What are the upstream impacts of internal combustion and electric vehicles?

My previous post comparing the nitrogen oxide emissions of electric and fossil-powered vehicles generated a number of comments (via social media and the blog) to the effect of:

“Power plants may be dirty, but you’re leaving out the upstream impact of refining the fossil fuels to power an ICE vehicle!”

That I did. It was only an analysis of (mostly) local NOx emissions, either from the car’s tailpipe, or the power plant used to generate the electricity (in MInnesota). NOx emissions can have significant local health impacts (inhalation, formation of ozone and smog, etc), but they can also travel long distances. Lifecycle or upstream impacts are also important to consider since we shouldn’t only be concerned about the local air quality impact of our transportation choices.

In an attempt to respond to these comments, I went digging for information on the upstream NOx impacts of the different vehicle fuels discussed in the post (electricity, gasoline and diesel).

The best, most usable, resource I found was the National Energy Technology Laboratory’s Upstream Dashboard Tool (NETL is part of the US Department of Energy). The UDT is “a fast and easy to use tool to determine the environmental profile of various energy feedstocks” according to the documentation. It includes emissions impact information on various “upstream” portions of energy fuels acquisition like raw material acquisition (mining or drilling), raw material transport (the truck, train or pipeline trip fuels must make before they are used) and the “energy conversion facility” (in the case of gas and diesel, this means the refinery process). Basically, you tell it to look at a fuel, and it will give you outputs like air and water emissions, solid waste generation, and water and land use requirements. And it’s all in an easy-to-use excel spreadsheet, just like they advertised!

This tool allowed me to look at the “upstream” impact of the coal and natural gas used in Minnesota’s power plants (to “fuel” an EV), and gasoline and diesel which would be used in ICE vehicles. So now I can answer the question: how do the fuels of ICE and electric vehicles used in Minnesota compare to each other in terms of NOx emissions, accounting for both the “tailpipe” emissions and the upstream emissions?

The upstream emissions

Here are the results from the Dashboard, translated into grams of NOx pollution per mile of vehicle travel:


The Tesla is in fact cleaner in terms of upstream emissions (before the creation of any kWh sent to the electric grid) – responsible for one third as much upstream NOx as either an average gas vehicle or one select diesel vehicle (without a defeat device). This is assuming Minnesota’s electricity mix, which includes 50 percent coal and about 14 percent natural gas. The tesla has no “energy conversion facility” emissions equivalent to a refinery for the liquid fuels, since I’m counting the burning of the coal as part of the downstream emissions.

So, extracting and refining liquid fossil fuels is in fact dirtier (in terms of NOx pollutants) than the extracting and transporting the fuel for an electric vehicle (powered from roughly 75 percent fossil fuels).

The complete picture

Now let’s take a look at the whole picture: from extraction to turning wheels. Here are the results with the downstream emissions included:


Electricity production in Minnesota is responsible for 1.4 pounds of NOx pollution per MWh, meaning an electric vehicle like the Tesla produces 0.21 grams of NOx per mile driven. With Minnesota’s current electricity generation mix, an EV is responsible for emitting about 30 percent more NOx “well to wheels” than typical gasoline vehicle, and 50 percent more than a diesel vehicle.

Electric vehicles can be better for NOx, if we kick coal

NOx rates change significantly based on the amount of coal in the electricity mix. In Oregon, which only gets 6 percent of its electricity from coal (and 32 percent from natural gas), the lifecycle NOx emissions of an EV like the Tesla would be 20 percent lower than an average gasoline vehicle. In Washington, where 75 percent of electricity comes from hyrdopower or other renewables, emissions would be less than half of a gas vehicle. In Wyoming, where 89 percent of electricity generation comes from coal, an EV would emit 80 percent more NOx per mile than a gasoline vehicle on a lifecycle basis. The United States as a whole emits 1.2 lbs of NOx per MWh, translating into a lifecycle per mile emissions rate for an EV that is about 10 percent higher than a gasoline vehicle.

Some Minnesota utilities are on a trajectory to reduce their coal use. However, there is an active political discussion going on right now about the future of coal-fired electricity in Minnesota, and the outcome is uncertain. As I said in the previous post, I think we need to electrify the transport sector to reduce climate risks. However, the choice cannot be between deploying electric vehicles or cleaning up the grid, both must be done simultaneously.


  1. If you’d like to check my math, here is the spreadsheet.
  2. This is still not a full supply-chain analysis, which would account for things like the mining of materials used to build EV batteries and car parts. This is just an analysis of fuels.
  3. Liquid fossil fuels, like gasoline, are getting dirtier over time, measured by carbon impacts, with the addition of new sources like tar sands. The UDT is based on national average compositions for gasoline, so the impact on pollutants like NOx is unclear using this approach. Regardless, electricity still needs to get a lot cleaner.

How many battery-electric vehicles are there in Minnesota?

Inspired by a previous post, I wondered how many battery-electric vehicles (cars that run on just batteries, not hybrids with plugs) there are in Minnesota. This information is not readily available from the DMV. But combining this data and this data from DOE yields an answer as of 2014: 644.

