History, Politics And Current Affairs

Belushi TD wrote: ↑Fri Nov 03, 2023 6:23 pm What I'm looking for is info as to when you would actually have to replace the engine vs replacing the battery.

Not sure you're going to find that for either propulsion type. Both will probably be "on condition" rather than "at X miles" and depend greatly on usage pattern, care, and even manufacturing variability. An engine may run fine for a long time with proper lubrication and care, and short of a catastrophic failure may just slowly lose compression and/or start burning oil. An EV battery is similar; short of physical damage or cells randomly going bad, the degradation is gradual and depends on charging habits, environment, etc. and that becomes a matter of when it's lost enough range or charging speed that it no longer meets your needs.

Barring damage or catastrophic failure, most EVs won't need replacement batteries until they're the equivalent of that clapped-out Accord that's on its fourth or fifth owner, with faded clearcoat, stained seats, CEL on, a bit of a shake, and on which new tires would double the value. They might only have two thirds of their original range by that point but for high school/college kids, or as a beater commuter, they'll serve just fine. But that assumes something else doesn't kill them first (e.g. an accident, rust, or flood damage).

There is nothing quite like a row of plug in chargers at a parking lot being supported by a gas powered generator nearby....

rtoldman wrote: ↑Fri Nov 03, 2023 8:22 pm There is nothing quite like a row of plug in chargers at a parking lot being supported by a gas powered generator nearby....

That’s an infrastructure/engineering problem.

As long as the politicians don’t get in the way (a big if), those are solvable.

And, as PDF has pointed out in other threads, using the petroleum in a more efficient generator than an internal combustion engine may be an improvement all around through the efficiency gains.

Belushi, I have a suspicion that most vehicles are scrapped with the original engines in them. Having owned a few 20 yo cars, I'd have to say the breathless spruiking of the longevity of BEVs makes me laugh. Unless they use Mercedes 1990 quality seat material and unobtanium plastic for the interiors (they don't), after 40 years they will look horrible on average, even if the battery is still 80%.

Johnnie Lyle wrote: ↑Fri Nov 03, 2023 11:21 pm

rtoldman wrote: ↑Fri Nov 03, 2023 8:22 pm There is nothing quite like a row of plug in chargers at a parking lot being supported by a gas powered generator nearby....

That’s an infrastructure/engineering problem.

As long as the politicians don’t get in the way (a big if), those are solvable.

And, as PDF has pointed out in other threads, using the petroleum in a more efficient generator than an internal combustion engine may be an improvement all around through the efficiency gains.

But is it more efficient, though?

It goes from creating rotational energy to electricity (which in some cases gets sent to California from as far as Arkansas) to charge a battery to become electricity to become rotational energy.

If you believe this study, https://www.msn.com/en-us/autos/news/st ... 20gasoline.

Study Reveals Electric Vehicle Fueling Is Actually Equivalent to $17.33 per Gallon

Poohbah wrote: ↑Sat Nov 04, 2023 1:10 am

Johnnie Lyle wrote: ↑Fri Nov 03, 2023 11:21 pm

rtoldman wrote: ↑Fri Nov 03, 2023 8:22 pm There is nothing quite like a row of plug in chargers at a parking lot being supported by a gas powered generator nearby....

That’s an infrastructure/engineering problem.

As long as the politicians don’t get in the way (a big if), those are solvable.

And, as PDF has pointed out in other threads, using the petroleum in a more efficient generator than an internal combustion engine may be an improvement all around through the efficiency gains.

But is it more efficient, though?

It goes from creating rotational energy to electricity (which in some cases gets sent to California from as far as Arkansas) to charge a battery to become electricity to become rotational energy.

PDF has some expertise in this and IIRC has posted estimates of the increase.

Poohbah wrote: ↑Sat Nov 04, 2023 1:10 amIt goes from creating rotational energy to electricity (which in some cases gets sent to California from as far as Arkansas) to charge a battery to become electricity to become rotational energy.

Johnnie Lyle wrote: ↑Sat Nov 04, 2023 3:50 amPDF has some expertise in this and IIRC has posted estimates of the increase.

There's a lot of "it depends" in here, but overall electrification tends to be pretty efficient:

• Converting from fuel to rotational energy in a car engine is pretty inefficient - at the design operating point (wide open throttle, low-ish engine speed) they're achieving about 35% of the energy in the fuel being converted into mechanical energy. Away from this design point, they suffer pretty badly: 20% seems to be a decent average estimate, but obviously when say idling it's 0% so it depends a lot on the driving you do.
• A combined-cycle gas turbine power station (basically a jet engine with a boiler and steam turbine on the back to recover the heat in the exhaust) will achieve 60% thermal efficiency all day long, including generation losses.
• UK estimates for power transmission losses are 1.7% on the high voltage network and 5-8% on the local network. Given that we happily ship gasoline around then UK-esque losses are probably more realistic than assuming all the electricity comes from Arkansas - call it 10% losses to make the maths easier.
• Electric cars have both published EPA cycle efficiencies and real-world values people share. Average is 0.3 kWh/mile

So working backwards:

1. Car consumes 0.3 kWh/mile.
2. 10% losses in transmission network -> 0.33 kWh/mile
3. 40% losses in the power station -> 0.56 kWh/mile

Lower calorific value of Octane (gasoline) is 44.4 MJ/kg (12.3 kWh/kg) so 1 kg of gasoline should provide enough energy for 22 miles.
1 US gallon of gasoline is just over 6 lbs (3.79 litres at ~0.75 kg/litre - ethanol is lighter and I'm assuming pure Octane here to make the maths easier). That means 2.84 kg/US Gallon and so 62.5 mpg. That's far better than almost all ICE cars manage, but not a panacea.

So amusingly if you charge a Tesla from a diesel generator (~40% efficiency) and it spends most of it's time sitting in traffic, that's still more efficient than burning it directly in a car.

jemhouston wrote: ↑Sat Nov 04, 2023 1:20 am If you believe this study, https://www.msn.com/en-us/autos/news/st ... 20gasoline.

Study Reveals Electric Vehicle Fueling Is Actually Equivalent to $17.33 per Gallon

Full document is at https://www.texaspolicy.com/wp-content/ ... tIsaac.pdf
I'd seen the graphs, laughed at them, but couldn't find the original - thanks. That's an interesting mix of talking about the way subsidies distort a market and adding up costs that don't exist in the real world. A good example: In the real world, people overwhelmingly charge their EVs overnight at home when demand on the grid is otherwise low (this can actually help a utility since it means they don't have to switch off plant overnight adding wear and tear to it). Their calculation assumes that the car is always charged at the point in the billing cycle when demand is at a maximum. It looks suspiciously like they've done this a couple of times, although the way the report is written it's probably impossible to reverse-engineer their calculations.