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The EPA lists the Nissan Leaf at 30 kWh per 100 miles. This is energy stored in the battery. Getting the energy into the battery involves a charging efficiency of about 80% (i.e. only 80% of the electricity coming out the wall socket makes it into the battery, the other 20% becomes waste heat).

First, your charging efficiency of 80% is too low. 90% is a better estimate. More importantly for your calculations though, the EPA fuel economy estimates already include the charging losses: "The recharge energy includes any losses due to inefficiencies of the manufacturer’s charger." (Source)

This means that you need to remove the first step of your efficiency calculation.

Furthermore, Momentum Dynamics claim that their losses are lower than with a wired charger (only 4% compared to 7%). If that were true, the consumption figure should be less than the 30 kWh per 100 miles.

The EPA lists the Nissan Leaf at 30 kWh per 100 miles. This is energy stored in the battery. Getting the energy into the battery involves a charging efficiency of about 80% (i.e. only 80% of the electricity coming out the wall socket makes it into the battery, the other 20% becomes waste heat).

First, your charging efficiency of 80% is too low. 90% is a better estimate. More importantly for your calculations though, the EPA fuel economy estimates already include the charging losses: "The recharge energy includes any losses due to inefficiencies of the manufacturer’s charger." (Source)

This means that you need to remove the first step of your efficiency calculation.

Furthermore, Momentum Dynamics claim that their losses are lower than with a wired charger (only 4% compared to 7%). If that were true, the consumption figure should be less than the 30 kWh per 100 miles.

This drops the energy efficiency of EVs below that of ICEs.

The EPA lists the Nissan Leaf at 30 kWh per 100 miles. This is energy stored in the battery. Getting the energy into the battery involves a charging efficiency of about 80% (i.e. only 80% of the electricity coming out the wall socket makes it into the battery, the other 20% becomes waste heat). Transmission over power lines is about 95% efficient. And electricity generated from coal plants is about 37% efficient, about 58% efficient for natural gas plants. Split the difference and call it 47.5%. So to move an EV 100 miles requires (30 kWh) / (0.8 * 0.95 * 0.475) = 83.1 kWh = 299 MJ worth of fuel if you're generating the electricity from fossil fuels.

The Nissan Versa hatchback (ICE equivalent to the Leaf) uses 2.9 gallons of gasoline per 100 miles. Gasoline has an energy density of 34.2 MJ per liter, or 129.5 MJ per gallon. So 2.9 gallons holds 375.4 MJ. Making the ICE vehicle slightly less energy-efficient than the EV (uses about 25% more energy than the EV).

Wireless inductive chargers have been built over 90% efficient in labs, but the typical chargers in commercial production are only 75%-80% efficient. That moves the EV's 299 MJ per 100 mile energy consumption up to 374-399 MJ per 100 miles. Meaning the EV consumes more energy than an equivalent ICE vehicle to travel the same distance.

Norway can get away with it because they get almost all their electricity from hydroelectric. But this idea won't work in countries heavily reliant on fossil fuels to generate electricity (most of the world). The EV still gets the advantage of being able to better filter out particulate emissions at the power plant using big effective filters, instead of poor transportable filters at the tailpipe of every car. But it would result in EVs generating more CO2 per mile than ICE vehicles, defeating much of the purpose of switching to EVs.

This drops the energy efficiency of EVs below that of ICEs.

The EPA lists the Nissan Leaf at 30 kWh per 100 miles. This is energy stored in the battery. Getting the energy into the battery involves a charging efficiency of about 80% (i.e. only 80% of the electricity coming out the wall socket makes it into the battery, the other 20% becomes waste heat). Transmission over power lines is about 95% efficient. And electricity generated from coal plants is about 37% efficient, about 58% efficient for natural gas plants. Split the difference and call it 47.5%. So to move an EV 100 miles requires (30 kWh) / (0.8 * 0.95 * 0.475) = 83.1 kWh = 299 MJ worth of fuel if you're generating the electricity from fossil fuels.

The Nissan Versa hatchback (ICE equivalent to the Leaf) uses 2.9 gallons of gasoline per 100 miles. Gasoline has an energy density of 34.2 MJ per liter, or 129.5 MJ per gallon. So 2.9 gallons holds 375.4 MJ. Making the ICE vehicle slightly less energy-efficient than the EV (uses about 25% more energy than the EV).

Wireless inductive chargers have been built over 90% efficient in labs, but the typical chargers in commercial production are only 75%-80% efficient. That moves the EV's 299 MJ per 100 mile energy consumption up to 374-399 MJ per 100 miles. Meaning the EV consumes more energy than an equivalent ICE vehicle to travel the same distance.

Norway can get away with it because they get almost all their electricity from hydroelectric. But this idea won't work in countries heavily reliant on fossil fuels to generate electricity (most of the world). The EV still gets the advantage of being able to better filter out particulate emissions at the power plant using big effective filters, instead of poor transportable filters at the tailpipe of every car. But it would result in EVs generating more CO2 per mile than ICE vehicles, defeating much of the purpose of switching to EVs.

That's ridiculous. For example the Kona is not 25% less efficient than the Model 3.

https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=39836&id=40585

Model 3 MPGe: 123
Kona: 108

123 / 108 = 14% difference... on top of the fact that Kona is also a smaller vehicle (if you disagree, you've clearly either never been inside a Model 3, been inside a Kona, or both; Kona's rear seat in particular is tiny). Leaf is closer, though still smaller in most internal passenger space measurements. It gets 97 MPGe highway, aka 27% more energy than the Model 3.

I'll repeat: Aerodynamics is done for a reason. It makes a big difference in range, charge times, and cycle life.

(Oh, and a note for the above: The average speed for said "highway" cycle is only about 55mph; the faster you go, the more streamlining matters)

Slightly different meaning here I think. The problem with that shape door is that it both lets rain water in

That's what gutters are for, as you'll find in every single car which has that form of hatch (which are numerous).

and reduces the overall available height considerably.

Which is why tapered vehicles are generally longer.

If you want a "city car" that never goes at highway speeds, but length is a critical factor, then sure, have a truncated rear end. But if you want an EV that's suitable for road trips, you want taper.

I had a 2014 Nissan Rogue. It's actually a rather nicely designed vehicle with a good layout, nice controls, and a lot of functionality. It is also one of the few mid-sized vehicles with a 3rd row seat. This is essentially, a modern station wagon with AWD.

However, I encountered two issues with my Nissan Rogue AWD.

