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Comment: Re:And how long does it take... (Score 1) 81

by Rei (#47727671) Attached to: How Does Tesla Build a Supercharger Charging Site?

As for my other issues with your post.

1. Actually time yourself going down the highway when you're on a long trip, from the moment you begin to decelerate to begin to get gas, to the moment you're back on the road up to highway speeds, and don't leave out the things people often due during stops long trips (why long trips? more in a second), including bathroom breaks, buying something at the convenience store, cleaning the windshield, heading over to a nearby restaurant to grab a bite to eat, whatever. Time a number of different stops on a long trip and average them out. You'll find they're a lot more than 5 minutes. EVs have all of that extra stuff too, mind you, but a lot of them can be done while charging, and even for the other stuff, you're adding a constant overhead, which reduces the ratio of the non-constant aspect (the actual filling itself).

2. Why constrained to long trips? Simple - because people don't stop at charging stations when they're not on long trips. It's pointless. You charge at home, and maybe when parked at other places like work or a mall if there happens to be a plug near you. It's a great inconvenience of gasoline cars which EVs don't have that one must regularly waste time at gas stations in their daily lives regardless of how long trips are. Overall gasoline car drivers waste a lot more time "filling up" than EV drivers. (and if you disagree and think the mere act of plugging and unplugging gives the edge to gasoline drivers somehow, then that still doesn't help with the wireless EV charging that's getting a lot of focus now, where you merely have to park and you start getting charge)

3. The page you linked for dimethyl ether said nothing (that I noticed) about generation from just electricity and, say, air/water. It did say that in the lab it can be made from cellulosic biomass (although it should be noted that no cellulosic fuel techs have thusfar worked out at a commercial scale). Let's just say you can do that, and that you get the 1000 gallons per acre-year reported for switchgrass.That's 0,93 liters per square meter-year. It's reported at 19,3 MJ per liter, so we have 18MJ per square meter per year. Let's say we lose 5% of this to distribution, and then burn it in a car running at a typical 20% average efficiency (peak is significantly higher, but peak isn't what matters). We have 3,4 MJ per square meter per year.

Now what if we ran EVs on solar panels on the same land? Let's say the solar farm is 50% covered with solar panels and gets a capacity factor (clouds, night, etc) of 20% and a cell efficiency of 20%. 1000W/m, so 20W/m electricity is produced on average. That's 20 joules per square meter per second, so 631 MJ per square meter per year. We reduce it by the average US grid efficiency of 92% and an average wall-to-wheels EV efficiency of 80% and we get 465 MJ per square meter per year. 136 times as land-efficient as the biofuel alternative

Now let's say we leave out all of these lossy bioprocesses behind and generate some sort of biofuel straight from electricity at a very unrealistic 80% efficiency (most processes for realistic fuels are way lower), plus the same generous 5% distribution losses, and that it's afforable. And let's say that they all burn their fuel at an impressive 40% efficiency (even fuel cells, while higher in peak efficiency, generally can't do that tank-to-wheels in real-world vehicle usage). Thus we get 192 MJ per square meter per year, 41% that of the EV. Are you really comfortable with plastering 2.4 times as much of the earth's surface with solar panels? Or 2.4 times more wind turbines, 2.4 times more dammed rivers, 2.4 times more nuclear power plants and uranium mining, etc? Is that, in your view, an ideal solution, even in this comparison highly biased in favor of fuels versus electricity?

Electricity is the universal energy currency, and we shouldn't be wasting it converting it between different forms needlessly. Not only does it mean a dramatically worse impact on the planet, it also means that even if your electricity to fuel conversion process is practically free in terms of consumables and capital costs (the reality generally being anything-but), that you have to pay many times more per kilometer that you drive, as you're (indirectly) consuming many times more electricity.

Comment: Re:And how long does it take... (Score 1) 81

by Rei (#47727513) Attached to: How Does Tesla Build a Supercharger Charging Site?

Now of course gas stations don't always have fully occupied pumps and that's the point, so that almost whenever you arrive, there's a free pump available.

That actually doesn't help your argument any. The longer it takes to fill up, the more you smooth out the random demand fluctuations.

