# Is there any battery chemistry that can compete with gasoline on energy density? **URL:** \ **Category:** Factual Questions\ **Created:** [February 24, 2015, 6:21pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536 "2015-02-24T18:21:18Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 26, 2015, 1:23pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/41 "2015-02-26T13:23:26Z")
> [@Amateur\_Barbarian](#): > > Any form of concentrated fuel-energy in a practical moving vehicle is potentially dangerous. People burn to death in moderate crashes in modern cars, even. I don’t see capacitors as inherently more dangerous than 20 gallons of highly volatile fuel. While you describe gasoline as ‘highly volatile’, it is actually very safe, we routinely put 25 pounds of the stuff in ordinary plastic jugs that you can just put anywhere you want. Gasoline burns, but can only burn as fast as the oxygen supply allows, which is pretty limited in an uncontrolled situation. If you spill 20 gallons of gas and light it, it will take quite some time to burn up, and will release that energy over a wide area. Contrast that with a substance that doesn’t need an outside element to combust, like TNT or nitroglycerine. A small fraction of the energy that 1 gallon of gasoline contains is enough to blow your car to smithereens. That is my issue with supercaps, they don’t have any inherent limiting factor to the energy release, all the energy is available in a fraction of a second. The same amount of energy that can bring your car up to 100mph (enough energy to spectacularly crush it against a wall) a dozen times will be released all at once if the containment is breached. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [February 26, 2015, 1:49pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/42 "2015-02-26T13:49:15Z")
> [@PastTense](#): > > If the price of gasoline massively increases while the price of natural gas only has limited increases this makes CNG cars attractive. But as pointed out I think, it would make using natural gas to generate electricity even more attractive … the point made by **Stranger** that the source to generate the electricity is fungible … and the fact that a power plant to battery to motive power is much more efficient per unit natural gas well to wheel than CNG is by far. The electricity infrastructure for daily commuters is also already in place. The use for CNG will be for trucks and other vehicles that require the range that a battery cannot easily provide. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 26, 2015, 2:07pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/43 "2015-02-26T14:07:47Z")
> [@Stranger\_On\_A\_Train](#): > > Hydrogen fuel cells are not a viable technology for transportation energy, notwithstanding the fact that hydrogen still has to be produced from some source which is generally less efficient and has a larger carbon footprint than just burning gasoline. Hydrogen is difficult to store, reacts with many common metallic materials to embrittle them, has high detonability, and worst of all, very low energy density even in liquid cryogenic form. Hydrogen as a transportation fuel, and the so-called “hydrogen economy” in general is a sham. There are segments where it makes some sense, but mass use in vehicles probably isn’t one of them. I was told something long ago that can put it in perspective: H2 is not a “fuel” - it’s an energy transmission system. The hydrogen is more a mechanical “battery” than a fuel like gasoline. But yes, it’s got tremendous energy losses from source to wheel and is thus suitable only for a narrow range of specialty purposes. > [@Cheesesteak](#): > > While you describe gasoline as ‘highly volatile’, it is actually very safe, we routinely put 25 pounds of the stuff in ordinary plastic jugs that you can just put anywhere you want. Gasoline burns, but can only burn as fast as the oxygen supply allows, which is pretty limited in an uncontrolled situation. If you spill 20 gallons of gas and light it, it will take quite some time to burn up, and will release that energy over a wide area. It’s “very safe” because we have 100 years of established infrastructure and experience with it. In road-going vehicles, I don’t see it as any safer or less safe than any other energy-dense system that can cause a localized fire or explosion. It’s not like a supercap battery in a Prius XVIII is going to level a city block. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 26, 2015, 2:22pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/44 "2015-02-26T14:22:31Z")
> [@Amateur\_Barbarian](#): > > It’s “very safe” because we have 100 years of established infrastructure and experience with it. In road-going vehicles, I don’t see it as any safer or less safe than any other energy-dense system that can cause a localized fire or explosion. > > It’s not like a supercap battery in a Prius XVIII is going to level a city block. It’s very safe because the energy release is limited by the underlying chemistry. You can put a gallon of gas in an open bucket, throw in a match, and you won’t die in a horrible explosion, despite the fact that the gas has as much energy as 30 pounds of dynamite. If you have a supercap that has the energy equivalent of 1 gallon of gas, and the containment fails, the energy is going to be released, all at once. It’s not going to spill on the ground and release slowly as oxygen is fed to the reaction, it’s going to go, because nothing is holding it in anymore. It doesn’t have to level a block, it just has to level your car, with you in it. ---
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [February 26, 2015, 2:28pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/45 "2015-02-26T14:28:11Z")
