Is Tesla really a green company?

[SageBrush]

1. You're assuming that the Prius' emission level will always remain the same.

Fair point. They have improved, based on the G4 Prius MPG ;-)

2. CO2 isn't the only pollutant.

Very true, but you don't want to compare Prius Nox to Fossil Fuel Nox coming out of a power plant.

3. ICE car emissions are mainly emitted where you breath them.

CO2 is not a local pollutant in the way NOx is.

 

[freds]

There's a crossing point coming in that the grid is going more and more renewable energy. Buying a Tesla provides an immediate reduction in what you emit and continues too for the life of the car (unless we keep crashing them). Image comparing a 12-15 year old tesla verse an ICE cars emissions when they both have 200K+ miles on them.

 

[nwdiver]

Yes; an investment in renewable energy provides a better environmental return on your dollar than buying an EV. But to focus solely on cleaning up the grid while neglecting the electrification of our cars is short-sighted. We're already adding wind and solar generation far faster than we're adding EV consumption. In addition to the need to eventually transition away from oil anyway... Millions of EVs tied to the grid will allow us to expand wind and solar far beyond what would otherwise be possible. If you want variable supply to comprise a majority of your generation then you need a way to control demand. EVs give you that control with proper demand management.

 

[deonb]

Keep in mind the leverage effect of the investment. The Model 3 is funded by the Model S that was funded by the Roadster.

So come 2020, each person who bought a Roadster effectively took 250 gas vehicles off the road and replaced them with EV's. And it will continue. Pretty neat.

Now imagine if those guys decided to have just put up solar panels instead.

Tesla is by no means out of the woods yet. So the leverage effect you get from buying a Model S today will still pay off many fold.

 

[Jonas_man]

1. You're assuming that the Prius' emission level will always remain the same.

2. CO2 isn't the only pollutant.

3. ICE car emissions are mainly emitted where you breath them.

The raw number doesn't even remotely tell the whole story.

The calculator mades the calculations using CO2e which includes all the dirty pollutants.
So my point is, changing to a Tesla will help reduce the carbon footprint even from a Prius.

 

[Jonas_man]

Say the extra cost of a Tesla compared to your Prius is Z, then

Between 48k/Z to 96k/Z

Ok thanks, that is huge. 48k vs 33

 

[lklundin]

Very true, but you don't want to compare Prius Nox to Fossil Fuel Nox coming out of a power plant.

I am unsure what your point is, so I just want to clarify:

In a comparison of produced emissions (CO2 and/or NOx) per power, any modern power plant easily beats the low-temperature[*] and thus inescapably inefficient process in any ICE. This is actually the reason why the BEV easily beats the ICE in CO2 emissions per driven distance, the efficiency of the electrical motor is not temperature dependent and can approach 100%.

[*] The efficiency of the limiting thermodynamic cycle (e.g. Carnot or Otto cycle) is a function of the operating temperatures.

 

[lklundin]

Assuming a Tesla model S uses 100kwh for 500kms it means i would need to use 1600Kwh for the same 8000kms
Charging at home the calculator says this:
0.32 metric tons: 1600 kWh of electricity in Finland

I could pretty much reproduce those numbers, given that Finland covers its electricity production with about 40% fossils (an about even mix of methane and coal), the rest is nuclear and renewable.

However, do not forget that as one of those Nordic, semi-socialist countries, Finland actually mandates that residents near the typical power-plant must use the plant's residual heat for residential heating. So the extra fuel burnt by the power plant to make the BEV run also contributes to heating up someones house, meaning that the environmental impact of running the BEV is even lower than the above calculations would indicate.

The idea that the BEV is polluting as much or more than the ICE is just FUD that over time will appear more and more like the reassuring statements of 'Baghdad Bob'.

 

[SageBrush]

Ok thanks, that is huge. 48k vs 33

Misunderstanding here.

