# What legitmate forms of energy do we have to choose from **URL:** \ **Category:** Factual Questions\ **Created:** [August 13, 2004, 6:10pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719 "2004-08-13T18:10:28Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![ataraxy22](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ataraxy22/32/307_2.png) [@ataraxy22](https://boards.straightdope.com/u/ataraxy22)\ **Post date:** [August 15, 2004, 3:57am UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/21 "2004-08-15T03:57:03Z")
Don’t forget hemp oil. ---
**Author:** ![Ranchoth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranchoth/32/1066_2.png) [@Ranchoth](https://boards.straightdope.com/u/Ranchoth)\ **Post date:** [August 15, 2004, 5:19am UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/22 "2004-08-15T05:19:17Z")
What does a Gerbil (or whatever) on a treadmill count as? ---
**Author:** ![InvidiousCourgette](https://avatars.discourse-cdn.com/v4/letter/i/e47c2d/32.png) [@InvidiousCourgette](https://boards.straightdope.com/u/InvidiousCourgette)\ **Post date:** [August 15, 2004, 10:15am UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/23 "2004-08-15T10:15:51Z")
> [@Crafter\_Man](#): > > One of the best “judges” of whether an energy source is a fuel or energy vessel is the free market. If commercial companies are selling an energy source for use in large-scale power distribution systems, then it’s virtually guaranteed the energy source is a fuel and not an energy vessel. I agree to a certain extent. I would argue, however, that because an energy source is not being used to any large extent now, it does not preclude its large scale use in the future. The use of biomass as a fuel is not widespread, though it is already being exploited in significant quantities in countries such as Brazil (in the case of alcohol). As and when the world’s oil stocks are used up, more biomass production is widely predicted. Economics and not physics prevent earlier adoption. ---
**Author:** ![EvilGhandi](https://avatars.discourse-cdn.com/v4/letter/e/f17d59/32.png) [@EvilGhandi](https://boards.straightdope.com/u/EvilGhandi)\ **Post date:** [August 15, 2004, 10:52am UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/24 "2004-08-15T10:52:06Z")
Finagle states, “Well, there’re always the traditional ones – slaves and animals” I think he is correct. Most of the work done on my sites is done by pure human power. When we use power tools, I imagine they increse our efficiency, but without skilled men they’d be useless. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [August 15, 2004, 12:14pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/25 "2004-08-15T12:14:07Z")
> [@tygerbryght](#): > > Um, maybe I shouldn’t ask, but I can’t resist. :o > > What, pray tell, is an illegitimate form of energy? I think **Crafter Man** already answered that question pretty throuroghly. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [August 15, 2004, 4:19pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/26 "2004-08-15T16:19:50Z")
> [@tygerbryght](#): > > What, pray tell, is an illegitimate form of energy? Ones that won’t be viable for 30 years, that are just theoretical or small scale. I was asking about forms of power we currently have access to that are proven to work on a large scale. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [August 15, 2004, 5:42pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/27 "2004-08-15T17:42:12Z")
> [@SteelWolf](#): > > Legitimate forms of energy are: > > 1. Electromagnetic > 2. Weak nuclear forces > 3. Strong nuclear forces > 4. Gravitational potential > > Oh, you meant power sources we can harness to do useful work? (sorry, I’ve been hanging out with way too many physics geeks…) Ask those physics geeks sometime to explain to you the difference between _force_, _energy_, and _power_. You appear to be using the terms interchangeably. Hint: You have apparently attempted to list the four fundamental forces, presuming you omit the word _potential_ in item #4. (There is a difference between gravitational force, gravitational potential, and gravitational potential energy.) ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [August 15, 2004, 5:56pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/28 "2004-08-15T17:56:34Z")
> [@Crafter\_Man](#): > > Despite the fact there are studies that “prove” a PV array generates net power after 4 or 5 years, I think they neglect a lot of variables. In fact, I strongly suspect that no PV array has _ever_ generated one net watt. I don’t suppose you can provide a cite for this? You’ve made this assertion in other threads, and so far as I can tell have backed it up solely by your gut intuition. How about something a little more authoritative? ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [August 15, 2004, 6:25pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/29 "2004-08-15T18:25:46Z")
