Eh, it's more like... exactly what the title says: EVs are just more efficient.
1 gallon of gas contains 33.7 kWh of energy. [1]
The average ICE car goes 24 miles on 1 gallon of gas. That's 0.7 miles per kWh (24/33.7 ≅ 0.7).
The Tesla Model 3 goes about 4.1 miles per kWh. That's 5.8x further per kWh, or 5.8x more efficient!
Most of the difference is because ICE engines are inefficient. They waste energy. Just like the article says. :)
The point made by the article about the source of electricity from power plants was simply that EVs are more efficient even when charged from coal fired power plants! Your point about the "ICE in some power plant somewhere" is temporarily true... as the grid de-carbonizes there will be fewer and fewer emissions from grid-scale generation. (Nuclear + renewables is my personal guess for where we're headed.)
It's kind of sad that several threads here are playing devil's advocate. Unless some dramatically better tech takes the world by storm in the next 2-3 years, EVs are going to completely take over the market. Economies of scale should dramatically drive down costs over the next 5-10 years, and then all new cars will be EVs. No one will want the old, expensive, dirty, loud ICE cars. And this is really good news for everybody!
And even this comparison is lenient towards the ICE. That one gallon of gas doesn’t just poof into existence into the gas tank of the car, there’s a certain kWh requirement of energy to go from not having that gallon of gas, to having it.
Obviously the same is true for the electricity in the EV, but that’s dependent on the energy mix in your area. If it’s primarily renewables, this is another efficiency increase in favor of the EV.
> 1 gallon of gas contains 33.7 kWh of energy. [1]
The average ICE car goes 24 miles on 1 gallon of gas. That's 0.7 miles per kWh (24/33.7 ≅ 0.7).
The Tesla Model 3 goes about 4.1 miles per kWh. That's 5.8x further per kWh, or 5.8x more efficient!
Doesn’t this ignore how the fuel was produced, and delivered (refineries, fuel trucks, power plants, charger losses)? Are those losses negligible compared to the 1kWh once inside the battery or fuel tank? If so, then the comparison is fair
It feels really satisfying to read being said clearly what you would think should really be obvious to everyone, rather than the constant FUD and waffling about EVs.
> Eh, it's more like... exactly what the title says: EVs are just more efficient.
The articles point is also that BEVs are more efficient even if a fossile plant is used, since the plant can operate at better efficiency than a small ICE that also need to idle and rev to bad rpm ranges. Which was what I was trying to convey.
Which opening could you pour gasoline in a Tesla Model 3 to achieve anything else than a fire hazard? Any amount of those "33.7 kWh" gallons will get you exactly zero miles – how is that more efficient?
It's alluded to in the article, but the energy extraction from combustion in power plants is also more efficient than the combustion engine in your car (almost double in the case of natural gas using combined cycle).
Diesel engines, like all internal combustion engines are limited by the Carnot Theorem. The maximum theoretical efficiency for diesel is in the low 80% range.
No actual diesel engines can muster up much higher than 60%.
> Diesel electric systems are highly efficient ~85%.
That's 85% of the crankshaft energy moving the wheels. Once you multiply in your ICE efficiency which will be around 30% for anything that fits in a car or truck you're looking at 25%
Burn the same deisel in a big turbine and chemical->wheel efficiency going via power lines and a battery will be in the 30-40% range, but with the advantage of being able to mix in solar.
Moving a giant metal and plastic box for each individual human is still a gross waste of resources though and we should subsidize mass transit and active transport infrastructure rather than spending vast amounts of common money on roads and parking lots.
Wasn't that sorta the premise of the Chevy Volt? Though I think most HEV still include a direct drive from the ICE.
Personally I'd be interested in a pure electric drive HEV with a high efficiency diesel generator. Give me just enough battery for around town (100 miles maybe?) and just enough generator to extend my trip to ~300 miles. The generator doesn't need to be large (and expensive) enough to be capable to drive from directly at highway speeds, but just enough to extend the range when needed.
