You made another mistake by drawing your energy box around the car, excluding the energy losses associated with producing the electricity in the first place. Power plant efficiency can be as low as 25% for peak power, then there are transmission line losses, the more distance, the higher the loss, and finally inverter losses between the battery and electric motor of about 10%. And then, of course, in cold weather battery output can drop as a much as a third, and there are losses in hot weather as well.
According to the EIA, the average efficiency, rather than peak, is between 35% and 40%. It's relatively high for gas turbines but lower for other fossil fuel sources. As coal and oil get phased out, the efficiency improves. Solar and wind power, of course, may only extract a small portion of the available energy, but as their use becomes more common, the overall efficiency of electrical generation will continue to rise.
An important thing to consider is that it is easier to improve the efficiency of static large scale power plants than mobile small scale power plants. This decoupling simplifies engineering and opens the door to higher overall efficiency. For example, excess heat from a fossil fuel plant can be used for heating or industrial processes. Since electric cars use most of their electrical power for motion, even small gains in generation efficiency benefit the entire electric fleet immediately.
You’re forgetting the copious amounts of energy that go into refining petroleum to produce fuel. If you’re going to raise the energy budget of turbines, etc., let’s not assume gasoline magically appears ready to pump from gas station pumps…
The point of my comment was that we should include all sources of energy losses in any fair comparison of the alternatives. Not sure what you intended by using the word "copious," but I found a reference that claimed the energy required to refine a barrel of oil in 1974 was 707,000 Btu (https://www.osti.gov/biblio/7261027). A barrel of crude oil has a heating value of about 5,800,000 Btu, so the refining energy loss in 1974 was about 12%.
EROI of Oil is very similar to coal or gas. So no matter which fuel you use to produce your electricity, you have the same "copious amounts of energy" in the upstream chain.
Since they cancel each other out, including them doesn't change the picture one iota.
"But this is not true. With a switch to electric vehicles, we get rid of most of the ‘wasted’ energy from oil. "
You should write 'gasoline' here not 'oil'. Around the same amount of oil would have to be extracted and turned into many other products irrespective of whether all our cars run on gasoline or electricity. (ie only 40% of a barrel of oil is gasoline and the other 60% IS used and in high demand including the plastics, tires, etc in EVs, the asphalt in roads, etc).
Other than the oil for lubricants in engine etc, the wasted energy is from gasoline, not oil.
If you look at it from an even broader angle: each and every barrel of oil that is extracted is used. Every liter of gasoline or diesel that I save by driving an electric car will be used elsewhere in the world. The climate doesn’t care where in the world the carbon emissions happen.
That is why we (only) need carbon emissions trading, and carbon-related tariffs for imports from countries that do not participate.
Instead of subsidising a specific technology like electric cars, at the end of the day the market would find the most carbon-efficient solution to individual mobility.
I know I am theorizing, but a lot of „climate protection“ that we see put into practice, decided by politicians instead of engineers, driven by opinions disguised as „science“, is awful.
I am very grateful to Hannah for helping to deal with climate change in a sober and factual way.
A gallon of fossil fuel in a gasoline powered car will get you 20% of that energy's worth of transportation.
A gallon of fossil fuel in an electrical power plant will get you 35% x 80% = 28% of that energy's worth of transportation.
That's a 40% bonus. It's like going from 30 mpg to 42 mpg.
Alternatively, it would let us put one more car on the road for every existing 2.5 cars already running with no additional fossil fuel needed.
Even better, solar and wind power will make transportation increasingly efficient. As with automobiles, industry just needs a bit of prodding from the government. That's how we got railroads, automobiles , antibiotics and computers.
Drew - mine was a different point. You can't extract just the parts of oil from the ground that you want, leaving the rest in there. You have to extract OIL - from which gasoline is made. So as long as all the other products are used, a full switcth to EVs will NOT reduce the demand for oil at all. (Plus then we'd have to flare the gasoline or dispose of it somewhere if we didnt use it in cars). A thorny systems problem
I am many things but dishonest is not one of them. I am honest to a fault.
Let me try to simplify another way.
EACH barrel of oil contains 3 fractions - light (L) medium (M) and heavy (H). Each of those fractions are turned into viable products in human system. Light results in propane, butane, gasoline etc. Medium results in jet fuel, distillate, heating oil, diesel etc. Heavy results in asphalt, bitumen, tar, bunker fuel etc.
If you remove demand for the light fraction you STILL need the same amount of oil extracted from the ground to fulfill demand for all the other fractions. I live in the USA where our oil is extremely light - so much so that the refineries require purchasing oil produced in other countries that is heavier so as to make refineries profitable.
Some molecules can be pushed into other product pools (Jet fuel, chemical feedstock), some can be exported (to the US, at the time) and you can change the hardware in a refinery to make less of it (changing catcrackers, which make more gasoline, for hydrocrackers, which make more diesel). On the whole, this is very expensive and takes time to change.
If all gasoline demand went away IN THE LONG TERM we'd need about 10-20% less oil. But in the short (and medium term) we'd still need the diesel for trucks, Jet fuel for aircraft and fuel oil for ships, as well as the chemicals, the lubricants and the bitumen. IE the SAME AMOUNT OF OIL. There may be price effects as well. Historically, we've always found new uses for cheap molecules. E.g. originally kerosene was used for lamps (displacing whale oil), then when society electrified and started using light bulbs, internal combustion engines started running on light petroleum products. Later, the jet engine was invented and optimized to run on amply available kerosene. More recently, we've seen a growing number of ethane-crackers in the US because of fracking, which unlocked tons of shale gas of which only the methane (C1) is high-value and the ethane (C2, the main constituent of so-called "Natural Gas Liquids") is a byproduct for which the industry needed to find an application. Similarly, if we stopped using gasoline overnight then those molecules would become relatively cheap and find a new home in some other application, would be my guess...