I meant a range -- as low as 48,000 lbs / Z dollars
-- As high as 96,000 lbs / Z dollars

 

[SageBrush]

In a comparison of produced emissions (CO2 and/or NOx) per power, any modern power plant easily beats the low-temperature[*] and thus inescapably inefficient process in any ICE. This is actually the reason why the BEV easily beats the ICE in CO2 emissions per driven distance, the efficiency of the electrical motor is not temperature dependent and can approach 100%.

1. NOx is not efficiency dependent
2. NOx increases with combustion temperature
3. NOx from coal is extremely high, from NG much lower*
4. NOx is captured by post combustion processes with varying success

A Prius emits about 3 mg/mile NOx;
so about 150 mg/gallon at 50 MPG which has 33.7 kWh of energy
Thus about 4.5 mg/kWh

*Power plant NOx emissions:
About 2 million short tons per year in 2012 according to the EIA
Producing about 4.2 * 10^12 KWh a year according to EIA
This works out to about 430 mg/kWh from the overall sector

Yes, you read that right. About a 100 fold difference in emissions.
I told you not to inquire ;-)

This calculation is not a lifecycle analysis but the bottom line is that a catalytic converter is a *much* better NOx trap than whatever is on power plants (usually urea SCR I think.)

Addendum: Power plant corrected from 450 to 430 mg/kWh
Addendum #: This lifecycle study of the different pollutants emitted with ICE use is fantastic. I'd like to find a study as well done for electricity from US power plants.

 

[EinSV]

Renewable energy (especially solar) and Tesla go hand-in-hand. The grid in the US is becoming cleaner all the time -- e.g. last year 67% of new US energy sources were renewables. – 2015: U.S. Installed More Renewables Than Fossil Fuels | ENS

BEVs will help accelerate this trend. For example, I ordered two Model 3s, which makes the case for rooftop solar for me a no-brainer (despite having to replace my existing roof to do it).

A new vehicle will likely be on the road for 15 years, and the current advantages of BEVs over ICE and hybrids will just get stronger and stronger over that lifetime as dirtier sources of energy are phased out.

 

[SageBrush]

Renewable energy (especially solar) and Tesla go hand-in-hand.

Absolutely!

 

[Saghost]

1. NOx is not efficiency dependent
2. NOx increases with combustion temperature
3. NOx from coal is extremely high, from NG much lower*
4. NOx is captured by post combustion processes with varying success

A Prius emits about 3 mg/mile NOx;
so about 150 mg/gallon at 50 MPG which has 33.7 kWh of energy
Thus about 4.5 mg/kWh

*Power plant NOx emissions:
About 2 million short tons per year in 2012 according to the EIA
Producing about 4.2 * 10^12 KWh a year according to EIA
This works out to about 430 mg/kWh from the overall sector

Yes, you read that right. About a 100 fold difference in emissions.
I told you not to inquire ;-)

This calculation is not a lifecycle analysis but the bottom line is that a catalytic converter is a *much* better NOx trap than whatever is on power plants (usually urea SCR I think.)

Addendum: Power plant corrected from 450 to 430 mg/kWh
Addendum #: This lifecycle study of the different pollutants emitted with ICE use is fantastic. I'd like to find a study as well done for electricity from US power plants.

The Prius number appears to be mg/kWh of chemical energy in the input fuel - the EIA number appears to be per kWh of output electricity. Even assuming the Prius is operating 100% of the time at the peak efficiency point, it'd seem like the Prius number should be almost 3x higher (37% thermal efficiency at 220mg/kWh peak BSFC.) Or am I missing something?

 

[lklundin]

1. NOx is not efficiency dependent
2. NOx increases with combustion temperature
3. NOx from coal is extremely high, from NG much lower*
4. NOx is captured by post combustion processes with varying success

A Prius emits about 3 mg/mile NOx;
so about 150 mg/gallon at 50 MPG which has 33.7 kWh of energy
Thus about 4.5 mg/kWh

*Power plant NOx emissions:
About 2 million short tons per year in 2012 according to the EIA
Producing about 4.2 * 10^12 KWh a year according to EIA
This works out to about 430 mg/kWh from the overall sector

Yes, you read that right. About a 100 fold difference in emissions.
I told you not to inquire ;-)

This calculation is not a lifecycle analysis but the bottom line is that a catalytic converter is a *much* better NOx trap than whatever is on power plants (usually urea SCR I think.)

