You were moderated insighful for this howler? You must have a very large family...
Borrowing a phrase, your post is so wrong it's not even wrong.
Google is your friend, ask him.
How very helpful. (Not.)
From what I can determine, the best power plants are about 60% more efficient than the best automotive engines. I'm not sure that qualifies as A LOT all in caps, but it is substantial. But when you factor in the losses in the motor, transmission lines, charger and batteries, I suspect the net benefit to electric cars powered by fossil fuel powered power plants is extremely small.
And if your power plant burns diesel fuel, and your car engine burns diesel fuel, the general method that it's converted into mechanical energy will be similar. The power plant may use a slightly different engine, but the general heat engine principals will remain, and the waste products will be the same as well. (The power plant may be able to filter them better, however.)
(Most fossil fuel power plants are powered by coal. Not many coal powered cars, so an apples to apples comparison is difficult. There are some diesel powered power plants, however, especially in the smaller ones.)
I'd love to hear some more typical values of the efficiencies involved, if you can provide some. Please do give some citations rather than just presenting some figures.
Ultimately, I've heard that the most efficient power plants are only
50% or so efficient when you don't include cogeneration. Car engines, the most efficient around 30% efficient. I'm not sure 60% more efficient qualifies as A LOT (especially all in caps.) (But it's certainly a substantial difference.) Also, we're talking about the `best' here... I don't know how different `typical' figures are.
And then if you're powering an electric car, you'll need to reduce that 50% efficiency by a number of factors -- loss due to transmission lines, internal resistance of the battery, self-discharge of the battery, loss in the motor that powers your electric car, etc. (I do believe the small losses in the generator at the power plant are included in the 50% figure.) That wasn't my original point, but if you want electric cars because they're more efficient (i.e. use less fuel, create less pollution) then you need to take these factors into account. Most of these factors are relatively small, except for losses in the batteries themselves, but added up they do become substantial.
And also having a heavy bank of batteries in your car further increases energy usage. An electric motor that can generate a certain amount of power generally weighs less than the equivilent IC engine, but when you include the batteries needed to power it for an hour or two the total weight is much greater than that of the IC engine and it's fuel tank. (Which is why IC engines are still used in R/C planes. Electric planes have certainly taken off for many many reasons, but for the highest performance planes, they're still gas or glow powered. If batteries ever improve enough that you can get similar energy density to a glow engine at similar costs, the only people who will still be flying glow is those who do it because 1) they don't want to replace what they have and 2) they like the noise and smell.)
As for pollution, most power plants burn coal, which creates even more nasty pollution than gasoline. But yes, they also have more scrubbers and such to clean up the pollution. But what happens to the junk the scrub out of the smokestacks? It's still pollution, even if it doesnt' go into the air.
In any event, you've made some good arguments (ones that I was already aware of, mind you), but you still haven't provided anything that could be called `proof'. I was sort of hoping that somebody had done a scientific study that I wasn't aware of, and that the power plants were at least twice as efficient as car engines...
Compare this to nickel-metal Hydride cells that are rated to last 10 years.
Really? These must be special cells. The NiMH cells I buy for my many electical devices and my R/C airplanes don't last more than three years or so (even the ones I don't abuse by high charge or discharge rates.)
The reason Ni-Cd are not used is the Cadmium is a toxic heavy metal.
Not only that, but NiMH cells have higher capacity than NiCd cells. And they're less succecptible to voltage depression, though I doubt that's really an issue in a a hybrid car.
The person telling the story about the vegetable oil/diesel powered car explained it very well.
Just because the grid is coal and oil and natural gas right now doesn't mean it won't be mostly wind, solar and nuclear in the future.
Well, it's not now. Right now, in the US, it's mostly powered by fossil fuels. Just like your car. (And I'm guessing that the hydroelectric and nuclear plants are run at the rate that they want to run them at most of the time, and so any extra capacity needed is provided by fossil fuel plants. So if you burn the fuel in your car or at the plant... it's still being burned.)
If his car had solar cells on top, or was powered by a sail, then yes I'd think it was fair to say how efficient the car is. But not with what these people are doing.
That it's the batteries that give them higher MPGs?
That's part of it. There's several things that give them good fuel efficiency --
- because of the batteries, they can have a smaller engine, which more often running at the rate where it's most efficient. The electric motor picks up the slack if more energy is needed, and the generator picks up the extra energy if less energy is needed.
- they could even turn off the engine entirely when the car is at a stop light. I don't know if this is done or not.
- braking energy is used to charge the battery.
But there's a few things that aren't related to the batteries --
- the cars are smaller
- they're more aerodynamic
- they probably use special low rolling friction tires
- etc.
It's not ALL about the battery. You won't be seeing any hybrid SUVs that get 70 mpg but are shaped and sized like a Ford Explorer, for example.
The drivetrain and auxillary systems (A/C, alternator) in a car sap as much as 30% of the engine's actual output.
In an electrical car, you have these same losses. (Well, you don't have an alternator, but you still have to power most of the things that the alternator powers. Fortunately, alternators are quite efficient.)
