Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Does that use a lot of energy?

hannahritchie.github.io

Post reply on HN
Print view View original

181–190 of 226 posts

Re: Does that use a lot of energy?

#181

Post by londons_explore »

Interestingly, the latest generation of LED lights are so efficient that it makes little financial sense to bother having a light switch. 330 lumens per watt from recent Phillips bulbs!

The cost of having an electrician wire that switch is probably more than a little 2.5 watt light will use in it's lifespan - particularly when you account for the fact lights in hallways are probably in use most of the time anyway.

Add in the effort of switching the light switch a few times a day for many years and it's certainly the case! Or the risk of fumbling in the dark for a light switch at the far end of a room or in a house you aren't familiar with.

Obviously you might still want to turn it off for maintenance, but you have the breaker for that.

Re: Does that use a lot of energy?

#182

Post by kkfx »

Nice! A small note: airfryer tend to cycle on/off much less then slow-air/static ovens so they consume way more per unit time, gas ovens never fully stay "off" when operating, they just reduce the flames.

Re: Does that use a lot of energy?

#183

Post by zahlman »

londons_explore wrote: post #181

Interestingly, the latest generation of LED lights are so efficient that it makes little financial sense to bother having a light switch. 330 lumens per watt from recent Phillips bulbs! The cost of having an electrician wire that switch is probably more than a little 2.5 watt light will use in it's lifespan - particularly when you account for the fact lights in hallways are probably in use most of the time anyway. Ad…

What if you want to turn it off to have darkness?

Re: Does that use a lot of energy?

#184

Post by ZeroGravitas »

OldSchool wrote: post #143

Kind of a stretch to suggest that an internal combustion vehicle requires 3x more "energy" to move it than an equally physics-burdened (weight, friction, etc) electric vehicle... This is only "true" if the energy stored in the vehicle's battery got there without any relevant conversion inefficiency; If those joules came from a gas-fired plant, overall efficiency is only about 35-40%: comparable to a typical internal…

The upstream energy costs of supplying fossil fuels can also be counted. They add about 1/4 or 1/5th of the total in what are called "Well to wheel comparison". The comparison in the article is "tank to wheel'

It's not a direct analogue to energy but CO2 emissions per km are roughly 4 times lower for an EV charged on the EU grid in 2025, well to wheel.

Re: Does that use a lot of energy?

#185

Post by Symbiote »

DuckConference wrote: post #179

Most clothes washer cycles are about an hour, is the motor really averaging 800 watts over that time?

The EU Energy label on the first (more expensive) washing machine I looked at said 440Wh for a cycle, so 800Wh for an average one isn't unreasonable.

Re: Does that use a lot of energy?

#186

Post by Symbiote »

keybored wrote: post #98

My electricity provider has a rough breakdown. Which I was kind of incventivized to look at because of money. Heating is the big one. The electricity bills are seasonal. Next. I can do my laundry at night because the electricity is cheaper.. oh wait I can’t. That’s apparently unsafe. So I have to do it in the evening. Okay. I’m not going to move my whole small freetime evening around to save a buck on the half-evenin…

I often do my laundry at night, what's the problem? I set it to finish roughly when I intend to get up.

Turning the lights off made a lot of sense in the 1990s and earlier, when each bulb was 60W.

Re: Does that use a lot of energy?

#187

Post by Sharlin »

20after4 wrote: post #88
Sharlin wrote: post #38

For reference it would be good to have per-passenger numbers for "sitting on a diesel bus", "sitting on an electric bus", "sitting on a tram", "sitting on a commuter train" as well.

The marginal cost of one extra passenger is going to be very nearly zero. The vast majority of the cost is just moving the bus / train / plane, and the overhead / inefficiencies in the system. I've seen somewhere the numbers for one passenger on trains and planes but I can't remember where that was. Just know it is a very very small amount for the added weight of one more passenger.

Yes, I know, and marginal numbers would also be great to have. But just the naive cost of energy per passenger-kilometer averaged would be good to see, given that it too would be much less than that of a private car.

Re: Does that use a lot of energy?

#188

Post by tmnvix »

jwilliams wrote: post #28

It was genuinely a surprise to see how much relative energy petrol cars use (and shame on me - I'm an electrical engineer). I mean I think I knew it intuitively, but this simple chart blew my mind.

And then look at how little distance you need to travel to produce 1kg of CO2.

Re: Does that use a lot of energy?

#189

Post by wink »

creeble wrote: post #40
janalsncm wrote: post #17

Wow, putting everything in the same units is really informative. Running my 450 watt gpu for a day is approximately equivalent to driving a car 10 miles.

I doubt your 450w gpu runs at that wattage 24 hrs, unless you're mining with it. My (admittedly old) gpu+CPU idles around 50-75w.

I think you simply can't predict any number without really measuring it.

Ryzen + GPU + 1h of gaming, but 3 screens attached.

still a "desktop computer" - stuff in the browser can spike GPU wattage, but I don't think it will be meaningfully different over several hours of true idle..

My problem is more like: I could measure that, but I'd have to recable everything to have the power meter behind the power strip with just PC + screens... which I will probably do at some point, but it involves redoing 50% of the cables in this room.

Re: Does that use a lot of energy?

#190

Post by pcchristie »

noosphr wrote: post #105
oceanplexian wrote: post #102

Earlier quoted context omitted.

> internal combustion is hilariously inefficient It's inefficient but not hilariously so. Modern ICE are quite amazing technology. Combined gas turbines (you know, the energy source that powers your electric car) are about 60% efficient for the really good ones, minus 5-7% transmission losses, minus 10-12% charging losses, minus 20% loss in cold climates, lands you at around 35-40% efficiency from fuel source to the…

This is something that always gets lost in these conversations. Whenever you do the real world calculation for what an electric cars CO2 profile looks like it turns out to be the same as a gasoline car unless your country is majority nuclear.

This is wrong, and by a long way.
Post reply on HN