In short, its complicated, but unless there is a system change, replacing all ICE cars w EVs will not meaningfully change the amount of oil consumed in global economy in any <10 year horizon, and only slightly after that. Heres a podcast I did on this: https://youtu.be/CDBJdQnjE2o and here is 13 min snippet: https://youtu.be/nT6sE69J8yo
As an aside, please don't accuse people of being dishonest without researching the larger point they are making. thanks
Fair point, though I would argue that many of those oil-derived co-products are (likely to be) subject to their own transition/replacement trends - via recycling, plant-based plastics, synthetics, power-to-liquid processes, etc.
Thank you, Hannah, very interesting, I learned a few things.
However, I wonder how the EPA came up with 22% of regenerative braking. An F1 race car has the most sophisticated braking energy regeneration system on earth, and those cars brake a lot more and a lot harder than passenger cars, and still I do not believe that they come even close to 22%.
Do you have access to any background information supporting the EPA claim?
The question that springs to mind: does this analysis take into account the inefficiencies of generating and transmitting the electricity that we put into our cars? I'm assuming that, for now, most people are charging using utility generated power and not solar panels on their houses.
“We would also need to factor in losses within a power plant itself; if you’re producing electricity from coal or gas, you will also have large heat losses in converting the raw fuel into electric power. For renewables, these losses are much smaller.”
I've used this exact same form of analysis myself ... but now reckon it's deeply flawed.
In thermodynamics they talk about the "quality" of different energy forms ... like heat and electricity and potential energy. Converting from a low quality energy to a high quality energy has an inevitable cost. So converting heat to electricity is intrinsically inefficient. But regarding it as a loss in a pejorative sense has to be carefully thought through.
Solar panels produces electricity without heat. Does that make them more efficient than a nuclear reactor that uses heat to drive a generator? You need about 4-10 gigiawatts of panels to get the same electrical energy as 1 gigawatt of nuclear (depending on where you are on the planet ... 10 for Germany). So in Germany, you need to mine about 70,000 x 10 tonnes of stuff to produce your panels. That's a lot of stuff. The thermodynamic efficiency has a considerable downside in terms of resource use (land and minerals).
Most of the worlds energy is used as heat ... so why get this from electricity via PV panels?
Energy efficiency isn't an end in itself, it's just one of many metrics that we need to think about to decarbonise intelligently. It's a little bit like water. If you have it in abundance, does it matter if you waste it? As long as it is zero carbon, the answer is "no". Storing it for a rainy day has costs ... storage isn't free from a resources perspective.
I always appreciate efforts to debunk energy misconceptions. But as often seems to be the case, I'm unclear on who actually says the things you're debunking here:
"When people compare how much gasoline we burn to how much low-carbon energy we generate, decarbonising transport seems almost impossible. They assume that we would need to produce the electricity equivalent of our global gasoline consumption."
Can you point us to some examples of the people who assume this? Are you thinking of academics, journalists, fossil fuel PR people, the general public, or someone else?
I guess I'd say those concerns are valid even when we do the math correctly, taking efficiencies into account. In order to electrify everything™, we'll have to generate and distribute substantially more electricity than we do today.
Of course it would be wrong and foolish to assert that this can't be done, as "we won't have enough energy" would seem to imply.
Anyhow I'm still wondering WHO the bad guys are here.
It's not aimed at 'bad guys'. There are no 'bad guys' here. It's just a common (and very understandable) misconception about how final or useful energy demand differs from primary energy demand. I get these comments a lot.
Looking at total energy use today looks like an overwhelming decarbonisation challenge, which makes people despondent and think that achieving it is impossible. I'm making the case – and trying to clarify for those that are confused – that we won't need to produce as much low-carbon energy as most people think.
I withdraw the term "bad guys" which was just a tongue-in-cheek shorthand for "people [who] assume that we would need to produce the electricity equivalent of our global gasoline consumption."
Honestly in the paragraph I'm quoting from it sounds like you're saying *everyone* makes this assumption. I can certainly see how some people might make this error, especially if they focus on final energy (which I try to avoid in my teaching for this very reason). But my question remains: Who are the people you're getting these comments from? I ask because I'm trying to get a sense of how widespread this error actually is, and whether it's coming from people who should know better or from people who don't know much about energy at all.
My anecdotal evidence is that this error is semi widespread? Even if they don't directly say 'we won't have enough energy' the argument is we can't all buy EVs because the grid won't support it.
In my mind that argument is the same, but I could be wrong.
An example of that argument from a popular website:
---
"Politicians don't mention that when they promise every car will be electric. They also don't mention that the electric grid is limited.
This summer, California officials were so worried about blackouts they asked electric vehicle owners to stop charging cars!
Yet today, few of California's cars are electric. Gov. Gavin Newsom ordered that all new cars must be electric by 2035! Where does he think he'll get the electricity to power them?
"Roughly speaking, you have to double your electric grid to move the energy out of gasoline into the electric sector," says Mills. "No one is planning to double the electric grid, so they'll be rationing."