Let's say the time per pump is 5 minutes and the time per charger is 30 minutes, so we have to build 6x more chargers to service the same number of vehicles (and that you have to build the charging stations more frequently due to the range). So we'll compare a 4 pump gas station with a 24 charger EV station. So let's say that we get the following rate of people arriving (picking some numbers at random):

1:00: 1
1:05: 0
1:10: 6
1:15: 7
1:20: 3
1:25: 0
1:30: 0
1:35: 2
1:40: 1
1:45: 8
1:50: 6
1:55: 0
2:00: 1

What happens in these scenarios? First, gasoline:

1:00: 1 pump in use
1:05: 0 pumps in use
1:10: 4 pumps in use, 2 people waiting
1:15: 4 pumps in use, 5 people waiting
1:20: 4 pumps in use, 4 people waiting
1:25: 4 pumps in use, 0 people waiting
1:30: 0 pumps in use
1:35: 2 pumps in use
1:40: 1 pump in use
1:45: 4 pumps in use, 4 people waiting
1:50: 4 pumps in use, 6 people waiting
1:55: 4 pumps in use, 2 people waiting
2:00: 3 pumps in use, 0 people waiting.

What about the charging station?

1:00: 1 charger in use
1:05: 1 chargers in use
1:10: 7 chargers in use
1:15: 14 chargers in use
1:20: 17 chargers in use
1:25: 17 chargers in use
1:30: 16 chargers in use
1:35: 18 chargers in use
1:40: 13 chargers in use
1:45: 14 chargers in use
1:50: 17 chargers in use
1:55: 17 chargers in use
2:00: 18 chargers in use

With the gas station, 23 people needed to wait, some of them for a rather long time. With the charging station, nobody needed to wait. Despite the fact that the charging is 1/6th the speed, that doesn't actually imply you need 6x more chargers. In the above example, we see that the gas station should have had 8 pumps while the charging station 18 chargers, or 2.25x more.

More on the other problems with your post in just a second - I just felt that this particular aspect deserved a whole post on its own.

Comment: Re:That's not quick? (Score 1) 81

by Rei (#47727425) Attached to: How Does Tesla Build a Supercharger Charging Site?

Not to mention that building a gas station takes a heck of a lot longer.

It's one thing I don't get about EV opponents. Not only are EVs supposed to not have any new inconveniences relative to gasoline vehicles, and not only do inconveniences that gasoline vehicles have that EVs don't have not count toward EVs, but EVs aren't even allow to have the inconveniences that gasoline vehicles have. It's always stuff like "EVs suck because it takes 11 days to build a fast charging station, but don't bother checking into how long it takes to build a gas station!" or "EVs suck because batteries are flammable (Ed: even though most EV battery types aren't particularly flammable), but don't bother asking about the flammability of gasoline!" or "EVs suck because batteries are heavy and bulky, but don't bother asking about the weight and size of internal combustion engines vs. electric motors!" or "EVs suck because batteries are toxic (Ed: Actually, most types nowadays have little toxicity), but don't bother asking about the toxicity of the several tonnes of gasoline the average driver puts into their car every year, their filling spills and fumes, their oil leaks, etc, and the massively dirty industry that produces all this!" Etc.

I don't get these people.

Comment: Re:Check your local fracking mixture (Score 1) 289

by drinkypoo (#47719349) Attached to: Scientists Baffled By Unknown Source of Ozone-Depleting Chemical

CCl4 is not soluble is water, and would not make hydrocarbons more mobile or more soluble. It would however, readily dissolve in hydrocarbon fluids

You mean like diesel fuel?

  where it would be difficult and expensive to separate.

The petroleum is going into a fractional distillation column. Its whole purpose is to perform this kind of separation. While the process might be difficult and expensive, it is a process which the petroleum will undergo anyway.

Comment: Re:Fire (Score 2, Interesting) 139

by Rei (#47718877) Attached to: How Argonne National Lab Will Make Electric Cars Cheaper

Nuh uh! There are also compressed air cars - they only explosively decompress upon tank failure! ;)

At least with batteries, flammability or explosiveness aren't a fundamental requirement of how you're trying to propel the vehicle, just an unfortunate side effect of some variants of the technology (even not all types of li-ions are flammable). There's lots of people who assume that flammability is a consequence of electrical energy density, but that's just not the case. The actual charge/discharge lithium batteries via intercalating into the anode or cathode is more an atomic-scale equivalent of compressing air into a tank, you're having little affect on the substrate flammabilities and you're not even changing their chemical bonding, you're just cramming lithium ions into the space between their atoms. The flammabilty of some types comes from side effects, such as flammable electrolytes or membrane failures leading to lithium metal plating out; these aren't a fundamental aspect of the energy storage process.

