1.21 gigawatts

[mopc]

I'm a fan of the movie Back to the Future, and in the movie it is stated that a bolt of lightning contains 1.21 gigawatts. Is it true? I always wanted to ask that to specalists but kept forgetting!!!

[Lurker]

I thought it was 1.21 Jigawatts, not something real, just designed to sound really, really big!!

[W.F. Tomba]

I thought it was 1.21 Jigawatts, not something real, just designed to sound really, really big!!
Some people pronounce giga- like "jiga".

[mopc]

I thought it was 1.21 Jigawatts, not something real, just designed to sound really, really big!!
Some people pronounce giga- like "jiga".

Actually the official script of the movie spells it "jigowatts", so the intention was to create a crazy unit of measurement. But I just wanna know how mant watts are in a bolt of lightning.

[Vega115]

well...a gigawatt is equivalant to one billion watts. a watt is one joule per second....


so i guess 1.21 Gigawatts may be a lot...

[Grey]

In fact a typical bolt of lightning is somewhere around a gigawatt, though occasionally you can get much larger than that (a hundred to a thousand times more powerful!) Of course, it's very short-lived, so the amount of energy isn't as large as it might seem from the power, though still pretty impressive.

[Kristophe]

One of my professors pronounces giga with a soft g. I have a really, really difficult time not laughing at her...

[AT]

I took a week of Ancient Greek before I quit; In that class, 'giga' is said 'Jiga'. So.. maybe its only half wrong.

[Inferno]

Found this in IMDB tivia section - which probably means someone got it from the Back to the Future DVD special features.......or just made it up:

In the film's script the word "gigawatt" is spelt "jigowatt". Bob Gale and Robert Zemeckis had been to a science seminar and the speaker had pronounced it "jigowatt".

[kg034]

In fact a typical bolt of lightning is somewhere around a gigawatt, though occasionally you can get much larger than that (a hundred to a thousand times more powerful!) Of course, it's very short-lived, so the amount of energy isn't as large as it might seem from the power, though still pretty impressive.

For another fun number in the Giga range, the heat generating elements of current microprocessors dissipate heat on the order of several gigawatts/m^3. Thank God they're tiny :)

Also, check out the
Wikipedia energy scale (http://en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29). You'll find out that a bolt of lightning releases about the same energy as a tankful of gasoline.

[A Thousand Pardons]

I took a week of Ancient Greek before I quit; In that class, 'giga' is said 'Jiga'. So.. maybe its only half wrong.
I just checked my Ame.Her.Dic., and the soft g is the first pronunciation every time (jigabit, jigabyte, jigacycle, jigahertz). That's probably the way it is on dictionary.com too then.

[W.F. Tomba]

I took a week of Ancient Greek before I quit; In that class, 'giga' is said 'Jiga'. So.. maybe its only half wrong.
I just checked my Ame.Her.Dic., and the soft g is the first pronunciation every time (jigabit, jigabyte, jigacycle, jigahertz). That's probably the way it is on dictionary.com too then.
What does it mean that it's first? Does the American Heritage Dictionary order the pronunciations according to how prevalent they are?

[Crazieman]

Soft G has always been the correct pronunciation.

But the American tech industry got to it first, and will be abused for the rest of time. Might as well rewrite the rule.

[CTM VT 2K]

The first time I saw it, I thought he said 12.21, not 1.21. I'm still not 100% certain he didn't say 12.21 gigawatts. Not really adding anything material to the debate I guess, just my own musings on it.

[farmerjumperdon]

As a youngster one of my favorite exhibits at the Museum of Science & Industry in Chicago was the lightning bolt generator. Can't remember the proper terminology, but they had a stack of monstrous capacitors in the middle of the room that were charged up, I believe it was 10 units of 100,000 volts or watts each. They sounded a bell, at which time everyone was warned to hold this rail that went around the display. The stack was then discharged via a rod sticking out the top of the stack (which I'm guessing was 12 to 15' tall). A bolt of lightning then went from the top of the stack to a copper pipe that circled the ceiling at the perimeter of the room. The noise and flash were fantastic.

I could have some details wrong as it has been a long time; but I thought it was 1 million volts.

