function calls, classes, etc which use letters that are not in the English character set.:P No translation needed, just let me type them without getting spammed with syntax errors like happens in most programming languages. And for that matter, I'd be happy if I could even *type* a thorn here on Slashdot without having it magically disappear.
*Someone* should be evaluating teachers. Do you want it to be someone who knows what they're talking about or someone who doesn't?
I know, I know, it's happening during the Obama administration, so it must be a bad idea. But can we get past that for just a second and think about this objectively? Should we be evaluating with people who don't know a darn thing about STEM subjects? Or maybe just with standardized tests? So is it okay if Mrs. Johnson teaches her students that we're all inhabited by body-thetans so long as her students can pass a state or national standards test?
Corps members will lead ongoing professional meetings and teacher development activities; assist their schools and school districts in evaluating and providing feedback to other teachers; and validate and disseminate effective practices to improve STEM instruction.
Uh oh. People with scientific backgrounds, evaluating my older sister, a grade-school teacher who thinks the moon landing was faked? That could spell trouble for her;)
An interesting side effect of this scheme, whether by design or by accident, should be to help push creationism out of the classroom. People with degrees in scientific fields are far less likely to be creationist than the general public. If these people are evaluating other teachers, I can't help but think that'll have an influence. Even when teachers aren't supposed to be teaching it, I remember having a number that tried to work it in subtly. I remember a science teacher who, when we were covering the dating of rocks as discussed in the textbook, added in something like, "but you can't trust the numbers on how old rocks are because if you take different samples from the same rock you can get really different ages".
How exactly is a paper saying that algal oil is only profitable "under the optimistic case" at $100/barrel, when tar sands oil is profitable at $15-30 a barrel, shale not much more, and electricity is one-third the cost of even today's gasoline, helping your case any?
And as I have stated repeatedly, you pump the water in.
Desert: No water to pump in. That's why it's a desert. Why is this a hard concept? The deserts that do have rivers going through them which could be tapped typically have those rivers way-overtapped already.
You can use saltwater, which there is no shortage of.
Assuming it's a coastal desert, which most aren't, that's a nonstarter, because you can't just randomly pick and choose a water mineral mix and have it work with these optimized algal species. They're optimized for very specific (typically freshwater) conditions. And the water has to be pure - no "gunk", no bacteria, not even viruses. Otherwise, you might as well just let *everything* in, use open ponds, and get lousy yield figures.
Yet somehow EV cars have less space and a ton of batteries backed in.
I didn't say that EVs currently win the space/mass comparison - only that you're doing the comparison wrong. Yes, gasoline engines still win the comparison, but not by the sort of dramatic margins you get when you only compare one piece of the picture. Battery tech only needs about a 3x advancement in energy density to win the comparison (and in the past two decades, it's advanced 4.5x). The size of the other components is key to this. The motor that drives the Tesla Roadster, for example, is about the size of a watermelon.
And besides, that is really irrelevant since hydrogen cars derive the same benefits of an all electric engine.
And then throw on top of it a large number of huge disadvantages.
All problems dissipate with advances of technology
The problem is that battery EVs are advancing faster, and in some regards hydrogen is going *backwards*. For example, the more battery capacity you add, the faster you can pump current in (plus, the newer cells are higher power,a compounding factor). To the contrary, the higher the pressure you run your tanks and the more storage mediums you use to extend H2 range, the *slower* your vehicle fills, and that's compounded by the need to pump more total hydrogen. And much of the issues of the gross inefficiencies of the H2 fuel cycle will never go away. You're doing so many extra, wasteful steps to make it and transport it compared to electricity.
again the only real reason the exist in any numbers now is HUGE subsidies from taxpayers
The subsidies for EVs is a blip on the radar in terms of total cost, and for high end EVs, the subsidy is pretty irrelevant. And EVs are not just approaching from the "high end consumer" and "subsidized low-end consumer" side, but also the industrial side. EVs have been slowly moving out from the warehouse into larger and larger transport roles; for example, the port of LA now uses some truly massive EV trucks to haul crates in order to help deal with the port's huge air pollution problems.