Count of Battery Electric Vehicles in the US by State - 2014

View a larger map.

Is a Tesla cleaner than a dirty diesel?

If you are a Minnesota driver, the answer is yes, but not by much it would not meet federal emissions standards for light duty vehicles. Including energy generation, a Tesla will produce slightly far fewer NOx emissions per mile than a “defeated” VW. But a Tesla in Minnesota is far three times dirtier, in terms of NOx emissions, than the average car on the road, or than federal emissions standards allow for light duty vehicles.

(I was kind of surprised by these results. If you think f I’m missing something here, let me know and I’ll make corrections to calculations and notes, as appropriate.)


Tesla is running this ad, apparently (UPDATE: this may not be an ad, but may have been produced by that twitter user. If you know the source, let me know), and Elon Musk says cars should be tested at random to see if they meet emissions requirements. This is in response to the Volkswagen Scandal.

It’s fairly clear at this point, that in many locations with cleaner electricity sources, EVs have a carbon benefit over ICE vehicles (this EPA calculator gives you results for your area). Minnesota is one of those places, even though our electricity still comes mostly from fossil fuels.

chart (3)

But what about nitrogen oxide (NOx), the pollutant at the heart of the VW Scandal? (Here’s a rundown of the bad stuff NOx does to things that breath air) A VW with a “defeat device” could emit up to 35 times the federal emissions limits for NOx. That could be as high as 2.45 grams or 0.0054 pounds per mile. So how does an EV, like the Tesla, compare?

A Tesla uses 33 kWh for every 100 miles traveled (or 0.33 kWh per mile). According to federal statistics, Minnesota power plants emit 1.4 pounds of NOx pollution for each MWh of electricity generated (Xcel Energy shows a similar 1.5 lbs/MWh in its reporting). That means a Tesla is responsible for 0.210 grams of NOx per mile. So, to fact check the ad: yes, driving a Tesla (in Minnesota) is slightly quite a bit cleaner than a diesel VW with a defeat device.

However, that Minnesota Tesla is responsible for emitting 1.5 times more NOx per mile than the dirtiest cars allowed on the road by federal emissions standards, and 3 times more NOx per mile than the allowable fleet average NOx emissions. So it’s too early for Tesla owners to get smug about their impact on the environment. In fact, they are squarely in dirty-diesel territory. (UPDATE: my math was off in the preceding calculation, it has been corrected). You might interpret that ad another way: Tesla has actually defeated emissions testing – by moving the tailpipe from the car to a distant power plant (UPDATE: again, not sure this is a real ad).

Electric vehicles can be better for NOx – if we kick coal

If you were driving a Tesla in Washington State, which has a NOx emissions rate of 0.3 lbs/MWh, you’d actually be emitting 35 percent less NOx per mile than the average light duty vehicle. Why? Because Washington residents get most of their electricity from emissions-free hydropower.

The break-even point seems to be 0.46 pounds of NOx/MWh, which is about equal to the emissions rate for the state of Oregon. This is what their electricity sources look like:

chart (4)

Oregon only gets 6 percent of its electricity from coal. Minnesota is currently at 50 percent. It’s clear what we need to do to make EVs cleaner: reduce Minnesota’s use of coal for making electricity.

We probably need to electrify transportation to meet the State’s aggressive climate action goals. However, we don’t want to just trade carbon benefits for dirtier air and all the associated impacts (asthma, deaths). We need to simultaneously begin the transition to electric vehicles, AND rapidly decarbonize and de-coal our electricity grid.


  1. Brendan Jordan asserts via twitter that 50 percent of Minnesota EV owners use wind power for their EV charging. This means they either buy, or their utility supplies, wind “credits” to supply the amount of electricity they use for EV charging. If the credit tracking system works, this wind is “additional”, and does in fact reduce emissions. If it’s true (I haven’t seen the data) that’s great, and just another argument for decarbonizing the whole grid. However, this is not the “default” when you plug your vehicle into a charging station at home or at work. Also free wind for EV charging is not offered by Xcel Energy, Minnesota’s largest utility.

Transit priorities

I have mixed feelings about streetcars. But if we’re going to pick on them, let’s do it for the right reasons, like the fact that they don’t have dedicated right of way.  Yesterday the Pioneer Press reported that the Met Council was presented with a report about streetcars that “questions whether the costs outweigh the gains”.

Dollars are one way to measure cost, and if we’re spending too much to get gains, that is bad. How much money do we spend on transit elsewhere to get gains?

The proposed Nicollet streetcar in Minneapolis will cost $200 million and serve 9,200 riders in 2030. Bus Rapid Transit proposed for the Gateway Corridor will cost $469 million and serve 9,300 riders in 2030.  That’s double the cost per rider.  The Met Council has already adopted its Transportation Policy Plan, which includes the build-out of Gateway in the “Current Revenue Scenario” (meaning they don’t need any new money from the legislature or others). Bottineau and Southwest LRT also come in with price tags significantly higher per rider than the Minneapolis streetcar (Southwest is more than double).