ISSUE 1) Fuel Economy - It never came close to the estimated EPA mileage - not even in the ballpark. In fact if you review

RATED: 25 City, 31 Highway, 27 Combined.

Over the life of the vehicle I averaged 23.5 MPG. Now I drove nearly a 100 miles a day, mostly highway. And if you look at FuelEconomy.gov, you'll see my mileage was the norm.
https://www.fueleconomy.gov/fe...

Frankly, I believe that Nissan used a computer algorithm to put the vehicle in a more efficient low-power fuel economy mode for testing. I believe you only enter this mode if you are driving like 50 MPH. It is one thing, to expect EPA estimates to be off. But usually, when you buy a vehicle, you at least expect your HWY mileage to be better than the CTY rating. And considering my prior vehicle was a Nissan Versa, rated at 30CTY, 37HWY, 33C, in which on the same commute I averaged around 36.5MPG. So yes, I felt very deceived.

ISSUE 2) 36K/3YR warranty - so I added the extended warranty at purchase as well. I had an intermittent issue with the AC they told me to bring it in when it was occurring. However, when it finally did and completely failed. The vehicle was at 37,000 miles and 13 months of age. Took them a week to diagnose and fix the problem. Which they claimed was the blower motor fuse, and that the blower motor was fine. Nissan refused to cover it under warranty. A 13 month old vehicle that had the problems in it's first year. Fuses are considered replaceables, so the extended warranty didn't cover it. $700+ to fix a brand new car. I fought with Nissan national, and they finally covered half the cost. Within 6 months, the problem was back. Nissan wanted more money to diagnose.

Driving a 100 miles a day in summer heat sweating while going thru a nasty divorce and battling depression is NO FUN. There were days I damn near wanted to drive the thing off the road, or into a showroom. Finally, I gave up, why fight to struggle and pay for a vehicle that wasn't working. It needed a set of four new tires - runflats so about double the price. And I gave up and let the bank take it.

Thanks Nissan...

Love the car, but the fact Nissan wouldn't stand behind their product when it was only a year old. NOT COOL!!!!

(And without a doubt they are cheating on the EPA mileage and need to be penalized on it like Kia was.)

[...] emitting around 24 pounds of carbon dioxide and other global-warming gases for every gallon of gas. About five pounds comes from the extraction, production, and delivery of the fuel, while the great bulk of heat-trapping emissions—more than 19 pounds per gallon—comes right out of a car’s tailpipe.

How does one gallon of gas turn into 19 pounds of CO2? I was going to call BS but then I found the answer: https://www.fueleconomy.gov/fe...

Turns out it's 19 pounds after Oxygen is added.

Moving energy by powerline is no way cheaper than moving petro to your gas station....

Tesla's charging stations are all getting solar, with the goal of removing them from the grid entirely. You could do the same thing.

Grid losses are dependent upon the state where you live; they run from 2.2% to around 13%, with the nationwide average being around 10% losses. However, once the energy is in your electric car, you lose a further 40% of it before it drives the wheels; for gasoline engines the further losses are 80% (source: Trump Administration).

So even if you live in the worst case state for electricity transmission losses, and the gasoline you use magically appears at the pump with no energy inputs for refining and transport, you're still losing more net energy with your gasoline car than with your electric vehicle.

Burning a gallon of fuel releases 20 pounds of CO2. That means this carbon capture solution would add. one or two bucks to the price of a gallon of gas. It may be a tenable alternative to abandoning fossil fuels.

Oops. I compared the EcoBoost Escape to V6 Taurus. There is an EcoBoost taurus. The Escape doesn't destroy the Taurus, but is does best it, even with the most efficient engine option. 3 MPG better in City driving.

Oops. I compared the EcoBoost Escape to V6 Taurus. There is an EcoBoost taurus. The Escape doesn't destroy the Taurus, but is does best it, even with the most efficient engine option. 3 MPG better in City driving.

So many liars on /. these days. Sad.
I seriously doubt that your 2013 is able to double the MPG that the 2014 does. And that is EPA miles, which are better than what you can obtain.

This site https://www.fueleconomy.gov/fe...
says that the Tesla Model S AWD gets about 98MPGe, or if you want less "equivalents"and more hard numbers - 35kWh/100miles.

So cost per mile:
ICE: $3/gallon * (1 gallon / 25 miles) = $0.120/mile
Tesla: $0.24/kWh * (35kWh/100miles) = $0.084/mile
Ignoring purchase and maintenance costs of course.

And of course the superchargers are intended for occasional, rushed charging with the assumption that most of the people most of the time will use home/work trickle chargers paying market rates of closer to $0.12/kWh. or about $0.042/mile.

You can back out ICE efficiency from the EVs on the road. Let's use the Nissan Leaf (you'll see why later). EPA rating of 30 kWh per 100 miles. 112 MPGe combined, 101 MPGe.highway. Top speed of 93 MPH.

30 kWh per 100 miles = 108 Megajoules per 100 miles. Since we're trying to do a comparison and ICE cars don't have regenerative braking, we need to compare the highway mileage. Since the Leaf gets 101 MPGe on the highway vs 112 MPGe combined, this works out to (112/101)*(108 MJ) = 119.8 MJ per 100 miles on the highway. Note that this is energy stored in the battery. To do the comparison, we need energy at wheels to the ground.

Electric motor + inverter efficiency is typically about 85%-93% (page 35). That's for a Prius' motor (the only one I could find detailed stats for), but they're all pretty similar at these levels of power output. Since there's no gearing, if you align the Leaf's top speed of 93 MPH with 6000 RPM, then the highway speed of 55 MPH corresponds to (55/93)*(6000 RPM) = 3550 RPM. Which puts us right around 90% efficiency.

I couldn't find any numbers for battery discharge efficiency. Battery charging efficiency for a Tesla with the home charger is about 85%. Battery discharge efficiency is typically a bit worse (even more so at higher loads, which is why jackrabbit or ludicrous mode starts kill your rnage). so go with 80%. (For those of you complaining this is too unfavorable to EVs, a lower discharge efficiency here corresponds to lower ICE efficiency later on.)

So 119.8 MJ from the battery becomes (119.8 MJ)*(90%)*(80%) = 86.3 MJ per 100 miles wheels-to-ground. The extra energy is lost as heat to the battery, wiring, inverter, and motor.

