# Forums

## Evironmental footprint

As I did preorder the Model S I of corse end up discussing with a lot of people about it. Most common argument of other people is, that the enviromental footprint is just as high as with a gas car. My google search only dig out the following article:

http://pubs.acs.org/cen/news/88/i33/8833news6.html

In the end the article say that if a gas-car emits 60 to 80 mpg (in the german article the say between 3-4 liters of gas) the Gas car will be just as 'enviromental friendly' as the electric car. For this calculation the take the normal energy mix which you get when you don't get a eco-friendly package.

What I just don't get is, that everywhere it's stated that the electric engine is way more effective than a gas one. That enerergy made in any plant is more enviroment friendly than burning it in the car. The study also shows that the battery inpact on the footprint is only 15% of the vehicle...

so how can it end up right beside my 5 year old prius? wich would burn 4.3l of gas theoretically. For me that just doesn't make sense.. but then they are probably smarter than I am.

Are there any other studies?
What do you guys think?

AlfredG | December 2, 2010

Christian - Here is the original report your link refers to (in English):
http://pubs.acs.org/doi/pdf/10.1021/es903729a
The report includes energy used to produce the whole car. The efficiency of energy used when driving plays a smaller role in this particular study.

If you look at the details there you can also see that some assumptions made are conservative.
Other points to consider are:

1) If you drive a Tesla Roadster behind a Prius (exactly the same way) across a test track where the Prius reaches the 4.3l/100km (55 mpg US) you mentioned, your Roadster would have consumed about the equivalent of 1.4 liters of Mogas (140Wh/km) and that with a car with incomparably more performance. If you drive the Roadster behind a Ferrari across the same track representative for his nominal consumption of 15 l/100km (16mpg US) you would still have only used the energy equivalent of 1.4 l/100km. So you would have consumed about 10 times less. Even allowing for generation and distribution of electricity will leave the Roadster very much ahead. So it all depends on the comparisons chosen.

2) In real life cars with combustion engines rarely achieve their nominal tested consumption. A lot of mileage is done e.g. with cold engines in urban traffic. I have not found a good report quantifying these effects across the fleet, but they are thought to be substantial. See e.g. http://is.gd/i5tw3 (in German).
More calculations and estimates I have gathered here: http://web.me.com/alfredar/

- Alfred

Brian H | December 2, 2010

Christian;
EVs may well be terrible "enviromentally". Environmentally, however, they're excellent. Which does make sense.

Much of your spelling, on the other hand, ...

;)

qwk | December 2, 2010

Much of the information on the web is biased, so take that with a grain of salt.

I use the common sense technique.

To make gasoline you have to find, drill,pump from ground, transport from middle east, pipe from tanker, REFINE, pump to trucking point, truck to gasoline station, pump in your car.

That is very much energy wasted which no one factors in when using this calculation.

Then ann ICE also uses more fuel to warm up to temp, and it idles. Two energy wasting steps electric cars avoid.

As far as manufacturing goes, they also forget that an ICE needs fuel filters, oil filters, OIL, air filters, spark plugs, Spark plug wires, cap&rotor, belts, clutches, fuel pumps, alternators, starters etc. When you take all this into account, the ICE looks worse and worse.

Of course none of these studies take this into account, because they are probably sponsored by...............

ggr | December 2, 2010

Here's an analysis by a colleague of mine of the environmental impact of emissions of Grid EVs versus ICE. Because power generation plants are either very efficient, or (hydro, wind, geothermal) cause no emissions at all, the bottom line is that electric vehicles cause about 1/20th of the pollution per mile traveled. (This doesn't count manufacture, only running.)

http://www.ka9q.net/ev/ev_emissions.html

Greg.

ChristianG | December 5, 2010

Sorry for my spelling, but it's even bad in german so don't expect anything else in english ;)

Well if the study takes in account that you have to dig for certain materials from the battery i of corse think that they do the same for the ICE car... but it's not really clarified wath they take in account for the ICE Ccar.

Like I said I drive a prius myself, and I can confirm that you almost never achieve to get the claimed usage of fuel. Actually I drive almost the worst possible way for a hybrid. I go to the highway for 10 minutes, with cold engine, and thats it. I end up having 6.4 litres. If i drive longer distances it gets way better.

