# Forums

## Reduced Carbon Footprint ?

I recently read the concentration of CO2 in the atmosphere is increasing faster than ever before. So I am wondering: how much less carbon does a Model S put into the atmosphere when compared to an average ICE powered vehicle assuming the ICE gets say 20mpg or maybe 25mpg and is driven say 12,000 miles per year?

It depends on the fuel source for the electricity you put into your car. It should be less overall anyway but coal versus gas versus solar involve big differences in CO2 footprints.

Where I live, about 15-20% of the electricity generated is from renewable sources (wind, solar, geo, hyrdro). Over 50% is gas and nuclear makes up the rest along (possibly with coal).

If you have a solar array on top of your house, you will substantially change the equation. Someone did a calculation that a 4kWh array may be enough to offset the charging of an S model over the course of a year.

We have an 8.1 kWh array on our house so when I get my S, I should be ahead of the game.

ZoomZoom | 17 maggio 2013

Given that electricity generated by "coal versus gas versus solar involve big differences in CO2 footprints" is it possible to figure this out for say average USA electric power generation or average California electric power generation? If so, any idea what it might be? Is it 1 ton/year or 10 tons/year?

evanstumpges | 17 maggio 2013

If electricity is produced exclusively from an old, inefficient coal power plant, the CO2 emissions from an electric car would not be significantly less than a similarly sized gas car and might actually exceed them. However, in the US the percentage of electricity produced from coal has been shrinking and I'm confident that this trend will continue as more renewables come online and the shift towards natural gas accelerates. Thus electric cars can be expected to gradually become cleaner over time, whereas gas cars will become dirtier over time as oil becomes more energy intensive to obtain.

The nice thing about electric cars for me is that with solar or wind energy, they can be driven with essentially no CO2 emissions (other than what is required to produce the solar panels or wind turbines). Gas cars will never have this luxury.

Last time I did the math, it is significantly cheaper per mile to drive an electric car powered from photovoltaic solar than it is for a similar gas vehicle.

All of my electric vs gas car analysis to date has has only gone back as far coal and gasoline as commodities. It would be interesting to go one step farther and compare the energy it requires to mine coal vs. drill for oil/refine gasoline. I suspect the ~7.5kWh (EPA estimate) required to refine a gallon of gasoline would tip the debate farther favor of electric cars.

evanstumpges | 17 maggio 2013

Above is a link to a paper I wrote on this topic in 2011 during college. If you skip down past the first few pages, I include a lot of formulas and calculations with a good deal of transparency. It should be public but let me know if you have any issues accessing. I'd be happy to take critique or feedback on my analysis if anyone finds it interesting or has questions. Some numbers might be a little out of date now, but the results wouldn't be too much different if calculated for a Model S today.

My analysis focused on the Tesla Roadster in Iowa, where electricity comes from a mix of coal and wind. The results came to an estimate of 237g of CO2 per mile. This is similar to the CO2 emissions from a 37.6MPG gasoline car.

So, if you have a 50MPG Toyota Prius, in Iowa switching to a Tesla would not likely be wise if all you care about is CO2 emissions. That said, not many vehicles average over 37.6MPG and even then there are so many other good reasons to buy a Tesla!

I'd guess that California's electric grid is one of the cleanest in the US so numbers there should be more favorable for electric cars in terms of emissions.

To really make an impact on CO2 emissions, the best option is to go all electric and charge from renewables...

nickatcammar | 17 maggio 2013

in quebec,the electricity come at more than 90% of hydro it is very interresting to know how is my co2 foot print .

TikiMan | 17 maggio 2013

Be that as it many, please realize the internal combustion engine is responsible for a high amount of infant mortalities. Oil spills destroy sea life, and expel high levels of radon gas in landfills that last for decades, causing untold health problems.

Electric vehicles will always have far less blood on their hands than ICE vehicles, no matter how you try to do the math.

dbullard | 17 maggio 2013

I pay my utility company (I live in Portland, Oregon) a little extra, so my carbon footprint is almost zero - all from hydro, wind, etc.

Brian H | 18 maggio 2013

Depriving plants of their staff of life is cruel and unwise in the extreme.

SamO | 18 maggio 2013

@Brian H,

But causing sea level rises and mass dislocation/death through emitting gigatons of CO2 is cruel and unwise to humanity in the extreme.

Lessmog | 18 maggio 2013

Yes, may the Tesla plant in particular populate & prosper perpetually!

carlk | 18 maggio 2013

You can always use renewable energy to generate electricity but you have always to burn gas in an ICE car. The easiest way to achieve zero carbon footprint is to instal a solar panel to generate electricity to charge your MS.

Tesla-David | 18 maggio 2013

I for one am someone who cares deeply about doing something about climate change not simply talking about it and wringing my hands. Last year, my wife and I downsized to a solar/heat pump equipped all-electric home. We also installed a heat pump water heater, and did an energy audit and weatherization repairs to make our home energy efficient. Buying a Tesla completed our transition to a sustainable lifestyle with a much carbon-reduced footprint. After monitoring my Tesla charging needs for four months, I just completed installation of an additional 3.2 kw solar panels, which boosts our solar system array up to 13.2 kw. We now produce enough electricity to cover our home needs and charging needs of our Tesla (my 35 mile commute takes about 9.6 kw/day, ~290 watts/mile). I also have a Prius, which has been converted to a plug-in with a 4 kw Enginer kit, which ups the gas mileage to aroun 70-80 mpg. I also joined "Citizens Climate Lobby", an activist group pushing for a "Carbon Tax" to put a price on carbon, prefereably at the source, that would return the revenues to the public. I am really tired of our inaction on this extremelly important issue, and in folks who deny there is a problem. The U.S. is responnsible for 25% of the carbon emmissions @ 4% of the earth's population. Our country is having a disproportionate impact, as compared to a citizen living in India or China. I know many people buy the Tesla for reasons that have nothing to do with saving the planet, but many like myself do, and I therefore look to the Tesla community to step up and consider adding solar panels to your home, by installing panels on your home if you have the right roof structure. For folks living in Washington State, there are a lot of incentives to promote solar installations, and we have a Governor, who is keenly interested in pushing clean energy alternatives, including Electric Vehicles.

Darmok | 18 maggio 2013

TM has answered the original question here:

http://www.teslamotors.com/goelectric#electricity

The S produces less CO2 everywhere according to TM's charts. If you happen to live in Idaho it's a whole lot less, in West Virginia less so. The good thing is that the S will continue to get cleaner as time passes. Not so for an ICE car.

We will soon be putting 8.32 kW of solar on the roof, which will take care of the S and most of the house. May have to get more when the X comes.

Brian H | 18 maggio 2013

Strange that the correlation between CO2 trends and temperature trends has been nil or negative for almost 2 decades. After the first few years of that, it was claimed it would take 15 years of projection fail to falsify the models. 17 years have now passed of no statistical linkage. The obvious conclusion is also the mathematically correct one. The models (GCMs) are junk.

However, the correlation between CO2 levels and agricultural and silvicultural production grows ever more robust. This was well on the way to resolving global food poverty before the biofuel-driven grain price spikes. (A brutal and sneaky way of achieving population reduction, I guess.)

rdalcanto | 18 maggio 2013

+1 Brian H.
Climate change (real or not) aside, we have a definite smog problem in the Salt Lake Valley, especially during the winter months when we have an inversion. I like the idea that my super fast MS will help clean up the air where I live.

Brian H | 18 maggio 2013

The locales with inversions like that are super territory for MS sales.