Rationing. That means some places will simply turn off some of the power. That's our final inconvenient fact: We just don't have enough electricity for all electric cars."
I'd be interested to know if that's the kind of writing HR is responding to in this article. FWIW I looked up Mills and quickly found an older piece in which he clearly explains the efficiency advantage that EVs have over combustion vehicles. He's quite knowledgeable about EVs but has a pessimistic outlook and chooses the more pessimistic numbers whenever some judgment comes into play. And Stossel, AFAICT, relies on people like Mills to do the arithmetic and then give him quotes he can use in his punditry. So although I have a lot of issues with their spin, I don't see any sign that either of them is suffering from the specific misconception that EVs use electricity just as inefficiently as combustion vehicles use fuel.
But replacing all existing ICE vehicles with EVs while costing a great deal and making billions of existing fossil fuel infrastructure and vehicles go to waste would only reduce total global CO2 emissions by less than 10%. That doesn’t include the emissions from mining minerals that would be needed.You are skilled at cost benefit analysis but I think you seem to ignore this fact.
"Greenhouse gas (GHG) emissions from transportation account for about 29 percent of total U.S. greenhouse gas emissions, making it the largest contributor of U.S. GHG emissions."
Of that 29%, more than half is passenger vehicles at 16%.
“Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight.
Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO2 emissions.”
So less than half of the 15% of global CO2 comes from cars and buses, meaning it’s under 10%. The US is higher because we love to drive our SUVs.
I'm sure she is well aware of all these things. Cars and infrastructure don't last forever anyway and the transition will take time so I don't think stranded assets will ultimately be a big issue. Your 10% figure seems a little low but it's true that vehicle emissions are just one part of the challenge. Fortunately, they're a part for which the solution seems pretty clear.
That is a different problem, but also a real concern. There are billions of dollars in existing fossil fuel infrastructure existing now which all the gasoline vehicles take advantage of, which is part of the reason they are more affordable and popular. If even half of all new cars were EV the current charging infrastructure would be overwhelmed and will take many years to build out.
There is no doubt that electric cars are very efficient users of energy. Their main disadvantage is the high energy and mineral intensity of battery production and the need to create a high density fast charging network before they become practical for everyone. Hopefully batteries will improve over the next few decades and high density charging points will become ubiquitous. In the meantime a sensible transition is to mix full EVs with plugin and full hydrids. It may well be the case that green synthetic fuels arrive before the type of battery technology needed to go full EV for all motor vehicles.
Right. I did see that, but since the other losses were given as specific average numbers, I was hoping for a similar detail. OTOH, it's probably something I should be able to look up, but it is surprisingly difficult to find numbers, but this doesn't look very good: https://www.energy.gov/fecm/how-gas-turbine-power-plants-work. The range seems to be from 30% to 60%. If that's accurate, it would imply that the argument Hannah is making is kind of weak in the absence of rooftop solar providing the power.
I'm not sure what happened. This was a reply to Tian Wen's reply to my question concerning the efficiency of production and transmission of electricity by power plants.
Thanks for the article. I think EVs are a good option for municipal fleets, school busses, and public transit. However, EV cars for the daily commute or general transportation might not be good options.
In terms of overall energy use (i.e., extraction and transport of resources needed to build petrol or EV cars, highway development & maintenance, car-induced urban sprawl and increased travel time), wouldn't it be better to develop alternatives? For example:
a) convert petrol cars to EV/hybrid,
b) redirect resources to regional and local rail (and electric busses)
c) support the walkable/rollable, 15-minute community that is supported by municipal, regional, and national planning policy
Equating the miles travelled per unit of raw energy requires the following factors to be considered
Conversion from raw energy to electricity: Coal (32%) or Gas (37%) power – but these provide 45% of supply mix (so .35*2% CO2 efficient) - 0.7 unit of electricity per unit of Fossil Fuel burnt
Electricity delivery over the power grid: Transmission efficiency – 92% efficient
Power delivery: Electric motor – 70-80% - 75% efficient
Rolling resistance: EVs are 750 heavier than an average 3000 lb car and require an additional 25% for rolling resistance compared to between 4-11% for a lightweight car (85% efficient)
So on average – 35% (*2) * .92 * .75 * .85 = 41% overall fossil fuel efficiency (to be compared with the petrol car at 20% overall fossil fuel efficiency)
That is an electric car currently has an equivalent 'mpg-fossil fuel' around 50% of a petrol car - this will improve as a greater % of electricity on the grid is from renewables.
The estimate is that the energy requirement to produce a petrol car is 474 gallons of petrol, an electric car required 25% more (118 gallons). Assuming a 10 year vehicle life and 50 mpg the energy equivalence point is 1180 miles per year - so the electric car only starts to reduce CO2 emissions after 1180 miles each year. Regenerative braking applies to both EVs and Petrol vehicles.
These calculations are based on UK data - here 10% of cars have an annual mileage below the 'break even' point, that is making these EVs would be a net addition to CO2 emissions
This is useful and the point about the need to et renewable energy up and running as uickly as possible is important. But the world's electricity supply system will still have to be a lot larger than it is now (2 times as big? 3 times?) IF we use energy, whatever its source in the profligate way it is used now and if those billions in the lobal South who need an electricity supply are to get one. This means reducing our access to motor cars and a lot of other forms of waste - in commodities, in heating and cooling buildings and so on.
