A 35mpg car emits about 250 grams of carbon per mile (a gallon of gasoline emits about 20 pounds of CO2).
US emissions per kWh using the most recent data is about 400-410 grams per kWh. A Model 3 gets about 4.1 miles per kWh. So each mile emits just 100 grams.
And in California (which has the most EVs of any state by far), where the electricity carbon intensity is more like 200 grams per kWh, it's just 50 grams per mile in the Model 3, or about a factor of 5 better than the gasoline car.
Depends on the type of food you're eating, your local electricity grid, and many other factors of course. And obviously this ignores both manufacturing costs and the physical and psychological benefits to biking, so I'm not saying everyone should ditch biking, but it's an interesting comparison.
I wasn't super serious about the comparison. :) (And e-bikes are much, much more efficient than an electric car... if they last long enough).
And yeah, I wasn't necessarily reading too much into the comparison since of course there are so many different factors that can tilt the numbers different ways, but I found it very thought-provoking regardless. Great point about e-bikes too.
Would this hold true for e-motorcycles as well, or are we really saying "slow moving vehicles are much more efficient than fast moving vehicles"?
Much of the efficiency benefit is from the lower drag due to lower speeds, but if the purposed served is comparable, then it's valid. Just depends on what you're looking at.
FWIW, even at 30mph, ebikes are over an order of magnitude more efficient than a Model 3 at 70mph (<28 vs. 280 WH/mile). Zero (electric motorcycle) states 180 WH/mile at 70mph.
Per seat, electric cars are generally much better than electric motorcycles and about half as good as much slower e-bikes (although if ridden at the same speed, almost as good).
The other one is the injuries per mile are much higher for motorcycles. One aught to account for that as well.
Side issue: Motorcycles are terrible from an emissions standpoint. Though of course an e-motorcycle would be better.
 Scaling factor vs size is highly positive.
Going a lower speed is also more fuel efficient (depending on the engine, but it takes less energy) as you have a lower air/road resistance.
Color me skeptical. A Model 3 has ~20x the mass of a rider & bike, give or take. Producing it, delivering it, and moving it around thus takes ~20x the energy in the best case, energy that has to come from a CO2 emitting source in both cases. As bad as meat & dairy might be, being 20x worse than automobile and electricity production combined is a really high and unlikely bar.
But efficiency of converting sunlight into energy isn't really what this argument is about, since we're more concerned with the CO2 output than the energy efficiency. The efficiency of human muscles factors in though, as it is only around 20%, compared to electric motors and batteries that are over 90% efficient. Regenerative braking is a big win for the electric car too, since it reduces the impact of the car's higher mass a lot. And when you look at the CO2 per calorie emitted by coal (and of course the US grid emissions are much better than this since we use many other better energy sources than coal), you get about 1.1g per calorie for coal compared to about 4.8g per calorie for fruit. So in a carbon emissions sense, food can also be much less efficient than electricity, even when that electricity comes from fossil fuels.
No single one of these factors is enough to tip the scales on its own, and of course the numbers can skew either way depending on what kind of food you eat, what kind of electricity you use, and many other factors. But I don't think the comparison is a totally crazy one.
Regenerative braking is fantastic as an idea, but it does not actually offset the mass in practice. Tesla's regen braking has all kinds of limits - 64% electric conversion efficiency right off the top, but it also caps the regen rate, it doesn't regen when it's too cold, and regen can't recapture a/c or air friction losses, which actually add up to the majority of a car's power consumption for highway driving. I backed that up with data nearby. Regenerative braking is a great example of how cherry-picking efficiency percentages from the components of a system doesn't really help us understand the overall system efficiency.
Anyway, I don't know what the end-to-end system efficiency of food is, and to be honest I'm skeptical of anyone who claims to, the few stats we have are already gross approximations that tend to lose their context and their error bars. Combining them is extra problematic. My really one and only point is that the scales are pre-tipped 20:1 because of the mass on the consumption end, so no matter what happens in between, in order for the scales to balance, the complete end-to-end efficiency of electric system plus electric car manufacturing combined has to be more than twenty times that of food + bike manufacturing. No matter how good electric is, the savings are very much hampered by automobile manufacturing and by power generation. So it's just not that likely that the complete system for e-cars is a factor of 20 more efficient. There are multiple parts of the process that are the same or worse.
