# Clean energy for the world based on using large capacitors **URL:** \ **Category:** In My Humble Opinion\ **Created:** [January 1, 2026, 4:19pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244 "2026-01-01T16:19:47Z")\ **Posts on this page:** 17\ **Page:** 4
**Author:** ![echoreply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/echoreply/32/3641_2.png) [@echoreply](https://boards.straightdope.com/u/echoreply)\ **Post date:** [January 2, 2026, 1:17am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/61 "2026-01-02T01:17:23Z")
> [@Chronos](#): > > > [@bodangus](#): > > > > At 10,000 Farads, a Graphene Supercapacitor / Battery is powerful enough to power up a Semi Truck while being the size of a paperback novel at this point” > > Sure, it has as much power as a semi truck (around 500 HP, or 370 kW) I think what that means is it can start a truck engine, not be as powerful as a truck engine. That isn’t too far beyond modern consumer devices. The biggest [Noco jump starter](https://no.co/gbx155/specs) is the size of a large paperback at 12" by 7" and 3" thick. It is just a lithium battery and claims to be good for an 8 liter diesel, which probably isn’t enough for most semi truck engines except under absolute ideal conditions, but isn’t that far off. Milwaukee has a capacitor based jump starter on the market. It takes about 1.5 minutes to charge from a tool battery, and then gives a few seconds of cranking from the capacitor. The reviews I’ve seen of it have been very mediocre. It works, but lithium packs (like the linked Noco) can provide more power and longer cranking. > **[M18™ HOTSHOT™ Jump Starter | Milwaukee Tool](https://www.milwaukeetool.com/products/details/m18-hotshot-jump-starter/3841-20)** > > Start gas or diesel engines in seconds - this M18™ HOTSHOT™ Jump Starter is always ready, and delivers up to 70 starts per charge. ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [January 2, 2026, 1:29am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/62 "2026-01-02T01:29:59Z")
> [@Chronos](#): > > If, as the picture at the top of the page suggests, they’re using a single layer of graphene as their electrolyte, that would certainly account for a very high capacitance, since capacitance increases when the distance between the plates decreases. But it would also mean that they’d have an extremely low breakdown voltage, which in turn would mean a very low energy capacity. What I am seeing about graphene says that it is a very good conductor. For the dielectric of a capacitor, you need an insulator. ---
**Author:** ![EinsteinsHund](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/einsteinshund/32/8400_2.png) [@EinsteinsHund](https://boards.straightdope.com/u/EinsteinsHund)\ **Post date:** [January 2, 2026, 1:45am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/63 "2026-01-02T01:45:06Z")
> [@Dewey\_Finn](#): > > So how do we convert loaves and fishes to an energy source? Easy, by eating them. ---
**Author:** ![bodangus](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@bodangus](https://boards.straightdope.com/u/bodangus)\ **Post date:** [January 2, 2026, 2:00am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/64 "2026-01-02T02:00:01Z")
And then what do they turn into? ---
**Author:** ![EinsteinsHund](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/einsteinshund/32/8400_2.png) [@EinsteinsHund](https://boards.straightdope.com/u/EinsteinsHund)\ **Post date:** [January 2, 2026, 2:04am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/65 "2026-01-02T02:04:16Z")
Heat, kinetic energy and shit. ---
**Author:** ![bodangus](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@bodangus](https://boards.straightdope.com/u/bodangus)\ **Post date:** [January 2, 2026, 2:19am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/66 "2026-01-02T02:19:16Z")
Don’t forget the smell. ---
**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:** [January 2, 2026, 2:41am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/67 "2026-01-02T02:41:46Z")
> [@echoreply](#): > > I think what that means is it can start a truck engine, not be as powerful as a truck engine. That might be what they want you to think they mean. What they actually said was “powerful enough”. As in, “has enough power”. Which is really friggin’ easy and unimpressive. > [@Ancient\_Nerd](#): > > What I am seeing about graphene says that it is a very good conductor. For the dielectric of a capacitor, you need an insulator. In other words, it has an extremely low breakdown voltage. I’ll point out again that that article was making future forecasts for the year 2015. In other words, it’s over 10 years old. None of us has heard of that company since then, which strongly suggests that they were just blowing smoke right from the get-go. It’s possible that they did make a capacitor using graphene, with an extremely high capacitance (but extremely low energy capacity). That’s something that’s possible. It might even have some practical application. Just, not very much practical application. ---
**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:** [January 2, 2026, 3:08am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/68 "2026-01-02T03:08:36Z")
And FWIW breakthroughs with graphene for supercapacitors are still could be right around the corner … > **[New graphene breakthrough supercharges energy storage](https://www.sciencedaily.com/releases/2025/11/251130205509.htm)** > > Engineers have unlocked a new class of supercapacitor material that could rival traditional batteries in energy while charging dramatically faster. By redesigning carbon structures into highly curved, accessible graphene networks, the team achieved... I mean sounds promising, and cool, but … ---
