Lithium battery costs have fallen by 98% in three decades • Hacker News Board

Re: Lithium battery costs have fallen by 98% in three decades

#41

Post by spockz » Sat, Apr 03, 2021, 6:00 PM UTC

natch wrote: post #21

f6v wrote: post #7

Earlier quoted context omitted.

Very much depends on the home. Tesla Powerwall 2 seems to be 13.5 kWh at 114 kg. Energy consumption can be anything from 30 to 40[1]. So one Powerwall 2 unit probably won't get you through the day if you use that much. [1] https://www.eia.gov/energyexplained/use-of-energy/electricit...

Getting you through the day is not really the point though. The point is 1) shifting some consumption during peak hours off of peak rates and 2) having backup to get you through a limited outage, not necessarily at your full normal consumption level but without having to be in the dark / without internet / without phone and possibly car charging. Nobody should evaluate this by whether one battery pack by itself provi…

I’m not sure about regulations in the US but in The Netherlands you cannot just attach a battery and think you are independent of the grid. To protect the net and people working on the net, power sources behind the meter must disengage when the net/mains power drops. This effectively disables your independence plan. If you want to be independent you have to get some expensive mechanism installed that will decouple your house from the net in case of net failure and bring it back when the mains is up again. And you need get it certified periodically.

So unless you have enough generation to completely decouple from the net you are not really independent or it will cost you.

Re: Lithium battery costs have fallen by 98% in three decades

#42

Post by ncallaway » Sat, Apr 03, 2021, 6:01 PM UTC

turbinerneiter wrote: post #37

ghaff wrote: post #22

Earlier quoted context omitted.

Electric heat isn't super common, especially in standalone houses, in areas where you need a lot of heat in the US. I don't know the numbers off the top of my head but electricity costs a lot more than gas or oil. You're right about the AC but I still use 20 kWh even with no AC (and no electric heat).

Thanks for the insight. I vaguely remembered that people run the ac in reverse for heat, but that is probably only in paces that almost need no heating. Do you know why you use that much? Do you heat your water with electricity? Fridge, freezer, tv, WiFi, Desktop PC, charging phones and laptop, ligths.

- AC is a very common consumer of large amounts of electricity (depending on the region, many regions will have almost no AC while other regions will have it in every building running almost constantly)

- Electrical heat is not the most common form of heating, but it's been growing a lot and is also a big consumer when it is used

- Laundry Washer/Dryer are pretty large consumers (mostly the dryer)

- Water heaters are often electrical

- Electrical ovens and stove ranges are pretty common, which can pull quite a bit depending on how much use they receive

- Microwaves pull a bit, but not huge

Re: Lithium battery costs have fallen by 98% in three decades

#43

Post by kragen » Sat, Apr 03, 2021, 6:01 PM UTC

abdullahkhalids wrote: post #33

labawi wrote: post #12

Earlier quoted context omitted.

> Average US household .. 29kWh/day > houses in the UK .. 3kWh/day Seems believable from what I've heard.

1 KWh/day for Fridge. Lights should do less than 0.5KWh/day. Washing machine is maybe 0.3KWh/day. Maybe, other electronics might add up to 1-2KWh/day. Cooling is not required most of the year. Maybe fans for a couple of months. Heating is separate (EDIT: UK figure), as others have noted. What else are you using electricity on?

Heating, which can easily be 5 kW, 120 kWh/day; many US houses are heated electrically, so it's not always separate. Air conditioning can easily be 3 kW, or 72 kWh/day, although it's usually only on during the daytime, so figure 30 kWh/day; it's common to run a 240 VAC circuit in the US for the air conditioner because the 2.4 kW of a standard 120 VAC 20 A circuit is insufficient. Incandescent lights could easily be 1 kW (which you get to offset against the heating part of the year), which is another 24 kWh/day. A household stove is usually about 4 kW if you're cooking on two burners, but you're probably only cooking about 2 hours a day, so that's 8 kWh/day if you cook at home. (Some people cook with other fuels, but others use electric stoves.) Hot water heaters are also a few hundred watts, I think; an on-demand tankless hot-water heater is on the order of 3 kW, but in the US hot-water tanks are far more common, constantly leaking heat through their fiberglass insulation.

In Arizona and New Mexico, where I grew up, common inefficient houses need air conditioning during the day and heating at night much of the year.

So it's easy to see how, even if cooling is not required most of the year, you could easily use 50 kWh/day of electrical energy in the kinds of huge houses people have in the US.

Re: Lithium battery costs have fallen by 98% in three decades

#44

Post by kragen » Sat, Apr 03, 2021, 6:03 PM UTC

harias wrote: post #40

kragen wrote: post #36

https://archive.fo/OiXyO is lacking images; is there an alternative?

This seems better: https://webcache.googleusercontent.com/search?q=cache:FeVho1...

Thanks!

Re: Lithium battery costs have fallen by 98% in three decades

#45

Post by spockz » Sat, Apr 03, 2021, 6:03 PM UTC

Tade0 wrote: post #6

dragosmocrii wrote: post #2

The article says that today a battery pack the size of a backpack and that weighs about 40kg, can power a house for a day. Is that really so? Would that be a normal house, being powered for an entire day? I find it hard to believe that battery would pack that much energy

40kg translates to 4-9kWh depending on the chemistry, meanwhile houses in the UK draw around 3kWh/day averaged over a year so unless a house is woefully inefficient, it checks out.