And, FYI, if you want to support H2 vehicles, your subsidy would have to be orders of magnitude greater. They're six-figures for a basic consumer sedan, and generally not even the bottom end of the six-figure range. They're just way more complicated and way more inefficient, and nowadays provide very little advantage over EVs, just tons of extra disadvantages.
Where did you hear that the Volt has two electric motors? That's one of the most bizarre claims I've heard yet. It has a single motor and a gasoline engine.
Don't like that site about the Volt? Here'ssomemore. Good enough for you?
You act like there's a ton of Japanese manufacturers out there. Toyota is going induction. Nissan is going brushless. The other two, Mitsubishi and Subaru, are bit players in the EV field with really minimalist vehicles; I don't think Subaru even has anything that can go highway speeds. In the US, we have Tesla, GM, and Ford actually selling highway-speed EVs. Tesla: all induction. GM: induction on sale, with a prototype unveiled that uses a brushless. Ford: assuming it uses the same motor as their Focus FCV, the focus EV is induction (the EV transit connect definitely is). Others: Th!nk: induction. BMW: two "demonstration" EVs, one induction and one PM.
Yes, there were more permanent magnet ones out there than I realized. But the basic point is the same: the concept that rare earths are necessary to EVs is simply false.
Let me be clearer, then: I'm talking about inductive AC synchronous motors. The Leaf (and apparently the ActiveE, hadn't checked out their motor tech) are the only modern highway-speed EVs with permanent magnets in its motor. Is that clear enough?
GM does not use a permament magnet motor. I linked to a GM site for you, where they quite clearly say it's an induction motor. The difference in motors between it and the Leaf is one of the oft-cited differences, so I'm surprised that you don't know that.
"Electric vehicles convert about 59â"62% of the electrical energy from the grid to power at the wheels" "Electric motor efficiencyâ"including inverter and gear reduction lossesâ"assumed to be 76.4â"80.2%, using estimates from Miller et. al. (SAE 2011-01-0887) and adjusting downward by 4% for parasitic losses." "Battery and battery charger efficiency are assumed to total 81% (roughly 90% each) based in part on estimates from published studies (Chae et. al., 2011; Gautam et. al., 2011)."
Hey, what do I know, I'm just quoting figures from actual hardware I've messed with. And, FYI, there's not a li-ion pack out there on the market that will get you as low as 90% efficiency. At least 90% efficiency in the charger is possible, although definitely on the low end. Even rapid chargers are usually more than that.
And I knew the wind, solar etc would come up. I find that funny given your insistence on talking about the current situation.
Um, FYI, they *are* now part of the current situation. Wind is nearing 20% of the generation in some US states like Iowa (where I lived before I moved to Iceland). Over here in Europe, solar is growing like crazy, although not here in Iceland (we're already nearly 100% renewables, of course;) ).. And it's strange that you wrote that comment, because solar wasn't in the list, but hydro was. You took what I wrote, added in something I didn't write, and took several I did. Solar wasn't in the list because it's not near 100% efficiency. That was a list of generation techs that are near 100% efficiency.
Then you go on to do some "funny math". First off, your doing the math is pointless to begin with because there's countless peer-reviewed studies on this already, which all show major benefits for going to EVs even on current grids, both in terms of CO2 emissions and in terms of other emissions (in the US, PM and SOx go up, NOx goes down, VOCs and CO are nearly eliminated, and all of said emissions are displaced away from population centers, leading to dramatically lower health consequences). But just to point out the "funny" side: you tacked in every loss you could for EVs, but then assumed that the gasoline appears at your car without a single loss in producing it. Did that not occur to you as strange?
Anyway. 50% efficiency for a large plant is doing well. As for larger having higher efficiencies, that's usually true w/ the caveat that smaller means use of energy that isn't economical to use in a larger plant, as well as more use of waste heat (heating the car), and of course those transmission inefficiencies.