Now, li-air, that involves an actual lithium metal electrode, and that is fundamentally flammable. Of course, so is gasoline. I have no doubt that they can reduce fire risks on li-air cells and keep them properly contained to prevent failure propagations. My bigger issues with li-air are its terrible efficiency, lifespan, and cost. I'm certain the latter would come down, and I expect that they can improve the lifespan, but I'm a bit uneasy about how much they can improve its efficiency. Right now, they're as inefficient as a fuel cell. : Who wants to waste three times as much power per mile as is necessary?

Comment: Re:non sequitur? (Score 1) 139

by Rei (#47718833) Attached to: How Argonne National Lab Will Make Electric Cars Cheaper

It is a non-sequiteur. The energy density of a li-ion battery doesn't even approach the theoretical maximum storage for the element lithium shifting between ionization states. That's hardly the only way this article is terrible, mind you. My head hurt every time they said the word "efficiency", it's like they were using it to mean everything possible except for actual efficiency. And if I read it right - who knows, the article is such a total mess - the researcher isn't talking about reducing battery cost, but increasing longevity. But maybe that was mangled too.

Comment: Re:Sigh (Score 0) 713

by drinkypoo (#47712321) Attached to: News Aggregator Fark Adds Misogyny Ban

I'm a different AC, but I think you made his point. "You are unlikely to see another human being for days" in those hundreds (is it really thousands?) of square miles precisely "because practically nobody lives there or will ever go there."

Yes, I did. I also made the point that his point is irrelevant. We're talking about a minuscule proportion of the population. It's not that their wishes should be ignored, exactly; I believe that creation and protection of rights is a valid pursuit. But "It is virtually impossible for people to not run into each other," is still a completely valid statement. Virtually nobody lives in a situation where they won't see other people. Someone always turns up, if only for a sample of something. Maybe you. And frankly, there really is nowhere like you describe in the USA, either. There's a number of large private ranches of thousands of acres; those guys often have stories of trespassers. And a large portion of the country is owned by the Bureau of Land Management, which regularly portions big sections of it off for military and police training, and which patrols it regularly and investigates fires, target shooters in hunting season and hunters out of season, and the like. Then there's the big state parks, which are full of state park rangers on horses and in Jeep of various types, and IIRC Chevy trucks. They manage to cover quite a bit of ground.

So yes, it is virtually impossible to not run into people. You have to go to significant lengths, especially since people are actually looking for people in those supposedly empty places. Sure, you could get lost in the asscrack of some mountain somewhere, but even getting there is beyond the reach of many people. Only a tiny slice of the world population even lives away from someplace where you can avoid seeing people for more than a few minutes at a time.

Comment: Re:Ready in 30 years (Score 5, Interesting) 295

by Rei (#47708629) Attached to: If Fusion Is the Answer, We Need To Do It Quickly

You're arguing against Tokamak fusion. But what about, say, HiPER? Looks to me to be a much more comercializeable approach, yet it's still "mainstream" fusion, just a slight variant on inertial confinement ala NIF to make it much smaller / cheaper / easier to have a high repeat rate (smaller compression pulse + heating pulse rather than a NIF-style super-massive compression pulse). The only really unstudied physics aspect is how the heating pulse will interact with the highly compressed matter; NIF and pals have pretty much worked out the details of how laser compression works out. Beyond this, pretty much everything else is just engineering challenges for commercialization, such as high repeat rate lasers, high-rate hohlraum injection and targeting, etc.

I've often thought (different topic) about how one can get half or more of fusion's advantages via fission if you change the game around a bit. Fusion is promoted on being passively safe (it's very hard to keep the reaction *going*, it really wants to stop at all times), it leads to abundant fuel supplies, and there's little radioactive waste (no long-term waste). But what about subcritical fission reactors? Aka, a natural uranium or thorium fuel target being bombarded with a spallation neutron source. Without the spallation neutrons, there's just not enough neutrons for the reaction, so the second the beam gets shut off, the reactor shuts down, regardless of what else is going on. It'd be a fast reactor, aka a breeder, aka, your available fuel supplies increase by orders of magnitude. And your long-term waste would be much, much less in a well-designed reactor. Spallation neutron sources have long been proposed as a way to eliminate long-lived nuclear waste by transmuting it into shorter-lived elements.

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