**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:** [January 2, 2026, 3:12am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/69 "2026-01-02T03:12:11Z")
> [@bodangus](#): > > 10,000 Farads is pretty big, True, but Farads are overrated. If you’re wanting to use a capacitor as an energy vessel, the capacitor’s max voltage spec is _ **much** _ more important that the amount of Farads. (Assuming, of course, the surrounding circuit can work at that voltage, including the buck/boost circuitry.) ---
**Author:** ![Ancient\_Nerd](https://avatars.discourse-cdn.com/v4/letter/a/ed655f/32.png) [@Ancient\_Nerd](https://boards.straightdope.com/u/Ancient_Nerd)\ **Post date:** [January 2, 2026, 3:31am UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/70 "2026-01-02T03:31:05Z")
> [@Crafter\_Man](#): > > Assuming, of course, the surrounding circuit can work at that voltage, including the buck/boost circuitry. The plate geometry determines the capacitance and voltage rating. Energy density is a function of the dielectric material. The spacing between the plates determines both the capacitance and the voltage. Fewer plates with wider spacing increases the voltage but reduces the capacitance. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [January 2, 2026, 12:45pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/71 "2026-01-02T12:45:33Z")
> [@dtilque](#): > > That’s true of every form of energy storage. None of them return all the energy put into them. In this universe, we obey the laws of thermodynamics. The Dinorwig pumped storage facility apparently runs at about 74% overall efficiency. Something I found interesting about it on the tour is that the pumps are actually the turbines run in reverse. That’s an impressive piece of engineering in my book. Was going to link the Wikipedia article, but I see that griffin1977 already did so upthread. ---
**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:** [January 2, 2026, 1:09pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/72 "2026-01-02T13:09:52Z")
Here’s my point. Let’s say I have two super capacitors. One is 400 F and has a max voltage of 100 V. The other is “only” 100 F but the max voltage is a little over double (210 V). The 100 F cap can store more energy than the 400 F cap. ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [January 2, 2026, 2:10pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/73 "2026-01-02T14:10:48Z")
Given that the underlying assumption of the thread seems to be “the atmosphere has enough useful static electricity to power the world for free if we only had a way to store it”, it seems odd that we’re focusing on the question of whether capacitors can capacitate. They can. That’s not even the beginning of the issues here. ---
**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:** [January 2, 2026, 2:13pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/74 "2026-01-02T14:13:47Z")
I think we’re mostly focusing on that because that was the only part of the question that was close to clear-ish in the OP, and by the time he explained the actual plan, the discussion kept on capacitors out of inertia. ---
**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:** [January 2, 2026, 2:29pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/75 "2026-01-02T14:29:57Z")
How about a facts question - There clearly is a certain amount of static electricity there, which comes out erratically and with poor predictability as lightning. Not likely to be any way to harvest it to any meaningful degree (typically diffuse and air is a good insulator), but if there was how much theoretically is there? ---
**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:** [January 2, 2026, 2:43pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/76 "2026-01-02T14:43:59Z")
Yea, energy in-and-of-itself is essentially free, and readily available. But the devil is always in the details: How much (current) energy do you need to expend to get the (future) energy? If, for example, you need to burn five barrels of oil to harvest three barrels of oils, then it doesn’t make sense to do it. To be viable, the energy you get has to be greater than the energy expended to get it. How predicable is the energy? How safe is it to get the energy? How much environmental damage does it cause to get it? If you do get the energy, and use it, is it a risk to health or the environment? How quickly can you get the energy? If there is 10^21 joules of energy just sitting around somewhere, but you can only extract 1000 joules an hour, is it really worth it? ---
**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:** [January 2, 2026, 2:58pm UTC](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244/77 "2026-01-02T14:58:58Z")
All part of practical reality. And early discussions of solar, wind, and tidal power generally included off hand remarks of how much energy was theoretically available, if only we could figure out practical means of harvesting it. Spoiler - absurdly big numbers with the devil _always_ in how to get it. I am confident that this energy is not able to be harvested efficiently - but still, if _theoretically_ it could be, how does it rank? [Previous page](https://boards.straightdope.com/t/clean-energy-for-the-world-based-on-using-large-capacitors/1026244.md?page=3)