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A lightning bolt would be worth only about a nickel (2015)

engineering.mit.edu

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Re: A lightning bolt would be worth only about a nickel (2015)

#91

Post by AnotherGoodName »

csdvrx wrote: post #77
themitigating wrote: post #63

Earlier quoted context omitted.

The typical house has 240 volt service in the US (two legs of 120v). I would also say a decent number of homes have 200amp as well

> The typical house has 240 volt service in the US (two legs of 120v). Can we wire that in a way to would allow installing .uk or .de Schuko Type-F plugs? It would be funny (and weird!) to have 220V available on a european socket for say a desktop equipped with a 1.5kW PSU for the upcoming Nvidia 4090 :)

You probably have a few such sockets around. Not the UK or eu form factor but 240v at least. Look at how your dryer or AC plugs into the wall and you'll see something different to the usual plugs.

Re: A lightning bolt would be worth only about a nickel (2015)

#92

Post by andrewla »

greenbit wrote: post #64
andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

Idk, I think OP indicated that a typical lightning bolt would power a typical house (presumably at the stated nominal full load) for about 15 minutes. I.e., you'd need 4 strikes per hour, per hour. Now granted most houses won't run at peak load all the time, maybe you'd only need one strike per hour per house - but that's still clearly a lot more lightning than is generally seen.

The article is short and such an indication should be easy to cite directly. If I missed it, please let me know.

As far as I can see, nowhere in the article does it give enough information (even if you take into account unit conversions) to say how much of a house's electricity would be supplied by a lightning bolt.

Re: A lightning bolt would be worth only about a nickel (2015)

#93

Post by MonkeyClub »

trelane wrote: post #88
andrewla wrote: post #76

Earlier quoted context omitted.

You're using a toy example to strawman the Joule counterpoint. How much do you use in a month, which is the typical billing cycle? Off-peak vs. on-peak cost?. In the end there's no practical utility to this. We just pretend that we're living in a world where you get a 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandesc…

> You're using a toy example to strawman the Joule counterpoint. Not a toy example. That's exactly how I estimate energy consumption for off the shelf devices. And for battery life (W*h but still). > 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandescent-equivalent and such. If you've lived with lighting you're respons…

Same here, I find the KWh to be a very useful unit for daily calculations of that sort, where I want a quick upper bound on things to make estimations.

Last year I switched off my fully-functional 2008 workstation (a lovely Fujitsu Celsius W370 on OpenBSD, a furry joy) because of such an upper bound difference (300W vs 65W for the ThinkCentre that hides among the books on my desk's side).

This sort of works in a similar way with light bulbs as well. Although lumen would be the appropriate unit for luminosity, the packaging uses wattage to indicate luminosity.

Although lumens and Watts are correlated, they aren't dimensionally equivalent as Joules and Watts are (CMIIW).

That "100W" on the package an electrically 14W bulb simply means "it's only using 14W, but shines like a 100W bulb, go ahead, BOGOF".

Re: A lightning bolt would be worth only about a nickel (2015)

#94

Post by jfim »

andrewla wrote: post #76
jfim wrote: post #71

Earlier quoted context omitted.

The kilowatt hour is a fantastic unit when talking about electrical consumption. Are you running a 100W load (0.1kW) for an hour? That's 0.1kWh. Running it for ten would make a whole kilowatt hour. This allows for easy calculations of how much something is going to cost in electricity, and the units are such that it's easy to do the math in your head.

You're using a toy example to strawman the Joule counterpoint. How much do you use in a month, which is the typical billing cycle? Off-peak vs. on-peak cost?. In the end there's no practical utility to this. We just pretend that we're living in a world where you get a 100W light bulb and know exactly what it will cost you, and not a world where half your bulbs claim to be 100W but are actually 14W with 100W-incandesc…

To take your example, your 14 Watt lightbulb would use about 0.35kWh per day if running all day, or about 10kWh per month of nonstop usage. At 0.15$/kWh, that's about a dollar and fifty cents, assuming you'd want to leave it on all day and night.

All of that math can be done in your head too, if you're willing to approximate the number of hours in a day to 25 and the numbers of days in a month to 30.

Re: A lightning bolt would be worth only about a nickel (2015)

#95

Post by ravi-delia »

andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The KwH makes sense if you consider that while units are largely path-independent, mental calculations are not. At any given moment, the sensible measure of your house's electricity usage is in kW. And to work backwards to figure out consumption, the hour certainly beats the second. Sure, you could call it 3.6e6 joules, but at that what point what does it buy you?

Horsepower is clearly insane though, I have no idea why you'd bother.

Re: A lightning bolt would be worth only about a nickel (2015)

#96

Post by dehrmann »

At one point, I realized that lightning is the breakdown of the dielectric material of a capacitor. This means you harvest electric by draining it with a large sheet or web of conductors at cloud level. No idea how well this would work or how much energy there is to collect, and it would be pretty impractical.

Re: A lightning bolt would be worth only about a nickel (2015)

#98

Post by garaetjjte »

jeramey wrote: post #90
csdvrx wrote: post #77

Earlier quoted context omitted.

> The typical house has 240 volt service in the US (two legs of 120v). Can we wire that in a way to would allow installing .uk or .de Schuko Type-F plugs? It would be funny (and weird!) to have 220V available on a european socket for say a desktop equipped with a 1.5kW PSU for the upcoming Nvidia 4090 :)

You’d probably need to do this with an AC-DC-AC transformer to also get the circuit converted to the 50hz cycle European power systems use, but it’d just be a waste because of the power losses involved (not to mention the expense of the transformers). Also, a typical 15A circuit in a home will handle ~1.8kw of sustained load, so as long as you can dedicate a circuit to such a rig, you’d be fine.

Computer power supplies won't care about 50/60Hz difference (maybe except some slight efficiency change).

Re: A lightning bolt would be worth only about a nickel (2015)

#99

Post by a9h74j »

benj111 wrote: post #21
agumonkey wrote: post #11

Earlier quoted context omitted.

A dude did that, it didn't last long, but I'm still thinking about opening one. Just to avoid the double madness of powering lights and devices so people spend energy in the air :) Even if you don't generate much, at least your biomechanical efforts are used somewhere.

Surely it's triple madness if you're driving to a gym to go on the running / cycling machine.

Not just driving to the gym, but driving twice around the parking lot to find a closer space for a shorter walk.

And wasn't it Mumford who observed that given the time it takes to earn the money to buy a car, on average it can be faster to walk than to drive.

Re: A lightning bolt would be worth only about a nickel (2015)

#100

Post by johnwalkr »

jfim wrote: post #71
andrewla wrote: post #60

> The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. “The typical house in the U.S. has 100 amp service or about 28 horsepower,” says Kirtley. Boy do I get frustrated when using compatible units without conversion. The unit that I hate more than any other unit in the universe is the KwH, which is dimensionally equivalent to the Joule, so I don't unders…

The kilowatt hour is a fantastic unit when talking about electrical consumption. Are you running a 100W load (0.1kW) for an hour? That's 0.1kWh. Running it for ten would make a whole kilowatt hour. This allows for easy calculations of how much something is going to cost in electricity, and the units are such that it's easy to do the math in your head.

Hours are usually more convenient to work with than seconds when talking about energy use (even in this case when you are comparing to other things. Plus it's the de facto standard unit more people are familiar with. Power bills, electric car capacity, and energy efficiency are all normally described in kWh.
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