[A Thousand Pardons]

I took a week of Ancient Greek before I quit; In that class, 'giga' is said 'Jiga'. So.. maybe its only half wrong.
I just checked my Ame.Her.Dic., and the soft g is the first pronunciation every time (jigabit, jigabyte, jigacycle, jigahertz). That's probably the way it is on dictionary.com too then.
What does it mean that it's first? Does the American Heritage Dictionary order the pronunciations according to how prevalent they are?
Ame.Her.Dic. (1970, p.XLII) says "All pronunciations given are acceptable in all circumstances. When more than one is given, the first is assumed to be the more common, but the difference in frequency may be insignificant."

[jfribrg]

I took a week of Ancient Greek before I quit; In that class, 'giga' is said 'Jiga'. So.. maybe its only half wrong.
I just checked my Ame.Her.Dic., and the soft g is the first pronunciation every time (jigabit, jigabyte, jigacycle, jigahertz). That's probably the way it is on dictionary.com too then.
What does it mean that it's first? Does the American Heritage Dictionary order the pronunciations according to how prevalent they are?

IIRC, the Oxford Dictionary lists definitions in the order that they entered the language. I'm not sure about the pronunciations.

[mopc]

The first time I saw it, I thought he said 12.21, not 1.21. I'm still not 100% certain he didn't say 12.21 gigawatts. Not really adding anything material to the debate I guess, just my own musings on it.

No, it's 1.21 gigawatts.

Well, the pronunciation issue is quite interesting, but how many watts are there in a bolt of lightning after all? Is Grey above correct, the typical lighnting has about 1 gigawatt???

If you have a machine that needs 1.21 gigawatts to work, would a bolt of lightning suffice???


What is a watt, afterall? And a volt? I never understood exactly what it means.

[cyswxman]

The basic formula is: Watts = Volts x Amperes
IIRC, a "typical" lightning bolt is estimated to have about 30 million volts and about 100K Amps. This gives W= 300 billion (or 300 giga) watts! However, some of that energy is lost through radiative heat (which results in thunder), thus the amount that could be potentially harnessed at the point of strike would be considerably less. And of course, it's only for an instant.

edited to correct figures

[kucharek]

The basic formula is: Watts = Volts x Amperes
IIRC, a "typical" lightning bolt is estimated to have about 30 million volts and about 100K Amps. This gives W= 300 billion (or 300 giga) watts! However, some of that energy is lost through radiative heat (which results in thunder), thus the amount that could be potentially harnessed at the point of strike would be considerably less. And of course, it's only for an instant.


Watts is not enery, watts is power! Energy is power times time. So, if you've 300GW for a millionth of a second, the energy in this would be 300000Ws=Nm=J, which would be 83kWh, which is not so impressive in terms of energy.

[Andrew]

Well, the pronunciation issue is quite interesting, but how many watts are there in a bolt of lightning after all?
It is not really meaningful to ask how many watts a bolt of lightning contains, the number just tells you how quickly it disipates energy.

[Grey]

Well, the pronunciation issue is quite interesting, but how many watts are there in a bolt of lightning after all? Is Grey above correct, the typical lighnting has about 1 gigawatt???
It's a figure I recalled, and doing a quick Google search, I see similar numbers. This introductory textbook (http://acept.la.asu.edu/courses/phs110/ds/appendixC.html), for example, agrees, since it gives the rough voltage as 100,000 V, the current as approximately 100 A, and power is voltage times current squared. Of course, this is certainly an estimate, and I do know that the high end can be significantly higher, as I mentioned.

If you have a machine that needs 1.21 gigawatts to work, would a bolt of lightning suffice???
If it only needs to be powered for the fraction of a second that is the typical duration of a lightning bolt, and wasn't too picky about the power level being very precise or very constant, I suppose it might.

What is a watt, afterall? And a volt? I never understood exactly what it means.
A watt is unit of power, and power is energy over time. That is, a 100 watt light bulb uses 100 joules of energy every second, changing that energy from electrical energy to light and heat. If you have a 100 watt light bulb on for 2 seconds, and a 200 watt light bulb on for 1 second, they will both have used the same amount of energy.