So. Yeah. Getting back to comparing.
slower recharge
How fast does your gasoline car recharge in your garage? Oh yeah, that's right... you have to go out of your way in your daily life to fill it up, and pay out the arse to do so.
strains our grid
BZZZT, wrong. Electric companies are some of the biggest promoters of EVs, as they help *stabilize* the grid and get better utilization of power plants. They're nice, even, predictable, predominantly nighttime loads. Used battery packs give grid operators an additional boon.
batteries require periodic replacement as efficiency falls off over time
The efficiency drop over time is trivial. Most people concern themselves with the range drop. The standard warranty on the packs is 8-10 years to 80% capacity. Hardly a problem, I would think.
that doesn't work well in cold climates
The packs are more cold tolerant than your PbA starter battery. Of course *all vehicles* lose range in cold weather, and EVs are no exception, but at least it'll start.
that doesn't handle long periods of storage.
100% false. Unlike gasoline cars, li-ion EVs couldn't give a rat's arse about how long they sit. There's no "fuel going stale" issues, there's no issue of the engine needing to turn over to pump the oil through, etc.
Same letter, but it's hardly an anachronism; I use it every day. And whenever Iceland comes up in the news, it's important to be able to type (for example, to spell people's names correctly, addresses correctly, even the name of our parliament). It's so common of a letter that it's in words like "you", "it", "they", "this", "that", and so forth. So having it magically disappear from text is really annoying. Strangely Slashdot supports eth (Ðð), though.
If you want examples, for fiber, kenaf is better in both production and tensile strength. For oilseed, there's dietary and food uses. For dietary uses, hemp oil is actually problematic in various respects in that it's sort of "in-between". For dietary uses, it has a small fraction as much omega-3, for example, as flax or walnut oil, but it has enough that it still goes rancid from being left out or exposed to heat. And for fuel, you get twice as much jatropha oil, for example, per acre.
Hemp isn't useless - it's just not the sort of miracle crop that a lot of people (most often, in my experience, stoners) like to make it out to be.
Public transport doesn't scale well to low population densities, and by trying to make it, you actually make the problem worse (running a nearly empty bus does nobody any good, and it's even worse when the bus is taking circuitous routes and constantly starting and stopping to pick up scattered passengers all over the place). The fewer people who need to go into a given area, the longer you need to make wait times to justify it, but the fewer people then who will want to do it because of the long wait times. The system just breaks down. The whole concept of "mass transit" requires that there be a "mass" of people involved.
It's great for high population density areas, though.
The problem is that there simply is no potential in sight for a battery that can realistically do what gasoline does - 300 miles on a single 2 minute fueling, that weighs only about 20 lbs and lasts for a million miles or more (how often do you replace a gas tank?).
Which is irrelevant when you've got an engine block that weighs three times as much as a comparable EV engine block and lasts a fraction as long and needs constaint maintenance even to keep it running normally, let alone when things inevitably break. You're talking one component of the net propulsion system out for comparison and acting like it's the entire propulsion system.
In the end we'll be using electric motors but powered probably by hydrogen,
Ha, hydrogen is a joke compared to EVs - shorter lifespan, order of magnitude more expensive in both fuel and powertrain, 25-50% the system efficiency, and on and on down the line, plus it barely outperforms EVs in range and fill time anymore.
Synchronous motors (aka "brushless DC" motors) do indeed use permanent magnets.
Which would be relevant if Tesla and the others used a brushless DC motor. They use induction-based AC synchronous motors. Almost all older EVs used brushless DC and "neighborhood electric vehicles" (aka, glorified golf carts) still do, as well as most hybrids, nearly all modern, highway speed EVs being developed/on the road are now using AC synchronous motors, which have no permanent magnet. This includes not just Tesla's powertrain (which it also shares with a couple other auto manufacturers and was used in, for example, the electric mini and Toyota's new RAV4EV), GM's vehicles, Think's, Renault's, BYD's, etc. Nissan is the only exception with the Leaf, and I doubt they'll stick with it for long.
