Cost of driving: electricity vs. gasoline

[RonL]

Who uses lead in their electric cars?

Because of low cost, and ease of recycle, I think lead and sulfuric acid are getting a bit of a kick in the pants.

Duration is low, but then so is the average daily commute. I think we are led into a false illusion of how much power and duration we really need.

 

[OmCheeto]

I inherited the solar panels from my dad. I no longer have to pay for energy. Unless I want more of course.

That's very nice for you, but I doubt your dad will be the charitable institution sufficient to supply the electrical energy needs to the rest of us. We should probably have to pay for our free solar energy.

Yes. But you'd have to spend the money on energy anyways. May as well make it clean. And we really don't know how long these panels will last. They may truly be a seventh generation device. Mine have so far made it through two, and are still operating at 100% rated capacity.

On another note, I emailed the gentleman from whom I stole the sunshine quote. He graciously stated that I could distribute any of the following information regarding EV's:

Cost to operate a vehicle is about more than fuel. ICE vehicles need oil, fuel filters, air filters and other things that EVs do not need at all. My EV (Chevy S10EV) does not even have a transmission, it is direct drive. EVs with regenerative braking don't need their brake pads changed as often. All of these need to be considered for a true cost of operation comparison. Also, what about your time (or your employees time) spent going to, from, and at gas stations. EVs charge overnight right in their parking spot and are fully charged each morning ready to go.

Another thing, including the battery replacement cost is misleading unless you are leasing the batteries. Most cars on the road are less than 12 years old. The number I have heard is 90% are newer than 12 years. Take a look next time you are on the road, unless you are at an antique car show, you'll like find this to be true. This means that the 10 year battery pack that will likely come with most EVs will service it for its entire life. There are Toyota RAV4's on the road today that have over 100,000 miles on their original batteries. My EV is a 1998 and it still has its original (NiMH) batteries.

It seemed relevant to the thread topic, so I left it unedited.

I will also be going to the local EV Association's "EV Awareness Day" tomorrow from 9:30 am to 5:00 pm
Pioneer Courthouse Square, Portland, Oregon.
Everyone is invited.

I will see if I can get some real world numbers for the cost of operating these vehicles from people who actually drive them.

 

[GTrax]

We have a very nice costing example with the stress on batterys.

30 kwh (ref: Wordsmiths baseline energy requirement)
30000 wh
1200 wh / pb battery (ref: written on the top of my battery)
... et al ..
We really need a cheap lithium ion battery.
A car getting 50 mpg would have the same per mile cost as the 7000lb pb electric.

It seems to me we have about three things going here.
1) The running cost of a gasoline vehicle, accounting various mandatory bits amortized over the miles the vehicle manages before we try to recover / recycle the dead bits.

2) The running cost of a electric vehicle, accounting a different set of mandatory bits, similarly amortized, this electric vehicle being possibly a notional one that is not in production yet, and might assume a battery technology that is not developed yet.

3) A completely different cost, expressed in terms of the the energy involved in dragging the user around, plus what was expended in the furnaces and mills and microelectronic plants in its creation, plus what it takes to keep it going for its life, plus what it takes to dispose of it, less what it keeps back by recycling long-lived useful stuff, or is recovered to become something else.

As a parting shot - we can figure the amount of fossil-derived carbon this activity would put into the atmosphere, though we know the real cost that will ultimately visit us is hard to quantify right now, but will be paid by our children.

Something like ..
\left[C_{gaso} = \frac{C_{fuel}}{mpg} \,\,+\,\, \frac{C_{tire}*n_{wheels}*m_{life}}{m_{tyre}}\,\,+\,\,\frac{C_{batt}*n_{batt}}{m_{life}}\,\, +\,\,\frac{C_{parts}}{m_{life}}\,\,+\,\,more.of.this\right]

C_{fuel}\,\,=\,\, the fuel price per gallon, etc..

OK - its a lame example right now, and we can refine it later. Some costs are buried in our averages. In trying for a comparison, we must try to approach like-for-like. The kW expended by a Jeremy Clarkson ( Er.. Ref: Top Gear - a questionable UK TV show) in seconds does not deliver the distance it might if he was not attempting comedy. A low-slung aerodynamic 20mph solar-powered death trap carrying a kings ransom in high-tech batterys and with tyres that will bio-degrade into fertilizer is not going to have the utility I need. I try to imagine my car, with all the space and features untouched - but gone electric!

This gets harder to reconcile

 

[GTrax]

Arrgh
I have no idea why it posted before I finished it. I did't see it happen.
Please help Mr. Moderator, and lose the part-finished posting

 

[OmCheeto]

A low-slung aerodynamic 20mph solar-powered death trap carrying a kings ransom in high-tech batterys and with tyres that will bio-degrade into fertilizer is not going to have the utility I need. I try to imagine my car, with all the space and features untouched - but gone electric!

This gets harder to reconcile

Yes. They had several "death traps" at the exhibit: 1 motorcycle, 2 scooters, 1 bike, 1 aero shrouded recumbent, and several 3 wheelers.

I didn't realize it until yesterday that Patrick's S10-EV was a sibling of the EV-1.
60 of the all electric S10's were sold, and hence, not crushed.

