Electric Transportation and the Environment
As part of an ongoing conversation on the environmental validity of electric vehicles, frequent commenter Glenn Doty writes:
… Every minute of usage from an EV bought or sold this year (or the next two or three decades for that matter), will always result in net additional damage to the environment rather than net additional good.
This is a quick excerpt from his much longer and quite thoughtful comment to the post linked above. I encourage readers to check it out.
I make a couple of points in response:
First, I need to understand the math here. Of the many thousands of people of science who have spent their careers studying the subject, as far as I can see, Glenn is the only one who comes up with such poor results for the environmental impact of electric transportation. Having said that, I note that there are many different ways to examine the issue. For example, most people do not account for what I see as the largest single cost of our dependence on oil: the military cost, in both dollars and lives, to maintain our access to petroleum around the world.
Secondly, looking at the big picture, we are part of a civilization, which, if it is to survive, must migrate from the use of hydrocarbon fuels, especially fossil fuels, in favor of renewables. I believe we should do everything we can to achieve this end. If this means selling EVs during the transition, and having some of them charged with electricity generated from coal-fired power plants, one could argue that this is acceptable, as it’s key to facilitating the much larger process; it’s a means to an end. While this is all happening, we are retiring coal plants, and building out our infrastructure to include high-voltage transmission to accommodate more wind and solar, smart-grid, energy storage (including EV batteries), etc.
Third — a key point that many people miss — because of the extreme inefficiency of internal combustion engines and the corresponding high efficiency of charging batteries and discharging them via electric motors, we can replace 100% of the cars and truck on our roads (not that this is happening tomorrow) with an increase in electrical power generation of only 14%.
Of course, a key piece of this conversation is: what is the rate of progress that our society is making towards a sustainable approach to energy and transportation? To me, it’s not so much a technological discussion, but rather a political one. In particular, do we have the political will to force our leaders in the direction of sustainability? So far, the answer seems to be no.
ExxonMobil’s ubiquitous advertisement, to the effect that the U.S. now generates more than half its energy domestically, is an effort to shut up those of use who are concerned about the national security issues associated with petroleum, e.g., fueling terrorism. Along with the other $1 billion spent by the oil companies and other conservative factions to convince us that global warming is a hoax, all this has been quite effective in obscuring the main issue: the continued and ever-expanding dependence of fossil fuels is destroying the only planet we have.
et tu, Craig?
🙂
Rhetorical devices never looks good on anyone, but it is more disappointing on this blog than most.
First: We’re treading well traveled ground here. When you plug in an electric car, you increase demand for electricity. That INCREASE in demand load must be responded to with spare capacity, not grid mix. There has not been one single study in support of electric vehicles that has ever analyzed spare capacity – they all use grid mix… which is nothing short of sophistry at its worst. By using grid mix, the supposition is that when a person plugs in an EV, the sun shines a little brighter on the solar collectors, gravity intensifies a little at hydropower dams, Planks Constant changes a little – allowing greater energy return from the nuclear power reactors, and the wind blows a little harder on the wind turbines – all so these energy sources that have no spare capacity can increase in perfect proportion to satisfy the new demand load. This supposition is nothing less than flat-out stupid.
The only energy sources that respond to iterative increases in demand load are sources that have spare capacity. The sources that have spare capacity are coal, natural gas, and diesel. You likely laughed when I mentioned “diesel”, because it would be foolish to assume they would choose the high-cost diesel when they could choose the lower-cost natural gas. But you are then assuming they would choose the high cost natural gas rather than choosing the lower-cost coal. The truth is there would be a mixture of coal and natural gas, heavily favoring coal, to satisfy the EV demand.
The fact that these “scientists” cannot avoid the simplest form of logical fallacy in a study that they are paid to conduct is all you will ever need to know about them.
I am hardly alone. I do not know a single person – an any field – that does not recognize the problems with electric vehicles. That includes you Craig… In the past we’ve had this conversation and you have yourself have conceded – and even posted – that under the current grid conditions electric vehicles are worse for the environment because they burn coal.
Whatever political mechanism there is keeping the support for EV’s alive, it has nothing to do with whether the advocates actually believe that this is good for the environment (it’s not), and I am hardly alone… though few people who understand it care enough about it to be politically active (the most informed people in the world on this topic work for power companies and grid management – these people desperately want less variation from peak to off-peak, which is something EV’s provide.).
