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

101–110 of 226 posts

Re: Does that use a lot of energy?

#101

Post by CollinEMac »

Rebelgecko wrote: post #45
jfengel wrote: post #43

I'm surprised that cooling takes less energy than heating. I imagine that depends a lot on the temperature range; they only need so much to cool a room even on a "hot" day in the UK. Still... AC still feels like magic. I know how it works and understand the over-unity factor. But it feels like it ought to take enormous energy for it to work at all.

I think specifically it's comparing gas heating vs AC. Heat pump heating would probably do better. In other words, it takes less energy to move heat inside/outside than to "create" it (With caveats like heat pumps are much less effective in extreme cold)

You can select gas heating vs electric heat pump. The heat pump looks to be about a third the cost of gas.

Re: Does that use a lot of energy?

#102

Post by oceanplexian »

MerrimanInd wrote: post #34
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.

When one gets in the weeds on EVs or ICE cars two things become shockingly clear: internal combustion is hilariously inefficient YET gasoline is hilariously energy dense. Most people's intuition is wrong on both of these points but then they cancel each other out. Edit: another important point is that the "cost" to acquire gasoline is only the very end of the process. The energy has already been gathered, stored, and…

> 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 wheel.

The Atkinson-cycle engine in the Toyota Prius gets around 40% give or take some losses in the drivetrain. Electric have plenty of upsides, but for some people with cheap gas+high electric costs+cold climate you would honestly be better driving a hybrid.

Re: Does that use a lot of energy?

#103

Post by noosphr »

NortySpock wrote: post #100
nomel wrote: post #75

Earlier quoted context omitted.

Where I am at least, people using less power because power because power need to profit more, is wild . They literally had record profits the last few years, rather than being forced to lay down solar. I think power should be a global endeavor, not some local for profit business with complete regulatory capture that makes competition illegal. Yes I'm angry, because I pay more in electric than most anywhere in the wor…

Energy security is national security. Cheap electricity means you can do things that made "no sense" with expensive electricity. (e.g. smelt aluminum) Cheap electricity means you can underbid regions that have expensive electricity... As Technology Connections said, "Panels that cover your electrical needs for the next 25+ years? In the Midwest, we call that a good deal!"

Most of those technologies also need uninterrupted power supplies. Something wind, solar and batteries for the next 50 years aren't.

Re: Does that use a lot of energy?

#104

Post by fragmede »

csours wrote: post #74
einpoklum wrote: post #67

Earlier quoted context omitted.

Isn't it better for trains to just to draw from the electric grid?

Do you have to run new electric transmission lines? Will you have to maintain those power lines?

Someone could graph the cost/benefit ratio on putting the batteries on the trains vs putting wires up everywhere.

Re: Does that use a lot of energy?

#105

Post by noosphr »

oceanplexian wrote: post #102
MerrimanInd wrote: post #34

Earlier quoted context omitted.

When one gets in the weeds on EVs or ICE cars two things become shockingly clear: internal combustion is hilariously inefficient YET gasoline is hilariously energy dense. Most people's intuition is wrong on both of these points but then they cancel each other out. Edit: another important point is that the "cost" to acquire gasoline is only the very end of the process. The energy has already been gathered, stored, and…

> 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.

Re: Does that use a lot of energy?

#106

Post by thefifthsetpin »

I clicked-through on one of the sources (a blog post on "ohmaticelectrical"), and the website is either hacked or is just really scummy. Here's what I was greeted with:

https://imgur.com/a/https-ohmaticelectrical-co-uk-scams-OmLx...

(The scammer didn't actually manage to put anything in my clipboard, so I'm not sure what they were hoping I'd run.)

Re: Does that use a lot of energy?

#107

Post by alnwlsn »

Waterluvian wrote: post #97
alnwlsn wrote: post #60

I attached a generator with some supercaps and an inverter to a stationary bicycle a few years ago, and even though I mostly use it as a way to feel less guilty watching Youtube videos, it does give me a quite literal feel for some of the items on the lower end of the scale. - Anything even even halfway approaching a toaster or something with a heater in it is essentially impossible (yes, I know about that one video)…

Any sense what the efficiency ratio was for your setup?

I'm as curious as you to be honest - putting a strain gauge on the pedals for measuring mechanical power has been on my list for quite a while. My own (probably inaccurate) measurements right after the generator says I can get 60-70Wh in an hour, but I can get to 100Wh if I try harder. I have reason to believe my setup underestimates power because my ammeter clamps at 5A and I know I can peak over that on the down stroke of the pedal.

I've seen numbers like 250W mechanical power for an average trained cyclist, so either my setup is rather inefficient, my measurements are off, or I'm going to find out that I'm nowhere near as strong as a real cyclist.

On the other hand, the stationary bike I got originally had a rubber belt, which it would chew excessively and I eventually swapped it for a chain because it kept slipping in spite of tensioning it more, suggesting I'm hitting the thing harder than it was originally designed for (how that translates into power I'm not sure).

Re: Does that use a lot of energy?

#108

Post by taeric »

djhworld wrote: post #55

I think stuff like this really crystalises how people misunderstand how much energy stuff uses. My parents for example sweat the small stuff and go around the house turning LED driven lights off to "save electricity" even though it would barely make a dent in their bill. Granted, they come from a time of incadescants burning 60-100w at a time so I can see why that habit might be deeply ingrained.

The ridiculously dramatic drop in power we dedicate to lighting is one that is just tough for folks to internalize. As you said, used to, you could have ~10 lights in your house that would add to upwards of 1kw. Nowadays, you can have 50 lights and barely hit 500w. Just mind blowing how far we dropped energy on those.

Same goes for televisions. Your modern TV is probably closer to the basic light bulbs before LEDs.

I'm assuming the general trend is true for all things solid state. That said, lighting is by far the biggest drop for most houses. Remarkably so.

Re: Does that use a lot of energy?

#109

Post by erelong »

not sure I understand the petrol car using 3x as much energy as an EV... wouldn't it make sense to convert gasoline to electricity then? I presume that must not be as efficient as other ways to convert fuel to gasoline? (I understand the math is there but... I'm temporarily failing to get it)

I think lists like these might be useful for energy audits and thinking about ways to make better use of energy

Re: Does that use a lot of energy?

#110

Post by oceanplexian »

mltvc wrote: post #11
quotemstr wrote: post #2

I like the comparison concept. It's like that "order of magnitudes every programmer should know" list, but applied to anyone who cares about energy. That said, and hot take: people shouldn't worry about energy independent of what they pay for it. The whole point of a price is to fold a complicated manifold of scarcity-allocation into a set of scalars anyone can rank against each other. Appealing to people's sense of…

How do you propose to convince people to get those externalities accounted without emotions? How do you convince people of the value of externalities that are far away in place or time (but not less real)?

The idea that you would be worried about how many electrons you use and it's relationship to climate change is on its face kind of ridiculous.

It's like worrying about how many times you personally ordered Chinese food affects the price of Diesel fuel in India. It's an absurd leap of logic, and the parent is right to call out these arguments which are almost always emotional.

Post reply on HN