So how much of the energy expenditure does regenerative braking in a Model 3 recover? From what I’m reading, it may be in the single digit percentages for highway driving. Tesla’s own web page says the theoretical max is 64% , and that’s only in a perfect situation (accelerate & immediately stop), it’s not accounting for driving for a long time without braking or using the electric features inside the car, e.g. aerodynamic loss, rolling loss, & heating & a/c. Wikipedia says including the accessories, typical best-case efficiency is around 50% . But if you accelerate and drive for a mile without braking, you’ve already lost most of your initial energy to air & tires & battery conversion loss, the brakes can only capture energy from what’s left.
Maybe an analogy is useful? There's a claim that you can cook 20 pounds of food in one type of bonfire setup with less fuel use than if you cooked 1 pound of food in a different type of bonfire. The amount of energy needed to actually perform the chemical changes on a pound of food, even multiplied by 20, is negligible compared to the vast quantities of energy that are going to other things.
I could have phrased it better.
I suspect the same is similar to any major (and therefor congested) urban area.
The real killer is the American-style sparse suburban living that requires long commutes on highways...
Carbon offset prices are determined by current carbon offset capacity. Like, number of acres where trees can be planted, number of carbon-scrubbing machines that can be installed at a certain location, etc.
Carbon offset supply is limited. Meaning, it cannot scale to the level the planet needs, at current prices. If we gave these carbon-offset companies X billion dollars tomorrow at current prices, it's not like our problems would be solved.
Therefore, carbon offset prices will go up as demand (read: more people seeking to offset carbon) goes up.
One way to battle that is to reduce carbon emissions while buying offsets. That will reduce the required "supply".
People who buy offsets without reducing their emissions, on the other hand, are effectively stealing resources from future people, by buying low and making it more expensive for the people buying later.
(If you really want to be a jerk about it, you can calculate your lifetime carbon expenditures and just offset all of it now while prices are cheap.)
I have to buy the offsets now though or no one will listen. Cool idea to buy the entire lifetime’s offsets.
And even among those who say they are concerned about climate change and the environment - it still can be very difficult to actually inspire some sort of productive urgency in them. Climate change is the most gradual disaster to ever to befall humanity and our psychology isn't built for that at all, en masse.
On the other hand, when you see the air is turning black from the bumper to bumper traffic in your city, and then you notice yourself coughing, and your lungs hurting, at the same time... well that's a different situation.
Isn't a large benefit also that the emissions generated by electric cars is centralised at the places producing the electricity, which makes it easier to clean up the pollution?
I like EV's but they still encourage auto dependence and its associated ills.
(Although this is improving with time and may be as low as 56kgCO2/kWhcapacity).
So a 50kWh Model 3 has about 5.5mT of emissions from its battery. The rest of it may have lower emissions than a conventional car (since there's no engine, exhaust, fuel tank, etc), but pessimistically we can just assume that the difference in manufacturing emissions between EV and standard is just the battery.
Over a 175,000 mile lifetime, a 35mpg gas car will emit 45.4 tonnes of CO2. And a Model 3 (4.1kWh/mile) will emit about 8.5 tonnes with Californian electricity or 17 tonnes with US average grid electricity. In either case, the vast majority of emissions is in the actual energy to fill up the vehicle, not the battery, and electric cars are FAR better (even with a >200 mile range battery which is considered very large in much of the literature) in this respect.
A factor of 3.2 times better in California (including the battery) and still a respectable factor of 2 times better in the US with current electricity mix. But of course, if you buy the EV now and it lasts 10-15 years (including secondary and tertiary owners), the US and Californian electric grid will be much better as coal (and later natural gas) is phased out.
With companies like Tesla... they are the D-Link of vehicles.
They absolutely don't want long term stable good cars. They want you at the 4-5 year mark to buy a new one. And given the company has harassed engineers poking at under the hood, they will highly likely damage your car via remote disables or other 'trickery'.