Gasoline has an energy density of 34.2 MJ/L = 129.5 MJ/gallon. To figure out how many gallons were used in 100 miles, we need the MPG of a gas-powered Leaf. Fortunately we have one - the Leaf's aerodynamic and rolling resistance is almost identical to the Versa since it shares the same body and frame (I had to go back to 2014 to get the hatchback version with a regular transmission). Highway mileage is 35 MPG. Meaning (129.5 MJ/gal)*(100 miles)/(35 miles/gal) = 370 MJ worth of gasoline consumed per 100 miles.

Overall highway efficiency of the ICE and drivetrain is then energy wheels-to-ground vs energy in the gasoline. (86.3 MJ)/(370 MJ) = 23.3%. It's rated at 26 MPG city, so overall efficiency in city driving is (26/35)*(23.3%) = 17.3%. A far cry from the 12% you came up with.

We can also calculate overall efficiency for the EV, from energy source to wheels-to-ground, just like we calculated it for the ICE vehicle from energy source (gasoline) to wheels-to-ground. The average efficiency of a coal plant is about 33%. The average efficiency of a natural gas plant is about 43%. Power line transmission losses are about 5%. As mentioned before, charging efficiency (for a home charger) is around 85%, discharge efficiency around 80%, motor efficiency around 90%. To get an overall efficiency of (33% or 43%)*(95%)*(85%)*(80%)*(90%) = 19.2% or 25%. If you use a fast charger like a Supercharger station, it's even worse, since the charging efficiency is even lower (more of the electricity is lost as heat) the more quickly you charge the battery.

So an EV powered by electricity generated from fossil fuels isn't any more energy efficient than an ICE vehicle. The reason it's cheaper to charge an EV is almost entirely because gasoline is damn expensive for an energy source. Coal costs about $50/ton and contains ab

You can back out ICE efficiency from the EVs on the road. Let's use the Nissan Leaf (you'll see why later). EPA rating of 30 kWh per 100 miles. 112 MPGe combined, 101 MPGe.highway. Top speed of 93 MPH.

30 kWh per 100 miles = 108 Megajoules per 100 miles. Since we're trying to do a comparison and ICE cars don't have regenerative braking, we need to compare the highway mileage. Since the Leaf gets 101 MPGe on the highway vs 112 MPGe combined, this works out to (112/101)*(108 MJ) = 119.8 MJ per 100 miles on the highway. Note that this is energy stored in the battery. To do the comparison, we need energy at wheels to the ground.

Electric motor + inverter efficiency is typically about 85%-93% (page 35). That's for a Prius' motor (the only one I could find detailed stats for), but they're all pretty similar at these levels of power output. Since there's no gearing, if you align the Leaf's top speed of 93 MPH with 6000 RPM, then the highway speed of 55 MPH corresponds to (55/93)*(6000 RPM) = 3550 RPM. Which puts us right around 90% efficiency.

I couldn't find any numbers for battery discharge efficiency. Battery charging efficiency for a Tesla with the home charger is about 85%. Battery discharge efficiency is typically a bit worse (even more so at higher loads, which is why jackrabbit or ludicrous mode starts kill your rnage). so go with 80%. (For those of you complaining this is too unfavorable to EVs, a lower discharge efficiency here corresponds to lower ICE efficiency later on.)

So 119.8 MJ from the battery becomes (119.8 MJ)*(90%)*(80%) = 86.3 MJ per 100 miles wheels-to-ground. The extra energy is lost as heat to the battery, wiring, inverter, and motor.

Gasoline has an energy density of 34.2 MJ/L = 129.5 MJ/gallon. To figure out how many gallons were used in 100 miles, we need the MPG of a gas-powered Leaf. Fortunately we have one - the Leaf's aerodynamic and rolling resistance is almost identical to the Versa since it shares the same body and frame (I had to go back to 2014 to get the hatchback version with a regular transmission). Highway mileage is 35 MPG. Meaning (129.5 MJ/gal)*(100 miles)/(35 miles/gal) = 370 MJ worth of gasoline consumed per 100 miles.

Overall highway efficiency of the ICE and drivetrain is then energy wheels-to-ground vs energy in the gasoline. (86.3 MJ)/(370 MJ) = 23.3%. It's rated at 26 MPG city, so overall efficiency in city driving is (26/35)*(23.3%) = 17.3%. A far cry from the 12% you came up with.

We can also calculate overall efficiency for the EV, from energy source to wheels-to-ground, just like we calculated it for the ICE vehicle from energy source (gasoline) to wheels-to-ground. The average efficiency of a coal plant is about 33%. The average efficiency of a natural gas plant is about 43%. Power line transmission losses are about 5%. As mentioned before, charging efficiency (for a home charger) is around 85%, discharge efficiency around 80%, motor efficiency around 90%. To get an overall efficiency of (33% or 43%)*(95%)*(85%)*(80%)*(90%) = 19.2% or 25%. If you use a fast charger like a Supercharger station, it's even worse, since the charging efficiency is even lower (more of the electricity is lost as heat) the more quickly you charge the battery.

So an EV powered by electricity generated from fossil fuels isn't any more energy efficient than an ICE vehicle. The reason it's cheaper to charge an EV is almost entirely because gasoline is damn expensive for an energy source. Coal costs about $50/ton and contains ab

https://en.wikipedia.org/wiki/...
https://en.wikipedia.org/wiki/...
https://www.fueleconomy.gov/fe...

• Coal costs about $50 per ton. A ton of coal has approximately 24 GJ of energy. That's about 0.21 cents/MJ.
• Gasoline costs about $2/gallon (without taxes), and has about 120 MJ/gallon, or 1.67 cents/MJ. (You gotta exclude the taxes because if we do switch to mostly EVs, then they're going to have to be charged the same taxes in order to maintain our roads.)

For the same amount of energy, coal is nearly an order of magnitude cheaper than gasoline, which gives the EV a huge advantage in terms of operating costs. This is not a bad thing - being able to transfer a cheaper but traditionally static energy source into use in a mobile application is an economic win. But don't confuse it for higher energy efficiency. Your EV wastes more energy than my diesel.

I expect that small and mid-sized sedans would be all-electric first.

The problem is these are not the vehicles producing the emissions. The whole thing stems from MPG being the inverse of fuel consumption. People see the big MPG number from a fuel-efficient vehicle and think they're making a big difference in fuel consumption. It's actually the opposite - the bigger the MPG of a vehicle, the smaller the impact it has on overall consumption and emissions. Switching from a 25 MPG sedan to a 50 MPG Prius results in less fuel savings (and thus less emissions reduction) than someone switching from a 15 MPG full-size SUV to a 25 MPG large sedan. Yes, that 10 MPG improvement results in more fuel savings and more emissions reduction than the Prius' 25 MPG improvement.