A volt is the unit of electric potential difference (what we normally call a "voltage" - that's like calling length "yardage", though interestingly nobody ever says "meterage"), a way of measuring how the electric fields present are trying to push charges around. Perhaps the best way to think of it is by analogy to gravitational potential, so you can think of a larger voltage as being "higher". If given a path to do so, electric charge will flow from a higher potential to a lower one, just like water would would flow to a lower level.

And as with differences in height, it only really makes sense to talk about differences in height (how high is something that's at 1000 m, if I don't specify that I mean 1000 m above sea level, or 1000 m above the ground, or use some other reference?). Generally when working with electrical circuits, our standard of reference is the ground, literally a wire connected by some easily conducting path to the Earth. Since the Earth is really big, any charge that might accumulate will be negligible, and the Earth as a whole can be considered uncharged.

Does that help?

[mopc]

Well, the pronunciation issue is quite interesting, but how many watts are there in a bolt of lightning after all?
It is not really meaningful to ask how many watts a bolt of lightning contains, the number just tells you how quickly it disipates energy.

So there is no machine that needs an X-number of Watts, for it all depends on for how long those watts stream in.

So the DeLorean of Back to the Future woudn't actually need 1.21 gigawatts, rather a certain number of volts???

[mopc]

Well, the pronunciation issue is quite interesting, but how many watts are there in a bolt of lightning after all? Is Grey above correct, the typical lighnting has about 1 gigawatt???
It's a figure I recalled, and doing a quick Google search, I see similar numbers. This introductory textbook (http://acept.la.asu.edu/courses/phs110/ds/appendixC.html), for example, agrees, since it gives the rough voltage as 100,000 V, the current as approximately 100 A, and power is voltage times current squared. Of course, this is certainly an estimate, and I do know that the high end can be significantly higher, as I mentioned.

If you have a machine that needs 1.21 gigawatts to work, would a bolt of lightning suffice???
If it only needs to be powered for the fraction of a second that is the typical duration of a lightning bolt, and wasn't too picky about the power level being very precise or very constant, I suppose it might.

What is a watt, afterall? And a volt? I never understood exactly what it means.
A watt is unit of power, and power is energy over time. That is, a 100 watt light bulb uses 100 joules of energy every second, changing that energy from electrical energy to light and heat. If you have a 100 watt light bulb on for 2 seconds, and a 200 watt light bulb on for 1 second, they will both have used the same amount of energy.

A volt is the unit of electric potential difference (what we normally call a "voltage" - that's like calling length "yardage", though interestingly nobody ever says "meterage"),

Funny thing, but in Portuguese we do: metro > metragem, quilómetro > quilometragem. Our word for "yard" is "jarda" but it's only used in medieval texts or translating American stuff, so we don't have "jardagem".


a way of measuring how the electric fields present are trying to push charges around. Perhaps the best way to think of it is by analogy to gravitational potential, so you can think of a larger voltage as being "higher". If given a path to do so, electric charge will flow from a higher potential to a lower one, just like water would would flow to a lower level.

And as with differences in height, it only really makes sense to talk about differences in height (how high is something that's at 1000 m, if I don't specify that I mean 1000 m above sea level, or 1000 m above the ground, or use some other reference?). Generally when working with electrical circuits, our standard of reference is the ground, literally a wire connected by some easily conducting path to the Earth. Since the Earth is really big, any charge that might accumulate will be negligible, and the Earth as a whole can be considered uncharged.

Does that help?

Helps a lot!!! Thanks!!! :D

Another question: what is electricity? What happens when a wire conducts electricity? Do electrons jump from atom to atom in the copper? What exactly is being conducted?

[kg034]

The basic formula is: Watts = Volts x Amperes
IIRC, a "typical" lightning bolt is estimated to have about 30 million volts and about 100K Amps. This gives W= 300 billion (or 300 giga) watts! However, some of that energy is lost through radiative heat (which results in thunder), thus the amount that could be potentially harnessed at the point of strike would be considerably less. And of course, it's only for an instant.


Watts is not enery, watts is power! Energy is power times time. So, if you've 300GW for a millionth of a second, the energy in this would be 300000Ws=Nm=J, which would be 83kWh, which is not so impressive in terms of energy.

As Wikipedia (http://en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29) points out, it is less energy than a modest tankful (12gallons~45liters) of gasoline. As kucharek points out, its just that amount of energy is released over a shorter time, and not during a 4 or 5hour drive. BABBlers, think about that next time you pop into one of those monstrosities called an SUV or a pick-up truck.

