Hybrids v. Electrics... am I the only one who sees a major drawback?

I do tend to keep my cars a long time...average 15 years...

 

Criminy. You are a nit picker. I say that the average car does at best 35% you reply "NO, the best ICE does 35%. That is what I said. Relax dude! I'm glad you have PV panels, would like to have them myself but my trees cast too much shade on my roof. Some day.... But of course you must realize I am talking about the average person. I'm familiar with the breakdown of electric energy sources, but fact is the US as a whole generates a lot of energy from coal and gas. So for those who might be plugging in to the grid today, there is something burning out there somewhere. Of course we need to change that. Finally the battery swap idea has it's skeptics but Shai Agassi is opening 100 stations in Israel and plans to open them in Japan too. Battery costs are high now, but hopefully production costs can come down. And given enough costumers, the price will come down. Remember when computer memory was expensive?

 

You're a bit high there, electricity transmission/distribution losses are estimated to be in the 7% range.

Electric power transmission - Wikipedia, the free encyclopedia

 

No, you said that the average car does at best 35%.

What Darell said, and he is completely correct, is that the best car does, at best, about 35%. The Prius Atkinson-cycle engine is the most efficient petrol engine out there (diesels are more efficient due to generally not having a throttle plate, reducing pumping losses, at the cost of increased NOx formation). The 2010 1.8L engine achieves 36.8% efficiency, if run in its most efficient region. However, this still produces way too much power for most uses. The 220g/kWh efficient region starts at about 10kW of output, which is about equal to wind resistance at 65mph. There are other losses as well (rolling resistance, transmission losses, etc) so you might be entering the most efficient region at 60mph.

My recollection of the Jetta TDI engine is that the BSFC chart shows a lowest consumption of 190g/kWh. That works out to 41.7%. Again, this is mid-range on the engine.

The average car, with an oversized engine and an Otto cycle, has to run with the throttle plate almost completely closed when cruising and not only is its peak efficiency much lower, it spends nearly no time at that point. Generally the cars are driven with incredibly low load on the engine - even the Gen 2 Prius uses more than twice as much fuel at 25% of maximum load. (It prefers to run the engine slower with more load, and in fact has a specific torque/speed curve that it follows, to maximise efficiency at each point on the power demand curve.)

 

Snoctor and Mike and Darell, you are all DEAD wrong. ;-)
j/k, but you are *are* cross talking
Snoctor points out that any old ICE maxes out at 35% efficiency, which is quite right. But his follow-on argument doesn't then follow, because of Mike's point that the *average* efficiency for the car is what matters, not the peak.

If we look at at the average ICE efficiencies a fleet of drivers experience, I'll guess the numbers will look something like the following:
Prius G2/G3: 30%
Dirty (err, "Clean") Diesel: 25%
Vanilla petrol ICE: 15 - 20%

I derive these numbers by starting from 34 kwH of energy/(US) fuel gallon, and around 0.25 Kwh/mile energy consumption. So e.g, the Prius ends up with an mpg of (34*.3)/.25 = 41 mpg. Actual Prius results, as many of us know, tend on average to be higher. Many reasons play into this, including brake regen and driver habits. I have tried and estimate my personal ICE efficiency, and I come up with ~ 33%. I'm pretty sure that my 60 - 70 mpg daily results are a result of decreasing energy/mile consumption to below 0.2 kwh/mile, and sometimes down to 0.15 kwh/mile even on extended city driving trips.

 

that implies that driving any other type of car would be free...SIGN ME UP!! cmon man!! be real.

what you "need" to pay back (btw, there is no payback on ANY CAR!!!) is

1) the difference in price of an EV verses a regular car
2) cost of "fuel" electricity is normally (in 85% of the country) cheaper by conventional means, and greatly available by unconventional means (wind, solar, squirrel cages, etc) gas, well... i guess you could convert to bio diesel and eat a lot of fried chicken or something
3) maintenance cost differences which is usually the big ignored subject.

i post what it costs me in "fuel" money only here for all to see. what i dont post is what else i have to pay for. 75% higher insurance rates, oil changes, etc. so what would "appear to be a 3 cents per mile difference is actually nearly double that. other than windshield wiper fluid, i have spent ZERO on maintenance for my Zenn.

that really depends on the source of the electricity. if getting it from green sources which would be more efficient than fossil fuels (after all, oil is a result of several months of sunshine, millions of years of pressure verses a sunny afternoon or a windy day right?)

the efficiency can potentially be much much higher

that is probably an overall estimate. and that is also controlled by distance. i know a guy who does remote line maintenance by helicopter. the new lines they are putting in are in the 4-5% range.

 

Really? I didn't realize that. LOL. Dave in Washington - go have some more coffee, and try extrapolating what I said. It's in there, so I'm sure after a few more coffees, you'll find it?

