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Comment: Re:That's not quick? (Score 1) 166

by Rei (#47727763) Attached to: How Does Tesla Build a Supercharger Charging Site?

I'm assuming that's not a 30 minute Tesla fast charge station, since that's only 50kW.

The two issues I have the most interest in are 1) whether they use some sort of battery buffer to balance loads on the grid connects (otherwise I think the utility company won't be very happy with the unpredictable megawatt drains ;) But maybe the utility company is handling balancing on their side), and 2) how cooling on the charger is handled. Just simple resistance calcs show that once you get to really high power chargers, you have to cool the wire to the car to keep its heating to an acceptable level at an acceptable cable mass, so I'm curious how they handle that. Personally I've felt that high power rapid chargers should provide coolant for the car itself as well via the charge port. Why should the car have to haul around such a major cooling system and coolant reservoir when the charger already has to have it and has to cool its cable all the way up to the car? However, I've never heard of anyone actually implementing such an approach.

Comment: Re:And how long does it take... (Score 1) 166

by Rei (#47727723) Attached to: How Does Tesla Build a Supercharger Charging Site?

Not to mention that they can be a loss leader. 250Wh/mi at a commercial power rate of $0.08/kWh is two cents per mile. So a 150 mile charge is $3. There are lots of businesses that would pay $3 to keep a potential customer there for half an hour, esp. if said potential customer will likely feel appreciate and that "he owes them". Charging can also be "free with purchase", and businesses can limit the charge rate if $3 for a half hour chage is too steep of a loss leader for them.

All this ignoring the green cred / pr advantage of offering said charging in the first place.

Comment: Re:And how long does it take... (Score 1) 166

by Rei (#47727703) Attached to: How Does Tesla Build a Supercharger Charging Site?

(in fact, that's another big problem with EVs in urban areas without private parking, but it's besides the point subject here).

It's also irrelevant. Even if everyone was suddenly sold on the concept of EVs, it would take decades first to be able to ramp up production to match that of gasoline cars, and then to phase out all of the gasoline cars on the road. It should be obvious, yet someone seems to pass right over EV opponents, that the first adopters are going to be those for whom it best suits their situation, and that it will only slowly migrate - over decades - down to an increasingly broad section of the population.

If humans are incapable of recognizing and responding to a slow, patently-obvious, decades-long-process by merely building power outlets, then the species unworthy of the term sentient.

(And just an extra FYI: The majority of people, in my experience, who live in urban areas without private parking take public transportation and don't own any car... but maybe you're referring to some other situation I'm not familiar with).

Comment: Re:And how long does it take... (Score 3, Insightful) 166

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 3, Informative) 166

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 5, Insightful) 166

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:Fire (Score 2, Interesting) 142

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) 142

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:Let us redefine "progress" (Score 3, Insightful) 105

by meta-monkey (#47713411) Attached to: World's First 3D Printed Estate Coming To New York

About half the cost of building a house is labor. They say in the article that aside from the guy running the printer, there are no labor costs here. I don't believe that's necessarily true, because there's still got to be somebody wiring the electrical and installing windows, but regardless, it could dramatically decrease the cost of building a home. It could also be a lot faster. Imagine that, just rolling up two trucks to a construction site: one carrying the printer, another with all the crushed rock, setting it up and letting it go. A week later, a finished home ready for a family to move into at half the cost. That brings the dream of home ownership within the reach of a lot of people who wouldn't have been able to afford it before. We live in exciting times.

Comment: Re:We need ...... Solar? (Score 1) 300

by meta-monkey (#47712567) Attached to: If Fusion Is the Answer, We Need To Do It Quickly

We are going to be stuck in this era for a very long time, unless someone outside of the corrupt energy group can step in and start the ball rolling.

That's what Elon Musk is doing with SolarCity. Combine his cheap solar panels with his cheap batteries from the gigafactory they're building and you've got your fantasy.

It is much easier to suggest solutions when you know nothing about the problem.

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