[Grey]

So there is no machine that needs an X-number of Watts, for it all depends on for how long those watts stream in.

So the DeLorean of Back to the Future woudn't actually need 1.21 gigawatts, rather a certain number of volts???
Most machines are designed for a certain voltage as well as wattage. For example, that lightbulb expects 100 watts of power, delivered at about 120 volts, which means that it's drawing a current of about 1.1 amps. You could theoretically have a current-limited voltage source that could provide the full voltage, but not that much power, and the light would be dimmer. How sensitive a given machine is to having exactly the right voltage and power depends on the characteristics of the machine (typically, the more complex it is, the more important it is to provide exactly what it expects).

[Grey]

Another question: what is electricity? What happens when a wire conducts electricity? Do electrons jump from atom to atom in the copper? What exactly is being conducted?
So remember that the voltage difference corresponds to an electric field that exerts on force on charged objects. The atoms are pretty hard to move, since they're held in place by the other atoms, but if the force is large enough, it will push the electrons along. How much force is required to do that depends on the material. For an insulator, the force needed is very large, so relatively little current flows for a given voltage. For good conductors like metals, it turns out that because of the details of the electron configuration in each atom, there are some electrons that remain trapped in the material as a whole, but aren't particularly strongly bound to any particular atom.* There ends up being roughly one such electron per atom for the good conductors. So if you apply any field at all, these electrons will flow very easily and you see a current flowing.

As an aside, the net flow of charge is very quick. So if you push a few electrons in one end of a copper wire, the time it takes for electrons to come out the other side is very short. But the speed of the electrons themselves isn't all that fast, comparable to a walking pace. The electrons you push in at this end repel the electrons nearest them, which move a little way down the wire, increasing the number of electrons in that part of the wire, so the electrons there are repelled, and move a little, and so forth.

* I won't go into the details here, but one of the impressive feats of quantum theory is being able to show just how this macroscopic property of a material (how well it conducts electricity) arises from the arrangement of electrons in each atom, and how the energy levels of those electrons change when the atoms are close together in a solid.

[Inferno]

Once we've sold this question, we can move on to how the time train in part 3 could operate just on steam!

[mopc]

Yeah, lets turn this into a Back to the Future science thread.

Other questions would be Mr. Fusion - the gadget Doc adapted to the DeLorean in 2015 to replace the plutonium fission device that powered the Flux Capacitor. Could fusion ever work with everything? I mean, Mr. Fusion turns even garbage into energy!

What about the hover technology - in 2015 (unfortunately we're not even close yet) things can float in the air - the hoverboard, for instance.

What about time travel itself - if possible, what sorts of paradoxes would time travel into the past cause? Would it destroy the "fabric of space-time continuum"? The universe?

The time train is really tough to explain - how could steam generate 1.21 gigawatts?

[Fortis]

Soft G has always been the correct pronunciation.

But the American tech industry got to it first, and will be abused for the rest of time. Might as well rewrite the rule.
And dont' get me started on gigabytes and gibibytes... (http://physics.nist.gov/cuu/Units/binary.html) :)

[mopc]

Resurrecting this thread, is it possible to turn anything into fusion fuel, like Mr. Fusion? After all, e=mc2!

[JohnOwens]

Also, check out the
Wikipedia energy scale (http://en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29). You'll find out that a bolt of lightning releases about the same energy as a tankful of gasoline.
You're welcome. :) You know, I actually had to fight a bit to keep those pages in existence, since some people thought the comparisons of powers and energies were completely useless. And even now, I see someone's gone and changed it so it's all on one page, rather than one page for joules, one for kilojoules, one for megajoules, etc., you get the idea. I'm not quite sure how I feel about this yet. :-k But I did contribute a lot of the energy numbers there, though it doesn't show up in the page history, since those pages were merged into that one in the end.

[Argos]

Resurrecting this thread, is it possible to turn anything into fusion fuel, like Mr. Fusion? After all, e=mc2!

Fusion is a process in which light elements, under great pressures (like in the core of stars), fuse together to form heavier ones. The simplest fusion process takes two light hydrogen nuclei to form a heavier helium nucleus (we say nucleus because at the fusion energies the atoms are stripped of their electrons; only the nuclei are involved). This is an extreme simplification.