AC motors like this used to be grossly impractical, but this has changed with the advent of readily available high power switching electronics. "Brushless DC" motors are history as far as EVs go.
Fueleconomy.gov says the following. " Electric vehicles convert about 59â"62% of the electrical energy from the grid to power at the wheels"
NiMH, yes. Possibly PbA. Not Li-ion. Li-ion cells are over 99% efficient in slow charging, and usually something like 96 or 97% in fast charging. The US grid averages about 93% efficient, chargers are usually around 93% efficient, and the drivetrains usually average around 85% efficient.
But of course, half of that is irrelevant in a conversation about *fuel density*. You only care about onboard losses.
And let's not forget that *generating* the power is far from efficient.
Depends on what type of power you're talking about. But in general you get better efficiencies at a large fixed plant with a given fuel than a small mobile generator, and much better scrubbing of any pollutants (plus have a far wider range of possible energy sources). Wind, hydro, tidal, and some forms of wave power are exceedingly efficient.
Nor the fact that in cold climates electric cars need to also expend energy to heat the vehicle.
More than gasoline, true, although the amount varies greatly depending on your implementation. Even 15% waste heat is not irrelevant when you're burning a dozen or two kilowatts on traction, and heat pumps can act as multipliers.
And to some extent, an elephant is like a dinoflagellate. Sorry, but the sort of cells that go into laptops have completely different behavioral properties than the spinels and phosphates used in EVs (except Tesla's, but Tesla overcomes their issues by babying the heck out of their cells), everything from cycle life to temperature tolerance to power output to energy density to flammability and on and on down the line.
As far as I can tell, we really have no idea how LiFePO4 is going to hold up in the real world;
Um, yes we do. They've been used in power tools for something like 7 or 8 years now. And they were first developed nearly 20 years ago. Beyond that, that's what accelerated aging tests are for.
But for older designs that use NiMH or older lithium ion chemistries, we know approximately how long they'll last, and it isn't pretty.
First off, older NiMH packs are doing just fine. Have you totally forgotten about hybrid vehicles and their very low pack failure rates? And second, not only is lumping cobalt-based 18650s designed for low cost and high energy density at the expense of power density and lifespan with chemistries with an entirely opposite design criteria ridiculous, but such 18650s *are* meeting their design criteria quite well. It's just that their design spec doesn't call for very long lifespan because the devices they go into aren't expected to need it.
The EV-1 didn't meet federal safety standards at the time they were released.
False. The EV1 was tested and approved by the NHTSA.
Even if GM could do that, they had a hard time getting all of their suppliers to even get the parts needed for the production run, let alone 10 years worth of spares.
Which is why you stock them up as needed before any supply lines get shut down, as is standard practice. Unless you actually don't give a flying flip about the vehicle and are just building it to fill a CARB requirement which you're actively suing to overturn. Hmm...
On the subject of parts, you may remember, GM actually sold off the rights to its batteries. Does that sound like a company that *wanted* to be making EV1s?
One could always do a feebate instead of a subsidy so that it's revenue neutral. And a country's lack of a proper safety net does not translate into "we should say screw you to the environment and resource security". It translates into "we need a better social safety net".
Oh I have an electric lawn mower as well and hate it. Why? very easy, I HATE DRAGGING THE DAMM CORD.
Then why'd you buy a corded one?
Fuel has about 45, batteries 1.8.
Grossly misleading, and not just because you cite the efficiency of the gas motor at 30%, which is peak efficiency, not average, which runs more like 20% or less in real-world driving, or because you act like batteries aren't increasing much when in reality they've increased in energy density about 4.5x in the past two decades and show no signs of stopping.
No, it's grossly misleading because the analogy is wrong. In a gasoline car, the engine is heavy and the fuel is light. In an electric vehicle, the "fuel" is heavy and the motor is light. You need to be comparing net system mass. Gasoline still *currently* wins that one, but not by that huge of a margin.