15 MPG = 6.67 gallons to drive 100 miles
25 MPG = 4 gallons to drive 100 miles, a 2.67 gallon improvement
50 MPG = 2 gallons to drive 100 miles, only a 2 gallon improvement

Because MPG is the inverse of fuel consumption, it's 1/MPG which is the important value. And the bigger MPG values mean less incremental fuel savings. The rest of the world uses liters per 100 km to avoid this problem. For some reason it's backwards in the U.S., and marketing has abused it to make people feel good about buying a Prius when it's about the smallest difference you can make in terms of driving.

You know how environmentalists scoffed at hybrid SUVs? That was actually the best place to put a hybrid engine. The 6 MPG improvement the Highlander Hybrid gets from 22 to 28 MPG results in a fuel savings of nearly 1 gallon per 100 miles. That's about the same savings as switching from a 33 MPG econobox to a 50 MPG Prius. If you can improve a tractor trailer's 6 MPG to just 6,4 MPG, that also saves about the same amount of fuel per mile. It's the big vehicles which consume a lot of fuel whose efficiency you want to improve first in order to produce the biggest reduction in fuel consumption and emissions. The Priuses, econoboxes, and small sedans are roundoff error.

Give Musk credit. He actually understands this, which is why his next project is an electric tractor trailer.

First, we need to drop our average per capita energy usage from 250 kWh/day to 125 kWh/day.

That number seems wrong. I looked at his website (the design is Geocities, circa 1998 - nice!) and it's not immediately obvious where that number came from, but it appears to be too high. In 2015 the US generated 4,077.6 TWh of electricity so that's around 35 kWh per capita per day. That year 3.22 trillion miles were driven, if everyone magically had a Telsa Model S (which uses 340 wh/mi, smack dab in the middle in efficiency for electric cars listed by the EPA) instead of their current car that would be another 9.3 KWh per day per capita.

So that's around 45 kWh for electricity and transportation, where does the other 205 kWh come from? Heating? The electricity number already includes all the electric heating (as well as commercial and industrial use) so it would just be oil and natural gas - do those really add up to 205 kWh? We used 27.3 trillion cubic feet of natural gas, but a ton of that is already included in the electric number. According to the EIA it was closer to 15 trillion for residential, commercial and industrial use. That would be another 38 kWh. We burned around 390 billion gallons of heating oil, that's another 1.5 kWh. I don't necessarily think that converting the total heat available in those substances to kWh is a valid comparison but let's ignore that for now. We are still only to 84 kWh per person per day, where is the missing 166 kWh?

Looking further on his site I think I see what the issue is. He just makes up numbers and then adds those to his total. For example, on this page he guesses at a number for kWh per airline passenger and then rather than using data like actual miles flown he just assumes every person makes exactly one intercontinental trip (from London to Cape Town) per year and extrapolates a 30 kWh usage for that. He does similar things throughout the site, instead of using actual consumption data he makes estimates based on broad assumptions. I'm sure he has interesting things to say but there's certainly no rigor in his numbers and it's a poor site on which to base a numbers post.

A typical modern compact family car ought to achieve real figures significantly better than those if driven sensibly. (And of course that's being very generous with "comparable", since a typical modern compact family car would be superior to the models you mentioned in almost every conceivable way.)

LOL no. According to the EPA list, excluding hybrids (which aren't "comparable") the best 2017 models get 35 combined MPG. In comparison, even under the new EPA rating calculation the 1990 Geo Metro XFI got 47 combined MPG and the 1990 Honda CRX HF got 43 combined MPG. Modern cars are fucking pigs -- even the tiny ones. (I can't link to the exact pages with the new EPA ratings for the old cars, but go here and fill out the drop-down lists.)

Incidentally, I would argue that a 1990 CRX is an objectively better car than a 2017 Smart Fortwo. It's not only more efficient, but it's also better-looking, has better handling / is more fun to drive, has more cargo capacity and is cheaper to maintain (Honda parts prices vs. Mercedes parts prices, and also because there's less fancy shit to break). Sure it won't be as safe in a crash, but that's the only downside -- and because of the better handling, it's somewhat less likely to crash in the first place.

You really couldn't. Not even close.

First of all, old Mercs and Volvos had most of the fancy safety systems you seem to think are necessary.

Second, NO. Traction control is absolutely not a safety feature -- all it does is help you start from a stop in slippery conditions, which is the opposite of safety. Anti-lock brakes are a safety feature, but Mercs have had that since 1978 (according to Wikipedia), and most cars have had it since the '90s. Electronic stability control claims to be a safety feature, but all it really is is a crutch for people too stupid to know not to drive too fast for conditions. Ditto with cameras, TPMS and other electronic bullshit -- it's all just crutches for people who are INCOMPETENT TO DRIVE in the first place!

A typical modern compact family car ought to achieve real figures significantly better than those if driven sensibly. (And of course that's being very generous with "comparable", since a typical modern compact family car would be superior to the models you mentioned in almost every conceivable way.)

LOL no. According to the EPA list, excluding hybrids (which aren't "comparable") the best 2017 models get 35 combined MPG. In comparison, even under the new EPA rating calculation the 1990 Geo Metro XFI got 47 combined MPG and the 1990 Honda CRX HF got 43 combined MPG. Modern cars are fucking pigs -- even the tiny ones. (I can't link to the exact pages with the new EPA ratings for the old cars, but go here and fill out the drop-down lists.)

Incidentally, I would argue that a 1990 CRX is an objectively better car than a 2017 Smart Fortwo. It's not only more efficient, but it's also better-looking, has better handling / is more fun to drive, has more cargo capacity and is cheaper to maintain (Honda parts prices vs. Mercedes parts prices, and also because there's less fancy shit to break). Sure it won't be as safe in a crash, but that's the only downside -- and because of the better handling, it's somewhat less likely to crash in the first place.

You really couldn't. Not even close.

First of all, old Mercs and Volvos had most of the fancy safety systems you seem to think are necessary.

Second, NO. Traction control is absolutely not a safety feature -- all it does is help you start from a stop in slippery conditions, which is the opposite of safety. Anti-lock brakes are a safety feature, but Mercs have had that since 1978 (according to Wikipedia), and most cars have had it since the '90s. Electronic stability control claims to be a safety feature, but all it really is is a crutch for people too stupid to know not to drive too fast for conditions. Ditto with cameras, TPMS and other electronic bullshit -- it's all just crutches for people who are INCOMPETENT TO DRIVE in the first place!