Your engine's transmission has an "overhead" that accounts
Electrical cars have similar overheads. Though it may be somewhat different for a well designed electrical car, as electric motors may be efficient over a larger range of speeds. But for now, most electrical cars have very similar drivetrains to gas cars or hybrid cars.
Power plants by comparison are very simple: produce steam to spin a turbine. Producing steam is straightforward and can be a 90+% efficient process. (Even home heating boilers can be 85% efficient)
Ok, now you're in la-la land, comparing apples and oranges.
No power plant is 90+% efficient at converting energy from fossil fuels into electricity. I don't want to hear about heat -- I'm talking electricity. Ultimately, a power plant or a car both use some sort of heat engine to convert heat into mechanical energy, and
heat engines are inefficient. A power plant may very well have a somewhat more efficient one, however.
If all you care about is burning fuel to make something hot, being 90+% efficient isn't difficult, as 100% of the energy is released in the form of heat -- the complication is in making sure that the heat goes where you want it.
But if you want to make something go with this energy, it gets much harder. I don't think heat engines (be they internal combustion engines, turbines, steam engines, whatever) get much over 50% efficient, and even that would be really good.
This is where fuel cells could really be good -- if we could convert gasoline into electricity without a heat engine, the process could possibly be much more efficient.
Apparantly it wasn't really clear what I meant when I talked about the efficiency of a car engine, because several people have now lectured me about the various places where energy is lost in a car. Well guys, guess what -- eventually ALL the energy is lost in a car to friction somewhere -- in the engine, drive-train, wheels, air resistance -- somewhere. Unless it drives up hill anyways, as that will store some energy as gravitational potential energy. Exactly how much of the energy is `wasted' depends on how you define waste.
I was talking about the engine itself, converting fossil fuel into mechanical energy. If you replace the engine of a gas car with an electric motor, you'll have all the same losses (except for the alternator (not directly, anyways), maybe no water pump, etc.)
I have serious doubts about burning a gallon of gasoline down at the power plant, powering a generator, transferring that electricity into your house, charging a battery, then discharging that battery into a motor being more efficient than just burning that gallon of gas in the engine in your car.
Motors and generators are quite efficient if done properly, and not much energy is lost in power lines, but batteries definately don't give out as much power as they were charged with, especially if quickly charged. Add up all those losses, and I suspect it's just more efficient to power your car with fossil fuel in the tank and a gas engine under the hood.
(Now, if you have abundant non-fossil fuel power available, like hydroelectric or nuclear, then things are totally different.)
One thing that can improve the overall efficiency of a power plant over a car engine is cogeneration
which is using the waste heat generated by a heat engine to heat homes and the like. But that's not what we've been discussing...
Maybe we need to start measureing "cents per mile."
That would be far more reasonable than claiming that your car gets 250 mpg because most of it's power comes from the power grid.
Of course, that's complicated by things like gasoline taxes and subsidies for power plants and the like, but on a microconomic level it works very well.
At this point in our economy, MPG has no relevance as far as efficiency, but instead operating costs. It costs up to $3.00/gallon in some parts of the US per gallon of gas.
Here in Texas, it's around $2.40/gallon now. The difference is probably mostly higher gasoline taxes.
If more and more people start driving electric cars (which is basically what we're talking about here) the states will start to want their missing tax money back, and they will get it. (After all, the gas taxes are supposed to pay for the roads and such, and electric cars use the roads too. Keying it to gas usage works pretty well, as small/efficient cars create less wear and tear than larger/less efficient cars) but it falls apart when you start using electric cars.
And the cost of electricity will start to go up as well. Most electricity in the US is produced by burning fossil fuels, and as those become scarcer, prices will go up, just like with gasoline. There's more intertia, but the prices for electricity will go up. And if there are certain fossil fuels that are less scarse, cars will start using them -- propane powered cars aren't uncommon at all, for example.
Ultimately, rising fossil fuel costs are going to be bad for the economy, but could be good for the environment, spurring people to get more efficient cars, drive less, having the government create more nuclear power plants, more solar power, etc.
(Alas, the global oil production really hasn't decreased -- instead, it's demand that's increased. China, for example, is buying more oil than ever. (As are we, I think.) The environment is screwed...)
A car's internal combustion engine will generate a LOT more pollution per unit of energy than a power plant.
I've heard this claim before, but can you actually provide any sort of proof to back it up? I suspect you can't, but I'd like to be proven wrong.
I do believe that the generators down at the power plant are in general more efficient than the engine in your car (though it's tricky to make an apples to apples comparison, as few power plants run on gasoline (though some probably do run on diesel)) but I suspect it's not a LOT more efficient.
Also, you were talking about `pollution per unit of energy' not efficiency, though in practice I suspect the two are just different ways of looking at the same thing -- after all, power plants will burn a given fuel in the same way that a car engine will, so the waste products will be the same. The power plant may be somewhat better maintained, however, and can have more things similar to a catalytic converters on a car.