Thanks - I appreciate it! You know, you should consider donating to my kickstarter page for developing a snark detector. We're nearly halfway to our goal!
You mean warming up lithium battery using the same power stored in the same battery? Isn't it a bit like trying to pull yourself out from swamp by pulling your own hair?
You mean like how a person burns the fuel in their body to maintain a core body temperature which is warm enough for them to continue metabolism? Why pick a strained analogy when there's a direct one?
Assume a specific heat capacity of 2J/gC for the pack and a pack energy density of 140Wh/kg. That's ~500kJ/kg vs 2kJ/kgC. Hence the pack stores enough energy to warm itself up 250 degrees celcius. Even if it's initial capacity was reduced by cold to a small fraction of that (which doesn't actually happen that much with automotive-style li-ions), there's no way it couldn't warm itself up to a reasonable temperature and restore its ideal voltage discharge curve.
Slashdot Mirror
function calls, classes, etc which use letters that are not in the English character set. :P No translation needed, just let me type them without getting spammed with syntax errors like happens in most programming languages. And for that matter, I'd be happy if I could even *type* a thorn here on Slashdot without having it magically disappear.
*Someone* should be evaluating teachers. Do you want it to be someone who knows what they're talking about or someone who doesn't?
I know, I know, it's happening during the Obama administration, so it must be a bad idea. But can we get past that for just a second and think about this objectively? Should we be evaluating with people who don't know a darn thing about STEM subjects? Or maybe just with standardized tests? So is it okay if Mrs. Johnson teaches her students that we're all inhabited by body-thetans so long as her students can pass a state or national standards test?
Uh oh. People with scientific backgrounds, evaluating my older sister, a grade-school teacher who thinks the moon landing was faked? That could spell trouble for her ;)
An interesting side effect of this scheme, whether by design or by accident, should be to help push creationism out of the classroom. People with degrees in scientific fields are far less likely to be creationist than the general public. If these people are evaluating other teachers, I can't help but think that'll have an influence. Even when teachers aren't supposed to be teaching it, I remember having a number that tried to work it in subtly. I remember a science teacher who, when we were covering the dating of rocks as discussed in the textbook, added in something like, "but you can't trust the numbers on how old rocks are because if you take different samples from the same rock you can get really different ages".
How exactly is a paper saying that algal oil is only profitable "under the optimistic case" at $100/barrel, when tar sands oil is profitable at $15-30 a barrel, shale not much more, and electricity is one-third the cost of even today's gasoline, helping your case any?
Desert: No water to pump in. That's why it's a desert. Why is this a hard concept? The deserts that do have rivers going through them which could be tapped typically have those rivers way-overtapped already.
Assuming it's a coastal desert, which most aren't, that's a nonstarter, because you can't just randomly pick and choose a water mineral mix and have it work with these optimized algal species. They're optimized for very specific (typically freshwater) conditions. And the water has to be pure - no "gunk", no bacteria, not even viruses. Otherwise, you might as well just let *everything* in, use open ponds, and get lousy yield figures.
I didn't say that EVs currently win the space/mass comparison - only that you're doing the comparison wrong. Yes, gasoline engines still win the comparison, but not by the sort of dramatic margins you get when you only compare one piece of the picture. Battery tech only needs about a 3x advancement in energy density to win the comparison (and in the past two decades, it's advanced 4.5x). The size of the other components is key to this. The motor that drives the Tesla Roadster, for example, is about the size of a watermelon.
And then throw on top of it a large number of huge disadvantages.
The problem is that battery EVs are advancing faster, and in some regards hydrogen is going *backwards*. For example, the more battery capacity you add, the faster you can pump current in (plus, the newer cells are higher power,a compounding factor). To the contrary, the higher the pressure you run your tanks and the more storage mediums you use to extend H2 range, the *slower* your vehicle fills, and that's compounded by the need to pump more total hydrogen. And much of the issues of the gross inefficiencies of the H2 fuel cycle will never go away. You're doing so many extra, wasteful steps to make it and transport it compared to electricity.