> [@Gorsnak](#): > > I don’t suppose you can provide a cite for this? You’ve made this assertion in other threads, and so far as I can tell have backed it up solely by your gut intuition. How about something a little more authoritative? The fact that the free market has not embraced PV systems for use in large-scale power distribution systems is a convincing indication that such systems do not pay for themselves. The folks who run the coal & oil companies are not stupid; if they truly believed PV systems were worthwhile, they would build them. ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [August 15, 2004, 6:34pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/30 "2004-08-15T18:34:27Z")
> [@Crafter\_Man](#): > > The fact that the free market has not embraced PV systems for use in large-scale power distribution systems is a convincing indication that such systems do not pay for themselves. The folks who run the coal & oil companies are not stupid; if they truly believed PV systems were worthwhile, they would build them. No. It is a convincing indication that the short-term return on investment on PV is small relative to the short-term ROI on other energy sources. And, of course, you completely neglect that the costs of various energy sources involve not only the energy costs of retrieving those sources, but a myriad of other costs as well - real estate, labour, etc. The mere fact that one breaks even monetarily on PV systems after some years is an indication that they do produce net watts, since the energy costs of producing/transporting/etc the panels are passed on to the buyer. I do not profess to _know_ that PV are net energy producers. However, you have not provided one shred of evidence that they aren’t. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [August 15, 2004, 6:42pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/31 "2004-08-15T18:42:09Z")
> [@Crafter\_Man](#): > > With a _legitimate_ energy source (a.k.a. “fuel”), you get more energy _out_ of it than what you _expend_ to obtain it. With this in mind, there are only a handful of legitimate energy sources. These include oil, gas, coal, hydroelectric, and nuclear. Only legitimate energy sources can be considered for use in large-scale power distribution systems. > > An energy source that produces _less_ energy when compared to the amount of energy expended to obtain it is not a fuel; it is an _energy vessel_. . One thing that is not considered here is the usefulness of the energy to start and later. For example, one can feed a draft animal on stuff that grows wild, and can’t be effectively used for anything. But of course, the raw energy of the plantstuffs used to feed a draft animal exceed the work you get out of it. ---
**Author:** ![Cooper](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@Cooper](https://boards.straightdope.com/u/Cooper)\ **Post date:** [August 15, 2004, 6:57pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/32 "2004-08-15T18:57:32Z")
> [@DrDeth](#): > > One thing that is not considered here is the usefulness of the energy to start and later. For example, one can feed a draft animal on stuff that grows wild, and can’t be effectively used for anything. But of course, the raw energy of the plantstuffs used to feed a draft animal exceed the work you get out of it. Aren’t we always harvesting energy that was vessled for us? This is just another example of how it is cheaper to harvest that energy (by letting the animal wander around and eat scrub plants). If we had to build our own sun, I don’t think solar power (in any of the forms we use to harvest it, such as biomass) would be a net gain for us since so much energy is radiated away from us. The question isn’t how much total energy is stored and how much is lost in the conversion, but how much we invest in retrieving or converting it. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [August 15, 2004, 7:04pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/33 "2004-08-15T19:04:26Z")