Addendum: Power plant corrected from 450 to 430 mg/kWh
Addendum #: This lifecycle study of the different pollutants emitted with ICE use is fantastic. I'd like to find a study as well done for electricity from US power plants.

I stand corrected, I made a serious mistake in lumping in the NOx with the CO2, which is the pollution that Tesla Motors is focusing on.

Thanks for providing these enlightening numbers.

 

[SageBrush]

The Prius number appears to be mg/kWh of chemical energy in the input fuel - the EIA number appears to be per kWh of output electricity. Even assuming the Prius is operating 100% of the time at the peak efficiency point, it'd seem like the Prius number should be almost 3x higher (37% thermal efficiency at 220mg/kWh peak BSFC.) Or am I missing something?

I suppose I was not explicit, but I was calculating NOx per mile. You can certainly correct for thermo efficiencies (~ 45% NG, ~ 37% Prius) and some processing differences but the final differences are so great that it is not going to matter to the final conclusion.

As I posted later, the lion's share of Prius NOx emissions are not tailpipe. The LCA link is very informative, but it also strongly hints that fossil fuels share many of the same NOX inputs upstream so I didn't try to compare them.

 

[Saghost]

I suppose I was not explicit, but I was calculating NOx per mile.

As I posted later, the lion's share of Prius NOx emissions are not tailpipe. The LCA link is very informative, but it also strongly hints that fossil fuels share many of the same NOX inputs upstream so I didn't try to compare them.

So you didn't get the 4.5 mg/kWh number you're using to compare with the powerplant by dividing the 150 mg/gallon by the 33.7 kWh of chemical energy contained in the gallon?

The point I was trying to make is that this would be the amount of NOx generated per kWh of chemical input energy, not per kWh of mechanical/electric output energy.

On the Powerplant side, you seem to be using the total NOx generated by powerplants and then the total electricity generated by the power plants - so it is grams of NOx per kWh of electrical output energy. Two different measures...

I suspect it'll be hard to convert the power plant to chemical input energy, so the obvious way is to convert the Prius to mechanical/electrical output energy.

 

[Jonas_man]

It would be very educational if anyone could get the amount of energy used to dig oil, transport it, refine it, transport it again and pump it to the car vs producing energy, operate the grid and charging the car.

Also for a true comparasion how much building all that equipment used in both sitatuons pollute.
Oil platform, trucks, refineries, gas stations vs dams, wind parks, pv, nuclear plants, cables, charging stations.

 

[SageBrush]

So you didn't get the 4.5 mg/kWh number you're using to compare with the powerplant by dividing the 150 mg/gallon by the 33.7 kWh of chemical energy contained in the gallon?

Yes.

I understand your point and I agree, so how about looking at it this way:
Prius: 3 mg / mile tailpipe only

Tesla:
430 mg for one kWh from grid good for ~ 3 miles, so 140 mg/mile plant to wheels

 

[SageBrush]

It would be very educational if anyone could get the amount of energy used to dig oil, transport it, refine it, transport it again and pump it to the car

Look at the link for lifecycle emissions in post #50

 

[Saghost]

Yes.

I understand your point and I agree, so how about looking at it this way:
Prius: 3 mg / mile

Tesla:
430 mg for one kWh from grid good for ~ 3 miles, so 140 mg/mile

I don't see anything wrong with that logic. Since it's EPA emissions results, the "~3 miles" part probably ought to be based on the EPA 33-38 kWh/100 miles measured from the wall (depending on the specific S in question - most of them are more on the 38 end, which would drive the number up a bit. You also probably should have a grid losses factor added in (I think I've seen 7%?)

As you say, then you need the upstream emissions and to figure out how much those are shared.

Or you can buy Solar Panels made with solar/wind energy to put on your garage roof and charge the Tesla with and stop trying to do progressively more complicated math.