Anyways, the show was too much of a success as I was not able to interrogate all of the owners as much as I had wanted. The numbers for the non-death trap vehicles ran from 60 to 240mpg equivalent, @$4/gal. The 60 mpg number is probably too low as the owner stated that he used a 48vdc charger "capable" of 40 amps, charging for 7 hours, yielding a 20 mile range at 32mph. The actual charge rate was probably much lower, and hence, the mpg was probably much higher. The owner also gave me a "why on Earth would anyone ask such a question" look. He said he has driven it daily for the past 6 years.


Cost's were difficult to pin down as some owners were professional EV modifiers and others were just hobbyists.

There were several apples to apples comparisons at the show, but I'll chose the co-chairman's 1975 Porsche 914.
190 mpg at 20 mph
200 mpg at 60 mph(don't ask me, you run the http://www.evalbum.com/1137")
range ~ 60 miles
curb weight: 900 lbs more than original(pbso4 batteries)
top speed 80 mph

There were faster EV's: The street legal http://picasaweb.google.com/patrick0101/2008OEVAEVAwarenessDay/photo#5219760695742855122" tops out at 120mph. It's sibling, the White Zombie, was not in attendance, does zero to sixty mph in 2.9 seconds.

So my answer to the OP is; you get what you pay for. You can buy a Tesla for $100,000, a Zap for $10,000, or build your own for between $5,000 and $1,000,000 and have whatever you want.

 

[Gambler]

Regarding operating cost between electricity and gasoline, what about a different approach ... looking at the cost of energy needed to propel the vehicle.

At 132 megajoules of energy per gallon of gasoline at $4.00/gallon, the cost would be $0.03/megajoules.

At $0.09/kWh of residential electricity (average in USA, not off-peak) and 3.6 megajoules per kWh, the cost would be $0.025/megajoules.

If this is correct, the difference is not so great.

For a real example, if your trip to work is 35 miles per day in a gasoline vehicle that gets 35 mpg, your daily consumption of gas would be 1 gallon and the energy in that one gallon used is 132 megajoules and at $4.00/gallon, that would be a cost of $0.114/mile.

With a plugin electric car of identical physical features (aerodynamics, weight, etc to make the comparison accurate) and also getting 35 mpg, the same trip would consume the same energy - 132 megajoules. With 3.6 megajoules per kWh, the energy would be 36.67kWh and at $0.09/kWh, the total trip cost would be $3.30 or $0.094/mile.

If this exercise is done correctly, the savings of using residential electricity are not as much afterall.

Is this exercise flawed?

 

[OmCheeto]

Regarding operating cost between electricity and gasoline, what about a different approach ... looking at the cost of energy needed to propel the vehicle.

At 132 megajoules of energy per gallon of gasoline at $4.00/gallon, the cost would be $0.03/megajoules.

At $0.09/kWh of residential electricity (average in USA, not off-peak) and 3.6 megajoules per kWh, the cost would be $0.025/megajoules.

If this is correct, the difference is not so great.

For a real example, if your trip to work is 35 miles per day in a gasoline vehicle that gets 35 mpg, your daily consumption of gas would be 1 gallon and the energy in that one gallon used is 132 megajoules and at $4.00/gallon, that would be a cost of $0.114/mile.

With a plugin electric car of identical physical features (aerodynamics, weight, etc to make the comparison accurate) and also getting 35 mpg, the same trip would consume the same energy - 132 megajoules. With 3.6 megajoules per kWh, the energy would be 36.67kWh and at $0.09/kWh, the total trip cost would be $3.30 or $0.094/mile.

If this exercise is done correctly, the savings of using residential electricity are not as much afterall.

Is this exercise flawed?

Yes, your exercise must be flawed.

See post 1 and 2 of this thread.
Wordsmiths calculations were correct.
russ waters confirmed it.

The other 36 posts were, well, what I would call a butterfly effect, and can effectively be ignored in the context of your problem.

 

[Phrak]

Regarding operating cost between electricity and gasoline, what about a different approach ... looking at the cost of energy needed to propel the vehicle.

At 132 megajoules of energy per gallon of gasoline at $4.00/gallon, the cost would be $0.03/megajoules.

At $0.09/kWh of residential electricity (average in USA, not off-peak) and 3.6 megajoules per kWh, the cost would be $0.025/megajoules.[/qoute]

You'll have charging energy lost as heat in both the voltage conversion and battery itself. I figure 15% is reasonable. Boost your 25 cents to 28.7 cents.

If this is correct, the difference is not so great.

For a real example, if your trip to work is 35 miles per day in a gasoline vehicle that gets 35 mpg, your daily consumption of gas would be 1 gallon and the energy in that one gallon used is 132 megajoules and at $4.00/gallon, that would be a cost of $0.114/mile.

That's what I get.

With a plugin electric car of identical physical features (aerodynamics, weight, etc to make the comparison accurate) and also getting 35 mpg, the same trip would consume the same energy - 132 megajoules. With 3.6 megajoules per kWh, the energy would be 36.67kWh and at $0.09/kWh, the total trip cost would be $3.30 or $0.094/mile.

I get that number from your data too.

If this exercise is done correctly, the savings of using residential electricity are not as much afterall.

Is this exercise flawed?