I don't trust anything that Musk puts his hands on. There's a good reason for that.
You can dislike Musk all you want, but it doesn't change reality.
In some cases you can even upgrade the hardware (e.g. the AP and MCU) with the latest shipping parts to keep your model fresh. This is not universally true - there is some drama over a promised Model S MCU upgrade which a lot of people want only apparently only a handful of owners have gotten, but overall the approach is very refreshing.
When comparing the per-distance numbers, though, the initial manufacture can be treated as a sunk cost; you would have paid it regardless of whether you bought an EV or conventional car.
EV's might well double the age of the average car on the road.
I would never buy a used car that has had lived through winters in places where roads are frequently salted.
 Chemical reduction dominates everything. The energy required for forming and assembly would be much less.
Good rule of thumb.
Since the average internal combustion vehicle uses 500 gallons a year, that is about 6 tons of CO2.
O weighs 16
And there's two Os in a molecule of CO2, and gas is mostly a bunch of Cs. The Os come from the air.
(and it's 20 pounds per gallon, not mile)
Short answer, it pulls oxygen from the air to make the CO2. Most of the mass of CO2 is from the O2 that came from the air, not the tank.
"PM2.5 emissions were only 1-3% lower for EVs compared to modern ICEVs. ... Non-exhaust emissions already account for over 90% of PM10 and 85% of PM2.5 emissions from traffic. ... Future policy should consequently focus on setting standards for non-exhaust emissions and encouraging weight reduction of all vehicles to significantly reduce PM emissions from traffic."
looks like they're just assuming electric vehicles behave like light trucks because they're heavier than most passenger vehicles and therefore attribute 67% more emissions due to brake wear and don't account for regenerative breaking. (They estimate 2% more emissions from tire wear than lighter vehicles).
I expect Tesla would happily hand you a bunch of this anonymized data since it's likely to paint them in a positive light.
There are ways to get brake wear - switch the regen setting to LOW, or do a track day :)
> The authors regret that as Victor Timmers did not carry out the research under the auspices of the University of Edinburgh, nor in collaboration or consultation with any personnel at the University of Edinburgh, the affiliation of “University of Edinburgh” has now been removed from this work at the request of the Institution. In addition, subsequent to the publication of the Paper, Victor Timmers has disclosed a potential Conflict of Interest with regard to the work, namely: “non-financial support from Innas B.V, during the conduct of the study”.
> The authors would like to apologise for any inconvenience caused.
Innas B.V appears to be the same consulting firm where the first author works.
Reading the paper full-text, you see a lot of policy recommendations and one wonders what the standing of the authors is for full-on policy recommendations, based on the very limited data in the paper.
Namely, the analysis is really just using vehicle weight as a scale factor on a primitive PM2.5/PM10 "emissions/kg" relationship. Re-suspension of road dust dominates these particulates (in their model, anyway), and EVs and ICVs both do this, so any PM reductions by EVs are dominated by road dust kicked up by their larger weight.
Here's a much more detailed review paper:
And here's a non-review that examines ozone emissions, but from a much more serious modeling point of view:
The top comment in the thread was about Teslas improving human/lung health through air quality in cities which is heavily affecting by the resuspension affect.
A significant difference, to be sure, but not dramatic. And battery technology is improving rapidly.
Combined with the fact that there's no exhaust, on balance EVs are already superior for health, as long as the local power plant is anything other than coal.
Tesla Model 3 range: 310mi (which is on the upper end)
Sure, this will get better as battery tech improves. Everyone knows that. But we're not talking about the future, we're talking about right now.
The Model 3 either meets your driving range needs or it doesn’t.
A bit all over the place. For one, they linked it directly with weight. But then they mentioned regen and decided to model it at 0 brake wear on EVs. Then they talked about EVs being made of lightweight materials such as aluminum, and the difference would be even larger if they WEREN'T. (what?)
It also models particular resuspension in the air as a function of vehicle weight, arguing that heavier vehicles are typically less aerodynamic -- which is probably not the case with EVs.
Comparing driving an existing gas/diesel burner for 10 years,
instead of buying a brand new electric car.