3kWh seems way too low. We consumed on average 7.3kWh/day. According to our energy supplier this was on the low side for our house type and family size.

Re: Lithium battery costs have fallen by 98% in three decades

#46

Post by nicoburns » Sat, Apr 03, 2021, 6:03 PM UTC

ghaff wrote: post #22

turbinerneiter wrote: post #17

Earlier quoted context omitted.

I think in the US it's common to heat and cool badly insulated houses with electricity, whereas in europe almost nobody cools, heat comes from other sources and insulation is taking way more seriously, especially for anything built recently. The best way to reduce your energy bill (whichever source) is to live in the right climate zone I guess.

Electric heat isn't super common, especially in standalone houses, in areas where you need a lot of heat in the US. I don't know the numbers off the top of my head but electricity costs a lot more than gas or oil. You're right about the AC but I still use 20 kWh even with no AC (and no electric heat).

Do you have any idea what that is going on? Just really inefficient appliances?

Re: Lithium battery costs have fallen by 98% in three decades

#47

Post by ghaff » Sat, Apr 03, 2021, 6:07 PM UTC

turbinerneiter wrote: post #37

ghaff wrote: post #22

Earlier quoted context omitted.

Electric heat isn't super common, especially in standalone houses, in areas where you need a lot of heat in the US. I don't know the numbers off the top of my head but electricity costs a lot more than gas or oil. You're right about the AC but I still use 20 kWh even with no AC (and no electric heat).

Thanks for the insight. I vaguely remembered that people run the ac in reverse for heat, but that is probably only in paces that almost need no heating. Do you know why you use that much? Do you heat your water with electricity? Fridge, freezer, tv, WiFi, Desktop PC, charging phones and laptop, ligths.

Not really. My electricity usage is considered normal so I've never really looked into it.

Additional freezer, washer & dryer, oven (I have a propane range but many do not), microwave, there's some additional water heating in the dishwasher as well as for drying, TVs, other electronics like printer stereo etc., furnace/water heater are oil but still have pumps etc.

Re: Lithium battery costs have fallen by 98% in three decades

#48

Post by kragen » Sat, Apr 03, 2021, 6:11 PM UTC

spockz wrote: post #41

natch wrote: post #21

Earlier quoted context omitted.

Getting you through the day is not really the point though. The point is 1) shifting some consumption during peak hours off of peak rates and 2) having backup to get you through a limited outage, not necessarily at your full normal consumption level but without having to be in the dark / without internet / without phone and possibly car charging. Nobody should evaluate this by whether one battery pack by itself provi…

I’m not sure about regulations in the US but in The Netherlands you cannot just attach a battery and think you are independent of the grid. To protect the net and people working on the net, power sources behind the meter must disengage when the net/mains power drops. This effectively disables your independence plan. If you want to be independent you have to get some expensive mechanism installed that will decouple yo…

This is correct in the US as well, except that I'm not sure about the periodic certification thing.

Re: Lithium battery costs have fallen by 98% in three decades

#49

Post by ghaff » Sat, Apr 03, 2021, 6:12 PM UTC

ncallaway wrote: post #42

turbinerneiter wrote: post #37

Earlier quoted context omitted.

Thanks for the insight. I vaguely remembered that people run the ac in reverse for heat, but that is probably only in paces that almost need no heating. Do you know why you use that much? Do you heat your water with electricity? Fridge, freezer, tv, WiFi, Desktop PC, charging phones and laptop, ligths.

- AC is a very common consumer of large amounts of electricity (depending on the region, many regions will have almost no AC while other regions will have it in every building running almost constantly) - Electrical heat is not the most common form of heating, but it's been growing a lot and is also a big consumer when it is used - Laundry Washer/Dryer are pretty large consumers (mostly the dryer) - Water heaters are…

AC is a big one. Where I live in New England, we usually have a couple spells where I really need to turn on my office window unit for a week or so. Those months can drive my electricity consumption up by 200 kWH or more for the month--and that's just one small window unit run intermittently during the day to cool one small room.

Re: Lithium battery costs have fallen by 98% in three decades

#50

Post by kragen » Sat, Apr 03, 2021, 6:13 PM UTC

ghaff wrote: post #13

Tade0 wrote: post #6

Earlier quoted context omitted.

40kg translates to 4-9kWh depending on the chemistry, meanwhile houses in the UK draw around 3kWh/day averaged over a year so unless a house is woefully inefficient, it checks out.

Really? Houses in the US draw 10x on average relative to the UK? That seems unlikely. ADDED: I can believe there's some difference because of AC but I basically don't have AC (just one window unit I run a few days a year), have oil heat, and have a somewhat smaller than average house but I still use about 20kWh/day. The delta does seem to be real though.

I wonder if your house is smaller than the world average or even the UK average? It probably has less thermal mass than the UK average. What are you spending your 800 watts on?