Only partially. The energy of the gasoline is much more ineffiently applied in converting from gasoline to the drive axle of the car. Maybe 25% efficient. Electricity from the battery is much more effiently utilized. From the battery, assume 80% efficiency under EPA driving conditions, maybe. I've already assumed 85% efficiency in charging the batteries. 85%*80% = 68% overall efficiency from electric meter to drive axle.

68% to 25% is an efficiency ratio of 2.7 to one. Reduce your estimated cost of electricity by a factor of 2.7.

Better refinement of these two efficiency factors is actually what I lack for a decent comparison.

 

[Gambler]

Thanks for the replies guys!

Yes, your exercise must be flawed.

See post 1 and 2 of this thread.
Wordsmiths calculations were correct.
russ waters confirmed it.

OmCheeto, I was quite sure I was making a fundamental mistake OR that I over-simplified my comparison. But before making an investment, I'd really like to be SURE of the financial beneifits so I can 'fairly accurately' calculate the breakeven point especially if the breakeven point is beyond the life of a new EV or Hybrid ! For that reason, I would like to see and be comfortable with all the data and figures. For example ...

Just for sake of example, I have read that steady-state 50 MPH driving uses 40 HP

Probably Wordsmith read from a reputable source but again, before making an investment, I'd like to have something more firm.

The energy of the gasoline is much more ineffiently applied in converting from gasoline to the drive axle of the car. Maybe 25% efficient. Electricity from the battery is much more effiently utilized.

Well duh! Thanks Phrak! I think you made the flaw in my reasoning very clear - efficiency factor differences between the 2 types of propulsion.

So, for a car to go 35 miles on 1 gallon, you certainly paid for 132 megajoules but only 33 (132 x 25%) was actually transferred to the axle.

To compare with an electric car of same characteristics, the 33 megajoules transferred to the axle would be 38.8 (33 / 80%) consumed from the battery and 45.7 (38.8 / 85%) that was consumed from the residential electrical source (noting your battery charging efficiency).

In this case, gasoline is not 21% higher ($4.00/$3.30=1.21) than electricity but 250% higher ($4.00/(45.7/3.6*0.09)=3.50). Make sense?

And in terms of cost per mile:

Gasoline: $4.00/g / 35 mpg = $0.114 / mile
Electricity: $0.114 / 3.5 = $0.03 / mile

So in terms of cost per gallon of gas equivalent, electricity is:

$4.00 / 3.5 = $1.14

So, now the figures begin to look like those published by many promoters of the EVs.

Thanks Phrak!

Note: I spoke to a Mechanical Engineer friend who confirmed your 25% figure of car efficiency. He was not completely sure of the factors for electric motor by batteries but guessed 70% which is exactly what you stated (80% x 85% = 68%).

 

[Phrak]

I think your numbers could be right. I am not quit following them. What do you get if the efficiency is 70% from battery to axle?

 

[mheslep]

30 kwh (ref: Wordsmiths baseline energy requirement)
...
3500 weight of pb batteries
...



lithium ion (ref: http://en.wikipedia.org/wiki/Lithium_ion_battery )
...
187.5 kg (or 400 lbs) required
...

It is not meaningful to compare lead acid and Li ion in this way as these two cases must be two entirely different vehicles. The 3500lbs Pb batteries must be carried in a light truck or better, which then requires much more energy storage to perform similarly, requiring more batteries, more weight and so on. Thus you can quickly see Pb is not feasible for any reasonable multi-passenger vehicle capable of highway speeds, regardless of cost.

 

[mheslep]

Hello All,

I'm trying to get a sense of the cost of using electricity e.g., plug-in hybrid vs. the cost of operating the same vehicle using gasoline. I've read a comparison using the btu value of gasoline vs watts/btu but I'm not sold on that idea since the vast majority of thermal energy in an automobile goes out the tailpipe. What I was thinking of was choosing a 'standard' car like a Ford Taurus, operated on a highway at a steady state for one hour. Using horsepower as the common denominator between gasoline and electricity As far as gasoline consumption, I would propose dividing the miles traveled in the hour by some reasonable highway MPG. Just for sake of example, I have read that steady-state 50 MPH driving uses 40 HP. Figuring 25 MPG highway, gasoline at $4.00/gal and electricity (746 W/hp * 40 hp. for one hour = 29.84 KWH. At $0.10/KWH, driving the 50 miles cost $2.98 using electricity or 2 gallons of gas = $8.00.

Obviously, the example is greatly simplified, but is it a fair comparison?
Thanks for your thoughts.
Wordsmith

The HP load for level cruising depends of course of the aerodynamics of the vehicle, but the average sedan cruising at 60mph requires more like only 30HP (22.38kW) to overcome air drag and rolling resistance, a bit less for aerodynamic sports cars.
http://mb-soft.com/public/headlite.html
Then the electric drive train efficiency of motor + battery is ~85% efficient. Thus 22.3kWhrs/0.85=26kWh must be stored in the batteries for the hour trip. Charging them before you go loses 10%, so one has to buy roughly 29kWhrs of energy to drive the 60 miles. That compares closely with published numbers of the upcoming Chevy Volt PHEV: 16kWh max charge on which it will travel 40 miles.