Heavy elements can fuse to form even heavier ones, but as the mass of the elements increases so does the energy required to fuse them. Until you get to fuse iron the process releases energy. For elements heavier than iron the process requires more energy than it releases.

Thus, you can see that few elements can yield an appreciable amount of energy in a fusion process. Garbage is comprised mostly of Carbon, lighter than Iron, so you could expect (little) energy release on the process. The problem would be how to start it.

[Moose]

Once we've sold this question, we can move on to how the time train in part 3 could operate just on steam!

Capacitors?

[Fram]

If 1 Watt is 1 joule per second, then what is meant by a kilowatthour? Is one kilowatthour the same as 3600 kilojoules?

Perhaps it's not in common use, but kWh is the unit by which electricity bills in Belgium are calculated. I have no idea if it's the same all over the world...

[mopc]

If 1 Watt is 1 joule per second, then what is meant by a kilowatthour? Is one kilowatthour the same as 3600 kilojoules?

Perhaps it's not in common use, but kWh is the unit by which electricity bills in Belgium are calculated. I have no idea if it's the same all over the world...

Yeah, kilowatt/hour is what's written on my electricity bill.

[Disinfo Agent]

You should write kilowatt-hour, though. Multiplied, not divided. 1 kWh = 1 kW * 1 h

One of my professors pronounces giga with a soft g. I have a really, really difficult time not laughing at her...
And why not? It comes from the same root (http://en.wikipedia.org/wiki/Giga) as words like "gigantic" (http://dictionary.reference.com/search?q=gigantic).

[Grey]

If 1 Watt is 1 joule per second, then what is meant by a kilowatthour? Is one kilowatthour the same as 3600 kilojoules?
Exactly correct.

[Frog march]

Resurrecting this thread, is it possible to turn anything into fusion fuel, like Mr. Fusion? After all, e=mc2!


there is quite a lot of Hydrogen in a banana skin(as was used in the film) to make quite a bit of energy., i would have thought....

[Russ]

Yeah, lets turn this into a Back to the Future science thread.

The time train is really tough to explain - how could steam generate 1.21 gigawatts?

There is a power plant that I work in from time to time that runs on steam. Coal is burned in a boiler, the steam from the boiler goes through piping to a turbine generator. The standard description for the power production of this plant is 1,200 megawatts. I could just as correctly be said 1.2 gigawatts. The routinely run the unit at 1.3 gigawatts so 1.21 is possible.

Assuming the train in BTTF generates that much power, it would have to be roughly the same size as the power station I work at. That means the boiler would have to be about 300 feet high by 100 feet square or= dimentions. It would have to turn about 34,000 gallons of water to steam per minute and burn about 1 ton of coal per minute. The turbine is a multi-stage, multi-reheat, condenser, paralell generator system about 100 yards in total lenght.

Well, maybe they were streatching the truth a bit in BTTF3. :lol:

Actually, the real problem would be conducting that much electricity from the generator to the flux capacitor within the confines of the DeLorian or the steam engine. :lol:

[Frog march]

Yeah, lets turn this into a Back to the Future science thread.
.
.


well if you did start a Back to the Future thread you could do it in honer of John Delorean, who died on Saturday..

http://news.independent.co.uk/world/americas/story.jsp?story=622452

[Van Rijn]

Yeah, lets turn this into a Back to the Future science thread.

The time train is really tough to explain - how could steam generate 1.21 gigawatts?

... (bits removed)

Actually, the real problem would be conducting that much electricity from the generator to the flux capacitor within the confines of the DeLorian or the steam engine. :lol:

Well there you have the answer: Just charge up a capacitor bank (or perhaps one really big "flux capacitor" and dump the charge all at once. ZAP! Next I'll explain how to design a flux capacitor and basic temporal mechanics ... (crickets chirping) ...

[Frog march]

What about time travel itself - if possible, what sorts of paradoxes would time travel into the past cause? Would it destroy the "fabric of space-time continuum"? The universe?

The time train is really tough to explain - how could steam generate 1.21 gigawatts?