The most efficient EV (Hyundai Ioniq) uses about 25 kWh per 100 miles. 310 miles range is them 77.5 kWh.

77.5 kWh / 20 minutes = 232.5 kW, or enough to power about 200 homes
77.5 kWh / (480 Volts * 20 minutes) = 484.4 Amps

And that's assuming 100% charging efficiency (not factoring in heat losses during charging).

I bought a 2014 Nissan Rogue, equipped with a 3rd row, rated at 32MPG HWY/25CITY. I expected to at least get around 27-28MPG. I do not get anywhere close to that. I recently drove a Jeep Cherokee rental. It got equivalent gas mileage. So ya, not happy with Nissan, as I sacrificed ability to "tow" for better gas MPG. And it hasn't been even close to the rating. And as you can see, my 23.5MPG is pretty typical. That's a "big" miss.
http://www.fueleconomy.gov/feg...

If that wasn't bad enough, my HVAC system has not worked properly since the vehicle was 13 months old. (But was out of warranty because I had just passed the 36,000 mile mark.)

So sick and tired of cars.

It was the #3 deciding factor of my purchase.

#1 - within my budget (this eliminated Tesla, sadly)

#2 - 3rd row seat

#3 - highest MPG possible.

#4 - AWD/Towing

I bought a 2014 Nissan Rogue, equipped with a 3rd row, rated at 32MPG HWY/25CITY. I expected to at least get around 27-28MPG. I do not get anywhere close to that. I recently drove a Jeep Cherokee rental. It got equivalent gas mileage. So ya, not happy with Nissan, as I sacrificed ability to "tow" for better gas MPG. And it hasn't been even close to the rating. And as you can see, my 23.5MPG is pretty typical. That's a "big" miss.
http://www.fueleconomy.gov/feg...

If that wasn't bad enough, my HVAC system has not worked properly since the vehicle was 13 months old. (But was out of warranty because I had just passed the 36,000 mile mark.)

So sick and tired of cars.

an internal combustion engine - as used in a petrol-driven vehicle - gets around 20% efficiency

Actually, the engines themselves are 30% to 40% efficient on modern gasoline-powered cars. There are some additional losses in the transmission, which is something like 95 to 98% efficient. Running outside the optimal load range also makes the engine a lot less efficient, but that's only relevant in stop-and-go traffic, and hybrid electric systems largely solve the issue. Even non-hybrid cars do a lot better in this respect than they used to, by automatically stopping and starting the engine at lights, and having more gears.

The efficiency of the complete drivetrain of a new ICE vehicle is 20% (standard) to 35% (efficient hybrid) for stop-and-go, and considerably better on the highway.

That's 6.189km per kWh, or about 162 grams of carbon dioxide of emissions - using worst case carbon generation - per km travelled.

Electric cars aren't 100% efficient, either; total up the losses in charging and discharging (86% efficient), power conversion (97%), and the motor(s) themselves (91%), and the total efficiency of the drive train is more like 76%.

An electric car? The infrastructure is already in place; there is negligible marginal cost in getting the power from the plant to the car.

That's not true. Even in the USA, grid transmission is only about 94% efficient. (It's much worse in developing countries; for India it's estimated at 70%. The huge difference is because building and maintaining reliable, efficient power transmission and distribution is not cheap, and some places are too poor to do it well.)

So best case, with a diesel S-class vehicle, you're about one third better than the Model S; worst case (5+ litre petrol engine), you're 50% worse.

We must adjust your 162 g/km estimate upward by 40% to account for the EV inefficiencies that you ignored, which gives us a revised estimate of 227 g/km - worse than all but the most over-powered of the four Mercedes models found in the document that you linked.

Another factor to consider as well is the cost of transporting the fuel: trucks have to carry that fuel (diesel, petrol, etc.) to the station, and you have to drive to the station to refuel.

You can't pretend this is a useful or fair comparison if you only consider the supply chain for the contents of the ICE car's gas tank, and ignore everything else. Mining and moving coal has a substantial environmental and economic impact as well. So does mining Lithium for batteries, or refining and doping Silicon for solar panels, etc.

There are really only two reasonable ways to estimate the true environmental impact of a product:
1) Start from nothing but labour and raw natural resources (think minerals still in the ground, not steel) and work your way up every stage of the production, supply, and maintenance chain - you can't assume trains are moving coal, until you've figured out the full impact of making and running trains from scratch.
2) Or, assume that the selling price of an item already accounts for its environmental impact (partially true).

(1) is probably more accurate, but if you're going to do it you need to do it for everything, or at least apply

The EPA tests were originally developed to quantify pollution generated by cars in the L.A. area, and using those tests to quantify gas mileage came later.

The EPA city cycle was not meant to represent the stop-and-go driving in Manhattan during rush hour. Rather, it was intended to be typical of an automobile trip in the L.A. area conducted on "surface streets", meaning major arterial roads that have stop lights and are not freeways. The average speed of that cycle is about 20 MPH. The EPA highway cycle was not meant to represent bombing down an open Interstate at 10-over a 70 MPH speed limit. Instead, it was to represent a trip on the 405 freeway in Los Angeles in the days before that road became a parking lot -- the test was meant to represent "moderate traffic" levels where the average speed is about 50 MPH.

Not only may your miles-per-gallon vary, the amount of BTUs in a gallon of gas can also vary downward from an alcohol-free summer blend that was probably the standard for the test -- the test conducted on rollers somewhere in Ann Arbor, MI doesn't actually measure the quantity of fuel used but instead measures the combustion products out the tailpipe and performs a mass balance with that standardized gasoline.

Taking the lower BTU fuel you may be getting into account, if you start the car engine from cold on a 70 deg-F day, don't run the A/C, and drive for about 10 miles in traffic where you average 20 MPH, you will roughly reproduce a city test, and I have found that the reading on a Scan Gauge, calibrated to tank fills, will get within 5 percent of the raw city numbers available here https://www3.epa.gov/otaq/tcld.... These numbers are considerable higher than the window sticker MPG rating available here https://www.fueleconomy.gov/. Driving on a not-that-hilly road (do this in both directions and take a harmonic average to compensate for net elevation change) on a 70-deg calm-wind day with the A/C off at a constant 55 MPH, if you can do that with angering other drivers, is a good proxy for the EPA highway test and will also get you within 5 percent.

"But no one drives that way!" someone will shout at you, and this may be true, but if you want to reproduce the EPA test conditions to see if you can match the (raw) EPA numbers, this is the way to check that.