That is still $2.9 for 60 miles, though overnight power is typically cheaper ($0.06/kWh here) so perhaps $1.7 for 60 miles, vs $9.6 for 2.4 gallons of $4gal/gas. In the narrow case where one makes nothing but short battery only trips for a 10,000 mile year one saves $1316/year over 25mpg gasoline powered travel, best case.

Some other considerations for weighing that possible cost savings:
o Plug-in hybrid $5000 to $15000 additional cost vs comparable gasoline vehicle, given the current battery costs.
o Gasoline might go much higher, or their may even be 1970's like fuel shortages in the 10 year life of the car, in which case an PHEV would be very handy.
o Gasoline might go much lower (EIA/DoE currently predicts below $3/gallon again by 2015, in 2008 dollars)

 

[Gambler]

I think your numbers could be right. I am not quit following them. What do you get if the efficiency is 70% from battery to axle?

It is a given that for a car of 35 mpg, the energy from the gasoline used to go 35 miles is 132 megajoules. Considering an efficiency of 25% (your figure), 33 megajoules were actually applied to the axle. So, for the same car in the same conditions going the same 35 miles, 33 megajoules would be applied to the axle from an electric motor drive system. If the efficiency "from battery to axle" is 70%, then 47.1 megajoules was consumed from the battery (33/.70). If your other figure of 85% in charging the battery is correct, the energy used from the plugin source would be 55.5 (47.1/.85).

Anyway, you put me on the right track in including the efficiencies of the different drive systems - gasoline & electric - which are very significant. Only now do I begin to understand the advantage of using an EV over gasoline cars.

 

[Phrak]

Gambler-

I didn't see what you were doing the first time. You're going down from gasoline to axle on one car and up from axle to electric meter on the electric. Brilliant.

 

[Gambler]

Exactly. I think it simplifies the comparison. The only challenge is to accurately determine the efficiencies for a vehicle of interest.

 

[WhoWee]

It looks as though it's time to dust this thread off again - with gasoline hovering around $4.00 per gallon?

 

[wavering]

I spent a bit of time doing an analysis BEFORE I found this thread, this is what I came up wth:

According to Wikipedia, the best power stations convert fuel to power at 60% efficiency whereas a car is nearer 40% efficiency. But of course, there are further losses from the power station to the wheels of your electric car. In summary losses are:

Power Staion losses = 40%
Transmission losses = 7%
Transformer/rectifier losses = 4%
Battery charge losses = 10%
Battery dis-charge losses = 10%
Electric motor losses = 10%

So if you start off with 100 units of fuel at the power station, you end up with about 39% at the wheels, as follows:
100 X 0.6 = 60
60 X 0.93 = 55.8
55.8 X 0.96 = 53.6
53.6 X 0.9 = 48.2
48.2 X 0.9 = 43.4
43.4 X 0.9 = 39.1

Whereas, if you have 100 units of fuel in your car you end up with 40% at the wheels

So, nothing in it really BUT the electric car has restricted range and what about the heating/cooling in extreme weather? If
the typical capapcity is 20KwH then a 2KW heater (cars are very badly insulated since in a petrol/diesel car, heat is a waste
product) could knock a further 10% off reducing the output available from 39 units to nearer 35

Also, if your car is not used the battery can lose 8% of its power per month just sitting there

As I see it, the key advantages of the elctric car is that it appeals to arts graduates who think it is pollution free and
it also appears very cheap in comparision to petrol/diesel because fuel at pumps (in most countries) is very heavily taxed
whereas electricity is (currently) untaxed.

All numbers form web searching. Any observations very welcome - I am not trying to score points (apart from over arts graduates who write in the media without any understanding of physics), just clarify it in my own mind.
Bob aka wavering
.

 

[WhoWee]

I spent a bit of time doing an analysis BEFORE I found this thread, this is what I came up wth:

According to Wikipedia, the best power stations convert fuel to power at 60% efficiency whereas a car is nearer 40% efficiency. But of course, there are further losses from the power station to the wheels of your electric car. In summary losses are:

Power Staion losses = 40%
Transmission losses = 7%
Transformer/rectifier losses = 4%
Battery charge losses = 10%
Battery dis-charge losses = 10%
Electric motor losses = 10%

So if you start off with 100 units of fuel at the power station, you end up with about 39% at the wheels, as follows:
100 X 0.6 = 60
60 X 0.93 = 55.8
55.8 X 0.96 = 53.6
53.6 X 0.9 = 48.2
48.2 X 0.9 = 43.4
43.4 X 0.9 = 39.1

Whereas, if you have 100 units of fuel in your car you end up with 40% at the wheels

So, nothing in it really BUT the electric car has restricted range and what about the heating/cooling in extreme weather? If
the typical capapcity is 20KwH then a 2KW heater (cars are very badly insulated since in a petrol/diesel car, heat is a waste
product) could knock a further 10% off reducing the output available from 39 units to nearer 35

Also, if your car is not used the battery can lose 8% of its power per month just sitting there

As I see it, the key advantages of the elctric car is that it appeals to arts graduates who think it is pollution free and
it also appears very cheap in comparision to petrol/diesel because fuel at pumps (in most countries) is very heavily taxed
whereas electricity is (currently) untaxed.

All numbers form web searching. Any observations very welcome - I am not trying to score points (apart from over arts graduates who write in the media without any understanding of physics), just clarify it in my own mind.
Bob aka wavering
.