Heck make the power units "modular" in 3 ft x 4 ft boxes and let me mix and match power sources. I'll start out with a 1 battery and 1 diesel setup, but could upgrade to 2 battery power packs later if I drive around town a lot. (^_^)
I was joking but actually modular "power packs" would be cool.. You could replace one at a time vs a full $20k battery. Or take one out and plug it into your home. Maybe even rent a extra diesel pack for that coast-to-coast trip. Hmmm, wish I had the energy to start random companies. ;)
I’ve seen talk before about EVs with gas range-extenders as a possible design. But in a rough sense, we’re at that point with all the new PHEVs on the market. Usually they have 20-45 miles of all-electric range, and then have normal regeneration beyond that. I understand that the power/weight/efficiency trade offs of a PHEV are not the same as having a range extender, but I wonder whether it doesn’t matter, that the economies of scale of current PHEVs and iterative improvements will provide most of the benefit at lower cost.
A nice thing about current PHEVs is that they have smaller batteries than full EVs, which could matter in a battery-constrained market.
> The generator doesn't need to be large (and expensive) enough to be capable to drive from directly at highway speeds, but just enough to extend the range when needed.
So you would need to park and let the generator slowly charge your car? Why not just charge the car at a charger at that point?
Make the generator large enough so that it can generate enough power to directly run the electric motor for highway driving.
A car only needs 10kW or so on average to do highway speeds, but you need peak power around 30kW at minimum (or about 70 to satisfy most people's expectations).
You only need the generator to be able to extend the driving time to around 8 hours to cover 99% of use cases, so if your battery can do 2 hours then the generator only needs to produce 3/4 of the energy in the minimal case.
What you are proposing would require the generator to be 3-20x as large as the alternative.
Sorry, maybe I was not clear. Assuming you are correct, I am saying the generator should produce 10kW of power, and OP is suggesting that the generator would generator < 10kW. I'm saying the generator should keep up with the energy demand of cruising on the highway.
A car that uses 10kW average and has a 50km range is usable with a 7.5kW generator and stopping to charge every 200km. Knowing you have the ability to stop and charge or limp at 3/4ths speed to the next charger would allow more confidence pushing the boundaries.
A small battery means a 15 minute break to charge every 2 hours is viable and not a deal breaker for someone who only needs range infrequently.
Yah I figure use a super charger. Maybe refill gas too. If you could save $20k I'd say it'd be worth the hassle on the occasional road trip.
The main reason would be cost and weight. Full EV card are still too expensive for many. I'm guessing there's a sweet spot that'd be much cheaper than either but would provide more range when needed. But as the other commenter points out the ICE + 20 mile pack might win out on efficiency of scale.
But why include the gas engine at all if it doesn't extend your highway range? Keep your small <100 mile battery pack, skip the extra cost and weight of an engine.
The problem with the generator is it's more cost, weight, and maintenance. But it still makes sense in many scenarios, which is why many cars do something like this, like the BMW i3.
I wonder how reliable the portable diesel generators are. The huge ones in datacenters are known to have trouble starting up sometimes, so they're tested frequently.
But heat recovery is also paired with diesel, depending on the usage, with nearly complete conversion efficiency.
All the calcs for electric are bullshit. Every engineer that isn't a bleeding heart acknowledges this. They have either fudged the production cost or disregarded the recycling cost or ignored the mining expense, drive like a puritan with no climate control... on and on.
Well then how about an electric car driving full out in freezing temps? Or with the A/C max?
I can take nearly 100% of the waste heat from a diesel genset working at maximum efficiency with 42% conversion
Except building mild hybrids to avoid that problem might be more efficient than us building the mass production of lithium metals needed to make mass BEVs.
If we are battery constrained today, we need to consider the most efficient use of our limited battery supply. Start/stop idle technology is much cheaper than 1000lbs of lithium batteries in each vehicle.
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It looks like the most efficient solution involves like 50lbs of batteries, rather than the gross 1000+lbs of batteries that BEV fans want to use per car.