And even if the power plant pollutes just as much as a car engine for a given amount of energy, there's another advantage -- the polution is generally produced away from the city, which helps keep the polution around the people who actually use the cars down.
Not to mention that electricity can also come from cleaner sources like hydro or nuclear or whatnot.
That's certainly true. Alas, not much of the US's power comes from things like this.
If you charge your battery by plugging it in at the house, then you're cheating. MPG doesn't mean much when all the power doesn't come from the gas.
By this reasoning, I could build a car that has a little 1 horse power engine and a big bank of batteries which are charged by plugging it in at night. I could claim 1000 mpg, but that doesn't actually mean that my car is more efficient than any other car.
I agree that this may be useful, sort of more of a middle-ground between hybrids and electric cars, but really they should stop making mpg claims.
There really isn't much difference here. Either way you don't have the book anymore.
Back when I was in college (up through eight years ago) the going rate for new books was 100% (of course) and 75% for used. Selling them back got you either 66% or 50%, I forget which. Let's assume 50%.
If I buy a used book and sell it back, my final cost is 25% of the original total. If it's new and I sell it back, my final cost is 50%. Both of these values are signifigantly smaller than the 66% figure I'd save today by buying the expiring e-book.
2. They can be searchable.
Assuming that the DRM implementation permits this. It's not a given.
3. They could have interactive content such as audio clips and movies.
Some textbooks already have this, in the form of a CD in the back of the book.
As long as people have the choice between ebooks and paper books everything is great.
Can't argue there, or with the rest of your points.
In point of fact, in the real world, publishers are selling DRM'd textbooks for 33% less than the dead tree
But really, it's not so much the DRM that I have a problem with there. It's the expiration of the book after five months.
When I was in college, I could buy a used textbook for 75% normal cost, and sell it back most of the time for 50% normal cost. Total cost = 25%. This DRM'd book offers the use of a book (with more limitations) for the same period of time for 66% of the initial cost. Even if I buy a new book and sell it back, that's 50%, still better than 66%.
I'm sure the publishers will do anything to kill the market for used books, any way they can. But books you can't keep for later reference? Screw that.
Which means publishers can afford to sell them for less and still maintain their margins. Sounds like a win-win
Not to me it doesn't. In the real world, they'll sell them for very slightly less (or maybe the same or more if possible) and increase their margins if they can.
If the bookstore offered me a 33% discount upfront on the condition that they got the book back at the end of the semester, I'd take it. This is just the digital equivilent.
It's a good analogy as far as analogies go (exceptional, even -- good job!), but it's not the `digital equivilent' :
dead tree books are useful in ways that e-books are not. You can read them almost anywhere, without a computer. No batteries needed, though some light is indeed useful and a table is nice to have.
Creating an e-book costs less than a paper book. So there should be some savings there, something beyond what you'd get for giving the book back when you're done.
I can photocopy a page or few pages out of a book. If it's an e-book and DRM'd, I probably can't, at least not without bypassing the DRM, which I assume will be difficult, impossible for most people.
So far, I've not had any textbooks that only worked with Windows (or maybe MacOS.) I would not consider any changes in this regard to be a good thing.
So far, none of my textbooks track when I'm reading them and report home to let them know what I was looking at and for how long. I consider this to be a good thing.
If my friend forgot his book, I can lend him mine easily enough. With a DRM'd e-book, not so easy.
So far, I've never needed a network connection to use a textbook. But with the right DRM, you just might. And who knows what sort of spyware or other `bad' things you have to install that goes along with the DRM software.
So far, I've never had a computer crash lose my textbooks. The paper I'm working on, sure, but not the textbooks.
Of course, if the DRM isn't too restrictive, and the reader they give you is good (and these are some big ifs) often e-books are good things. No trees killed, easy to search, a CD weighs a lot less than a big book...
I suspect that DRM'd e-book textbooks are probably the future, and as offensive as the idea of them expiring in a few months is, I suspect it'll become much more common. But I don't have to like it, and were I still in school, I'd vote with my pocketbook by not buying them unless the discount was far more than 33%.
For the record, the `digital equvilient' would be a non-DRM protected e-book that comes on a CD that you return when you're done with it. (Yes, you could copy it. But you can copy text books too -- scanners and copiers are not hard to find.)
I can pick up a book from the 18th century and still read it. If our books are published online, what is to say that someone from the 23rd century will be able to read our works.
Nevermind the 23rd century -- what about 20 years from now? 20 years ago, computer data was stored on 5.25" floppies in various formats, on cassette tapes, 9 track tapes, etc. Reading these things today is difficult. Go back 20 more years, it's punch cards and paper tape. Almost impossible to read now, though they can be read manually if needed (due to their low-tech nature.)
Seems to me that 40 years from now, our CDs and DVDs will be difficult to read as well, and that's assuming that the media itself doesn't degrade.