The subsidies for EVs is a blip on the radar in terms of total cost, and for high end EVs, the subsidy is pretty irrelevant. And EVs are not just approaching from the "high end consumer" and "subsidized low-end consumer" side, but also the industrial side. EVs have been slowly moving out from the warehouse into larger and larger transport roles; for example, the port of LA now uses some truly massive EV trucks to haul crates in order to help deal with the port's huge air pollution problems.
And, FYI, if you want to support H2 vehicles, your subsidy would have to be orders of magnitude greater. They're six-figures for a basic consumer sedan, and generally not even the bottom end of the six-figure range. They're just way more complicated and way more inefficient, and nowadays provide very little advantage over EVs, just tons of extra disadvantages.
Where did you hear that the Volt has two electric motors? That's one of the most bizarre claims I've heard yet. It has a single motor and a gasoline engine.
Don't like that site about the Volt? Here's some more. Good enough for you?
You act like there's a ton of Japanese manufacturers out there. Toyota is going induction. Nissan is going brushless. The other two, Mitsubishi and Subaru, are bit players in the EV field with really minimalist vehicles; I don't think Subaru even has anything that can go highway speeds. In the US, we have Tesla, GM, and Ford actually selling highway-speed EVs. Tesla: all induction. GM: induction on sale, with a prototype unveiled that uses a brushless. Ford: assuming it uses the same motor as their Focus FCV, the focus EV is induction (the EV transit connect definitely is). Others: Th!nk: induction. BMW: two "demonstration" EVs, one induction and one PM.
Yes, there were more permanent magnet ones out there than I realized. But the basic point is the same: the concept that rare earths are necessary to EVs is simply false.
Let me be clearer, then: I'm talking about inductive AC synchronous motors. The Leaf (and apparently the ActiveE, hadn't checked out their motor tech) are the only modern highway-speed EVs with permanent magnets in its motor. Is that clear enough?
GM does not use a permament magnet motor. I linked to a GM site for you, where they quite clearly say it's an induction motor. The difference in motors between it and the Leaf is one of the oft-cited differences, so I'm surprised that you don't know that.
Hey, what do I know, I'm just quoting figures from actual hardware I've messed with. And, FYI, there's not a li-ion pack out there on the market that will get you as low as 90% efficiency. At least 90% efficiency in the charger is possible, although definitely on the low end. Even rapid chargers are usually more than that.
And I knew the wind, solar etc would come up.
I find that funny given your insistence on talking about the current situation.
Um, FYI, they *are* now part of the current situation. Wind is nearing 20% of the generation in some US states like Iowa (where I lived before I moved to Iceland). Over here in Europe, solar is growing like crazy, although not here in Iceland (we're already nearly 100% renewables, of course ;) ).. And it's strange that you wrote that comment, because solar wasn't in the list, but hydro was. You took what I wrote, added in something I didn't write, and took several I did. Solar wasn't in the list because it's not near 100% efficiency. That was a list of generation techs that are near 100% efficiency.
Then you go on to do some "funny math". First off, your doing the math is pointless to begin with because there's countless peer-reviewed studies on this already, which all show major benefits for going to EVs even on current grids, both in terms of CO2 emissions and in terms of other emissions (in the US, PM and SOx go up, NOx goes down, VOCs and CO are nearly eliminated, and all of said emissions are displaced away from population centers, leading to dramatically lower health consequences). But just to point out the "funny" side: you tacked in every loss you could for EVs, but then assumed that the gasoline appears at your car without a single loss in producing it. Did that not occur to you as strange?
Anyway. 50% efficiency for a large plant is doing well. As for larger having higher efficiencies, that's usually true w/ the caveat that smaller means use of energy that isn't economical to use in a larger plant, as well as more use of waste heat (heating the car), and of course those transmission inefficiencies.