Yes, we could be choosing arterial bus improvements on Nicollet instead of streetcars. That might be good.  But we could also be prioritizing expenditures across our regional transit system – looking at projects that have the highest cost-effectiveness per rider, or that most effectively address current inequities in job or destination access.

If we were really serious about costs and benefits, we’d be building projects like Hennepin Avenue Bus Rapid Transit tomorrow, which has a cost per rider 55 times lower than Gateway Corridor.  Instead, it’s on the “Increased Revenue Scenario” list, waiting in the breadline with the other high-value bus improvement projects, for the legislature to maybe, someday, hopefully fund.

Creating a low-carbon transportation system for MSP: Part One, Baselining

My latest at streets.mn does the carbon accounting which should have been part of the Draft 2040 Transportation Policy Plan developed by the Met Council.

Thrive MSP 2040, the new regional plan for the 7-county metro adopted by the Metropolitan Council, includes moderately strong language about addressing climate change.  But the main implementation tool we’ve seen so far from the Council, the Draft 2040 Transportation Policy Plan, doesn’t go nearly far enough.  In fact, it doesn’t even start where it should, with a baseline of emissions.

In this and future posts, I’ll try to do what I think the Draft Transportation Policy Plan should have done – identify where we’re starting from and where we need to go in terms of transportation-related greenhouse gas emissions.

It’s got charts, so you’ll want to read the rest.

My comments on the Draft Transportation Policy Plan

CurrentRevenueThe Metropolitan Council held a public hearing tonight on their draft Transportation Policy Plan. If you care about transit or transportation issues in the region, you should comment (you can do so through October 1). Here are four comments I have on the plan:

  1. Our urban areas are significantly underserved by this plan. Even under the “increased revenue scenario”, we will spend $5 on transit to serve suburban commuters for every $1 we spend on transit improvements to places where transit makes economic sense (see here for my attempt at a geographic breakdown of projects). The Met Council, in the Thrive 2040 plan, has said they want to match transit service to the number of riders and intensity of land use. This plan does not do that.
  2. The plan currently prioritizes projects like Gateway BRT (9,000 riders at $50,000 per rider) over projects like Hennepin Ave BRT (23,000 riders at $896 per rider). This is an example of how our urban areas (that are expected to grow significantly) are underrepresented in this plan.
  3. The Transportation Policy Plan, as an implementation plan of Thrive 2040, should identify how our transportation system will be planned to reduce greenhouse gas emissions (another goal of Thrive). While the plan mentions “reducing vehicle trips”, there is no analysis in the plan of whether the scenarios presented will increase or decrease emissions from our regional transportation system. We can’t wait another 10 years for the next update of the regional plan to take significant action on climate change.
  4. It’s definitely not all bad. The Met Council for the first time has identified regional priorities for a bicycle network, which will give communities the ability to apply for funds to upgrade their local network if it matches the regional plan. Many of the transit projects identified are much needed improvements (Hennepin, Chicago, West Broadway), but are simply not adequately prioritized.

Let’s be pro-transit

My latest at streets.mn is all about positivity:

I’ll start by saying I have strong feelings about Southwest LRT. So do some people on this very blog. You probably do too. However, I won’t be contributing further to the gallons of spilled real and virtual ink or weeks of public testimony.  I’d like to talk about how we can set the stage for some other projects that could be really beneficial for transit-dependent and transit-interested communities. Nothing in this post should be interpreted as diminishing the importance of that LRT project, the upcoming decisions that will determine it’s fate/depth of its tunnel, or the correctness of any particular opinion about it.  But I have this urge to start some positive conversations about other projects that need some support.  Weird, right?

Car2Go first impressions

Over at streets.mn, I detail some of my first impressions of one of Minneapolis’ newest car-sharing options, Car2Go.

According to MPR, by 2014 there will be over 400 vehicles available to car-sharing customers.

The bulk of these will be in the fleet of Car2Go, which operates on a different business model than the rest, offerring “point to point” service.  Walk to a car anywhere in Minneapolis, drive where you want to go, then park it at any curb space in Minneapolis (expect rush hour zones).  Other companies require that you return their cars to a specified location at a specified time.  The trade-off is that their rates are generally cheaper.

Read the rest.

The greenhouse gas benefits of autonomous vehicles

stanley side view (2005-023-040)

Autonomous vehicles may bring a myriad of benefits, but I anticipate that one of the largest may be the actual reduction in the total size of the vehicle fleet.  Eventually autonomous vehicles will allow “whistlecar” service, and whether fully autonomous or not would, this service is likely to fundamentally change the ownership model of automobiles.  Like present-day car-sharing services or taxis, a whistlecar subscription would mean one car could serve the needs of many people, instead of remaining parked most of the day waiting for its one owner to return.  Once you’re done with a car, it can drive off and serve someone else in the vicinity, drive to a charging station (if it’s electric), drive to a garage for service, or perhaps even deliver packages.  When you can subscribe to an on-demand travel service available 24-7 (and eventually cheaper than owning a car), many people will choose not to own.

Setting aside all the other benefits of autonomous vehicles for the moment, I’ll explore just this one: the benefits of a reduction in the car fleet.  And in a limited way: the greenhouse gas implications of this reduction in vehicles. Continue reading