And of course if something is DRM'd to expire in five months, it's not supposed to be readable in six or more months, which would include 200 years later. And even if it's DRM'd but not set to expire, the odds of it being totally unreadable after just five years (because you can't get keys for it (company went under), or can't run the software, etc.) are very high.
This is one reason why I refuse to buy DRM'd music, for example. All the vinyl, tapes and CDs I've bought in the last 30 years, I can still listen to them today (if I hook up a turntable or tape player anyways.) mp3s I made ten years ago are still readable as well, as long as I didn't put them on any media that's hard to read.
But any DRM'd music that I paid for and downloaded today, the odds are very good that I won't be able to even listen to it a few years from now. The DRM software won't run on my new computer, or the purchases will be tied to that computer, or the disk will have failed and the DRM files were tied to that specific disk, or...
Screw that. I'll buy CDs and make my own mp3s or oggs. Downloaded music from places like iTunes isn't even really signifigantly cheaper, but yet the quality is lower and the usability is much lower.
Personally, there's no way in hell I'd buy 5 month DRM'd electronic textbooks for only a 33% discount. 75%, maybe. But 33%? Screw that -- I could save more than that by buying used and selling back to the store when I'm done. And for a text book, dead tree format is likely to be more convenient than e-book format anyways. And sometimes I like to keep my books for use in later classes...
Though I suspect that if you pay the extra 33% or so, they'll extend your DRM license for a year or so. Blech.
isn't exactly "bending like a reed in the wind" -using a graphical mail client would be.
Let's not say `graphical mail client' when we really should be more specific and say Outlook.
I guess one way to deal with it would be to just use Outlook. But that's certainly not the only way.
Why don't I use Outlook? That's easy enough to answer --
I run Linux on my desktop at work. (I'm more productive under Linux, even in a land of Microsoft users.) Outlook doesn't run under Linux, though I might be able to make it run under Wine, and VMWare or rdesktop to a remote Windows box is an option
I archive most of the technical email aliases at the company and make them searchable for everybody. IT ought to do this, but for now I'm the one doing it, and it's far easier to do this under *nix than Windows.
I like to be able to access my mail similarly from home or from work or from the road. Most people do this by always running Outlook from their laptop, the same laptop, but I prefer to just ssh in.
And it all works quite well. I don't have a problem with html emails -- I just have a line in ~/.mailcap that converts them to text for mutt --
text/html; lynx -dump %s | sed 's/^//' ; copiousoutput; nametemplate=%s.html
and I have other lines that will fire up OpenOffice for Word files, xpdf for pdf files, etc. If I get an.html email that I need to view with a graphical browser (rare), I have mutt tell Mozilla to load it up for me.
I wasn't complaining about the html emails -- I deal with them. Certainly, I'm not going to tell the rest of the company to change just so I can use my favorite mail reader.
I was agreeing that management often doesn't seem to know how to properly deal with email, and that's true no matter what mail reader I use.
javester said that it's not being maintained anymore, but I do see some recent updates at the Sourceforge page. If it's not being actively developed anymore, it would seem to be because it works pretty well now.
In any event, I've found it to work very well for my use.
I don't know where you live/work, but out here in the real world, not everybody is on board with plain text. Not anymore.
I use mutt and fetchmail in a company of Exchange users. Almost every email I get at work now, from everybody, is in html. (Unless I sent it to myself.) I don't like it, but I deal with it. It's certainly easier to deal with it than to try and change everybody else.
I could change jobs, but over something as trivial as html emails? No. I like my job, I like the people I work with, so I just bend like the reed in the wind...
Still, the executives are certainly worse about email ettiquette than most, and it's not just in this company -- everywhere I've worked I've found this to be the case. They don't include Subjects at all, or include useless ones like `message'. Some will type up a memo and send it as a.pdf file attachment, or worse as a.bmp file. They rarely trim anything when responding to a post -- they just top post away. (But many people do that...)
Use Regex (and similar functions) to strip off and/or replace specific tags/wordings (similar to web scrapping technique).
Of course, you really can't properly parse html just using regular expressions. You can get it right 90% of the time relatively quickly, and a day or so work will get you 5% more, but you could spend weeks trying to get that last 5% -- and never quite get it.
It's really better to use things that other people have made for parsing html. For example, if you use perl (and you should -- it's the ideal tool for this), HTML::Parser works pretty well, though there's a signifigant learning curve in using it.
It can programatically convert most Word documents into html documents, and does about as good a job as one could expect. And it makes better html than Word does itself.
I thought about this some more, and realized that I'm basically wrong about this.
If O2 specifically absorbs 60-64 GHz signals, then it also specifically emits 60-64 GHz signals, which would be... noise.
So in order to get good range with a 62 GHz signal, you'd need more power than you'd need with a lower (or higher, for that matter) frequency.
Of course, with such a high frequency, you could make very directional antennas that are very small, so you may be able to overcome the path loss with small but high gain antennas. It works for things like DirectTV -- the 11 or so GHz signal is attenuated by the atmosphere, and the satellite is 24,000 miles up, but we can pick it up with a dish that's only a few feet across, compared to the old satellite dishes. It has to be very precisely aimed right at the satellite, but since the satellite doesn't move around much, that's not a problem.