Is the plant coal burning?

 

[whocouldshebe]

I'm going to get a gas generator and use that to charge up my electric car to save gas! LOL Obviously a gallon of gas produces more power than a battery can collect from a gallon of gas. Any time you charge a battery you lose at least 60% of the electricity to heat and charge dissipation into the air around the terminals. You fail to consider this in price calculations. Just because a battery hold X number of KWH doesn't mean that's all you will get charged for. It costs you at least 3 TIMES X number of KWH to charge up the battery.

Gasoline engines are already extremely efficient at converting tiny gas explosions into physical movement. If we could just turn pistons off when the force isn't needed, the engine completely off when idle, lower weight, shrink the size, etc. then gas engines would murder the electric car industry on cost savings alone!

They do all this for electric vehicles, but not on gas cars, since there is no reason to conserve energy, there is an abundance already wasted, you could power a home from a single gas engine for hours off of a gallon of gas, plenty of amps there, then try and do that with an electric car battery, it'll pucker out in just a couple minutes.

All your comparisons are apples to oranges, I mean think about my first comparison, I could just as easily use a gallon of gas in a generator to charge 5 cars for an hour, then go drive each car for an hour off that same charge. Only crazies would say a battery stored charge is the best way to get electricity, when we just wasted enough electricity to power up 15 cars because of the 60% loss we trashed to charge up the 5 cars using a gas powered generator. Even solar is nutz, 60% loss at the panel, then another 60% loss to charge, just to charge up a AA battery. It would be tons more efficient to just use an ounce of gas in a tiny engine to get the instant power of 8 AA batteries with nearly 90% efficiency.

We should be working on smaller gas engines with higher efficiencies and ways to produce gas quickly instead of promoting tons of wasteful storage technologies. Yeah batteries are great, but only to store an excess charge that would otherwise be lost, but other than that, the answer is simple, if you don't need 100% of that energy NOW the turn it OFF NOW.

GAS ENGINES SHOULD TURN OFF WHEN THE ENGINE IS AT REST! EXTRA PISTONS SHOULD SHUT DOWN WHEN HORSE POWER IS NOT NEEDED! We don't need 6-8-10-12 cylinders unless for a light load. 2-4 is more than enough power to move 1 person from point A to point B at 200 MPH or better. Look at motorcycles and scooters, 80-120 mpg, the same engine could still move 4 people the same distance, just at lower acceleration/hp. The way engine power technologies is moving today is completely ridiculous.

 

[mheslep]

I spent a bit of time doing an analysis BEFORE I found this thread, this is what I came up wth:

According to Wikipedia, the best power stations convert fuel to power at 60% efficiency whereas a car is nearer 40% efficiency.

First, electric power plant conversion from fuel to electricity tops out at ~45%. The additional 20% refers to the use of the rejected waste heat for buildings or industrial processes. Second, most cars on the road today, that is, conventional spark ignition + gasoline cars, are closer to 25% efficient, tank to wheels. http://cta.ornl.gov/TRBenergy/trb_documents/an_assessing_tank.pdf" , as reported by GM the Chevy Silverado has a tank to wheels efficiency of 17%, well-to-wheels efficiency of 14%.

But of course, there are further losses from the power station to the wheels of your electric car. In summary losses are:

Power Staion losses = 40%
Transmission losses = 7%
Transformer/rectifier losses = 4%
Battery charge losses = 10%
Battery dis-charge losses = 10%
Electric motor losses = 10%

So if you start off with 100 units of fuel at the power station, you end up with about 39% at the wheels, as follows:
100 X 0.6 = 60
60 X 0.93 = 55.8
55.8 X 0.96 = 53.6
53.6 X 0.9 = 48.2
48.2 X 0.9 = 43.4
43.4 X 0.9 = 39.1

I'd have to check, but I believe the '7% transmission' losses, a commonly cited figure, includes transformer losses.

So, nothing in it really BUT the electric car has restricted range and what about the heating/cooling in extreme weather? If
the typical capapcity is 20KwH then a 2KW heater (cars are very badly insulated since in a petrol/diesel car, heat is a waste
product) could knock a further 10% off reducing the output available from 39 units to nearer 35

Yes, but 1) the maximum of 2KW for heat would only be used for a few minutes to knock the chill off the passenger compartment and fall rapidly afterward, 2) waste heat from the battery and motor can also be used to heat the passenger compartment.

Also, if your car is not used the battery can lose 8% of its power per month just sitting there

As I see it, the key advantages of the elctric car is that it appeals to arts graduates who think it is pollution free and
it also appears very cheap in comparision to petrol/diesel because fuel at pumps (in most countries) is very heavily taxed
whereas electricity is (currently) untaxed.

All numbers form web searching. Any observations very welcome - I am not trying to score points (apart from over arts graduates who write in the media without any understanding of physics), just clarify it in my own mind.
Bob aka wavering
.

Above you are essentially comparing well-to-wheels (as in natural gas/oil well) efficiency for electric vehicles to tank-to-wheels (vehicle fuel tank) for a gasoline powered vehicle. Gasoline also incurs losses getting to the vehicle: distribution via pipeline and then tanker truck, during which time there's spillage, http://www.nytimes.com/1988/05/10/us/gasoline-evaporation-termed-a-pollution-factor.html" , etc.