These are downright lazy arguments at this point. The F150 ranges 4000-5800 lbs. The F350 ranges 5900-7700 or more. Similar numbers for the Silverado to the F150 I think. And where I live at any given time in any given parking lot a random rock/cinder block is more likely to hit them than any other model. The metals thing is a problem the markets will solve because the tech is largely solved.
Yes and we need to end the weapons race of ever increasing car sizes. It makes accidents much more deadly, uses much more energy to move people and takes up unnecessarily large amounts of space in our cities.
And the comparable GMC Hummer EV is 9,063 lbs, 2,923 pounds of which are batteries.
> The metals thing is a problem the markets will solve because the tech is largely solved.
The metals thing comes from Russia (nickle) and Congo (Cobalt), and Argentina/China (Lithium).
The steel thing is *already* solved, with 88% of USA's steel being composed of recycled steel. You're hoping that some magic recycling process spins up over the next years to make Lithium sustainable, when it clearly isn't right now.
Nickel is mostly produced in Indonesia and some pacific islands. Most growth of new nickel is in Indonesia. Its refined in China.
Lithium is mostly from Chile, Argentina and Australia but its mostly refined in China.
> You're hoping that some magic recycling process spins up over the next years to make Lithium sustainable, when it clearly isn't right now.
The amount of lithium even if 100% recycled isn't nearly enough to cover what is needed. We know how to recycle it, in fact we have far more recycling capability then we have material that we can recycle. Everybody invest in recycling but there is not much to actually recycle yet.
Saw a new GMC Hummer a few hours ago for the first time, it was pretty strange to see because I thought it was a "new Bronco" at first or something (from the front). Then saw Hummer and GMC and was even more confused, but least knew what it was.
Seeing your comment above made everything make sense; it's pretty dang "not my style" but whatever floats (or tows) your boat
> The metals thing is a problem the markets will solve because the tech is largely solved.
There's lots of things the markets haven't "solved".
Also, getting a lot more nasty things out of the Earth will also most probably mean more dead kids in the mines of Africa, but I'm sure the market won't advertise that. At least the Saudis don't directly kill kids in their oil-fields explorations (they kill them only indirectly in Yemen, with the guns they've purchased from the West using the money they got from the oil-fields).
Yes, and you have to go even further and more general. The solution is actually urbanism. You can't just build trains and hope everything is gone be fine.
Living in low or high density urban environments is far more efficient in pretty much every single way that we can measure. CO2, energy, land use, water use and so on, and not just by a little but by a huge margin.
Transport can be electrified trains, trams, trolly buses, metros. This uses very few battery materials and essentially no new technology. All technology read to deploy in large numbers.
This would also 'solve' the housing crisis as increasing density around transportation with mixed use is what leads to much cheaper living cost (housing and transportation need to be seen together).
This talk by famous City Planner Peter Calthorpe is really good and goes into detail. He and his teams were charged with making a few projection plans for California and have really good numbers on all of these things (except the nuclear I mentioned):
Like Berlin and Munich and Prague and Düsseldorf and Warsaw and Amsterdam and The Hague. I lived there, without a car. I rented a few times when not on train or flight out of town.
It's not for every city, though switch out trams for busses (Stockholm) and it could work in many places.
specifically, hybrids that have at least 20 miles of range and are plug in. this is an amount that allows the majority of commutes to be fully electric.
Next your gone tell me you could replace the plastic wheels with once made out of steel. Crazy stuff.
For this to work however you need to change far more then just the buses, you need to change the whole development pattern. I put some great links in my other comment.
The most efficient solution for 80% of trips is 10lbs of batteries and a wire for 19%
But sodium batteries are very nearly in mass production so while we're continuing to insist that petrol is 100% of the problem cars cause rather than 50% I guess that will do.
Much idling could be avoided if traffic engineers would design roundabouts instead of 4-way stops. Nevertheless, some newer cars shut off at intersections and are designed for that.