I'm a dumbass. I read finite as infinite and posted accordingly...
Actually, one certainly could argue that the EM spectrum is infinite -- because it is. The only problem is that we rely on certain properties of radio waves, and some of them fall apart as the frequencies get higher and higher. But we certainly could encode data into IR, light, UV, etc. -- and certainly do -- but it's not radio anymore.
(But it works well for fiber optics, and it works well for IR remote controls, and it could work well for very narrow band transmissions using lasers...)
I.E. what about this frequency dictates this property?
Because the amount of data you can transmit depends on two factors -- 1) the signal to noise ratio and 2) the bandwidth available.
Suppose you can use 60 to 61 GHz for this -- that gives you one full GHz of bandwidth. Compare this to an 802.11b channel that's only 30 MHz in size, and you can see that you can transmit over 30 times as much data in a given amount of time.
The higher the frequency, the more bandwidth is generally available, as a rule of thumb.
Also, if 60 GHz really is attenuated by oxygen so strongly, then the noise should be attenuated as well. This means that people could increase the transmitted power with little danger of interfering with users very far away, and therefore increase the S/N ratio and get even more data transferred. (Though in general, I'd say the absorbtion of the signal by oxygen is a bad thing, even though it might have a useful aspect or two.)
Err...if I'm not mistaken, shouldn't that be the other way around?
Good observation, but the key word in `the higher your radio frequency, the harder it is to pass through solid objects' is radio. Yes, radio waves are electromagnetic radiations just like gamma rays, but it's a rule of thumb, not a hard and fast rule that applies to all EM radiation of any frequency.
And as a rule of thumb, for radio, it's true, as long as you're not talking about going through things that are good conductors of electricity.
(Radio waves have a hard time passing through things are good conductors of electricity, so in general if the signal does get through it's because there was a hole, and the wavelength of the signal is smaller than that of the hole -- so in that case, smaller wavelengths get in better. For example, inside a jet airliner, your cell phone may work, but your AM radio probably won't.)
No, it's not. You can keep going higher and higher in frequencies, but as you get above a few GHz problems start happening -- the attenuation due to air and things like rain increases, you get signals that can't even go through trees or walls, and the cost of the components to deal with these ultra high frequencies goes up -- and eventually you don't have radio at all, but instead infrared. (The edge of the IR range is often given at
300 GHz though of course there is no distinct line between radio and IR.)
Yes, there's lots of spectrum out there if you're willing to go to high enough frequencies. But it's not infinite.
PC Gamer listed
Total Annihilation as the `Best Game of All Time' in 1988. Granted, I'm not sure it's quite the best game of all time, even at the time, though I'd argue it certainly belonged in the top 10. Now, I'd say it belongs in the top 20.
But it didn't even make this list's top 100? And yet Dune 2 did? Dune 2 may have started the RTS genre, but TA polished the interface until it shined. Games like Starcraft certainly had a much better story (and I like my games to have good stories) but TA had the interface down better than anything that came before and I think anything that came after it. And it was so much fun in multiplayer, and the ability to add units (and Cavedog kept releasing new ones) kept it fresh for a long time...
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From what I can determine, the best power plants are about 60% more efficient than the best automotive engines. I'm not sure that qualifies as A LOT all in caps, but it is substantial. But when you factor in the losses in the motor, transmission lines, charger and batteries, I suspect the net benefit to electric cars powered by fossil fuel powered power plants is extremely small.
And if your power plant burns diesel fuel, and your car engine burns diesel fuel, the general method that it's converted into mechanical energy will be similar. The power plant may use a slightly different engine, but the general heat engine principals will remain, and the waste products will be the same as well. (The power plant may be able to filter them better, however.)
(Most fossil fuel power plants are powered by coal. Not many coal powered cars, so an apples to apples comparison is difficult. There are some diesel powered power plants, however, especially in the smaller ones.)
I'd love to hear some more typical values of the efficiencies involved, if you can provide some. Please do give some citations rather than just presenting some figures.
And then if you're powering an electric car, you'll need to reduce that 50% efficiency by a number of factors -- loss due to transmission lines, internal resistance of the battery, self-discharge of the battery, loss in the motor that powers your electric car, etc. (I do believe the small losses in the generator at the power plant are included in the 50% figure.) That wasn't my original point, but if you want electric cars because they're more efficient (i.e. use less fuel, create less pollution) then you need to take these factors into account. Most of these factors are relatively small, except for losses in the batteries themselves, but added up they do become substantial.
And also having a heavy bank of batteries in your car further increases energy usage. An electric motor that can generate a certain amount of power generally weighs less than the equivilent IC engine, but when you include the batteries needed to power it for an hour or two the total weight is much greater than that of the IC engine and it's fuel tank. (Which is why IC engines are still used in R/C planes. Electric planes have certainly taken off for many many reasons, but for the highest performance planes, they're still gas or glow powered. If batteries ever improve enough that you can get similar energy density to a glow engine at similar costs, the only people who will still be flying glow is those who do it because 1) they don't want to replace what they have and 2) they like the noise and smell.)
