How much does air pollution cost the U.S.?

Re:How much does air pollution cost the U.S.? by Robotbeat on Tuesday October 08, 2019 @05:29PM (#21197473)

That was me. :) The assumption was that if you have a particularly high emissions source of most of your calories (like virtually all meat especially ruminants or, interestingly, fresh fruit and not much grains, sugars, or oils), then biking could be worse. But it's just to point out how efficient electric cars can be and how diet can start to play a bigger role.

I wasn't super serious about the comparison. :) (And e-bikes are much, much more efficient than an electric car... if they last long enough).

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by NickM on Tuesday October 08, 2019 @07:17PM (#21198337)

Oh my gosh, wow, what a strange coincidence! I totally did not notice that I was replying to the same person who wrote that post. Small world :)

And yeah, I wasn't necessarily reading too much into the comparison since of course there are so many different factors that can tilt the numbers different ways, but I found it very thought-provoking regardless. Great point about e-bikes too.

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by gpm on Tuesday October 08, 2019 @05:49PM (#21197663)

> (And e-bikes are much, much more efficient than an electric car... if they last long enough).

Would this hold true for e-motorcycles as well, or are we really saying "slow moving vehicles are much more efficient than fast moving vehicles"?

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by Obi_Juan_Kenobi on Tuesday October 08, 2019 @06:32PM (#21198004)

In practical terms, while ebikes may have a slow top speed, they move through congested areas much more quickly, so for trip-substitution purposes, the efficiency is apples-to-apples. More direct routes at steady speeds is a real benefit to ebikes.

Much of the efficiency benefit is from the lower drag due to lower speeds, but if the purposed served is comparable, then it's valid. Just depends on what you're looking at.

FWIW, even at 30mph, ebikes are over an order of magnitude more efficient than a Model 3 at 70mph (<28 vs. 280 WH/mile). Zero (electric motorcycle) states 180 WH/mile at 70mph.

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by Robotbeat on Tuesday October 08, 2019 @08:47PM (#21198851)

Agreed. That fits with my info. Pack a Model 3 with 5 people and go 30mph, and the efficiency per person is about the same as an ebike.

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by consp on Wednesday October 09, 2019 @04:05AM (#21201079)

If you go steady speed the lower Cd and higher efficiency of the drivetrain might actually make it more efficient than the bike.

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by Robotbeat on Tuesday October 08, 2019 @05:53PM (#21197696)

I think in this case it's small vehicles (low mass, low aerodynamic cross section) that are more efficient. Electric cars would only be marginally more efficient (~50% better) at low speeds due to rolling resistance (whose coefficient is basically constant with respect to speed) and parasitic loss from the computer, infotainment, climate control, etc.

Per seat, electric cars are generally much better than electric motorcycles and about half as good as much slower e-bikes (although if ridden at the same speed, almost as good).

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by Gibbon1 on Tuesday October 08, 2019 @07:39PM (#21198471)

Two things I can think of is gasoline powered motorcycles aren't that much more efficient than a Prius. And a Prius seats four. I suspect the same applies when you switch to electric[1].

The other one is the injuries per mile are much higher for motorcycles. One aught to account for that as well.

Side issue: Motorcycles are terrible from an emissions standpoint. Though of course an e-motorcycle would be better.

[1] Scaling factor vs size is highly positive.

[ Parent | on HN ]

Re:How much does air pollution cost the U.S.? by Balero on Tuesday October 08, 2019 @05:54PM (#21197705)

It takes less energy to accelerate less mass. So the lighter your vehicle the more fuel efficient it is for the same speed/acceleration.

Going a lower speed is also more fuel efficient (depending on the engine, but it takes less energy) as you have a lower air/road resistance.

[ Parent | on HN ]