One way in which all cars are inefficient is that they use over a tonne of metal, glass and plastic to move (most often) about 70kg of person. In this respect and electric car is less efficient than the equivalent ICE one, as it is usually about 50% heavier, so the energy saving will be less than the 80% calculated here. An electric bicycle uses 20 times less energy than a small electric car. The energy saving in going from an ICE car to an electric bicycle is about 97%.
I wonder whether EVs are really effective in diminishing carbon emissions. A lot of the numbers being put forward seem to be theoretical. Take e.g. the EPA claim of 34% energy recovery from braking in urban traffic. That sounds good but defies physics.
Another point I do not see at all being argued is the fact, that EVs start saving CO2 only from 65.000 - 70.000 km on (disclosed e.g. by VW) because manufacturing an EV is so much more costly in CO2 emissions. Considering that the average mileage is 13.000 km per year (e.g. in Germany), an EV you put on the road today will effectively start saving CO2 in 5 five years at best. By then it may need a new battery and the hoped-for gain will never materialise.
There must be lower hanging fruit in curbing carbon emissions.
I’d be curious to know how hybrid cars compare, once their battery is depleted. In other words, does regenerative braking improve the efficiency of a petrol car?
I’d look forward to a post that compares power plant efficiencies, from old lignite plants to new gas plants. That way we could have an overall picture, as you point out.
A hybrid definitely benefits from regenerative braking which is why their city (stop and go) MPG is as high as their highway MPG. The number Hannah states is low because of this since many new cars are hybrids (and since we are comparing EVs it’s fair to ignore older cars). Also some of the losses in an ICE car (climate controls, rolling resistance, drag) also are present in EVs. Weight is also a factor since batteries are heavier. The most efficient vehicle is probably a bicycle, if we ignore size and number of passengers.
Excellent article. There are many other factors to be integrated into this thinking. Three that come to mind immediately:
1. The market price for energy as consumed by the user differs between electricity and petroleum based fuels. Shouldn't the analysislook at both the relative number of ergs consumed and the cost per erg for e vs p (electric versus petroleum based) transport?
2. The pricing distortions produced by government regulation. For example, the electricity market is in part highly regulated and in part sort of unregulated. Government regulation of petroleum processes is different. This breaks down into differences in the cost of energy production infrastructure and the operation (and efficiencies/inefficiencies) of the production, storage-logistics and distribution of the energy products. (I am not opposed to government regulation but I'm thinking about the asymmetries applied to electricity's and petroleum-based fuels. How do we make them more even? Or should we?)
I'm not so sure that is true anymore: https://www.tesla.com/model3. What gas car that is as nice as a Model 3 can you get for that price? I'm not saying they don't exist, but that it's pretty competitive as an initial price and add to that the incredibly low maintenance costs and I suspect they are completely competitive.
If you have the money and it fits your lifestyle then by all means go for it. I'll feel better about buying when solid state batteries are standard---longer range and lifetime of battery, lower cost. If I were to buy a new full size truck now the base model is 34K, base on electric is 60K.
Lexus ES350h, BMW 330i, Genesis G70, Mercedes Benz C class, Toyota Crown, Audi A5 among others. Other than acceleration the Model 3 is not very comfortable or fun to drive.
They are indeed nicer - and every one of the cars you mention cost more and other than the two Korean cars considerably more than a Model 3. That was kind of my point.
If you use the actual price of a Model 3 in the USA (not the fake Tesla “price after gas savings” which subtracts $4800 for 6 years of gasoline but assumes electricity is free) and the $7500 tax subsidy) its over $50,000 which is the same range of those other vehicles without added options. The Tesla has a bare bones interior and forces all controls onto the hard to use while driving touch screen and German cars and Lexi have nicer features in their base models.
That’s great, but America needs to focus on building non-car infrastructure. Bike lanes, rail, and transit-oriented housing development are way better for the planet than EVs could ever be.
You made another mistake by drawing your energy box around the car, excluding the energy losses associated with producing the electricity in the first place. Power plant efficiency can be as low as 25% for peak power, then there are transmission line losses, the more distance, the higher the loss, and finally inverter losses between the battery and electric motor of about 10%. And then, of course, in cold weather battery output can drop as a much as a third, and there are losses in hot weather as well.
According to the EIA, the average efficiency, rather than peak, is between 35% and 40%. It's relatively high for gas turbines but lower for other fossil fuel sources. As coal and oil get phased out, the efficiency improves. Solar and wind power, of course, may only extract a small portion of the available energy, but as their use becomes more common, the overall efficiency of electrical generation will continue to rise.
An important thing to consider is that it is easier to improve the efficiency of static large scale power plants than mobile small scale power plants. This decoupling simplifies engineering and opens the door to higher overall efficiency. For example, excess heat from a fossil fuel plant can be used for heating or industrial processes. Since electric cars use most of their electrical power for motion, even small gains in generation efficiency benefit the entire electric fleet immediately.
As I was reading the article I figured that someone would have already pointed out this basic mistake.
You’re forgetting the copious amounts of energy that go into refining petroleum to produce fuel. If you’re going to raise the energy budget of turbines, etc., let’s not assume gasoline magically appears ready to pump from gas station pumps…
The point of my comment was that we should include all sources of energy losses in any fair comparison of the alternatives. Not sure what you intended by using the word "copious," but I found a reference that claimed the energy required to refine a barrel of oil in 1974 was 707,000 Btu (https://www.osti.gov/biblio/7261027). A barrel of crude oil has a heating value of about 5,800,000 Btu, so the refining energy loss in 1974 was about 12%.