So. Yeah. Getting back to comparing.
slower recharge
How fast does your gasoline car recharge in your garage? Oh yeah, that's right... you have to go out of your way in your daily life to fill it up, and pay out the arse to do so.
strains our grid
BZZZT, wrong. Electric companies are some of the biggest promoters of EVs, as they help *stabilize* the grid and get better utilization of power plants. They're nice, even, predictable, predominantly nighttime loads. Used battery packs give grid operators an additional boon.
batteries require periodic replacement as efficiency falls off over time
The efficiency drop over time is trivial. Most people concern themselves with the range drop. The standard warranty on the packs is 8-10 years to 80% capacity. Hardly a problem, I would think.
that doesn't work well in cold climates
The packs are more cold tolerant than your PbA starter battery. Of course *all vehicles* lose range in cold weather, and EVs are no exception, but at least it'll start.
that doesn't handle long periods of storage.
100% false. Unlike gasoline cars, li-ion EVs couldn't give a rat's arse about how long they sit. There's no "fuel going stale" issues, there's no issue of the engine needing to turn over to pump the oil through, etc.
You know, all the reasons people don't want them.
Demand way outstrips supply, FYI.
Sure - here you go.
Well (n): a spring or natural source of water.
Desert (n): Any area in which few forms of life can exist because of lack of water, permanent frost, or absence of soil.
Once again, you didn't really think this one through.
Yes, because the BLM will grant a permit to mine coal or drill for oil, but not to build a solar plant,
-..... huh?
Did this conversation just zap a wand of polymorph at itself?
Same letter, but it's hardly an anachronism; I use it every day. And whenever Iceland comes up in the news, it's important to be able to type (for example, to spell people's names correctly, addresses correctly, even the name of our parliament). It's so common of a letter that it's in words like "you", "it", "they", "this", "that", and so forth. So having it magically disappear from text is really annoying. Strangely Slashdot supports eth (Ðð), though.
If you want examples, for fiber, kenaf is better in both production and tensile strength. For oilseed, there's dietary and food uses. For dietary uses, hemp oil is actually problematic in various respects in that it's sort of "in-between". For dietary uses, it has a small fraction as much omega-3, for example, as flax or walnut oil, but it has enough that it still goes rancid from being left out or exposed to heat. And for fuel, you get twice as much jatropha oil, for example, per acre.
Hemp isn't useless - it's just not the sort of miracle crop that a lot of people (most often, in my experience, stoners) like to make it out to be.
Public transport doesn't scale well to low population densities, and by trying to make it, you actually make the problem worse (running a nearly empty bus does nobody any good, and it's even worse when the bus is taking circuitous routes and constantly starting and stopping to pick up scattered passengers all over the place). The fewer people who need to go into a given area, the longer you need to make wait times to justify it, but the fewer people then who will want to do it because of the long wait times. The system just breaks down. The whole concept of "mass transit" requires that there be a "mass" of people involved.
It's great for high population density areas, though.
Which is irrelevant when you've got an engine block that weighs three times as much as a comparable EV engine block and lasts a fraction as long and needs constaint maintenance even to keep it running normally, let alone when things inevitably break. You're talking one component of the net propulsion system out for comparison and acting like it's the entire propulsion system.
Ha, hydrogen is a joke compared to EVs - shorter lifespan, order of magnitude more expensive in both fuel and powertrain, 25-50% the system efficiency, and on and on down the line, plus it barely outperforms EVs in range and fill time anymore.
Which would be relevant if Tesla and the others used a brushless DC motor. They use induction-based AC synchronous motors. Almost all older EVs used brushless DC and "neighborhood electric vehicles" (aka, glorified golf carts) still do, as well as most hybrids, nearly all modern, highway speed EVs being developed/on the road are now using AC synchronous motors, which have no permanent magnet. This includes not just Tesla's powertrain (which it also shares with a couple other auto manufacturers and was used in, for example, the electric mini and Toyota's new RAV4EV), GM's vehicles, Think's, Renault's, BYD's, etc. Nissan is the only exception with the Leaf, and I doubt they'll stick with it for long.