Roundabouts have a failure mode that 4-way stops don't, akin to starvation in computer science. Consider a roundabout in a right-hand traffic country with connections in the 4 cardinal directions. If at a given time of day, there's a constant stream of cars from the west that want to go east, and virtually no traffic from the north or east, then a car trying to enter the roundabout from the south will be waiting a very long time.
> Roundabouts have a failure mode that 4-way stops don't, akin to starvation in computer science.
Putting roundabouts onto streets is not a binary decision: some intersections could be roundabouts, some could be lights, and others could be roundabouts with lights.
If there's that much traffic, a four way stop will be even worse than a roundabout. You'll need a turbo roundabout, traffic lights or grade separated intersections in that case.
Four way stops are one of the dumbest inventions of man kind that are way over used in North America. Everyone has to stop all the time and it leads to scary situations at 2 way stops because people don't expect those anymore.
A single “pause” (traffic light, roundabout, stop sign, even just a speed camera or change in speed limit…) in the stretch of the east-west road leading up to the roundabout can usually solve this. You only need occasional breaks in traffic to allow the secondary traffic to join.
A lot of walking would be eliminated too if you actually completely got rid of perpendicular intersections. You kind of need cars to stop sometimes to make it possible for people not in vehicles to get through safely.
There are still crosswalks which are distributed around the circle. Rarely there are pedestrian tunnels to get inside the doughnut, like in Paris to visit the arch.
Those crosswalks tend to be -in my experience - some of the most stressful to interact with. If they're controlled then you've just made the whole thing even worse than they were before. If they're not then you've got a much harder time as a pedestrian to figure out when it's safe to cross (because of the curve) and the traffic all wants to free flow.
I dunno. Maybe I just haven't experienced the right ones, but my experience is that the most pedestrian friendly urban spaces have mostly (roughly) straight lines and right angles and lots of natural or man made barriers to free flow of cars to prevent them from going too fast. I don't know how you can square that circle.
I definitely like the idea of this but it seems like the tendency is always the opposite because it's much cheaper to build a pedestrian overpass than a car one, even though they're also an accessibility nightmare and usually kind of a terrible experience and aesthetic blight in their own right.
Most roundabouts of that type I know have replaced similarly sized all asphalt intersections. Now there is more green. When planned ahead there really isn’t that much extra real estate required if you are willing to have steeper grades for pedestrians only for example.
Oh wow never knew this had a name and have been curious on the origins/history of the "diagonal crosswalks" for a long time - have only seem them in specific districts/neighborhoods in Oakland/SF.
Thanks for the link, a bit sad to read to following(!)
> later fell out of favor with traffic engineers there, as it was seen as prioritizing flow of pedestrians over flow of car traffic.
Mathematically speaking I am not sure why they are not all like this. It means one pedestrian phase in the sequence (so sequence is quicker) and everyone is a winner. There is one near me it is a joy to go diagonal!
It's only better if the intersection has high, consistent pedestrian traffic. Unfortunately, many cities aren't built to be pedestrian friendly so those criteria are rarely met outside of busy cities, downtowns, and college towns.
It's not the idle at the stop sign that matters, it's the slowing and and re-accelerating afterward. Idle itself uses a trivial amount of gas - equivalent to around a tenth of a mile for a 15 second idle.
While partly true, it is important to note that improving efficiency of a single large energy source is easier to do than improving energy efficiency of a million cars.
Also, with solar and wind in the fray, and increasing renewable energy share, having an all electric energy consumption economy is better logistically and environmentally.
Even if current power generation for the grid isn't optimal (or clean), the move to EVs is the only way to allow for a cleaner system to work at all. That just isn't possible with ICE cars.
I dunno about about that. There's no reason ICEVs can't run on methanol, the production of which can actually be carbon negative. This is likely where shipping will go, so no reason cars couldn't do it. You can even convert modern cars over fairly cheaply, so you don't need to produce an entirely new vehicle.
The reving and idling or low power output of the ICE can be avoided if it is in some power plant somewhere.