As for pollution, most power plants burn coal, which creates even more nasty pollution than gasoline. But yes, they also have more scrubbers and such to clean up the pollution. But what happens to the junk the scrub out of the smokestacks? It's still pollution, even if it doesnt' go into the air.
In any event, you've made some good arguments (ones that I was already aware of, mind you), but you still haven't provided anything that could be called `proof'. I was sort of hoping that somebody had done a scientific study that I wasn't aware of, and that the power plants were at least twice as efficient as car engines ...
[ it = claiming 200 mpg from your hybrid car ]
The person telling the story about the vegetable oil/diesel powered car explained it very well.
Well, it's not now. Right now, in the US, it's mostly powered by fossil fuels. Just like your car. (And I'm guessing that the hydroelectric and nuclear plants are run at the rate that they want to run them at most of the time, and so any extra capacity needed is provided by fossil fuel plants. So if you burn the fuel in your car or at the plantIf his car had solar cells on top, or was powered by a sail, then yes I'd think it was fair to say how efficient the car is. But not with what these people are doing.
- because of the batteries, they can have a smaller engine, which more often running at the rate where it's most efficient. The electric motor picks up the slack if more energy is needed, and the generator picks up the extra energy if less energy is needed.
- they could even turn off the engine entirely when the car is at a stop light. I don't know if this is done or not.
- braking energy is used to charge the battery.
But there's a few things that aren't related to the batteries --
- the cars are smaller
- they're more aerodynamic
- they probably use special low rolling friction tires
- etc.
It's not ALL about the battery. You won't be seeing any hybrid SUVs that get 70 mpg but are shaped and sized like a Ford Explorer, for example.
No power plant is 90+% efficient at converting energy from fossil fuels into electricity. I don't want to hear about heat -- I'm talking electricity. Ultimately, a power plant or a car both use some sort of heat engine to convert heat into mechanical energy, and heat engines are inefficient. A power plant may very well have a somewhat more efficient one, however.
If all you care about is burning fuel to make something hot, being 90+% efficient isn't difficult, as 100% of the energy is released in the form of heat -- the complication is in making sure that the heat goes where you want it.
But if you want to make something go with this energy, it gets much harder. I don't think heat engines (be they internal combustion engines, turbines, steam engines, whatever) get much over 50% efficient, and even that would be really good.
This is where fuel cells could really be good -- if we could convert gasoline into electricity without a heat engine, the process could possibly be much more efficient.
Apparantly it wasn't really clear what I meant when I talked about the efficiency of a car engine, because several people have now lectured me about the various places where energy is lost in a car. Well guys, guess what -- eventually ALL the energy is lost in a car to friction somewhere -- in the engine, drive-train, wheels, air resistance -- somewhere. Unless it drives up hill anyways, as that will store some energy as gravitational potential energy. Exactly how much of the energy is `wasted' depends on how you define waste.
I was talking about the engine itself, converting fossil fuel into mechanical energy. If you replace the engine of a gas car with an electric motor, you'll have all the same losses (except for the alternator (not directly, anyways), maybe no water pump, etc.)
I have serious doubts about burning a gallon of gasoline down at the power plant, powering a generator, transferring that electricity into your house, charging a battery, then discharging that battery into a motor being more efficient than just burning that gallon of gas in the engine in your car.
Motors and generators are quite efficient if done properly, and not much energy is lost in power lines, but batteries definately don't give out as much power as they were charged with, especially if quickly charged. Add up all those losses, and I suspect it's just more efficient to power your car with fossil fuel in the tank and a gas engine under the hood.
(Now, if you have abundant non-fossil fuel power available, like hydroelectric or nuclear, then things are totally different.)
One thing that can improve the overall efficiency of a power plant over a car engine is cogeneration which is using the waste heat generated by a heat engine to heat homes and the like. But that's not what we've been discussing ...
Of course, that's complicated by things like gasoline taxes and subsidies for power plants and the like, but on a microconomic level it works very well.
If more and more people start driving electric cars (which is basically what we're talking about here) the states will start to want their missing tax money back, and they will get it. (After all, the gas taxes are supposed to pay for the roads and such, and electric cars use the roads too. Keying it to gas usage works pretty well, as small/efficient cars create less wear and tear than larger/less efficient cars) but it falls apart when you start using electric cars.
And the cost of electricity will start to go up as well. Most electricity in the US is produced by burning fossil fuels, and as those become scarcer, prices will go up, just like with gasoline. There's more intertia, but the prices for electricity will go up. And if there are certain fossil fuels that are less scarse, cars will start using them -- propane powered cars aren't uncommon at all, for example.
Ultimately, rising fossil fuel costs are going to be bad for the economy, but could be good for the environment, spurring people to get more efficient cars, drive less, having the government create more nuclear power plants, more solar power, etc.
