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Does that use a lot of energy?

hannahritchie.github.io

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Re: Does that use a lot of energy?

#111

Post by ramidarigaz »

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.

> 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.

Not at all true: https://www.carboncounter.com/

US-specific but you can even pick a state and it will use the generation mix of that state

Re: Does that use a lot of energy?

#112

Post by quickthrowman »

MostlyStable wrote: post #80
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.

I turn LED lights off because of the difference in operational life, and I don't like changing bulbs. M GE bulbs say they have a rated lifetime of 13 years......at 3 hours of usage per day. So if they don't get turned off, then that 3 hours can very easily become 12, and now you are at a rated lifetime of ~4 years instead.

A ‘standard’ (A19 shape, E26 base) 8W 800 lumen LED lamp costs around $5 and will use about $20 of energy over a 15,000 hour lifespan, assuming $0.15/kWh.

That works out to around $0.035 per day for the lifespan of the lamp if you run it constantly for 24 hours a day, I wouldn’t waste time thinking about it. It’s an extra $10 over 12 years, you’re still using the energy.

Investing in occupancy or vacancy sensor wall switches at $25 a piece would be the best option, then you don’t need to remember to turn the lights off!

Re: Does that use a lot of energy?

#113

Post by quickthrowman »

taeric wrote: post #108
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…

> 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.

For commercial and industrial installations, VFDs have probably been the biggest efficiency gain, even moreso than lighting. Half of all electricity consumed is used by motors. Thank goodness for solid state power electronics!

Re: Does that use a lot of energy?

#114

Post by beejiu »

erelong wrote: post #109

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

70% of the energy in a petrol car is lost as heat. Only around 30% or less of the energy actually propels the car. I imagine that's why there's a big difference.

Re: Does that use a lot of energy?

#115

Post by GuB-42 »

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)…

Did you try charging an e-bike with your contraption?

I don't know what you can take of this, maybe you can see it as advance pedaling, or to get a feel for energy conversion losses. Anyways, it is the kind of harmlessly stupid idea that I would want to try just because I could.

Re: Does that use a lot of energy?

#116

Post by quickthrowman »

erelong wrote: post #109

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

Gasoline engines are around 30-35% efficient, the rest is lost as heat. That goes for whether they’re spinning an alternator as part of an engine-generator set or just moving a vehicle.

You can’t get more than 35-40% efficiency so converting to electricity is a wash, you lose the energy to heat no matter what.

Also, the chart does not take into account how the electricity for the EV is generated, it would be just as inefficient as the gasoline car if the electricity was generated by burning hydrocarbons, but that detail is left out.

Re: Does that use a lot of energy?

#117

Post by adiabatichottub »

erelong wrote: post #109

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

Yeah I'm not sure that EV number maths out. That's 18kw at 60mph for 10 minutes. It sounds really low to me. Going 45mph on a 110lb eMoto with 180lb rider takes ~6kw.

Re: Does that use a lot of energy?

#118

Post by quickthrowman »

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.

You can reject 4 watts of heat with 1 watt of electricity using vapor-compression refrigeration.

You can get that up to 7 or 8 watts (or more!) per watt with evaporative cooling towers and vapor-compression combined.

AFAIK you can’t move heat into somewhere using cooling towers, they only increase cooling efficiency.

Heat pump heating is limited to around 4W of heat moved for every 1W of electricity, with the efficiency dropping as delta T drops (aka as it gets colder outside)

You can generate 1 watt of heat with 1 watt of electricity and a resistive heater, they’re more or less 100% efficient.

Re: Does that use a lot of energy?

#119

Post by Waterluvian »

alnwlsn wrote: post #107
Waterluvian wrote: post #97

Earlier quoted context omitted.

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 st…

Oh don’t sell yourself short. It can certainly be both! (:

Thanks for sharing the details.

Re: Does that use a lot of energy?

#120

Post by alnwlsn »

Waterluvian wrote: post #119
alnwlsn wrote: post #107

Earlier quoted context omitted.

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 st…

Oh don’t sell yourself short. It can certainly be both! (: Thanks for sharing the details.

All in good fun of course, it has to be healthier than watching Youtube just sitting around normally.
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