I assume too that with the EV we will not get the same distance as they claim on one load.

Timo | December 5, 2010

Depends almost completely how your drive. With moderate speeds you can drive Roadster over 300 miles. In slow city traffic nearly 400 miles. In 75-80mph freeway less than 200 miles.

Those EPA range calculations need to be taken as they are: estimates using certain parameters. If you know how much and what way your driving differs from those parameters you can estimate how far you can expect to drive with one charge. That, and then there is a very accurate battery charge meter that can show you your range in few mile tolerance.

Samuel H. | December 9, 2010

Most people I have spoken to don't think that an electric car has a "fuel gauge". This myth has got to be eradicated.

About the cold engine, in an electric, this matters little. The batteries, however, cannot run cold. That is why Tesla's vehicles have a battery warmer and cooler that keeps the battery at the optimum temperature.

Please buy a Tesla and sell that Prius. Question, what is the max range of a Pruis and what is the average mileage of a Prius in your experience?

Douglas3 | December 9, 2010

Actually, the batteries DO run cold in the Roadster; they just don't permit regenerative braking (charging) until the battery pack warms up.

Samuel H. | December 10, 2010

I did not know that. I do know that performance is greatly reduce by too cold batteries. I have lots of experience using RCs in the winter. The same car or plane that does 20 min. a charge in the summer will do 5 min. or less in the winter if it is not kept warm before use. Thanks for more info.

Douglas3 | December 10, 2010

So far I have not seen any significant impact on the range due to low temperatures, at least at -9C. I plan to try it at colder temperatures when I have the chance.

Samuel H. | December 10, 2010

Interesting.

Please let us know how the cold test goes.

ChristianG | December 10, 2010

@Samuel H

Don't know what you mean about the max range.. you mean the pure electric? I guess if you're lucky you'll get 2 miles and you have to drive around 40 km/h and not accelerate too much. But then that hybrid never was ment to drive on pure lectric, the electric motor should help the Gas Motor to avoid peaks... so it's just a cool feature to drive in silent mode throu the parking lot.

Like I said my average is around 6 litres per 100 km. But that's me only driving short range distances on a highway. If I do longer trips, even on the highway I'm often under 5 litres.

The Model S is defenitely high on my priority list, but it will all depend on the price here in europe. It's an expensive car and it's really close to what I'll be able to spend then. but yeah, can't wait until it comes out.

Samuel H. | December 10, 2010

I meant what is your range in hybrid mode using electric and gas in concert for max efficiency. Sorry didn't make myself clear. In other words, how far can you theoretically drive in your Prius?

ChristianG | December 14, 2010

The standard mode is 'hybrid', wich means the ICE gets some support from the Electric motor and stores some engergy when riding down and breaking. This results in a lesser gas consumtpion compared to a ICE car the same size.

additionally you can drive a very short distance (2-4km), in very slow speed (40km/h) in pure electric wich makes sence in parking lot's or stop and go traffic. The energy comes from the same 'small' battery. The battery itself is never charged it get's its energy a bit from regen braking and most of it from the ICE.

So in the end it's just Gas consumptions. The prius has a 45L tank wich means:
If I use the stated 4.3l / 100km I'll get 1046.5 km

My average over the year is 6l / 100km = 750 km

Long range trips were around 5.3l / 100km = 850 km

But like I said, the 'range' kinda is limited as in the end It's a gas car. you refill it in 5 min. and you boldy go where everybody else also go...

If you drive long distances my

Samuel H. | December 15, 2010

I heard somewhere that the Prius could only go 130 miles/209 km.

Timo | December 15, 2010

You have heard wrong then. Prius has big enough fuel tank to have range of somewhere in 1000km range.

Tesla 940 | December 17, 2010

I rented a Prius last year for a week and drove nearly 2,500 miles. Most of the driving was in the 70 - 80MPH range. My average MPG for the entire trip was ~ 48. Not willing to run out of gas I didn't push the empty needle too far. I usually filled up after about 400 miles. I believe the gas tank was about 11 gallons - 11*48 = 528.

Timo | December 17, 2010

70-80 mph is quite fast for European roads (autobahns etc. excluded). 50-60mph average would be closer to truth in Europe. That gives you a lot more range.