The sticker MPG at fueleconomy.gov has had more than one "adjustment" performed to down rate it from the raw MPG. This was done because the published EPA ratings made people who considered themselves to be "good drivers" feel bad about themselves and their expensive new car purchases, and we cannot have any of that. Or rather, the "consumer" gas mileage numbers were proportionately reduced to "better reflect how real-world driving conditions on more congested city streets and with higher speed limits on highways affect mileage" whereas the Federal Test Procedure and the raw numbers for computing CAFE (corporate average fuel economy) were left the same so as to not keep changing the rules to which the car companies had to comply.

Now the down-adjusting is based on fleet averages, and your car may vary. A case in point is that Consumer Reports praised the Ford C-Max hybrid as being a lot more "fun to drive" than the Toyota Prius but slammed it for being much further off the EPA sticker in real-world driving than the Prius. Well, duh, Consumer Reports! Were you to drive both vehicles in a true "EPA city granny cycle", they probably would get proportionately higher than the window sticker as is the raw "test car" number. But left to the lead foot of a "normal driver", the C-Max with its bigger gas engine will indeed accelerate better yet use more gas than the small-engine sluggish Prius.

I also expect "eco-cars" like the Prius to suffer more from "normal driver" in relation to EPA test cycle driving because their power plants are more matched to the "granny cycle." A real "muscle car" may suffer le

The current generation MX-5 has 155hp in the US model, 129hp in the UK/Europe model; and it's verified by Guinness as the best-selling sports car of all time. It doesn't get 50mpg in the US though. Our version gets 27/34/30mpg (City/Highway/Combined.)
https://www.fueleconomy.gov/fe...

Grandparent is most likely on the other side of the pond and has the has the European version, which is rated at 35.8/57.6/47.1mpg. (Holy crap!!!)
https://www.mazda.co.uk/cars/m...

I have a Skyactiv Mazda 3. And I routinely beat the mileage I'm supposed to get according to the specs. It's rated 27/38/31, and I usually get about 42 on the freeway and 32 combined. So it's quite believable to me that the UK/EU MX-5 can beat it's rated combined driving MPG and top 50.

Figure you use the commercial 150 Watt/m^2 panels, and that's a peak generating capacity of 750 Watts. Capacity factor for solar in the U.S. is about 0.145 (this accounts for angle of the sun, weather, etc.). So (0.75 kW) * (0.145) * (24 hours) = 2.61 kWh. In other words, if you left your solar panel-covered Tesla S parked outside for a typical continental U.S. day, it would generate 2.61 kWh.

Why on earth would you use 150W/m2 panels? That's 15% efficiency, terrible by today's standards. Good modules are closer to 25% efficient.

Capacity factor is not 0.145 everywhere, don't pretend it is. Some places make more sense for solar, others make less sense. In California the capacity factor is 0.25 averaged over a year. That's not the highest capacity factor you'll find in the US either. Obviously it makes less sense to do this in, say, Alaska. Don't play dumb.

Charging efficiency of the Tesla battery is about 80%. So only about 2.09 kWh actually makes it into the battery (the rest heats up the battery and charger).

as somebody else pointed out, the EPA fuel economy already includes this loss, so you are double-counting here.

The best EPA-rated Tesla S uses 33 kWh/100 miles. So leaving your PV-encrusted Tesla parked out in the sun all day will charge the battery enough to move you 6.3 miles.

Adding up the efficiency increase, capacity factor increase, and removing your extra charging subtraction, I came up with 22.6 miles charged for the solar-encrusted Tesla. Not so bad when you actually use realistic numbers.

The Tesla S is approx 2 meters wide by 5 meters long, about half of which is windows. If you covered the rest with solar panels (only projected area matters), that's 5 m^2 of panels.

Figure you use the commercial 150 Watt/m^2 panels, and that's a peak generating capacity of 750 Watts. Capacity factor for solar in the U.S. is about 0.145 (this accounts for angle of the sun, weather, etc.). So (0.75 kW) * (0.145) * (24 hours) = 2.61 kWh. In other words, if you left your solar panel-covered Tesla S parked outside for a typical continental U.S. day, it would generate 2.61 kWh.

Charging efficiency of the Tesla battery is about 80%. So only about 2.09 kWh actually makes it into the battery (the rest heats up the battery and charger).

The best EPA-rated Tesla S uses 33 kWh/100 miles. So leaving your PV-encrusted Tesla parked out in the sun all day will charge the battery enough to move you 6.3 miles.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

No, I'm not wrong:

http://www.fueleconomy.gov/feg...

For the 2.0 engine on the Focus, the manual gets 26/36, the AM-S6 auto gets 26/38, and the AM6 auto gets 27/40.

http://www.fueleconomy.gov/feg...

For the Fiesta, the manual gets 28/36, the auto gets 27/37.

http://www.fueleconomy.gov/feg...

For the Mustang, the 2.3L gets 22/31 with manual, 21/32 with auto. With the 3.7L V6, it gets 17/28 manual, 19/28 auto. With the 5.0L V8, it gets 15/25 manual, 16/25 auto.

http://www.fueleconomy.gov/feg...

For the Chevy Cruze, the manual gets 29/41 and the auto 30/42.

http://www.fueleconomy.gov/feg...

For the Camaro, the 2.0L turbo manual gets 21/30 and auto gets 22/31. On the 3.6L V6, the manual gets 18/27 and auto gets 19/28. On the 6.2L V8, the manual gets 16/25, and the auto gets 17/28.

http://www.fueleconomy.gov/feg...

For the Honda Civic 2.0L, the manual gets 26/38, the auto gets 30/41.

http://www.fueleconomy.gov/feg...

Fro the Subaru BRZ, the manual gets 22/30 and the auto gets 25/34.

So yes, you're full of shit, and I've proven YOU wrong with references.

The CO2 emissions from a car are directly proportional to the amount of fuel it uses, hence inversely proportional to the MPG number. If the half a million estimate is based on the average car in the US (around 25.5 MPG), then the methane leak equals 700.000 Golf TDis (which use 36 MPG).

The Tesla car has higher instantaneous torque and a flat torque curve. The cost for me to drive 300 miles on gasoline is around $25 now; on biofuel, it's around $35; on diesel, it's around $12; on electricity, it's $3. Battery storage loses less energy in conversion than biofuel chemical storage. Electric cars are less complex and require less maintenance than reciprocating piston engines. Superior power, performance, durability, longevity, and cost doesn't seem inferior.