> [@Gorsnak](#): > > No. It is a convincing indication that the short-term return on investment on PV is small relative to the short-term ROI on other energy sources. And, of course, you completely neglect that the costs of various energy sources involve not only the energy costs of retrieving those sources, but a myriad of other costs as well - real estate, labour, etc. > > The mere fact that one breaks even monetarily on PV systems after some years is an indication that they do produce net watts, since the energy costs of producing/transporting/etc the panels are passed on to the buyer. > > I do not profess to _know_ that PV are net energy producers. However, you have not provided one shred of evidence that they aren’t. I do not have a cite; it is simply this electrical engineer’s gut feeling that a system based on PV technology requires more energy to manufacture, run, and maintain that what you can get out of it. Tell you what, **Gorsnak** , if you truly believe PV arrays “pay for themselves” and are the wave of the future, you should take some capital and _invest_ in it. Here are some links to get you started: [http://www.sunedison.com/invest.html](http://www.sunedison.com/invest.html) [http://www.nanosolar.com/investors.htm](http://www.nanosolar.com/investors.htm) [http://www.powertech-solar.com/investment.html](http://www.powertech-solar.com/investment.html) [http://www.oksolar.com/info/money.html](http://www.oksolar.com/info/money.html) Get back with me in 10 years and let me know how you’re doing. While you’re at it, you might find the following interesting. It’s an article about a homeowner who installed a PV system: [http://www.hollowtop.com/cls\_html/solar\_power.htm](http://www.hollowtop.com/cls_html/solar_power.htm) At least the guy is honest: > [@](#): > > If you do the number crunching, our solar electric installation doesn’t seem to make much economic sense. Given the total cost of the project, it is unlikely that the system would ever recover its costs. Even with more than half the cost subsidized by the USBC Rebate and the Renewable Energy Tax Credit, our share of the cost could easily take 20-30 years to recover. It may seem like a poor investment on our part, as well as a waste of other people’s money to subsidize this technology that doesn’t pay for itself. It’s also a “battery-less” system, which means they still need to be connected to the grid for it to work. What a colossal waste of money. :rolleyes: ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [August 15, 2004, 7:25pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/34 "2004-08-15T19:25:51Z")
> [@Crafter\_Man](#): > > I do not have a cite; it is simply this electrical engineer’s gut feeling that a system based on PV technology requires more energy to manufacture, run, and maintain that what you can get out of it. > > Tell you what, **Gorsnak** , if you truly believe PV arrays “pay for themselves” and are the wave of the future, you should take some capital and _invest_ in it. Here are some links to get you started: > > Get back with me in 10 years and let me know how you’re doing. > > While you’re at it, you might find the following interesting. It’s an article about a homeowner who installed a PV system: > > [http://www.hollowtop.com/cls\_html/solar\_power.htm](http://www.hollowtop.com/cls_html/solar_power.htm) > > At least the guy is honest:It’s also a “battery-less” system, which means they still need to be connected to the grid for it to work. What a colossal waste of money. :rolleyes: So, still no evidence. Very nice. Perhaps you would like to point out where I have stated that I “truly believe” that PV is a net power producer? I _don’t know_. But I’d like to. Hence, I’d like some evidence, one way or the other. You have produced none, hence I don’t feel like I’m any closer to the answer. Your investment “argument” is stupid. Even if there’s a major breakthrough and PV _is_ the wave of the future, there’s no reason to believe that investment in current PV companies would pan out. Only with a crystal ball to determine which of these companies would turn out to be the Microsoft of PV would it be smart. The others may well go the way of Amiga. And going without batteries and remaining hooked into the grid is not “a colossal waste of money.” It’s the smart way to go. Use the grid as a storage device. Batteries are expensive, and involve a loss of efficiency. Why not rather contribute your excess energy into the grid when you’ve got it, and draw energy when you need it and it’s dark? This has nothing to do with whether PV produces more energy than it costs to produce. It does have something to do with whether we can use _solely_ solar power, but that’s not particularly relevant to my question. So long as we have a base of non-solar power production that can be varied, it makes better sense to vary that production than it does to dump PV-produced electricity into and out of batteries. ---