BTW 11 gallons = 48 liters, Planar energy 1.2kWh/L batteries give you 57.6kWh, which means ~260mile range for Roadster using battery that is no bigger than Prius gas tank. Double that and have same range as Prius without filling tank/recharging battery.

ChristianG 4.8L/100km with Prius is quite possible. One of my friends has average 5L/100km with Saab 9-5 (basically same car as one of the Cadillac models for you Americans). All you need is a very steady driving style and he does that semi-naturally. No excess gas usage, no revving in high gears, anticipating slowdowns etc. One of the most relaxing person to drive with. (not at all like my other drive-a-lot friend, that makes you grip the handles like if they are your only hope between this life and the abyss)

ConnorO79 | December 18, 2010

Well the way I think of it is; gas cars can only run on gas, which is very environmentally unfriendly. However electric cars can run on electricity made for fossil fuels OR sustainable sources like solar or hydro or wind etc.
So electric cars have the potential to be environmentally neutral, minus the parts production etc.

Douglas3 | December 18, 2010

Not neutral. Electric cars are much more efficient. Even powered by coal their carbon footprint is a fraction of a gas car.

searcher | December 19, 2010

Unusual thoght maybe but wonder if we looked at whole planet and do studies on if their are any ways we could have hydroelectic grid worldwide. Hydroelectric seems very environmentally friendly to me, again know there would be daunting challenges but that is what high tech people have thrived on historically speaking.

Klaus | December 19, 2010

@Timo those are imperial gallons. 11 US gal = 41.6 liters.

Timo | December 19, 2010

How do you know which gallons those are? Are you "Tesla 940" with new username?

dsm363 | December 20, 2010

Google works pretty well: Hydroelectric power
http://en.wikipedia.org/wiki/Hydroelectricity

ChristianG | December 20, 2010

@Timo
I know that it's possible to come close to the said 4.3l / 100km... BUT my ride to my work does not allow it. It is a short ride, 10km and it's only highway (fast 120km/h). Driving short distances is very bad for the prius. If you drive longer it starts getting better like I said. But if I drive longer it's Highways again...

@Hydropower
Like it's stated in the article it causes many problems too, however if you do it on a smaller scales there some pretty good ways to get 'some' power. Like taking a river and only take part of the water to make the energy. Only little land is flooded by water and the eco system is untouched. Buuuut it's not nearly as efficient as the big damn-lakes.

A very promising way to get energy beside Wind and Solar Power is this http://en.wikipedia.org/wiki/Wave_power_plant ... even as it too may cause problems it sounds pretty cool.

Timo | December 20, 2010

Um, sorry Klaus, you refer to my calculation, not Tesla 940 post. (It seems that you really need to sleep every few days. Things look somewhat clearer with fresh eyes).

Imperial gallons would have been 50 liters, I apparently clicked wrong field in my converter and used US dry gallon.

Brian H | December 21, 2010

Wave and tidal power is VERY hardware-intensive, and if you try to use ocean water, the salt makes it much more expensive to keep running and uncorroded.

All these big renewables projects are massive uglification of the environment. They will be scrap for recycling within a decade.

Timo | December 21, 2010

"uglification" I don't think I have heard that before :D

Very illuminating word though. And very true statement.

Klaus | December 21, 2010

@Timo you got that apology in just in time. I was about to lay some harsh response on you. ;)

ChristianG | December 22, 2010

@Brian_H
Yep every building is an uglyfication ;) and especialy when it has an indistrual look it's much worse.

Still Wave power building are probably out of sight of the ordenary human beeing as most of don't use boats on regular bases. How much impact they have on the ecosystem where they are employed I don't know. But it seems to be much less then other other projects...

Vawlkus | December 22, 2010

They do design underwater trubines to be long life items you know. They just brought one up near me, and while it had been down for a year, it was still immaculate when they brought it up. The reason they had to bring it up was that they underestimated the strength of the current where they situated it, and the current ripped the blades right off :)

DarrellH | December 22, 2010

If you want to see an existing tidal power site, check out TWIT.TV's "Green Tech Today 6: SeaGen". There is a segment (audio and/or video) on a tidal power project that is producing power just outside of Belfast, Ireland. A company has set up a 1.2M watt tidal energy converter. It looks promising and it certainly isn't as ugly as an oil platform or derrick.