(Alas, the global oil production really hasn't decreased -- instead, it's demand that's increased. China, for example, is buying more oil than ever. (As are we, I think.) The environment is screwed ...)
I do believe that the generators down at the power plant are in general more efficient than the engine in your car (though it's tricky to make an apples to apples comparison, as few power plants run on gasoline (though some probably do run on diesel)) but I suspect it's not a LOT more efficient.
Also, you were talking about `pollution per unit of energy' not efficiency, though in practice I suspect the two are just different ways of looking at the same thing -- after all, power plants will burn a given fuel in the same way that a car engine will, so the waste products will be the same. The power plant may be somewhat better maintained, however, and can have more things similar to a catalytic converters on a car.
And even if the power plant pollutes just as much as a car engine for a given amount of energy, there's another advantage -- the polution is generally produced away from the city, which helps keep the polution around the people who actually use the cars down.
That's certainly true. Alas, not much of the US's power comes from things like this.By this reasoning, I could build a car that has a little 1 horse power engine and a big bank of batteries which are charged by plugging it in at night. I could claim 1000 mpg, but that doesn't actually mean that my car is more efficient than any other car.
I agree that this may be useful, sort of more of a middle-ground between hybrids and electric cars, but really they should stop making mpg claims.
If I buy a used book and sell it back, my final cost is 25% of the original total. If it's new and I sell it back, my final cost is 50%. Both of these values are signifigantly smaller than the 66% figure I'd save today by buying the expiring e-book.
Assuming that the DRM implementation permits this. It's not a given. Some textbooks already have this, in the form of a CD in the back of the book. Can't argue there, or with the rest of your points.When I was in college, I could buy a used textbook for 75% normal cost, and sell it back most of the time for 50% normal cost. Total cost = 25%. This DRM'd book offers the use of a book (with more limitations) for the same period of time for 66% of the initial cost. Even if I buy a new book and sell it back, that's 50%, still better than 66%.
I'm sure the publishers will do anything to kill the market for used books, any way they can. But books you can't keep for later reference? Screw that.
- dead tree books are useful in ways that e-books are not. You can read them almost anywhere, without a computer. No batteries needed, though some light is indeed useful and a table is nice to have.
- Creating an e-book costs less than a paper book. So there should be some savings there, something beyond what you'd get for giving the book back when you're done.
- I can photocopy a page or few pages out of a book. If it's an e-book and DRM'd, I probably can't, at least not without bypassing the DRM, which I assume will be difficult, impossible for most people.
- So far, I've not had any textbooks that only worked with Windows (or maybe MacOS.) I would not consider any changes in this regard to be a good thing.
- So far, none of my textbooks track when I'm reading them and report home to let them know what I was looking at and for how long. I consider this to be a good thing.
- If my friend forgot his book, I can lend him mine easily enough. With a DRM'd e-book, not so easy.
- So far, I've never needed a network connection to use a textbook. But with the right DRM, you just might. And who knows what sort of spyware or other `bad' things you have to install that goes along with the DRM software.
- So far, I've never had a computer crash lose my textbooks. The paper I'm working on, sure, but not the textbooks.
Of course, if the DRM isn't too restrictive, and the reader they give you is good (and these are some big ifs) often e-books are good things. No trees killed, easy to search, a CD weighs a lot less than a big bookI suspect that DRM'd e-book textbooks are probably the future, and as offensive as the idea of them expiring in a few months is, I suspect it'll become much more common. But I don't have to like it, and were I still in school, I'd vote with my pocketbook by not buying them unless the discount was far more than 33%.
For the record, the `digital equvilient' would be a non-DRM protected e-book that comes on a CD that you return when you're done with it. (Yes, you could copy it. But you can copy text books too -- scanners and copiers are not hard to find.)
Seems to me that 40 years from now, our CDs and DVDs will be difficult to read as well, and that's assuming that the media itself doesn't degrade.
And of course if something is DRM'd to expire in five months, it's not supposed to be readable in six or more months, which would include 200 years later. And even if it's DRM'd but not set to expire, the odds of it being totally unreadable after just five years (because you can't get keys for it (company went under), or can't run the software, etc.) are very high.
This is one reason why I refuse to buy DRM'd music, for example. All the vinyl, tapes and CDs I've bought in the last 30 years, I can still listen to them today (if I hook up a turntable or tape player anyways.) mp3s I made ten years ago are still readable as well, as long as I didn't put them on any media that's hard to read.
But any DRM'd music that I paid for and downloaded today, the odds are very good that I won't be able to even listen to it a few years from now. The DRM software won't run on my new computer, or the purchases will be tied to that computer, or the disk will have failed and the DRM files were tied to that specific disk, or ...
Screw that. I'll buy CDs and make my own mp3s or oggs. Downloaded music from places like iTunes isn't even really signifigantly cheaper, but yet the quality is lower and the usability is much lower.