EROI of Oil is very similar to coal or gas. So no matter which fuel you use to produce your electricity, you have the same "copious amounts of energy" in the upstream chain.
Since they cancel each other out, including them doesn't change the picture one iota.
hi Hannah - nice analysis.
A small error (w large implications)
"But this is not true. With a switch to electric vehicles, we get rid of most of the ‘wasted’ energy from oil. "
You should write 'gasoline' here not 'oil'. Around the same amount of oil would have to be extracted and turned into many other products irrespective of whether all our cars run on gasoline or electricity. (ie only 40% of a barrel of oil is gasoline and the other 60% IS used and in high demand including the plastics, tires, etc in EVs, the asphalt in roads, etc).
Other than the oil for lubricants in engine etc, the wasted energy is from gasoline, not oil.
Good point, thank you!
If you look at it from an even broader angle: each and every barrel of oil that is extracted is used. Every liter of gasoline or diesel that I save by driving an electric car will be used elsewhere in the world. The climate doesn’t care where in the world the carbon emissions happen.
That is why we (only) need carbon emissions trading, and carbon-related tariffs for imports from countries that do not participate.
Instead of subsidising a specific technology like electric cars, at the end of the day the market would find the most carbon-efficient solution to individual mobility.
I know I am theorizing, but a lot of „climate protection“ that we see put into practice, decided by politicians instead of engineers, driven by opinions disguised as „science“, is awful.
I am very grateful to Hannah for helping to deal with climate change in a sober and factual way.
A gallon of fossil fuel in a gasoline powered car will get you 20% of that energy's worth of transportation.
A gallon of fossil fuel in an electrical power plant will get you 35% x 80% = 28% of that energy's worth of transportation.
That's a 40% bonus. It's like going from 30 mpg to 42 mpg.
Alternatively, it would let us put one more car on the road for every existing 2.5 cars already running with no additional fossil fuel needed.
Even better, solar and wind power will make transportation increasingly efficient. As with automobiles, industry just needs a bit of prodding from the government. That's how we got railroads, automobiles , antibiotics and computers.
+1 for Hannah’s sober and factual analysis
That would not be nearly the same amount of oil. A full-on switch to EVs would still be a significant reduction in oil use.
But you are right that all car infrastructure uses a ton of oil, which is why it’s smarter to focus on non-car modes of transport.
Drew - mine was a different point. You can't extract just the parts of oil from the ground that you want, leaving the rest in there. You have to extract OIL - from which gasoline is made. So as long as all the other products are used, a full switcth to EVs will NOT reduce the demand for oil at all. (Plus then we'd have to flare the gasoline or dispose of it somewhere if we didnt use it in cars). A thorny systems problem
So now you’re just being blatantly dishonest. If we use less gasoline we will have to extract less oil.
It’s true that oil creates a loot of thorny systems, but when we reduce the demand for oil we reduce the need to extract it.
(Sigh)...
I am many things but dishonest is not one of them. I am honest to a fault.
Let me try to simplify another way.
EACH barrel of oil contains 3 fractions - light (L) medium (M) and heavy (H). Each of those fractions are turned into viable products in human system. Light results in propane, butane, gasoline etc. Medium results in jet fuel, distillate, heating oil, diesel etc. Heavy results in asphalt, bitumen, tar, bunker fuel etc.
If you remove demand for the light fraction you STILL need the same amount of oil extracted from the ground to fulfill demand for all the other fractions. I live in the USA where our oil is extremely light - so much so that the refineries require purchasing oil produced in other countries that is heavier so as to make refineries profitable.
Some molecules can be pushed into other product pools (Jet fuel, chemical feedstock), some can be exported (to the US, at the time) and you can change the hardware in a refinery to make less of it (changing catcrackers, which make more gasoline, for hydrocrackers, which make more diesel). On the whole, this is very expensive and takes time to change.
If all gasoline demand went away IN THE LONG TERM we'd need about 10-20% less oil. But in the short (and medium term) we'd still need the diesel for trucks, Jet fuel for aircraft and fuel oil for ships, as well as the chemicals, the lubricants and the bitumen. IE the SAME AMOUNT OF OIL. There may be price effects as well. Historically, we've always found new uses for cheap molecules. E.g. originally kerosene was used for lamps (displacing whale oil), then when society electrified and started using light bulbs, internal combustion engines started running on light petroleum products. Later, the jet engine was invented and optimized to run on amply available kerosene. More recently, we've seen a growing number of ethane-crackers in the US because of fracking, which unlocked tons of shale gas of which only the methane (C1) is high-value and the ethane (C2, the main constituent of so-called "Natural Gas Liquids") is a byproduct for which the industry needed to find an application. Similarly, if we stopped using gasoline overnight then those molecules would become relatively cheap and find a new home in some other application, would be my guess...
In short, its complicated, but unless there is a system change, replacing all ICE cars w EVs will not meaningfully change the amount of oil consumed in global economy in any <10 year horizon, and only slightly after that. Heres a podcast I did on this: https://youtu.be/CDBJdQnjE2o and here is 13 min snippet: https://youtu.be/nT6sE69J8yo
As an aside, please don't accuse people of being dishonest without researching the larger point they are making. thanks
Fair point, though I would argue that many of those oil-derived co-products are (likely to be) subject to their own transition/replacement trends - via recycling, plant-based plastics, synthetics, power-to-liquid processes, etc.
