Is The US Grid Really Getting Greener For Our Electric Cars?


A Chevrolet Volt Taps The Grid For A Little Juice

A Chevrolet Volt Taps The Grid For A Little Juice

InsideEVs readers are all more than familiar with the long tail pipe argument against EVs.  There have been many academic studies conducted to prove that grid powered EVs are cleaner than an ICE, so we will try not to repeat any of that work.

Instead, we decided to pull the most up-to-date data from (2003 – Feb 2013) and see what the trends are for the US on the whole.  Below you can see the annual output by source:

All Data Via  -- Click To Enlarge

All Data Via — Click To Enlarge  (Note: 2013 numbers are for the trailing 12 months ending February 2013, as to not skew for the seasonality of power production)

The big trends to take notice of are massive decline in petroleum and coal and the noticeable decline in nuclear production.  These declines are mostly compensated for with the nearly doubling of natural gas generation and a ten-fold increase in wind production.

Solar has also seen a ten-fold increase in production, but its absolute numbers are still very low.  However, the trend is moving in the right direction, and fast.

Also look at the relatively flat total electricity demand.  There has been no significant elevation in demand for the last 10 years.  In that time lots of new capacity has hit the grid, outpacing retirements of old facilities.  That means there are assets under-producing, which conveniently answers the “can the grid handle it” question that is often the follow on to the long tailpipe argument.

All Data Via  -- Click To Enlarge

All Data Via — Click To Enlarge

In the data above, the decline in coal use is obvious, dropping 13% in ten years.  Since there are many critics for and against nuclear being renewable, I displayed the data both with and without nuclear.  Geothermal, Biomass, Solar, and especially wind have all made gains to increase the contribution to the grid by roughly 3% over the last 10 years.

With the record capacity installations of wind and solar recently, it will be interesting to see what the full year 2013 production data looks like.

We will leave you with the graphical version of this data.  Let us know what other trends you find in the comments.

All Data Via -- Click To Enlarge

All Data Via — Click To Enlarge

Categories: Charging, General


Leave a Reply

12 Comments on "Is The US Grid Really Getting Greener For Our Electric Cars?"

newest oldest most voted

What is up-to-date KWh CO2 cost? Say, for 2012 year.

Pulling the 2012 data from for CO2 emissions from electricity generation (2,039 million metric tons), and dividing by the total energy produced in 2012 (4,061,658 MWh), gives 0.502 metric tons / kWh. Additionally coal counts for an oversized 74% of those emissions (1,514 MMT / 2,039 MMT) while only producing 37.4% of the power.


likely per Mwh
it gives 502g=1.1pounds per KWh

as here you have
705g=1.554 pounds perKWh for 2009year, it’s great improvement

and here i found another number:
The 1999 national average output rate,(4) 1.341 pounds of CO2
It equals 608g per Kwh
So 2009 numbers looks very strange, but anyway, improvement is actual

Sorry, that power number was in Thousand MWh not MWh, so move some decimals around and it gives you 0.502 kg / kWh. Never do math before morning coffee…


And comparing
2012 Nissan Leaf
25 miles: 8.5 KWh (EPA)
Total 4.26kg of CO2

2012 Nissan Tiida (same car body gasoline car)
1 mile: 335g
25 miles: 8.375kg of CO2
So even the average grid is already twice better

Mark H

Very very nice read Josh. Well done!


What’s always lost in naysayers’ long-tailpipe arguments is the fact that such a ridiculous number of EV buyers install solar. So while it’s already greener to drive electric, buying an EV has been a catalyst for folks to seriously go green. I personally installed enough PV after our Leaf purchase that we could power five EV’s.

I would imagine the solar installs will decrease as a ratio once they become more mainstream, but who knows, maybe not? I would love to see it become the new norm to have both.

I am not sure how residential PV is counted in these numbers. gets data on power produced for the grid. I am digging more to clarify how they handle net metered PV.

Gregory Lemieux

I just have to point out something that really hit me looking at these graphs. Nuclear is nearly on par with natural gas in total generation (although natural gas has gone up in recent years). I dug into the data on the website and learned that just 66 nuclear plants generated 790 million MWh in 2011! Compare that to the 1646 natural gas plants generating 1,013 million MWh. It really gives you a sense of the energy density inherit in nuclear power. Not to mention that it’s basically CO2 free energy.


Just BTW: Why is power cheaper at night, wholesale, or with retail time-based rate plans? Because, in the middle of the night, your power company is wasting fuel keeping their large generators spinning. Load may be at 20%, but the plant will be burning 50% of the fuel it uses at peak demand in the middle of the day, not 20%. It’s almost exactly like a gas car at a red light, or coasting down a hill, or only using 3hp going level at 30mph, but still using 6hp or more worth of gas. The first wave of electric car owners charging at night will not produce ANY EMISSIONS. Tell that to the next person who brings up the long tailpipe.

There are many complexities to wholesale power pricing, but I will give you a couple of the main drivers for low prices during low demand.

The grid will always attempt to dispatch the cheapest forms of energy available. This dispatching is typically done on a hourly bases based on the predicted demand. Whatever sources offer the lowest pricing during low demand get dispatched.

There are often times where energy sources that have a hard time ramping up and down (nuclear and coal) offer prices below what is profitable, because they know demand will come back up in the next hour and do not want to shut the assert down.