**Author:** ![InvidiousCourgette](https://avatars.discourse-cdn.com/v4/letter/i/e47c2d/32.png) [@InvidiousCourgette](https://boards.straightdope.com/u/InvidiousCourgette)\ **Post date:** [August 15, 2004, 7:43pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/35 "2004-08-15T19:43:21Z")
> [@Crafter\_Man](#): > > Tell you what, **Gorsnak** , if you truly believe PV arrays “pay for themselves” and are the wave of the future, you should take some capital and _invest_ in it. There is a distinction between something “paying for itself” and something being a worthwhile investment. A PV array might pay for itself in 10 years, 100 years, whatever. In my business, something would only be considered a worthwhile investment if it paid for itself within 5 years. I think we can take it as self evident that PV arrays do not usually satisfy this criteria. If this were not the case, it would be reasonable to expect that we would see much more of them. I think it would be a fairer challenge to ask **Gorsnak** to provide a cite that demonstrated a PV array has ever paid itself back, as per his contention. I think it is also fair to ask you to provide a cite, as opposed to a gut feeling, that > [@](#): > > no PV array has ever generated one net watt as per your contention. I would not accept either postulation as being correct without seeing evidence. This is GQ after all. 🙂 ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [August 15, 2004, 7:49pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/36 "2004-08-15T19:49:49Z")
I have provided a cite in a past thread - in [this post](http://boards.straightdope.com/sdmb/showpost.php?p=5105049&postcount=12) The study cited there claims to take into account all the factors **Crafter Man** says are never taken into account - transportation, production of manufacturing facilities, etc, and says that PV cells in 2000 paid for themselves energywise (not costwise) in about 10 years out of a 30 year lifespan. The study doesn’t show any of their numbers, however, so I take it with a grain of salt. Still, it’s the closest thing to evidence I’ve seen on the matter. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [August 15, 2004, 8:21pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/37 "2004-08-15T20:21:20Z")
Like I said, I have no cite, and it’s my gut feeling (as an EE) that no PV-based power system has ever produced _one net watt_. It’s also my opinion that if technology progressed to the point where PV-based systems _did_ produce net power, the power companies would be scrambling to build them. ---
**Author:** ![matt\_mcl](https://avatars.discourse-cdn.com/v4/letter/m/7ab992/32.png) [@matt\_mcl](https://boards.straightdope.com/u/matt_mcl)\ **Post date:** [August 15, 2004, 8:24pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/38 "2004-08-15T20:24:45Z")
Microwave. But you have to be careful – sometimes the satellite goes out of alignment and burns a path through your city, destroying property and setting fires. Oops. 😉 ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [August 15, 2004, 8:28pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/39 "2004-08-15T20:28:33Z")
> [@Gorsnak](#): > > transportation, production of manufacturing facilities, etc A large-scale PV-based system also consumes quite a bit of permanent real estate. Did they also take into account the _opportunity cost_ of the land? Probably not. And did they include the inefficiency of DC to AC inversion? ---
**Author:** ![Gorsnak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gorsnak/32/7587_2.png) [@Gorsnak](https://boards.straightdope.com/u/Gorsnak)\ **Post date:** [August 15, 2004, 8:41pm UTC](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719/40 "2004-08-15T20:41:41Z")
> [@Crafter\_Man](#): > > A large-scale PV-based system also consumes quite a bit of permanent real estate. Did they also take into account the _opportunity cost_ of the land? Probably not. And did they include the inefficiency of DC to AC inversion? Real estate isn’t an energy cost, unless you’re planning on using it to grow biomass for energy production instead. Most rooftops aren’t being used for biomass production, to my knowledge. I don’t know if they included the inefficiency of inversion. What is it, about 10%? So add a year to their estimate. Doesn’t change the conclusion much. Anyways, the inefficiency of inversion is irrelevant to the question of whether PV is a net energy source. The only reason inversion is necessary is because we happen to use AC for most of our electrical needs - except that half the stuff I’m powering converts it back to DC before it’s finally used. Saying that PV only produces the amount of energy left after converting it to AC and back to DC again is like saying that the US dollar is worth $USD0.95, because that’s what I’d have left after converting it to $CAD and back to $USD. [Previous page](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719.md?page=1) [Next page](https://boards.straightdope.com/t/what-legitmate-forms-of-energy-do-we-have-to-choose-from/259719.md?page=3)