AC motors like this used to be grossly impractical, but this has changed with the advent of readily available high power switching electronics. "Brushless DC" motors are history as far as EVs go.
NiMH, yes. Possibly PbA. Not Li-ion. Li-ion cells are over 99% efficient in slow charging, and usually something like 96 or 97% in fast charging. The US grid averages about 93% efficient, chargers are usually around 93% efficient, and the drivetrains usually average around 85% efficient.
But of course, half of that is irrelevant in a conversation about *fuel density*. You only care about onboard losses.
Depends on what type of power you're talking about. But in general you get better efficiencies at a large fixed plant with a given fuel than a small mobile generator, and much better scrubbing of any pollutants (plus have a far wider range of possible energy sources). Wind, hydro, tidal, and some forms of wave power are exceedingly efficient.
More than gasoline, true, although the amount varies greatly depending on your implementation. Even 15% waste heat is not irrelevant when you're burning a dozen or two kilowatts on traction, and heat pumps can act as multipliers.
And to some extent, an elephant is like a dinoflagellate. Sorry, but the sort of cells that go into laptops have completely different behavioral properties than the spinels and phosphates used in EVs (except Tesla's, but Tesla overcomes their issues by babying the heck out of their cells), everything from cycle life to temperature tolerance to power output to energy density to flammability and on and on down the line.
Um, yes we do. They've been used in power tools for something like 7 or 8 years now. And they were first developed nearly 20 years ago. Beyond that, that's what accelerated aging tests are for.
First off, older NiMH packs are doing just fine. Have you totally forgotten about hybrid vehicles and their very low pack failure rates? And second, not only is lumping cobalt-based 18650s designed for low cost and high energy density at the expense of power density and lifespan with chemistries with an entirely opposite design criteria ridiculous, but such 18650s *are* meeting their design criteria quite well. It's just that their design spec doesn't call for very long lifespan because the devices they go into aren't expected to need it.
False. The EV1 was tested and approved by the NHTSA.
Which is why you stock them up as needed before any supply lines get shut down, as is standard practice. Unless you actually don't give a flying flip about the vehicle and are just building it to fill a CARB requirement which you're actively suing to overturn. Hmm...
On the subject of parts, you may remember, GM actually sold off the rights to its batteries. Does that sound like a company that *wanted* to be making EV1s?
One could always do a feebate instead of a subsidy so that it's revenue neutral. And a country's lack of a proper safety net does not translate into "we should say screw you to the environment and resource security". It translates into "we need a better social safety net".
Desert (n): Any area in which few forms of life can exist because of lack of water, permanent frost, or absence of soil.
You didn't really think that one through very well, did you?
As for your former concept, well, there's quite a few reasons why most companies are trying to grow them in enclosed vats.
Then why'd you buy a corded one?
Grossly misleading, and not just because you cite the efficiency of the gas motor at 30%, which is peak efficiency, not average, which runs more like 20% or less in real-world driving, or because you act like batteries aren't increasing much when in reality they've increased in energy density about 4.5x in the past two decades and show no signs of stopping.
No, it's grossly misleading because the analogy is wrong. In a gasoline car, the engine is heavy and the fuel is light. In an electric vehicle, the "fuel" is heavy and the motor is light. You need to be comparing net system mass. Gasoline still *currently* wins that one, but not by that huge of a margin.
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They don't. Any more questions?
You mean like how a person burns the fuel in their body to maintain a core body temperature which is warm enough for them to continue metabolism? Why pick a strained analogy when there's a direct one?
Assume a specific heat capacity of 2J/gC for the pack and a pack energy density of 140Wh/kg. That's ~500kJ/kg vs 2kJ/kgC. Hence the pack stores enough energy to warm itself up 250 degrees celcius. Even if it's initial capacity was reduced by cold to a small fraction of that (which doesn't actually happen that much with automotive-style li-ions), there's no way it couldn't warm itself up to a reasonable temperature and restore its ideal voltage discharge curve.