Personally, there's no way in hell I'd buy 5 month DRM'd electronic textbooks for only a 33% discount. 75%, maybe. But 33%? Screw that -- I could save more than that by buying used and selling back to the store when I'm done. And for a text book, dead tree format is likely to be more convenient than e-book format anyways. And sometimes I like to keep my books for use in later classes ...
Though I suspect that if you pay the extra 33% or so, they'll extend your DRM license for a year or so. Blech.
I guess one way to deal with it would be to just use Outlook. But that's certainly not the only way.
Why don't I use Outlook? That's easy enough to answer --
- I run Linux on my desktop at work. (I'm more productive under Linux, even in a land of Microsoft users.) Outlook doesn't run under Linux, though I might be able to make it run under Wine, and VMWare or rdesktop to a remote Windows box is an option
- I archive most of the technical email aliases at the company and make them searchable for everybody. IT ought to do this, but for now I'm the one doing it, and it's far easier to do this under *nix than Windows.
- I like to be able to access my mail similarly from home or from work or from the road. Most people do this by always running Outlook from their laptop, the same laptop, but I prefer to just ssh in.
And it all works quite well. I don't have a problem with html emails -- I just have a line in ~/.mailcap that converts them to text for mutt --and I have other lines that will fire up OpenOffice for Word files, xpdf for pdf files, etc. If I get anI wasn't complaining about the html emails -- I deal with them. Certainly, I'm not going to tell the rest of the company to change just so I can use my favorite mail reader.
I was agreeing that management often doesn't seem to know how to properly deal with email, and that's true no matter what mail reader I use.
javester said that it's not being maintained anymore, but I do see some recent updates at the Sourceforge page. If it's not being actively developed anymore, it would seem to be because it works pretty well now.
In any event, I've found it to work very well for my use.
I use mutt and fetchmail in a company of Exchange users. Almost every email I get at work now, from everybody, is in html. (Unless I sent it to myself.) I don't like it, but I deal with it. It's certainly easier to deal with it than to try and change everybody else.
I could change jobs, but over something as trivial as html emails? No. I like my job, I like the people I work with, so I just bend like the reed in the wind ...
Still, the executives are certainly worse about email ettiquette than most, and it's not just in this company -- everywhere I've worked I've found this to be the case. They don't include Subjects at all, or include useless ones like `message'. Some will type up a memo and send it as a .pdf file attachment, or worse as a .bmp file. They rarely trim anything when responding to a post -- they just top post away. (But many people do that ...)
It's really better to use things that other people have made for parsing html. For example, if you use perl (and you should -- it's the ideal tool for this), HTML::Parser works pretty well, though there's a signifigant learning curve in using it.
It can programatically convert most Word documents into html documents, and does about as good a job as one could expect. And it makes better html than Word does itself.
If O2 specifically absorbs 60-64 GHz signals, then it also specifically emits 60-64 GHz signals, which would be ... noise.
So in order to get good range with a 62 GHz signal, you'd need more power than you'd need with a lower (or higher, for that matter) frequency.
Of course, with such a high frequency, you could make very directional antennas that are very small, so you may be able to overcome the path loss with small but high gain antennas. It works for things like DirectTV -- the 11 or so GHz signal is attenuated by the atmosphere, and the satellite is 24,000 miles up, but we can pick it up with a dish that's only a few feet across, compared to the old satellite dishes. It has to be very precisely aimed right at the satellite, but since the satellite doesn't move around much, that's not a problem.
(But it works well for fiber optics, and it works well for IR remote controls, and it could work well for very narrow band transmissions using lasers ...)
Suppose you can use 60 to 61 GHz for this -- that gives you one full GHz of bandwidth. Compare this to an 802.11b channel that's only 30 MHz in size, and you can see that you can transmit over 30 times as much data in a given amount of time.
The higher the frequency, the more bandwidth is generally available, as a rule of thumb.
Also, if 60 GHz really is attenuated by oxygen so strongly, then the noise should be attenuated as well. This means that people could increase the transmitted power with little danger of interfering with users very far away, and therefore increase the S/N ratio and get even more data transferred. (Though in general, I'd say the absorbtion of the signal by oxygen is a bad thing, even though it might have a useful aspect or two.)
And as a rule of thumb, for radio, it's true, as long as you're not talking about going through things that are good conductors of electricity. (Radio waves have a hard time passing through things are good conductors of electricity, so in general if the signal does get through it's because there was a hole, and the wavelength of the signal is smaller than that of the hole -- so in that case, smaller wavelengths get in better. For example, inside a jet airliner, your cell phone may work, but your AM radio probably won't.)
Yes, there's lots of spectrum out there if you're willing to go to high enough frequencies. But it's not infinite.
But it didn't even make this list's top 100? And yet Dune 2 did? Dune 2 may have started the RTS genre, but TA polished the interface until it shined. Games like Starcraft certainly had a much better story (and I like my games to have good stories) but TA had the interface down better than anything that came before and I think anything that came after it. And it was so much fun in multiplayer, and the ability to add units (and Cavedog kept releasing new ones) kept it fresh for a long time ...