I think most people know this. But how long will it take for the "fuel" savings between electrical grid vs at the pump, to justify an all electric vehicle, versus a hybrid, or conventional vehicle of the same size, etc? I did this calculation before buying the Prius - that is, in fuel savings alone between the Prius and a comperable (but cheaper) non-hybrid vehicle...how long will it take for the fuel savings to equal the cost difference between the prius, and the other non-hybrid vehicle3s i looked at. For my comute, and assuming the average cost of gas over the next 5 years is around $3.25, it will be 7 years. I'm sure an all electric car would have significantly greater fuel savings...but the big question is, how much will that car cost? If it approaches $40K, then I doubt I could ever justify the added cost based solely on fuel savings. That's the point.

Higher insurance rates? What? Why? Mine dropped from what I was normally driving because insurance companies look at the demographics of the average Prius driver, and they are usually older, more experienced and drive slower...so expected payouts for accidents should actually be lower. Not sure why your's is higher?

Oil changes? Some cars have all maintenance included, while many more do not. If a $50 oil change every 5,000 miles is a big deal, then you might consider changing your own oil as many of us old timers did (for years).

What are the "etc" things you speak of?

 

i own an Electric car and 2 Priuses, the 75% figure i mention is the difference in insurance costs that i pay...

 

The electric car is 75% higher than the Prius, or visa versa? What electric car do you own? Home made, or one of the few commercial electric vehicles that you can register for street use?

 

look at signature, i own a Zenn. its insurance rates are lower. but its also slower, limited range, etc. that is why its cheaper i guess. both the Zenn and Pri qualify for the same "green" discounts so they are even on that... not quite sure i agree with that but


www.zenncars.com

 

darell,

bicycling --> showering --> danger

ergo, bicycling --> danger


glen

 

Thanks. I have never heard of Zenn before? I've certainly never seen a dealership. Where are they located (besides your area or Quebec)? I mean where do you go if it breaks, or needs service?

 

A Zenn dealership opened in my town of Albuquerque, NM. The car looks quite nice, but is hobbled by an ~ 30 mph max speed, and lead batteries are used.

 

Thats ironic because after I ride my bike I usually take a shower. :doh:

 

WA state and Montana immediately change LSV laws to allow 35 mph. i bought my Zenn in Seattle. i live in Olympia which is like 60 miles away, but my dealer has a contract shop in Oly for waranty work since there are more than a handful of Zenn owners in my area.

i actually see a half dozen of them running around town

 

Thanks. I'll keep an eye out should a dealership open in my area. If I can ask -

(1) How much (high and low)?
(2) Range on a full charge? Assume max spped @35mop. There are not too many places where I live that you can go much slower.

 

well, because of the expected announcement of a revolutionary charge storage technology of which Zenn has a 10% stake in, they will stop production of the Zenn on April 30th. sooo, you havent got a lot of chances left.

 

If by revolutionary you mean revolving 'ready by next year' promises, then I hear ya

 

What you say is true, but NOT the whole story. You have to compare average efficiency, not just peak efficiency. In a power plant, such as even the dirtiest coal plant that might be only 40% efficient -- it is 40% efficient pretty much 99.9% of the time. While the ICE in a Prius is perhaps 30%-35% efficient this is the peak. You don't get that number all the time. You get 1/3 to 1/2 of that for the first 5 or 10 minutes during warmup. If your commute ends 5 minutes later you actually averaged much less than 30 or 35. On your commute home you repeat the warmup cycle all over again. While the coal plant only does a startup and shutdown a couple of times per year (maybe) for maintenance.

Most cars have a "peak" efficiency of closer to 20% or 25%. And some NG combined cycle power plants get up to 60% efficiency. When you average in all the non-fossil energy sources (nuclear, hydro, wind, solar, geothermal) it is clear that the typical EV mile will burn much less fossil fuel than the current fleet by 2x or 3x.

Also, this is where EVs and PHEVs will improve things a lot. They will reduce the warmup penalty.

3PriusMike

 

Hi Mike,
I certainly agree with the dictum to use average efficiency, and in the end we may just be arguing over the meaning of a "big" difference.

A coal plant starts at 40%, and 7% is lost to transmission across distances, and another 5 - 10% from the house to the car battery, putting us at 35%. From there 5% loss until the shaft, leaving us with 33%. I average about 30% delivery of petrol energy to the shaft in my Prius.

Is 10% a lot ? Sure, but considering how the EV dollars could otherwise be used to fuel alt energy, I'd say it is a little. By this I mean e.g, that I'm a lot more inclined to have a PHV and PV, than an EV car only. I'm as enamored as the next guy with 200 mile EV range cars, but I have little doubt that blended solutions are a much smarter use of green dollars.