Q. why did the chicken cross the road.
A. he didn't, because his grandchick shot him when he got to the other side.

[Donnie B.]

I have a theory (which is mine).

I think that the hard-G pronunciation of "giga- " is preferred now for reasons of political correctness. "jigawatt" or "jigabyte" is strongly suggestive of the word "jigaboo", a racial slur. Not so with the hard-G version.

You think?

[Disinfo Agent]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...

[Fortis]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...
Though, ironically, they really mean Gibibyte. :)

[mopc]

Yeah, lets turn this into a Back to the Future science thread.
.
.


well if you did start a Back to the Future thread you could do it in honer of John Delorean, who died on Saturday..

http://news.independent.co.uk/world/americas/story.jsp?story=622452

Yeah, I heard that, unfortunately I opened this thread much earlier... they should make a movie about him.... did you know the DeLorean was made in Northern Ireland?

[um3k]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...
I don't. I haven't heard anyone else pronounce it that way, either. Unless I misunderstand what is meant by "hard g."

[JohnOwens]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...I don't. I haven't heard anyone else pronounce it that way, either. Unless I misunderstand what is meant by "hard g."
G as in "golf", as opposed to soft g in "giraffe", e.g.

[Disinfo Agent]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...
Though, ironically, they really mean Gibibyte. :)
I didn't get that one. :-? It must be some computer scientist pun. :P Could you explain it?

[Avatar28]

Gibibyte, mebibyte, etc are the "official" names for the binary based numbers (powers of 2).

Eg:

Kilobyte = 1,000 bytes (10^3)
Kibibyte = 1,024 bytes (2^10)
Megabyte = 1,000,000 bytes (10^6)
Mebibyte = 1,048,576 bytes (2^20)
Gigabyte = 1,000,000,000 bytes (10^9)
Gibibyte = 1,073,741,824 bytes (2^30)

And so forth. Nobody much really uses them, but that's the official way of doing it.

[um3k]

Or maybe it was due to the influence of "gigabyte". I think many people pronounce "gigabyte" with a hard g, too...I don't. I haven't heard anyone else pronounce it that way, either. Unless I misunderstand what is meant by "hard g."
G as in "golf", as opposed to soft g in "giraffe", e.g.
Ok, nevermind then. I was confused. I pronounce it with a hard g. :oops:

[at0z]

It's quite simple really and you really have to be accurate when considering the two technical explanations given in Part 1: 1.21GW + 88MPH = Time Travel

Doc Brown says 'this sucker is electrical', ie needs 1.21 GW normally from plutonium then from a bolt of lightening and finally from Mr Fusion. This all happens in Part 1.
The car+gasoline is for getting it up to 88MPH.

All the vehicles after Part 1 no longer require Plutonium or a Bolt of Lightening. Doc Brown has (or has knowledge of) Mr Fusion.

The first train is required to push the Delorean to 88 MPH. The only problem was getting the train to go that fast - solved with Doc's wacky fireworks in the boiler.

The last train that IS a time machine clearly has a Mr Fusion. You might ask how? Well Doc would have definitely been curious as to how small safe fusion works when he discovered them in the future so he knows how to build one and therefore can now make the 1.21 GW required without need for Plutonium or Lightening.

Jules and Verne are both young boys and not babies so we know that enough time has passed to allow Doc to have made the required tech to allow this all to work.

Furthermore, the train has been to the future for a hover conversion (either that or Doc retrofitted it himself in the past, but this is unlikely and the idea is meant to be that we know he has been popping about time a bit) so maybe he only needed his fusion technology to work just the once then once he got to the future he got a proper Mr Fusion.

I hope this clears up any confusion. Doc doesn't need to make the steam power the Flux Capacitor.

Hang on, CAPACITOR? So surely it could just be charged up til it holds the 1.21 GW unless it doesn't have that capacity? But surely if it HAS to have that capacity in order to work? Maybe it's too short lived to hold its charge? OK, new can of worms....

And you know I even bloomin' registered on this forum just to post this response to all the old 'how does the train do 1.21 GW' queries...

I just hope someone reads this or I wasted my time ;)

[mugaliens]

You'll find out that a bolt of lightning releases about the same energy as a tankful of gasoline.

Except when it hits a tankful of gasoline. Then it releases twice as much.