Second, we cannot migrate from fossil fuels by migrating to natural gas and coal (the only sources of spare capacity on the grid in most regions on the country). Those are both fossil fuels. The only question is which path causes more damage. The math:
Every kWh of coal-sourced electricity results in ~1.1 kg of CO2, ~1 g of SO2, ~500 mg NOx, ~100 mg of CO, ~25 mg of VOC’s, ~5-50 mg of particulate soot, ~0.3 mg of Hg, ~0.2 mg of Pb, ~0.01 mg of Cd and other toxic metals, and ~0.1 ng of radioactive isotopes.
Every kWh of natural gas-sourced electricity results in ~0.5 kg of CO2,,and ~15 g of CH4 (leakage from piping to the power plants), and very little of the other pollution recognized from coal – though there clearly will be more CO, and some NOx, VOC’s, and soot; while SO2, Pb, Cd, and other toxins will be at least 2 orders of magnitude lower… I don’t have access to any good study on the exact nature of the emissions profile other than GHG related emissions.
Every gallon of tar-sands-sourced gasoline emits ~14 kg of CO2, ~20 mg of SO2, and >1 ug of any metal. There will be some CO, VOC’s, and NOx – based largely on the vehicles exhaust system and the age of the catalytic converter. These will be somewhere between the coal and natural gas-sourced electricity profiles for the average vehicle..
If you just take the assumption that a vehicle will use natural gas-source electricity (sophistry), and you just want to compare the GHG emissions of the Tesla S (37 kWh/100 miles) vs the Lexus E5 300h (40 mpg)… So first we need to avoid another dumb supposition: “if it takes 37 kWh of electricity from the battery to travel 100 miles, then the power company is generating 100 kWh of electricity for every 100 miles traveled). That’s dumb. We’ll be kind and only assume a 10% loss on the battery charging, and we’ll assume a 6% transmission loss. So the 37 kWh that it takes to move the Tesla S 100 miles requires 43 kWh.
You have the following:
Tesla: 43 kWh * (0.5 kg/kWh-CO2 + 0.015 kg-CH4/kWh) = 21.5 kg-CO2 + 0.645 kg-CH4, for a total of ~35 kg-CO2e of global warming emissions.
Lexus: 2.5 gallons of gasoline * 14 kg-CO2/gal = 35 kg-CO2 total global warming emissions.
So if you assume 100% natural gas sourced electricity, it’s a wash between a high quality luxury hybrid vehicle burning gasoline, and the Tesla S (other than the embodied carbon, which is probably 10-15 tons-CO2e greater for the Tesla S). If you assume even 1% of the energy is coal, we start seeing far worse emissions for the Tesla S than the Lexus. If we consider the fact that the Tesla S burns electricity constantly while it’s not being driven… then the comparison gets worse still.
Third – a key point many people mis-state – is that Americans travel ~2.98 trillion miles in any given year. If we see 100% of that transferred to Tesla S’s, then we’ll have a total of 1.28 PWh of additionally generated electricity (assuming 43 kWh/100 miles, still ignoring the electric consumption of idle Tesla S’s). That’s 31% of last-year’s total electricity generation, not 15% (the study you cited must have been from the same drunken yahoos that believe the sun shines brighter when they plug in their EV’s). But even if it were only 7%, or 0.15%, the only thing that matters is whether the overall environmental impact would be better or worse. It is, of course, absurd to imagine that people will all switch to Tesla S’s… But it’s far more absurd to assume they’ll chose something more efficient rather than less efficient. We’re America. We’ve got an average fuel economy of ~23 mpg!! Why would we all switch to ultra-lightweight ultracompact EV’s that get ~34 kWh/100 miles when we could choose hulking monster SUV’s that have 500 kWh motors and can pull houses!!! Sure they’d require 100 kWh/100 miles, but who cares? We’re America!…
*shrug*
I think estimating an average of 43 kWh/100 miles for a possible future EV America is downright generous.
Anyway… The point is that it would be worse for the environment with our current electrical grid to switch to EV’s I’ve taken too long a lunch, and I have to go back to work.
🙂