Comparing between a new gas car vs a new electric car is of course favorable for the electric car under most circumstances.
Depends where you are. Electricity in France for example is 90% carbon-free
I also find this line of reasoning problematic. The climate change effect of EVs is _indirect_, but that doesn't mean it's _weak_. It a required step for a huge amount of emissions reductions. Climate change is hard precisely because the economy is full of network effects and path dependencies where you can argue against each individual change by saying that it doesn't do that much for the climate by itself (and for each change, there will be motivated actors making those arguments when the alternative will hit their pocketbooks).
Well, because they are not that much better. Still more people are killed directly by cars (40,000 a year in the USA, more than guns deaths), and they still cause plastic pollution due to their tires.
If anyone actually cares about pollution or human health, they will not be buying any car.
My family is low-car— I'm a four season bike commuter and my partner can largely get around during the day by walking and transit. Because we put less than 10k km on our car each year, I don't think buying a new Tesla or Prius makes sense for us, either from a cost or environmental standpoint. We were previously in a 2003 Volvo station wagon, and now in a 2013 Mazda 5. Neither of these cars is the most efficient on a per-km basis, but we're tackling that by just keeping the total number of km to a minimum.
Now, I am in Ontario where we have snowy winters, so almost all cars tend to rust out and be done within 10-15 years— it's not like the southwest where there are lots of truly ancient vehicles still being used as daily drivers. Perhaps the situation is different there.
How does snow accelerate rust?
Also it's pretty humid there, apparently?
Need to go full EV to meet our goals.
Edit: made headlines https://www.theguardian.com/cities/2019/jul/17/a-city-suffoc...
>In the first major attempt to estimate the health and economic costs of air pollution in Africa, an Organisation for Economic Co-operation and Development report found that air pollution in Africa already causes more premature deaths than unsafe water or childhood malnutrition.
>Given the lack of PM2.5 ground measurements in Africa, the PM2.5 data derived from the WHO air quality model for Africa should be viewed with caution.
>The review  concluded that (based on the few studies) 17%, 10%, 34%, 17% and 22% of PM2.5 levels in Africa are due to traffic, industry, domestic fuel burning, unspecified source of human origin and natural sources - such as dust and sea salt.
 https://www.oecd-ilibrary.org/development/the-cost-of-air-po... https://www.oecd-ilibrary.org/the-cost-of-air-pollution-in-a...
These seem like other numbers based on extrapolation, in that the sector comparisons and time comparisons are probably accurate on a relative basis, but saying that air pollution is 5% of GDP is most likely off by a large factor; it could be 2% or 10%.
How many other big categories have trillion dollar externalities? It’s only a $20 trillion economy - can the list be longer than 20 things?
And when we say something costs a $1 trillion in externalities annually, that should literally mean money that can be picked back up into the economy if you can clean it up. Mostly, to put it bluntly, because less people are having their lives cut short.
I find thinking about the scale of the damages and really trying to appreciate it is what creates the moral imperative to act. My personal belief is that technology is always the way forward. E.g. That by 2050 we could reduce the driving externality by 90% through automation. That we will eliminate coal for renewables.
I have less of a feel for what the technological path forward is for non-utility & transport air pollution - for some reason it’s a lot harder to grasp the damage being done. It’s certainly less visceral.
The drop is SO2 from utilities (coal) is particularly impressive. But a 20% overall drop in just a few years is kind of stunning - it works out to savings of $1.6 trillion per decade. That’s $1.6 trillion in economic damage from air pollution which will not be occurring due to progress in cleaning up our environment.
Sometimes it’s very important to step back and remind ourselves how much progress really is being made.
One of the biggest effects I see is the cultural shift to accept living in a polluted world. People resign to accept it even though they can make a difference, and I don't just mean through individual change.
I've seen thousands marching for climate change recently, I've seen numerous local/state governments in the USA fighting hard, not to mention numerous friends who have adopted low-carbon behaviors specifically due to climate change. There is far from loss of hope here, there is a lot of emotion: anger, shame, incredulity, depression, but there's a lot of motivation and optimism too.