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|User Info||ROFL! Buy A Tesla Electric Car? No F*#ing Way; entered at 2012-02-26 11:05:31|
Less than 24% of my utility's power comes from coal but even if it was 100% an EV still pollutes less than an ICE because it doesn't waste over 40% of its energy as heat. Also, you have to remember that your gasoline has to be found, drilled, pumped, shipped halfway around the world (using bunker fuel), refined, trucked to your gas station, and then pumped into your car.
Wrong wrong wrong wrong.
If the electricity comes from a combined-cycle plant (e.g. natural gas) it is likely no more than 50-55% efficient thermally. A nuclear plant is around 30% thermally efficient because it must use Rankine-cycle turbines. A coal plant is somewhere in the middle for newer designs and close to the nuclear plant for older ones.
So we'll give you 50% -- to start with.
Then there are losses in the transmission lines, transformers and such, probably totaling 10% by the time the energy reaches your house. So now we've got 45% of the original power left (50% * .1 = .05 of the original is lost)
That's at the wall. Now your charger has an inefficiency too. Most GOOD chargers are around 80-85% efficient. The battery pack ITSELF has losses during charging as well; a good part of the energy goes into heat. This is a highly-variable number - when the battery is near flat up to about 80% full charging is quite efficient (~80-85%) but the last 20% is a different matter; efficiencies there are closer to 50%. We'll give you the 80% because I'm feeling generous and prefer to overstate advantages to make my point (it makes the numbers look better for you.)
So now we're at 32.5% and the power is in the battery.
But the motor and controller has inefficiency too. The best electric motors are approximately 80% efficient including their controller losses. You can do better under certain very-specific circumstances, but a car isn't one of them since it must operate at variable speeds and loads. We'll use 80%.
You now have 26% of the energy in the fuel at the power plant delivered to the wheels.
To put this in perspective today's best ICE's deliver around 25-30% efficiency end-to-end, including the drive line losses (in the ~5% range.)
So on a BTU-delivered basis, all you did was shift where the pollution takes place. You spent $100,000 with a $40,000 battery pack replacement expense on a given time cycle (incidentally, lithium batteries tend to last about ~2-3 years from manufacturing date, irrespective of use, before they are down about 20-25% from their manufactured capacity -- that's probably about when you'll notice, and in another year or so you'll be buying a new one.) In addition you sucked off the government teat, so you didn't pay the entire cost of either the vehicle or the battery pack production.
Then there's the lithium itself -- it's a rare-earth element and is quite intrusive to get out of the ground. It is naturally-occurring but the amounts are in the tens to hundreds of ppm range, which means you're digging up a ****load of rock to get a modest amount of material. Your EREOI calculations "conveniently" ignore this, but that is dishonest, as the energy required to produce the materials that go into the battery is a big part of the reason the battery pack costs $40,000. To be fair in your comparison you must impute that $40,000 over every mile you drive on the pack; if it lasts 60,000 miles then you have a roughly 66 cent/mile imputed energy cost in the battery. Put a different way there's 400 barrels of oil in the battery (nearly 17,000 gallons!) that are depleted as you drive the car.
The Tesla may be a nice car, and I'm sure it's damn fun to drive, but in terms of energy efficiency and "green-ness" you're a fool if you bought it for that reason. End-to-end it is no better than an ICE in terms of energy efficiency and since most of the electricity is generated in this country from non-nuclear sources you're still burning fossil fuels -- it just happens anywhere from a dozen to a few hundred miles from where your car is.
I can afford a Tesla but I refuse to buy one, as my Jetta diesel is more efficient on an end-to-end basis, it is vastly more practical (it will haul far more than the Tesla will), it has a 750 mile range on one tank of fuel, it can be refilled in under 5 minutes and it can run on any source of diesel now or in the future. This includes conventional "from the ground" petroleum, CTL (if we ever get our heads out of our asses and build thorium fueled MSRs, using the coal as a feedstock for CTL plant instead of burning it directly) or if available vegetable and animal oil processed into ASTM-compliant diesel using methanol and lye, with much of the process chemicals involved being recoverable.