I'm going to venture that it's not even a rounding error.

In fact, in places it will likely have increased the CO2 emissions, again rounding error figures, due to the electricity generation mix and associated losses with generating that electricity (30-60% efficiency), plus transport losses (0.5 - 10%), plus charging loses, plus the efficiency of the motor itself.

The internal combustion engine in a car is around 20% efficiency while a coal power plant is around 55%. Gasoline powered drivetrains are also fairly inefficient leading to around 16% "tank to wheel" efficiency. Electric motors are about 90% efficient. An electric car is making more efficient use of the energy. It's also centralizing the source of the pollution rather than having to try to deal with it in every car on the road.

The idea that electric vehicles are "dirty" because of electricity produced from coal is now widely viewed as a myth [1]. The electric grid in the US (and worldwide [3]) is consistently and rapidly moving away from coal, which increases the "clean" factor of EVs over time [2].

[1] https://greentransportation.info/energy-transportation/evs-n...

[2] https://electrek.co/2017/06/05/electric-cars-cleaner-than-ga...

[3] https://cleantechnica.com/2017/05/16/coal-use-china-india-li...

A coal power plant can reach up to ~60% if coupled with steam turbines, otherwise it's ~30%.

Petrol cars can do a lot better than 20%

There is a study, link below, showing what the subsidy should be for electric cars and in a lot of places in the US the subsidy should be negative.

Granted things might've changed since then, but probably not to overturn the gist of it, which is the point I'm making. In places, EV cars are not the solution.

Quite happy to be proven wrong, at the of the day I've only got a passing interest on the topic so I'm not exactly 100% up to speed with any new studies, etc ...

https://www.citylab.com/environment/2015/06/where-electric-v...

City Lab has debunked that notion twice [1, 2].

"[I]t’s important to realize that the situation reflected in this data represents the past, not the present. States across the country are rapidly cleaning up their grids, thanks to cap-and-trade programs, investments in renewable energy, tightened air quality standards, and more coal plants put to sleep." [2]

"Here’s the cool thing about electric vehicles in the U.S. right now: In many areas, the longer you own one, the cleaner it gets." [1]

[1] https://www.citylab.com/life/2017/06/electric-vehicles-are-c...

[2] https://www.citylab.com/transportation/2016/12/the-surprisin...

If Tesla was actively working to prop up our fossil fuel based electricity grid, than I think this would be a fair argument. But they are not. Instead they are actively engaged in the solar+storage market, and they have stated multiple times that they believe the grid can be 100% renewable.

In the short term, yes, folks will need to rely on existing fossil fuel technologies to build factories, transport materials, and power the grid. That is because there is no other economically viable option. To expect the entire clean energy industry to bootstrap itself only using clean energy is a fallacy. In 20-30 years when the grid is more green and clean transportation is widely available, then arguments like these would be valid.

I'm just pointing out that both effects are, at this point in time, just rounding errors

> what has been the net reduction of CO2 usage

I think it is too late and too optimistic to hope for CO2 reduction.

The world only aims for a moderate decrease in CO2 rate of increase.

Not eating meat is much more efective to saving the planet than buying a Tesla.

http://www.businessinsider.com/is-eating-meat-bad-environmen...

Well of course, doing almost anything is much more effective than buying a Tesla. More cars are not planet saving at all, and it is delusional to think so.

That is a poorly phrased question to consider the value of the investment. Specifically, 'to date' is not appropriate for an investment. It is like looking at a half built widget factory and asking what is the net reduction in human labour for all widgets because of the factory, to date?

What is the net change in CO2 usage that results from the investments Tesla has made?

This is literally the point of the Model 3. They need 500,000+ cars on the road in order to move the dial on petroleum dependence. Other car makers need to copy Tesla because electric cars are better and cheaper to own, etc. We're not at that tipping point yet. A lot hinges on the Model 3 being a success.

Tesla has made fewer than 190000 cars total, to date. Over 77 million cars were sold worldwide last year. And that's just cars.

With more EVs, we won't breathe so much car exhaust in cities. This is important.

A tiny reduction in the rate of increase of CO2 emissions. Every bit helps, but it's not saving the planet.