> [@Cheesesteak](#): > > It’s very safe because the energy release is limited by the underlying chemistry. You can put a gallon of gas in an open bucket, throw in a match, and you won’t die in a horrible explosion, despite the fact that the gas has as much energy as 30 pounds of dynamite. > > If you have a supercap that has the energy equivalent of 1 gallon of gas, and the containment fails, the energy is going to be released, all at once. It’s not going to spill on the ground and release slowly as oxygen is fed to the reaction, it’s going to go, because nothing is holding it in anymore. It doesn’t have to level a block, it just has to level your car, with you in it. Hm - can someone explain what the physics are of the explosive release in a failing supercapacitor? ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 26, 2015, 2:30pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/46 "2015-02-26T14:30:30Z")
Okay. As cars explode into fireballs with their occupants inside pretty much every day of the year, I still don’t see a technically “more volatile” energy source being any worse. Yes, it’s a hazard. Yes, accidents happen. No, I don’t think it’s impossible to engineer the overall safety to match what we expect with liquid-fuel cars. No, I don’t think it’s a good net argument against supercaps as high-efficiency vehicle ‘batteries.’ When the national speed limit was raised, a very, very bright co-worker (CalTech, with honors) ranted and swore that vehicle fatalities were going to go up 18%. He was correct in the narrowest possible technical sense, but that it’s a more complex situation than the kinetic energy in vehicles at highway speeds simply didn’t occur to him. He paid for lunch six months later, when (as I predicted) fatalities actually fell a measurable degree. Allee samee here. That some kinds of batteries and supercaps are more volatile and self-contained explosive sources does not necessarily translate to any higher risk overall. ---
**Author:** ![iljitsch](https://avatars.discourse-cdn.com/v4/letter/i/77aa72/32.png) [@iljitsch](https://boards.straightdope.com/u/iljitsch)\ **Post date:** [February 26, 2015, 3:08pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/47 "2015-02-26T15:08:22Z")
> [@amateur barbarian](#): > > okay. As cars explode into fireballs with their occupants inside pretty much every day of the year _[citation needed]_ ---
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [February 26, 2015, 3:31pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/48 "2015-02-26T15:31:22Z")
> [@iljitsch](#): > > _[citation needed]_ [http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires](http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires) There were 164,000 vehicle fires in 2013. Considering there are only 365 days in a year, I would say that it is true that it happens “every day”. ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [February 26, 2015, 3:43pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/49 "2015-02-26T15:43:20Z")
**Cheesesteak** , I’m trying to understand your concern; When a capacitor discharges or “quacks” it is all electrical energy which goes to ground, in the case of a mangled car, probably through whatever part of the frame offers the best path. If you don’t have anything to ignite, like 25 gallons of gasoline, you have a flash, a quack and it’s done. You don’t have batteries catching fire like Li-ion batts on the Dreamliner, releasing fumes or like gasoline. **Stranger** , as usual, is likely right but supercaps do have their uses; especially in short term release like storing regenerative braking or replacing batteries in present day cars. We are in the process of replacing some diesel gensets at work and they use 500 farad supercaps in place of the start battery. Zero maintenance, 20 yr life, operates from -40 to 65 C. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 26, 2015, 3:46pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/50 "2015-02-26T15:46:57Z")
And about 0.2% of those resulted in a fatality. My feeling is that a 100 mile capacity supercap is going to go off like a car bomb if the structure fails. That supercap will have the same energy capacity as 50lbs of TNT. It gets cracked by a hard collision, the energy has to go somewhere, and it’s not going to go there in nice orderly fashion. Perhaps, overall, it could be made safer than what we have today. Me, I’d rather stick with batteries. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [February 26, 2015, 3:47pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/51 "2015-02-26T15:47:00Z")
> [@boffking](#): > > [http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires](http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires) > There were 164,000 vehicle fires in 2013. Considering there are only 365 days in a year, I would say that it is true that it happens “every day”. I have seen vehicle fires. But never one that could be described as exploding fireballs. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 26, 2015, 3:49pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/52 "2015-02-26T15:49:59Z")
> [@swampspruce](#): > > **Cheesesteak** , I’m trying to understand your concern; When a capacitor discharges or “quacks” it is all electrical energy which goes to ground, in the case of a mangled car, probably through whatever part of the frame offers the best path. If you don’t have anything to ignite, like 25 gallons of gasoline, you have a flash, a quack and it’s done. If the flash itself contains the energy equivalent of 25 gallons of gasoline, (or 2.5gal for that matter) how big a flash will it be? ---