The only way that diesel costs half as much as gasoline on a cost/trip basis is if you treat the whacky CA fuels market as the boundaries of your universe, with $2.60/gal reg and $2.40/gal ULSD.

In most of the US, you're looking at $1.50/gal reg and $2.10/gal ULSD, and then that difference goes away. An engine that has 25% higher energy efficiency running on a fuel that has 10% greater volumetric energy density cannot overcome a fuel that costs 35% more per volume.

In the rest of the universe, you also amortize the cost of the vehicle that gets you there and add it to the energy cost. A vehicle that costs 3-4x as much makes much of that difference go away as well.

BTW: At CA electricity and gas prices you're claiming that a 100% efficient Tesla, consuming only 62MJ of electricity, will make that trip, but a gasoline powered car would require 1180MJ to make the same trip. That is a 5% fuel-to-travel efficiency, not the 14-30% that is known.

All in all, your figures are crap.

Do they still make 10 mile per gallon cars? Are you in America or something?

The rest of us are up to 80 mpg.

And yet, desipte your "all 'murrican iz the evilz" attitude, in 2016, the worst gas milage cars come from Italy, a Lambo and a ferrari at 12 mpg - probably 10 in real life.

In fact, none of them are made in America - All the worst gas milage cars except the Infinti's are made in ........

Get ready for it.........

your 80 miles per gallon, environmentally superior......

Here's the link. http://www.fueleconomy.gov/feg... Trucks not surprisingly either, won't be getting as good as predicted, but once again, despite Europe having the edge in all things compared to their dull unsophisticated American brethren, the worst truck gas milage for 2016 are two offerings from Mercedes Benz. Where are they located?

Go figure, huh?

Pardon my sarcasm, but you deserve it.

How can you claim " lower emissions and higher mileage" are competing requirements?

If you are getting more miles per gallon, then you are emitting fewer emissions per mile. A car getting 45 MPG, is emitting 0-200 CO2 (g/mile); while a 20-23 MPG car is getting 379-456 (g/mile) (source). Fuel economy is correlated with emissions. If you increase the MPG, you lower the emissions.

I confess, I'm the "certain type of reader" who is scoffing at this bizarre statement and wondering where it came from (and wondering how it got modded insightful). It not only completely contradicts the government's resources on the subject, but common sense as well. You say, "I can pretty much guarantee that the consumer doesn't give a rat's ass about emissions when they could be saving money on gas which may also be artificially expensive." but the reality is that saving money on gas IS lowering emissions.

You don't really believe those numbers, do you? That chart claims that the Dodge Omni got 35 city and 55 highway. Two years later, according to the EPA the same car got only 26 city and 35 highway. What happened in those 2 years to cause a 33% reduction in mileage? Better testing.

Electric vehicles are very cheap, if only because the federal government subsidizes $7,500

The tax break is **up to** 7500. For the Fusion as a plug in hybrid, the tax break is 4000$: https://www.fueleconomy.gov/fe... and that was on the top of the line car, Fusion Energi. When we asked the salesman about any tax breaks or refunds, he had to ask his manager and he said it was only 250$.

I would not be surprised to find a better constructed idiot (though I do not expect most people to know) attempting to drive with a trailer.

How to put it? While I'd expect accidents because of the trailer, I'd expect accidents no matter what - after all, most accidents in the country, much less the world, don't involve trailers at all.

Basically, the number of accidents would be at 'acceptable' levels such that U-haul and such would be willing to rent them out. You're always going to have 'better idiots', but that can't be used as an excuse to not deploy a technology unless the results are too catastrophic - and a 'few' accidents here and there are acceptable.

I think it should be something you can disconnect from the vehicle, when you get to your destination, and used as a generator as well as a then-static EV charging platform.

Shouldn't be a problem to provide. A Model S uses 37kwh to go 100 miles. At 60 mph, that would be 22.2 kWh/h or 22.2 kW. Please note that this is a 'napkin back' calculation and is more for estimation. There are many real world considerations, including but not limited to: actual driving speed, any grade, additional drag from the trailer, the range of the EV assuming you're starting with the battery full and are willing to end driving with it near empty, any breaks taken, that you're skipping the 'battery' part which removes a 10% loss step, etc... Honestly, I think 22 kW would be 'oversized' in most situations.

And if a ~22kW generator isn't enough for your camp site...

Adaptive steering is going to help on vehicles that are equipped with it.

It's actually on the trailer. But I'm of the opinion that technological solutions are often superior to education, because education can be ignored, and often ends up being less effective and more expensive(time's expensive).

In the end, consider this: Most of the accidents you've described were to a person's own property. My scale of 'caring': Other people's lives. The operator's life. Other people's property, the operator's property. If they only damage their own stuff, who cares? If the trailers are costing people their lives, the it matters a great deal.

In the end, I think you're picturing a larger trailer than I am. Seriously, what's I'm figuring on would be tiny. How tiny? Not visible from the rear view mirror tiny.

You're also figuring on a 'vast increase'. I'm not, and even if there is, most of it would be on the highway where it's the safest, not on the roads in the cities.

As for added danger - how do you balance this against cars that will do things like apply the brakes themselves to keep you from hitting something? Backing cams?

It may be possible, safer, to simply engineer a method that allows carrying this generator behind the vehicle without it actually being towed.

As you say, such capacity would have to be engineered into the vehicle. You're looking at about 600 pounds for the generator and fuel alone. Well within range for a class 1 hitch that most EVs can take, but they're normally only rated to 70 pounds or so for tongue weight. Hell, it'd exceed the capability for the class 3 on my light truck if you wanted to just suspend it there. I can't put much more than a bike rack or grill on my hitch if it's going to just be suspended there.

Plus, you might not be thinking about this, but it'd affect the balance of the whole car, and not in a good way. So no, it's not a 'trivial matter'.

I am not attempting to troll by asking this question, but I am curious: what percentage of the miles driven in that Yukon have just 1-3 people, and little luggage? What percentage of the miles are driven with 7 people, 7 suitcases, and an 8,000-lb trailer?

It is a fair question...

I would have to say that a bunch of the time, it indeed has 1 or 2 people in it, but equally so, it has 4 to 5 people in it.

Just today I took the kids to an event that was about 30 min each way, total distance was 46 miles, I averaged exactly 17 MPG on that trip, thus burning about 3 gallons of gas, give or take.

Could I have taken my 3 kids in something smaller? Sure, I could have, but I wouldn't want to. They have room to spread out and have their own space, have their stuff, and enjoy the ride. Which is of course the other part, that truck is made for highway cursing, it is quite comfortable at 75 mph with the cruise control set and the music playing.

