Alternative Fuels Discussion Thread

[homeforsummer]

My understanding is that this is primarily a weight issue:

http://jalopnik.com/electric-and-hybrid-cars-might-produce-as-many-toxins-a-1775747577

So while regenerative braking might save on brake dust, the added weight of batteries and the use of low rolling resistance tires can result in offsetting non-combustion emissions. Of course, that's not comparing a Prius to a Suburban. There's another element too, which is which non-combustion emissions are the most harmful. Tires? Brakes? Road dust?

I remember reading that article a while back, but didn't really investigate it further.

My first question would be whether it takes into account that the low-rolling resistance tyres typically used on EVs tend to be a harder compound than typical all-seasons, which I'd expect to have an impact on how much particulate matter they shed (the Jalopnik writer muses that the particles they break down into are more dust-like, though I'd be interested to see data either way). The graph seems to show tyre wear as being higher, presumably calculated based on extra weight, but without buying the study to dig through I can't see whether they assume all use the same tyres.

I expect driving style has some bearing on it too - i.e. driving slower and less aggressively (as you'd expect the average EV driver to do so) would result in less tyre and road wear. I can only speak for myself, but whenever I drive an EV/hybrid/whatever I tend to drive a lot more smoothly than I do a conventional vehicle, and whenever I see a Leaf or Zoe on the motorway it's always doing ten under...

The other thing I'd be interested in seeing is how the quoted study and the one I mentioned earlier came to their proportions for particulate matter. The difference in year might have something to do with it (2010 vs. 2016) or perhaps the location (London traffic vs. general research), but one study quoting that 50% of PM10s come from brake dust alone and another that shows a much smaller fraction of non-exhaust PM10 (which is apparently 90% of all PM10 emissions) is quite a discrepancy. Probably a mix of things - London traffic (much of which is diesel and therefore produces higher particulate matter anyway) tends to crawl along slowly using fuel inefficiently, and involves a lot of braking - two things I'd expect to skew results in an EV's favour, since it's producing no exhaust particulates and probably using brakes a lot less.

As ever, it's one of those things that clearly needs a lot more research in controlled tests. I wonder how long it'll be until non-exhaust emissions start becoming regulated as exhaust emissions have.

 

[Danoff]

I wonder how long it'll be until non-exhaust emissions start becoming regulated as exhaust emissions have.

We may be headed that direction, and a decent argument can be made for it. I'm a little concerned though, because those non-exhaust emissions are largely coming from safety equipment on the vehicle.

 

[homeforsummer]

We may be headed that direction, and a decent argument can be made for it. I'm a little concerned though, because those non-exhaust emissions are largely coming from safety equipment on the vehicle.

Indeed. Tyres and brakes tend to be rather important in that respect.

There may be more wiggle room with road surfaces, which are obviously designed to offer grip but also tend to be laid down by the lowest bidder and therefore presumably have room for improvement. But then that comes down to whether anyone is willing to pay for more resilient, better-surfaced roads.

The elephant in the room is road transport full stop in densely populated areas, if particulate matter is otherwise unavoidable. It'd depend on the individual city - you probably couldn't remove road transportation from say, Los Angeles, but it'd be much easier to do so viably in London. No need to regulate particles from engines, brakes, tyres and roads if you simply remove the traffic altogether.

 

[kikie]

Reviving this thread because of a youtube clip I just saw.

 

[homeforsummer]

Good vid (that's a good channel in general). Explains the issues with both hydrogen and battery electric vehicles very well - and articulates what I've been saying for years, which is that hydrogen is too inefficient a technology to be as viable as batteries on the same sort of scale.

I can certainly see a value for fuel cell cars for larger, longer-range vehicles, where the refuelling time and the potential range could make a big difference (I've driven the Honda Clarity and it was a unique pleasure driving an EV that I knew could be filled up in a matter of minutes), but I suspect most road transport will end up using batteries.

 

[Danoff]

I can certainly see a value for fuel cell cars for larger, longer-range vehicles, where the refuelling time and the potential range could make a big difference (I've driven the Honda Clarity and it was a unique pleasure driving an EV that I knew could be filled up in a matter of minutes), but I suspect most road transport will end up using batteries.

It seems like using good old fashioned gasoline for that would be at least as effective. The gas-powered generator charging electric batteries in the car seems like a win until battery technology can close the gap. Hydrogen seems like an unnecessary complication.

 

[homeforsummer]

It seems like using good old fashioned gasoline for that would be at least as effective. The gas-powered generator charging electric batteries in the car seems like a win until battery technology can close the gap. Hydrogen seems like an unnecessary complication.

True. Particularly as combustion engines continue to get more efficient, and companies are producing more aerodynamic vehicles. I'm thinking more if the economies of various fuels change to such an extent that combustion is no longer viable, but certainly for the time being hydrogen just doesn't make a great deal of sense.

 

[Eunos_Cosmo]

It will never happen, but for me it would be very awesome to use NASA's Krusty reactor as an onboard power supply unit for electric cars. Figure 1-paper tower roll sized chunk of uranium per 10kw. So for a viable small car, you'd need probably 6 of them. We're not talking scorched-earth performance here, but imagine, practically speaking, never needing to refuel or recharge.

 

[Danoff]

It will never happen, but for me it would be very awesome to use NASA's Krusty reactor as an onboard power supply unit for electric cars. Figure 1-paper tower roll sized chunk of uranium per 10kw. So for a viable small car, you'd need probably 6 of them. We're not talking scorched-earth performance here, but imagine, practically speaking, never needing to refuel or recharge.

Imagine the car accident mess.

I imagine that could either be made to perform better on earth. There are a lot of hidden costs for engineering something to operate in space.

In a way though, lots of electric cars are ultimately powered by nuclear reactors.

 

[Eunos_Cosmo]

Imagine the car accident mess.

I imagine that could either be made to perform better on earth. There are a lot of hidden costs for engineering something to operate in space.

In a way though, lots of electric cars are ultimately powered by nuclear reactors.

Its passively cooled and intrinsically safe. Chances of a meltdown are extremely low. Radiation might be a slight issue. Pretty sure Krusty runs cooler than a rotary engine's exhaust primaries. First responders should wear oven mitts.

I want to open my hood and see this:

Its a shame that nuclear research has been so maligned. There's a lot of cool tech out there in development that will probably never see the light of day in real world applications.