Returning to the subject topic for a moment, the cost of driving, not efficiency, with respect to fuel costs alone one will pay three times more for gasoline per mile than for electricity in an electric car. With respect to maintenance, some http://online.wsj.com/article/SB10001424052748704584804575644773552573304.html" The remaining question is the cost of battery replacement - how long will it last, cost, etc.

 

[mheslep]

I'm going to get a gas generator and use that to charge up my electric car to save gas! LOL Obviously a gallon of gas produces more power than a battery can collect from a gallon of gas.

Most of that 'power' goes out the exhaust pipe as wasted heat.

Any time you charge a battery you lose at least 60% of the electricity to heat and charge dissipation into the air around the terminals...

False. No battery loses that much energy on charge including losses in the charger; lead - acid is very inefficient in discharge but Li Ion batteries used in electric vehicles are not; they incur losses approximately as the poster above suggested.

...Gasoline engines are already extremely efficient at converting tiny gas explosions into physical movement.

No, the designs for internal combustion engines are ingenious, integrating hundred or moving parts, and they have incorporated innumerable innovations in the last century. However they are still far short of the efficiency of an electric motor in converting stored energy to motion and will remain so.

 

[PattiM]

Thanks for the great discussion! I'm a physicist/researcher in combustion and the atmosphere and I'm thinking about switching from my Honda silverwing to this:

http://www.zelectricvehicle.com/17.html

The Carnot cycle rules everything from extracted resources (coal/oil) to power generation/distribution/use, but fiat currency is utterly labile. And, well... gasoline *is* going away forever. Prices will never go down except, maybe, for the wealthy and/or the few. This is clearly known and you can spend and afternoon at the Smithsonian Institute last March to get the gory details here:

http://www.youtube.com/watch?v=ZiG3I5DaPrE&feature=list_other&playnext=1&list=SP2817969CA87E5B47

So the question is not if, but when we will convert to electrics. And even when we do that, life in Western nations will never again be like it has been for the last 40 years. My problem is, even the best sources just don't yet know what it *will* be like - so I'm a little anxious about spending $6K at this time. My Honda cost $6K new in '07, but now is $9.5K new - so waiting can be a bad idea sometimes.

Thoughts?

The Patricia

EDIT: OOPS! (this may be off-topic) I just remembered that it is probably better to bicycle since I only live 4 miles to work. <<blush!>> Has anyone done an energy calculation for this case?

Has anyone thought about cross country trips? I guess you could rent a cheap motel ever few hours and surreptitiously use an extension cord to charge the scooter - or do it at a rest stop. Maybe that's a non-starter until an electric infrastructure is built.

 

[OmCheeto]

Thanks for the great discussion! I'm a physicist/researcher in combustion and the atmosphere and I'm thinking about switching from my Honda silverwing to this:

http://www.zelectricvehicle.com/17.html

The Carnot cycle rules everything from extracted resources (coal/oil) to power generation/distribution/use, but fiat currency is utterly labile. And, well... gasoline *is* going away forever. Prices will never go down except, maybe, for the wealthy and/or the few. This is clearly known and you can spend and afternoon at the Smithsonian Institute last March to get the gory details here:

http://www.youtube.com/watch?v=ZiG3I5DaPrE&feature=list_other&playnext=1&list=SP2817969CA87E5B47

So the question is not if, but when we will convert to electrics.

No one knows.

And even when we do that, life in Western nations will never again be like it has been for the last 40 years. My problem is, even the best sources just don't yet know what it *will* be like

It will be much quieter.

- so I'm a little anxious about spending $6K at this time. My Honda cost $6K new in '07, but now is $9.5K new - so waiting can be a bad idea sometimes.

Thoughts?

Most electric vehicles are primarily designed as urban vehicles, so if you do lots of long distance trips when off work, it may not make sense for you buy one.

The Patricia

EDIT: OOPS! (this may be off-topic) I just remembered that it is probably better to bicycle since I only live 4 miles to work. <<blush!>> Has anyone done an energy calculation for this case?

I usually quote 250 watt hours per mile. But I see your ZEV6100 claims only 41 through 64 watt hours per mile. So if you're paying $0.11 per kwh, it will cost you about a nickel a day to get back and forth to work. So if you don't mind your electric bill going up a $1.00 per month, and never having to go to a gas station again, then the ZEV might be a good idea.

Has anyone thought about cross country trips?

Most EV'ers would recommend renting a gas powered vehicle, if you insist on driving cross country. Personally, I'll take my EV to the airport and fly across country, then rent an EV when I get there.

I guess you could rent a cheap motel ever few hours and surreptitiously use an extension cord to charge the scooter - or do it at a rest stop. Maybe that's a non-starter until an electric infrastructure is built.

There are alternatives, and new alternatives will be thought up every day.

Trailer Maker Creates Novel Way To Unshackle The Electric Car

I guess this wouldn't work on your scooter, so I'd keep your Silverwing. Or you could invent a similar side-car device for your scooter.

Some might say these type devices defeat the purpose of having an EV, but I don't think so. EV's are incredibly inexpensive to operate, and renting a diesel-electric generator for your cross country trip seems quite logical, if you have some phobia of planes, or rental cars. Or even if it's simply that thousand mile long wind in your hair feeling that you're after.