Thank you, Hannah, very interesting, I learned a few things.
However, I wonder how the EPA came up with 22% of regenerative braking. An F1 race car has the most sophisticated braking energy regeneration system on earth, and those cars brake a lot more and a lot harder than passenger cars, and still I do not believe that they come even close to 22%.
Do you have access to any background information supporting the EPA claim?
The question that springs to mind: does this analysis take into account the inefficiencies of generating and transmitting the electricity that we put into our cars? I'm assuming that, for now, most people are charging using utility generated power and not solar panels on their houses.
Then, you'd have to account for the efficiency of transporting gasoline.
Hannah notes as much at the end of the post:
“We would also need to factor in losses within a power plant itself; if you’re producing electricity from coal or gas, you will also have large heat losses in converting the raw fuel into electric power. For renewables, these losses are much smaller.”
I've used this exact same form of analysis myself ... but now reckon it's deeply flawed.
In thermodynamics they talk about the "quality" of different energy forms ... like heat and electricity and potential energy. Converting from a low quality energy to a high quality energy has an inevitable cost. So converting heat to electricity is intrinsically inefficient. But regarding it as a loss in a pejorative sense has to be carefully thought through.
Solar panels produces electricity without heat. Does that make them more efficient than a nuclear reactor that uses heat to drive a generator? You need about 4-10 gigiawatts of panels to get the same electrical energy as 1 gigawatt of nuclear (depending on where you are on the planet ... 10 for Germany). So in Germany, you need to mine about 70,000 x 10 tonnes of stuff to produce your panels. That's a lot of stuff. The thermodynamic efficiency has a considerable downside in terms of resource use (land and minerals).
Most of the worlds energy is used as heat ... so why get this from electricity via PV panels?
Energy efficiency isn't an end in itself, it's just one of many metrics that we need to think about to decarbonise intelligently. It's a little bit like water. If you have it in abundance, does it matter if you waste it? As long as it is zero carbon, the answer is "no". Storing it for a rainy day has costs ... storage isn't free from a resources perspective.
I always appreciate efforts to debunk energy misconceptions. But as often seems to be the case, I'm unclear on who actually says the things you're debunking here:
"When people compare how much gasoline we burn to how much low-carbon energy we generate, decarbonising transport seems almost impossible. They assume that we would need to produce the electricity equivalent of our global gasoline consumption."
Can you point us to some examples of the people who assume this? Are you thinking of academics, journalists, fossil fuel PR people, the general public, or someone else?
Thanks Dan, that HUGE strawman jumped out at me too. Great that Josh and you were able to delve deeper.
Feels like a wasted article with this false premise at its core.
Anecdotal evidence but I have been in many conversations where the 'we won't have enough energy for EVs' has come up.
Oftentimes in discussions about current power grid problems etc.
I guess I'd say those concerns are valid even when we do the math correctly, taking efficiencies into account. In order to electrify everything™, we'll have to generate and distribute substantially more electricity than we do today.
Of course it would be wrong and foolish to assert that this can't be done, as "we won't have enough energy" would seem to imply.
Anyhow I'm still wondering WHO the bad guys are here.
It's not aimed at 'bad guys'. There are no 'bad guys' here. It's just a common (and very understandable) misconception about how final or useful energy demand differs from primary energy demand. I get these comments a lot.
Looking at total energy use today looks like an overwhelming decarbonisation challenge, which makes people despondent and think that achieving it is impossible. I'm making the case – and trying to clarify for those that are confused – that we won't need to produce as much low-carbon energy as most people think.
Thanks for replying.
I withdraw the term "bad guys" which was just a tongue-in-cheek shorthand for "people [who] assume that we would need to produce the electricity equivalent of our global gasoline consumption."
Honestly in the paragraph I'm quoting from it sounds like you're saying *everyone* makes this assumption. I can certainly see how some people might make this error, especially if they focus on final energy (which I try to avoid in my teaching for this very reason). But my question remains: Who are the people you're getting these comments from? I ask because I'm trying to get a sense of how widespread this error actually is, and whether it's coming from people who should know better or from people who don't know much about energy at all.
My anecdotal evidence is that this error is semi widespread? Even if they don't directly say 'we won't have enough energy' the argument is we can't all buy EVs because the grid won't support it.
In my mind that argument is the same, but I could be wrong.
An example of that argument from a popular website:
---
"Politicians don't mention that when they promise every car will be electric. They also don't mention that the electric grid is limited.
This summer, California officials were so worried about blackouts they asked electric vehicle owners to stop charging cars!
Yet today, few of California's cars are electric. Gov. Gavin Newsom ordered that all new cars must be electric by 2035! Where does he think he'll get the electricity to power them?
"Roughly speaking, you have to double your electric grid to move the energy out of gasoline into the electric sector," says Mills. "No one is planning to double the electric grid, so they'll be rationing."
Rationing. That means some places will simply turn off some of the power. That's our final inconvenient fact: We just don't have enough electricity for all electric cars."
---
source - https://reason.com/2022/11/16/electric-cars-are-good-but-we-still-need-fossil-fuels/
Reason.com is right leaning according to https://www.allsides.com/news-source/reason-foundation
3.4 million site visitors last month according to https://www.similarweb.com/website/reason.com/#overview
I'd be interested to know if that's the kind of writing HR is responding to in this article. FWIW I looked up Mills and quickly found an older piece in which he clearly explains the efficiency advantage that EVs have over combustion vehicles. He's quite knowledgeable about EVs but has a pessimistic outlook and chooses the more pessimistic numbers whenever some judgment comes into play. And Stossel, AFAICT, relies on people like Mills to do the arithmetic and then give him quotes he can use in his punditry. So although I have a lot of issues with their spin, I don't see any sign that either of them is suffering from the specific misconception that EVs use electricity just as inefficiently as combustion vehicles use fuel.
