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The embedded energy of a second vehicle won't be made up for in a 10-20mpg improvement, except in very very niche cases. The lifetime amount of fuel/electricit

The embedded energy of a second vehicle won't be made up for in a 10-20mpg improvement, except in very very niche cases. The lifetime amount of fuel/electricity used by a vehicle generally accounts for only half of the total energy. The other half is in it's manufacturing and disposal/recycling. And there's additional lost efficiency than just the mileage, because you're using twice the embedded energy and presumably aren't doubling the amount of driving you're doing. Maybe rentals or sharing schemes work in some cases, but they present their own inefficiencies, like less than perfect allocation, and transferring vehicles back and forth for each switch. But for the majority of cases, it's much more environmentally friendly to own one single vehicle that meets all of your needs, even if it's relatively inefficient. The most efficient vehicle for any particular person is usually the one that's already been built. (Which is why cash for clunkers was actually a bailout with negative environmental impacts, despite its branding of improved efficiency.)

freemint 5y ago
Why not? both cars will last roughly twice as long. Meaning if you can live with owning your cars twice as long there should be no extra embedded energy needed. (And one of the cars could even be an electric one you charge using ample solar powet
- beerandt 5y ago
  Because you're sitting on that embedded energy, at the opportunity cost of someone else not being able to use it. So it's additional supply of both material and embedded energy that otherwise could go to someone else, or wouldn't need to be spent until you were sending you old car off to be salvaged. There's a time value to it as well, just like with amortized financials. Think of it this way: if everyone used that strategy, we'd have twice as big of a vehicle market, requiring twice as much material and energy. Even if you expect each vehicle to last twice as long, it all has to be paid for with capital costs up front. Both your cash out of pocket, as well as manufacturing capacity and energy/resource extraction. You might get effective use efficiency of 50% for twice as long, but the overall cost in dollars, energy, and emissions is much greater because of amortization.

freemint 5y ago

Why not? both cars will last roughly twice as long. Meaning if you can live with owning your cars twice as long there should be no extra embedded energy needed. (And one of the cars could even be an electric one you charge using ample solar powet

beerandt 5y ago
Because you're sitting on that embedded energy, at the opportunity cost of someone else not being able to use it. So it's additional supply of both material and embedded energy that otherwise could go to someone else, or wouldn't need to be spent until you were sending you old car off to be salvaged. There's a time value to it as well, just like with amortized financials. Think of it this way: if everyone used that strategy, we'd have twice as big of a vehicle market, requiring twice as much material and energy. Even if you expect each vehicle to last twice as long, it all has to be paid for with capital costs up front. Both your cash out of pocket, as well as manufacturing capacity and energy/resource extraction. You might get effective use efficiency of 50% for twice as long, but the overall cost in dollars, energy, and emissions is much greater because of amortization.