**Author:** ![Rhodes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rhodes/32/273_2.png) [@Rhodes](https://boards.straightdope.com/u/Rhodes)\ **Post date:** [February 26, 2015, 3:50pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/53 "2015-02-26T15:50:12Z")
Here’s a relevant [xkcd what-if](http://what-if.xkcd.com/128/) column comparing the energy of batteries vs hydrocarbons. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [February 26, 2015, 4:51pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/54 "2015-02-26T16:51:39Z")
> [@boffking](#): > > [http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires](http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires) > There were 164,000 vehicle fires in 2013. Considering there are only 365 days in a year, I would say that it is true that it happens “every day”. vehicle fires have numerous causes. your link doesn’t support AB’s assertion that cars regularly “explode into fireballs.” ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [February 26, 2015, 5:13pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/55 "2015-02-26T17:13:34Z")
Energy doesn’t “go to ground” (or rather, some of it inevitably does, but not in the way you’re thinking). Current does “go to ground”, but that’s not what we’re worried about here. The danger of a breached capacitor isn’t electrocution; it’s explosion. The energy has to go somewhere, and where it goes will be heat. Pile that much heat together in a small space, and things go boom. The only sense in which energy is “going to ground” is in that you’re leaving a crater. Is this a problem? Absolutely. Do I know how to solve it? No, I’m a physicist, not an engineer. But I’m sure that by the time we have capacitors potent enough for this to be an issue, the engineers will have come up with some way or another to solve it. ---
**Author:** ![iljitsch](https://avatars.discourse-cdn.com/v4/letter/i/77aa72/32.png) [@iljitsch](https://boards.straightdope.com/u/iljitsch)\ **Post date:** [February 26, 2015, 5:31pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/56 "2015-02-26T17:31:14Z")
> [@boffking](#): > > [http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires](http://www.nfpa.org/research/reports-and-statistics/vehicle-fires/highway-vehicle-fires) > There were 164,000 vehicle fires in 2013. But how many balls? With only 300 people killed probably less than that 164k. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 26, 2015, 5:40pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/57 "2015-02-26T17:40:21Z")
> [@jz78817](#): > > vehicle fires have numerous causes. your link doesn’t support AB’s assertion that cars regularly “explode into fireballs.” We have, however, established that some posters have no sense of humor. That aside, are you contending that with about 33,000 vehicular accidents a year, with around 3,000 immediate fatalities, that there’s any day of any year that one of those ten fatalities and thousand accidents didn’t involve fire? —and all that in just the US, leaving out countries like India and China where a prevalence of tonka-toy cars on overcrowded and unsafe roads have much higher overall numbers? Let’s hop back out of Absurdistan and to topic. No, I don’t think any form of vehicle power source or plant under current serious consideration represents any greater net danger than gasoline/IC. Despite any individual characteristics of how each power source might fail. None are going to go up in a block- or city-leveling mushroom cloud, now that we’ve decided not to built 30-foot Impalas with nuclear reactors. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [February 26, 2015, 5:52pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/58 "2015-02-26T17:52:15Z")
> [@Amateur\_Barbarian](#): > > We have, however, established that some posters have no sense of humor. if your joke falls flat, it wasn’t funny. > [@](#): > > That aside, are you contending that with about 33,000 vehicular accidents a year, with around 3,000 immediate fatalities, that there’s any day of any year that one of those ten fatalities and thousand accidents didn’t involve fire? I’m not contending anything of the sort. Don’t put words in my mouth just because your attempt at “humor” didn’t work. you said something stupid, then **boffking** blindly linked to something about the number of vehicle fires. Vehicle fires have numerous causes- long term oil leaks on the engine which ignite (not gasoline fed,) electrical (not gasoline fed,) fuel leaks underhood (gasoline fed,) engine/transmission overheating (not gasoline fed,) fuel leak after collision (gasoline fed.) None of those involve “exploding,” gasoline doesn’t explode. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [February 26, 2015, 6:32pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/59 "2015-02-26T18:32:11Z")
> [@Amateur\_Barbarian](#): > > None are going to go up in a block- or city-leveling mushroom cloud, now that we’ve decided not to built 30-foot Impalas with nuclear reactors. They won’t level a block, but an explosive failure that releases the same energy as is stored in a gallon of gas will make your car look like it was hit with a Hellfire Missile. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [February 26, 2015, 6:54pm UTC](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536/60 "2015-02-26T18:54:47Z")
> [@jz78817](#): > > None of those involve “exploding,” gasoline doesn’t explode. As someone who has personally watched a car explode, Michael Bay-style, and seen footage of similar Rapid Vehicle Disassemblies, I’m pretty much done attempting to humor you or play high-school debate. No compact source of vehicle power is completely safe, including gas. It’s all about risk to value assessment, not physics experiments. [Previous page](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536.md?page=2) [Next page](https://boards.straightdope.com/t/is-there-any-battery-chemistry-that-can-compete-with-gasoline-on-energy-density/713536.md?page=4)