But replacing all existing ICE vehicles with EVs while costing a great deal and making billions of existing fossil fuel infrastructure and vehicles go to waste would only reduce total global CO2 emissions by less than 10%. That doesn’t include the emissions from mining minerals that would be needed.You are skilled at cost benefit analysis but I think you seem to ignore this fact.
I think 10% is low according to the US EPA
"Greenhouse gas (GHG) emissions from transportation account for about 29 percent of total U.S. greenhouse gas emissions, making it the largest contributor of U.S. GHG emissions."
Of that 29%, more than half is passenger vehicles at 16%.
https://www.cato.org/blog/blaming-us-passenger-vehicles-climate-change-ignorant-lucrative-1 - funny this article says cars are not the problem, when they are stated in the article 16% of the problem. :)
The good news is that emissions from mining minerals are closer to 95%, for lack of a better term, one time emissions, as batteries can be recycled. https://blog.evbox.com/are-ev-batteries-recyclable
So yes we will emit carbon as we mine the minerals, but then we can reuse the mineral over and over again making them into new batteries.
With fossil fuels we emit carbon mining them, emit carbon burning them, and then they are gone and we have to do it all over again.
Using Hannah’s own organization’s global data:
“Road travel accounts for three-quarters of transport emissions. Most of this comes from passenger vehicles – cars and buses – which contribute 45.1%. The other 29.4% comes from trucks carrying freight.
Since the entire transport sector accounts for 21% of total emissions, and road transport accounts for three-quarters of transport emissions, road transport accounts for 15% of total CO2 emissions.”
So less than half of the 15% of global CO2 comes from cars and buses, meaning it’s under 10%. The US is higher because we love to drive our SUVs.
https://ourworldindata.org/co2-emissions-from-transport?ssp=1&darkschemeovr=1&setlang=en-US&safesearch=moderate
I'm sure she is well aware of all these things. Cars and infrastructure don't last forever anyway and the transition will take time so I don't think stranded assets will ultimately be a big issue. Your 10% figure seems a little low but it's true that vehicle emissions are just one part of the challenge. Fortunately, they're a part for which the solution seems pretty clear.
That is a different problem, but also a real concern. There are billions of dollars in existing fossil fuel infrastructure existing now which all the gasoline vehicles take advantage of, which is part of the reason they are more affordable and popular. If even half of all new cars were EV the current charging infrastructure would be overwhelmed and will take many years to build out.
A grid that can handle all cars as EVs will take a while to build out.
I sometimes have to remind myself that the gas stations and infrastructure we take for granted for fossil fuel cars, also had to be built out.
I wonder how fast the gas infrastructure was build out in? This article had some interesting numbers but having a hard time finding sources - https://familytreemagazine.com/history/history-of-gas-stations/
There is no doubt that electric cars are very efficient users of energy. Their main disadvantage is the high energy and mineral intensity of battery production and the need to create a high density fast charging network before they become practical for everyone. Hopefully batteries will improve over the next few decades and high density charging points will become ubiquitous. In the meantime a sensible transition is to mix full EVs with plugin and full hydrids. It may well be the case that green synthetic fuels arrive before the type of battery technology needed to go full EV for all motor vehicles.
See Toyota solid-state battery announcement today
Right. I did see that, but since the other losses were given as specific average numbers, I was hoping for a similar detail. OTOH, it's probably something I should be able to look up, but it is surprisingly difficult to find numbers, but this doesn't look very good: https://www.energy.gov/fecm/how-gas-turbine-power-plants-work. The range seems to be from 30% to 60%. If that's accurate, it would imply that the argument Hannah is making is kind of weak in the absence of rooftop solar providing the power.
I'm not sure what happened. This was a reply to Tian Wen's reply to my question concerning the efficiency of production and transmission of electricity by power plants.
Or nuclear fission.
Thanks for the article. I think EVs are a good option for municipal fleets, school busses, and public transit. However, EV cars for the daily commute or general transportation might not be good options.
In terms of overall energy use (i.e., extraction and transport of resources needed to build petrol or EV cars, highway development & maintenance, car-induced urban sprawl and increased travel time), wouldn't it be better to develop alternatives? For example:
a) convert petrol cars to EV/hybrid,
b) redirect resources to regional and local rail (and electric busses)
c) support the walkable/rollable, 15-minute community that is supported by municipal, regional, and national planning policy
Why do you think EVs for daily commute or general transport are not a good option?
I don't have an EV yet, but friends who do love commuting in them. Never having to go to the gas station, change the oil, etc are benefits they love.
Or do you mean from an energy usage standpoint?
Sadly this is not a like for like comparison.