 

[mheslep]

Trailer Maker Creates Novel Way To Unshackle The Electric Car

Interesting idea, but at this price

The trailer, which Cashen expects will cost about $15,000 ...

they will have to rent the thing for the occasional long trip as one can buy a 4-seat gasoline vehicle for less.

 

[OmCheeto]

Interesting idea, but at this price

$15,000

Yah, I saw that. It might be the economies of scale at work. How many 25kw diesel generators are sold every year? Off the shelf tow-able generators of that capacity do cost that much. I guess I'm just used to the little ones I've been looking at that run closer to 6 watts/dollar. Still > $4000 though.

they will have to rent the thing for the occasional long trip as one can buy a 4-seat gasoline vehicle for less.

Yah. I think I realized they would be an expensive item to be parked next to your house 50 weeks out of the year

...and renting a diesel-electric generator for your cross country trip seems quite logical...

 

[PattiM]

I usually quote 250 watt hours per mile. But I see your ZEV6100 claims only 41 through 64 watt hours per mile. So if you're paying $0.11 per kwh, it will cost you about a nickel a day to get back and forth to work. So if you don't mind your electric bill going up a $1.00 per month, and never having to go to a gas station again, then the ZEV might be a good idea.

Wow! I spend about $35 a month to fuel the silver wing. That's a big difference that is only going to get bigger. But it would still take years to reach cost equivalency, even figuring in a smoothly extrapolated increase in the cost of gasoline (likely not valid). Rationing is a real possibility for the coming decade(s). I guess I could compensate a little by selling my silver wing.

 

[bahamagreen]

Whatever noble ideas about conservation, the reality is that it will be the cost comparison that is most influential to choice... but I don't see anyone making the right comparison, yet.

Cost of electricity vs gasoline is really about comparing one's existing vehicle to a new one with a high mileage equivalent... it is the operating cost break even point that must be found and the time it takes to get there...

I'm seeing a few ballpark figures here...
50 miles cost $2.98 using electricity=84mpg
35mpg/.3=117mpg
energy equivalent mpg at $4/gal: 104 mpg

Lets say 100mpg is considered...

Few people really run the numbers before replacing a gas guzzler with a new high mileage car. Doing so can be rather alarming, to say the least.

Let's say you already have an old truck that runs fine but gets only 12 mpg.
The new car gets 100 mpg but costs $35,000.
Let's say you drive 1000 miles per month.
And gas costs $4/gal

Driving the truck:
12 miles/gal at $4/gal is 3 miles per $1, so 1000 miles costs $333
So $333 per month to drive the truck

Driving the new car:
100 miles/gal at $4/gal is 25 miles per $1, so 1000 miles costs $40
So $40 per month to drive the new car
Plus the payment on the new car... with a perfect finance deal of 0 down and 0% for 7 years the payment would be $417
So $457 per month to drive the new car

The big question is, how long do you have to drive the new car to reach the break-even point after which you begin to realize savings over driving the truck?

You can already see right away that this point is beyond the first 7 years... the net monthly difference each month is going to be $417-333=$124 in favor of the truck for 7 years... let's see how much further it takes to break even and begin saving money.

The shift in cost of the new car happens when all the payments are finished in seven years. At that point the cost of operating the new car reduces to just $40.

During those 7 years, the $124 per month net difference in favor of the truck over the new car amounts to 84 months x $124 = $10416

So at the time the car is paid off the car has $10416 yet to save in order to catch up with the truck.

Now, after 7 years, only the fuel cost comprises the difference and the car has a net advantage of $333-$40 = $293 each month. The car is now catching up to the truck at the rate of $293 per month.

The car has $10416 to catch up, so at $293 per month it takes $10416/$293=35.5 more months to do so - almost another 3 years.

So, you have to drive the new car for about 10 years just to break even. This is what few people will bother to figure out - here an 833% improvement in gas mileage will begin to save you money only after 10 years of driving the new car.

I used an exaggerated mileage gap ( a gas guzzler vs a dream car priced low), a 0% finance, and did not include insurance, nor the 10 year time cost of money. Running more likely realistic values will just extend the break even point even further...

 

[OmCheeto]

Whatever noble ideas about conservation, the reality is that it will be the cost comparison that is most influential to choice... but I don't see anyone making the right comparison, yet.

Cost of electricity vs gasoline is really about comparing one's existing vehicle to a new one with a high mileage equivalent... it is the operating cost break even point that must be found and the time it takes to get there...

I'm seeing a few ballpark figures here...
50 miles cost $2.98 using electricity=84mpg
35mpg/.3=117mpg
energy equivalent mpg at $4/gal: 104 mpg

Lets say 100mpg is considered...

Few people really run the numbers before replacing a gas guzzler with a new high mileage car. Doing so can be rather alarming, to say the least.

Let's say you already have an old truck that runs fine but gets only 12 mpg.
The new car gets 100 mpg but costs $35,000.
Let's say you drive 1000 miles per month.
And gas costs $4/gal

Driving the truck:
12 miles/gal at $4/gal is 3 miles per $1, so 1000 miles costs $333
So $333 per month to drive the truck

Driving the new car:
100 miles/gal at $4/gal is 25 miles per $1, so 1000 miles costs $40
So $40 per month to drive the new car
Plus the payment on the new car... with a perfect finance deal of 0 down and 0% for 7 years the payment would be $417
So $457 per month to drive the new car

The big question is, how long do you have to drive the new car to reach the break-even point after which you begin to realize savings over driving the truck?

