for a TOU rate just to make a storage more attractive economically.

    Likewise, in markets that are losing retail net metering, it makes no sense to spend $$ on storage in order to make a yet-to-be purchased PV system more attractive. You have to look at both together and separately and compare with all rate schedules that may be available.

    Also keep in mind that peak periods under TOU and demand tariffs don’t often align particularly well with PV output. In my experience doing this type of analysis, it usually works out that less than 1/3rd of PV output occurs on-peak.

    And finally, any estimate of the relative value of EE vs. PV (such as the “one quarter” statistic you cite) is only useful in the aggregate. For any given home, the cost-value proposition of EE is always continuum — from low-cost high-value measures to high-cost low-value measures, and everything in between. The sweet spot of EE vs PV (and/or storage) is highly dependent upon the specific circumstances for a given home.

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