Tomorrow afternoon I am driving to the bike shop, my son's rear tire blew last weekend and broke the rim, so we're having it fixed. It is handy to be able to toss it in the back of the truck, it wouldn't fit in a small car like a Prius. Of course, it would fit in a minivan as well, but that actually doesn't accomplish anything, a Toyota Sienna Limited AWD gets a mixed MPG of 19 MPG, just 2 MPG worse than my truck, and it sucks to drive.

http://www.fueleconomy.gov/feg...

I use the cargo space in the back of my truck every week, I haul my 3 kids every day, and sometimes 1 or 2 more kids as well.

That is why I own it.

Maybe you want to review your numbers. I see compact and sedans seeing a 15 to 20% more efficient combined fuel consumption. Is that equal to no difference to you?

SUVs in order of efficiency:
http://www.fueleconomy.gov/feg...

Small and Family cars:
http://www.fueleconomy.gov/feg...

Maybe you want to review your numbers. I see compact and sedans seeing a 15 to 20% more efficient combined fuel consumption. Is that equal to no difference to you?

SUVs in order of efficiency:
http://www.fueleconomy.gov/feg...

Small and Family cars:
http://www.fueleconomy.gov/feg...

Make and models please. I have a hard time believing your SUV does better than your Civic unless you Civic is 15 years old and out of shape or your SUV is the smallest in it's class.

http://www.fueleconomy.gov/feg...

I took the most fuel efficient SUV and compared it to the least efficient and the most efficient CIVIC. Keep in mind the SUV is using a variable gear ratio which increases it's efficiency further giving it an advantage. If you go down the list of SUVs the next one in the last is 3MPG less efficient and that's a big deal.

I won't argue that SUVs are fairly efficient for their size but they generally are still bigger guzzlers than your small to medium size cars.

There's another reason. There are a lot more hybrid, diesel, and efficient trucks and SUVs becoming available. Most Americans' sense of the fuel efficiency of vehicles is distorted because it's measured in MPG. MPG is actually the inverse of fuel economy. Consequently the amount of fuel saved by vehicles like the Prius is exaggerated.

Here are the EPA figures for a 2004 3L 4WD Toyota Highlander, a 2015 3L 4WD Toyota Highlander Hybrid, and a 2015 Prius. Say you'd previously owned the 2004 Highlander and were looking to replace it. If you looked only at MPG, you'd think the Prius saves you a lot more gas than the Highlander Hybrid. The Prius gets 31 more MPG while the Highlander Hybrid only gets 9 more MPG.

But MPG is the inverse of fuel economy. Scroll down to "Annual Fuel Cost". The 2004 Highlander is estimated to cost $1900/yr in fuel. The Highlander Hybrid $1300/yr. The Prius $700/yr. In other words, switching to the Highlander Hybrid saves you $600/yr. Switching to the Prius saves you $1200/yr. The Highlander Hybrid gives you 50% the fuel savings of a Prius despite "only" getting a 9 MPG improvement vs 31 MPG improvement. How can this be? Because MPG is the inverse of fuel economy. Every time you double MPG, you save half the fuel you did in the previous doubling.

A lot of people laughed when hybrid trucks and SUVs first came out. If you want to save gas with a hybrid, why are you buying a big truck instead of an econobox like the Prius? But they were being deceived by MPG being the inverse of fuel consumption. If we as a country want to reduce fuel consumption, it's actually the low MPG vehicles like trucks and SUVs whose fuel economy you want to improve first by hybrid-izing them. They're the ones burning a disproportionately large amount of fuel, so improving their mileage first will save more fuel. Economy cars already burn so little fuel that making them a hybrid gets you little improvement. e.g. Dropping a hybrid in a 35 MPG economy car to get 50 MPG only saves you $350/yr by EPA estimates. While dropping the hybrid in a 19 MPG SUV to get 28 MPG saves you $600/yr. In other words, each SUV-buyer you can convince to buy a hybrid SUV instead saves nearly twice as much fuel as each environmentalist you convince to switch from their already-efficient car to a Prius.

If we really want to save gas, we should be concentrating on ways to improve the mileage of pickup trucks, SUVs, minivans, and tractor trailers (actually most of their cargo should be shifted to trains, but that's another argument). The rest of the world uses liters/100 km to avoid this misconception about fuel economy.

First, I'd mod you up if I could for posting numbers.

Having said that, though, most of the efficiency breakdowns I've seen indicate that aerodynamic loss is higher than rolling-friction loss, especially at highway speeds -- drag goes up as the square of velocity.

Looking at the page you linked, I'm a bit surprised that it says rolling resistance is two to three times higher on "tar or asphalt" than on concrete surfaces. I didn't think there was that much difference between standard, mature asphalt surface and concrete, and I imagine friction on fresh asphalt or tar would be much higher than either concrete or older asphalt. The numbers for cruising on a concrete freeway are smaller by a factor of two or three.

From the other direction, that 10% of the energy is a theoretical maximum; it assumes that your recovery process cools the tires right down to ambient temperature, that it imposes no additional drag (due to its weight or its contact with the tire), and that it sustains no losses in its own operation. None of these three assumptions seems reasonable.

It would be up to the engineers at Goodyear (not Ford) to post the actual measurements of energy that they can reclaim, and the effects that this system has on overall vehicle efficiency. I haven't seen those numbers. I suspect that we won't, or that if we do, they won't be very impressive. I'd love to be wrong, though.

A theory that ignores friction isn't especially interesting in this context.

Rolling friction is a pretty small contributor to energy loss for a moving car. Of this initially small amount of lost energy, some heats the road, and some heats the tire. As someone else observed below, the change in tire temperature is typically around 30 F, or 15-20 C, much less than a 10% change in absolute temperature. That means that a perfectly efficient heat engine could reclaim at most 10% of the thermal energy from the warm tires. In practice, the efficiency would be lower still.

Here's an infographic breaking down energy loss for an internal-combustion vehicle. Even if we assume that the electric vehicle has zero engine loss, rolling friction still represents at most maybe 20% of your energy loss. That means that you'd be reclaiming less than 2% of your total lost energy. In practice, considering the efficiency of the recapturing engine, it would probably be well under 1%; considering the added weight and mechanical loads of the recapture equipment, you might well end up losing net efficiency.

I'm not an engineer, but I have a basic understanding of thermodynamics. This story appears to be pitched at people who don't. If the engineers behind this want to convince people who know anything about physics or engineering, they're going to need something a lot better than this press release.