Equating the miles travelled per unit of raw energy requires the following factors to be considered
Conversion from raw energy to electricity: Coal (32%) or Gas (37%) power – but these provide 45% of supply mix (so .35*2% CO2 efficient) - 0.7 unit of electricity per unit of Fossil Fuel burnt
Electricity delivery over the power grid: Transmission efficiency – 92% efficient
Power delivery: Electric motor – 70-80% - 75% efficient
Rolling resistance: EVs are 750 heavier than an average 3000 lb car and require an additional 25% for rolling resistance compared to between 4-11% for a lightweight car (85% efficient)
So on average – 35% (*2) * .92 * .75 * .85 = 41% overall fossil fuel efficiency (to be compared with the petrol car at 20% overall fossil fuel efficiency)
That is an electric car currently has an equivalent 'mpg-fossil fuel' around 50% of a petrol car - this will improve as a greater % of electricity on the grid is from renewables.
The estimate is that the energy requirement to produce a petrol car is 474 gallons of petrol, an electric car required 25% more (118 gallons). Assuming a 10 year vehicle life and 50 mpg the energy equivalence point is 1180 miles per year - so the electric car only starts to reduce CO2 emissions after 1180 miles each year. Regenerative braking applies to both EVs and Petrol vehicles.
These calculations are based on UK data - here 10% of cars have an annual mileage below the 'break even' point, that is making these EVs would be a net addition to CO2 emissions
This is useful and the point about the need to et renewable energy up and running as uickly as possible is important. But the world's electricity supply system will still have to be a lot larger than it is now (2 times as big? 3 times?) IF we use energy, whatever its source in the profligate way it is used now and if those billions in the lobal South who need an electricity supply are to get one. This means reducing our access to motor cars and a lot of other forms of waste - in commodities, in heating and cooling buildings and so on.
One way in which all cars are inefficient is that they use over a tonne of metal, glass and plastic to move (most often) about 70kg of person. In this respect and electric car is less efficient than the equivalent ICE one, as it is usually about 50% heavier, so the energy saving will be less than the 80% calculated here. An electric bicycle uses 20 times less energy than a small electric car. The energy saving in going from an ICE car to an electric bicycle is about 97%.
I wonder whether EVs are really effective in diminishing carbon emissions. A lot of the numbers being put forward seem to be theoretical. Take e.g. the EPA claim of 34% energy recovery from braking in urban traffic. That sounds good but defies physics.
Another point I do not see at all being argued is the fact, that EVs start saving CO2 only from 65.000 - 70.000 km on (disclosed e.g. by VW) because manufacturing an EV is so much more costly in CO2 emissions. Considering that the average mileage is 13.000 km per year (e.g. in Germany), an EV you put on the road today will effectively start saving CO2 in 5 five years at best. By then it may need a new battery and the hoped-for gain will never materialise.
There must be lower hanging fruit in curbing carbon emissions.
Great data driven post!
I’d be curious to know how hybrid cars compare, once their battery is depleted. In other words, does regenerative braking improve the efficiency of a petrol car?
I’d look forward to a post that compares power plant efficiencies, from old lignite plants to new gas plants. That way we could have an overall picture, as you point out.
A hybrid definitely benefits from regenerative braking which is why their city (stop and go) MPG is as high as their highway MPG. The number Hannah states is low because of this since many new cars are hybrids (and since we are comparing EVs it’s fair to ignore older cars). Also some of the losses in an ICE car (climate controls, rolling resistance, drag) also are present in EVs. Weight is also a factor since batteries are heavier. The most efficient vehicle is probably a bicycle, if we ignore size and number of passengers.
Excellent article. There are many other factors to be integrated into this thinking. Three that come to mind immediately:
1. The market price for energy as consumed by the user differs between electricity and petroleum based fuels. Shouldn't the analysislook at both the relative number of ergs consumed and the cost per erg for e vs p (electric versus petroleum based) transport?
2. The pricing distortions produced by government regulation. For example, the electricity market is in part highly regulated and in part sort of unregulated. Government regulation of petroleum processes is different. This breaks down into differences in the cost of energy production infrastructure and the operation (and efficiencies/inefficiencies) of the production, storage-logistics and distribution of the energy products. (I am not opposed to government regulation but I'm thinking about the asymmetries applied to electricity's and petroleum-based fuels. How do we make them more even? Or should we?)
Its too bad EVs are so crazy expensive, those efficiencies have quite a pricetag.
I'm not so sure that is true anymore: https://www.tesla.com/model3. What gas car that is as nice as a Model 3 can you get for that price? I'm not saying they don't exist, but that it's pretty competitive as an initial price and add to that the incredibly low maintenance costs and I suspect they are completely competitive.
If you have the money and it fits your lifestyle then by all means go for it. I'll feel better about buying when solid state batteries are standard---longer range and lifetime of battery, lower cost. If I were to buy a new full size truck now the base model is 34K, base on electric is 60K.
Not a lot of competition in the truck space, but that's going to change.
Lexus ES350h, BMW 330i, Genesis G70, Mercedes Benz C class, Toyota Crown, Audi A5 among others. Other than acceleration the Model 3 is not very comfortable or fun to drive.
They are indeed nicer - and every one of the cars you mention cost more and other than the two Korean cars considerably more than a Model 3. That was kind of my point.
If you use the actual price of a Model 3 in the USA (not the fake Tesla “price after gas savings” which subtracts $4800 for 6 years of gasoline but assumes electricity is free) and the $7500 tax subsidy) its over $50,000 which is the same range of those other vehicles without added options. The Tesla has a bare bones interior and forces all controls onto the hard to use while driving touch screen and German cars and Lexi have nicer features in their base models.
That’s great, but America needs to focus on building non-car infrastructure. Bike lanes, rail, and transit-oriented housing development are way better for the planet than EVs could ever be.