You can already see right away that this point is beyond the first 7 years... the net monthly difference each month is going to be $417-333=$124 in favor of the truck for 7 years... let's see how much further it takes to break even and begin saving money.

The shift in cost of the new car happens when all the payments are finished in seven years. At that point the cost of operating the new car reduces to just $40.

During those 7 years, the $124 per month net difference in favor of the truck over the new car amounts to 84 months x $124 = $10416

So at the time the car is paid off the car has $10416 yet to save in order to catch up with the truck.

Now, after 7 years, only the fuel cost comprises the difference and the car has a net advantage of $333-$40 = $293 each month. The car is now catching up to the truck at the rate of $293 per month.

The car has $10416 to catch up, so at $293 per month it takes $10416/$293=35.5 more months to do so - almost another 3 years.

So, you have to drive the new car for about 10 years just to break even. This is what few people will bother to figure out - here an 833% improvement in gas mileage will begin to save you money only after 10 years of driving the new car.

I used an exaggerated mileage gap ( a gas guzzler vs a dream car priced low), a 0% finance, and did not include insurance, nor the 10 year time cost of money. Running more likely realistic values will just extend the break even point even further...

This all assumes that there was nothing wrong with the old original vehicle.

The second to last car I bought lasted 4 years, at which point I determined that I was incapable of keeping it on the road without a multi-thousand dollar investment. Not only would it not pass DEQ, but nearly every luxury option on the car had failed. I also referred to it as a Chrysler Ebola, as it leaked fluids from every orifice.

I've already pointed out that incredibly modestly powered diesel electric generators(25 kw = 34 hp = $15,000) cost more than a lot of cars on the road. This is a function of the economies of scale, IMHO. This is also probably why electric vehicles are so expensive.

But I'm not an electric purist. I understand the perceived needs of the many outweigh the dreams of a few. So my vehicle of choice, is a hybrid. And if you've missed the news blurb about Leno's Volt, having a hybrid doesn't mean you don't have a potentially 100% electric vehicle:

Jay Leno Drives Chevy Volt 11,000 Miles Without Gas, Nets 2,365 MPG
Gas 2.0
According to Leno, the Volt he bought last year came with a full tank of gas, and since then he has traveled 11,000 miles using less than half a tank of gas. The 9.3 gallon tank isn’t all that big, and Leno’s claim would indicate that he has used less than 4.65 gallons of gas over 11,000 miles of daily driving his Volt in California’s oft-congested traffic. That means, at worst, Jay Leno is averaging around 2,365 MPG.

It just means you have that $15,000 tow-able fossil fueled generator trailer already installed in your car.

And I know that people are biting at the bit to point out that the 2,365 mpg number is a bit disingenuous, which I will not refute, but a pair of emails I received yesterday kind of hint of things to come:

Subject: ... Solar is now on
Date: July 20, 2012 3:02:22 PM PDT

Greetings,

I finally got all the inspections and approvals today and am now generating electrons.

Whoo hoo,

--------------
Subject: Re: ... Solar is now on
Date: July 20, 2012 3:18:44 PM PDT

Congrats! I turned on my system in March and it is totally cool to see my meter putting energy in the grid on a sunny day AND be able to charge my Leaf at the same time . . . charging my car on sunlight

I know these vehicles are currently fairly expensive, and I don't apologize for the fact that I could only afford to buy a brand new non-hybrid gas powered truck 3 years ago, but the numbers to me say, gas should eventually be used, logically.

PattiM, are you still listening? This means if you can't afford to keep both your Silverwing, and buy your Z, just keep your Silverwing.

ps. I'm retiring 3 years early, as I see this whole thing as an incredible business opportunity. 680 dtg!

 

[bahamagreen]

Interesting you mention the Volt...

GM now has a 30 day return full refund in effect on all its vehicles.
The purchase of a Volt qualifies for a $7500 tax refund.
The applicable tax form for claiming the refund does not specify a minimum period of ownership - only that the VIN number be indicated for the new Volt that was owned during some part of the tax year.

One might expect to see a lot of used Volts (less than 30 days) begin to appear on the market.

 

[OmCheeto]

Interesting you mention the Volt...

GM now has a 30 day return full refund in effect on all its vehicles.
The purchase of a Volt qualifies for a $7500 tax refund.
The applicable tax form for claiming the refund does not specify a minimum period of ownership - only that the VIN number be indicated for the new Volt that was owned during some part of the tax year.

One might expect to see a lot of used Volts (less than 30 days) begin to appear on the market.

Well, that really gives the comparison of driving "electric vs. gas" a new spin. It can actually be profitable to drive electrics!

What a delightful scam. I'll email Barry about this immediately.

Thank you.

ps. I decided Barry might be getting too many emails, so I just sent one to my Senator Merkley. He just made a 300 mile road trip in an EV two weeks ago. I figured he'd be receptive to some non Earth shattering input.

Also, according to another website, the 300 mile trip only cost $9.

Yippie!