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Comment by debok | Hacker News Reader

A kettle uses ~1.5KW, a geyser ~2KW, an oven ~5KW, a stove about ~3KW. These are fairly high estimates I got from some quick googling. If you add these all up, and account for some more appliances (HVAC, fridge/freezer etc.), I think it is safe to estimate that a household less than 20KW at peak, even though it is a fairly high estimate.

So going backwards from there, 1.2MW = 1200KW and 1200KW / 20KW = 60 households at peak usage. Which is a very conservative estimate.

For future reference I will use 1MW = 50 households as a conservative rule of thumb. Maybe 100 households per MW is closer to reality, but that feels fairly lenient to me.

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If the average home was using 10kW constant it be using 240 kWh a day, which is enormously high.

In terms of average usage an average sized home in the US is much closer to 50kWh a day, so roughly 2kW average demand. That would mean 1 MW is enough for 500 homes on average. The one thing that doesn’t is peak demand load, say when everyone gets home from work and turns everything on at the same time or a particularly cold or hot day.

Edit: the average US home uses just shy of 1000 kWh a month, or just over 30 kWh a day.

I’m really surprised by this data. In Poland, it’s around 2000 kWh/year, which is 6kWh/day - 5 times less!

The USA includes many places where air conditioning uses electricity, and some places where heating uses electricity.

They also have huge and inefficient appliances, but that's probably a smaller impact on the figures.

Ok, but what do you actually use? I have a very small 3-bed house in the UK, and over the last few months we've been averaging 1100-1200kWh of electricity per month(and we heat using gas, although we do have an electric car).

It's not me, I'm talking about average for Polish houselhold

Air conditioning makes up a big part of that, made worse by worse insulation and larger houses.

Of course Poland needs heating, but that doesn't show up in Electricity usage as most people heat with natural gas or oil.

Actually, most people would heat with coal. Natural gas and oil are far less popular.

According to to stat.gov.pl [1] the average Polish household uses ~24.6 GJ of energy annually per 1 inhabitant. That's 6800 kWh annually per 1 inhabitant.

According to eia.gov [2][3] the average US household uses annually 56.6 million BTUs of natural gas and 10500 kWh of electricity. 56.6 million BTUs is 16600 kWh. That would bring the total to 27100 kWh.

But wait...the Polish data is per inhabitant. The average number of people per household in the US is 2.6. Dividing 27100 by 2.6 gives 10400 kWh. Alternatively, the average Polish household is 2.47 people, which would give Polish per household usage of 16800 kWh.

The US does appear to use more energy per household (total or per inhabitant) than Poland, but by a factor of about 1.6, not 5.

[1] https://stat.gov.pl/en/topics/environment-energy/energy/ener...

[2] https://www.eia.gov/todayinenergy/detail.php?id=57321

[3] https://www.eia.gov/energyexplained/use-of-energy/electricit...

Thanks for breaking this down cleanly and providing sources! Greatly appreciated!

Finland is probably like 15000 kWh/year/house (for a new house more like 10000 kWh/year). All the heating of the house & water is done by electricity, though.

8.2 kwh/day for a household in Lithuania, neighbours Poland. Sounds about right.

2022 stats: 3.289 TWh during 2022 consumed, 1.1M households, do the math...

Source: https://www.lrt.lt/naujienos/verslas/4/1887046/litgrid-60-pr...

Last month I used 1402 kwh in Washington State, which is high for me.

2600 sq ft home kept at 71f, electric heat pump, & heat pump water heater, but I had a few holes in the walls for several days due to repairs during the coldest month of the winter so far which messed up my average using electric heaters to backfill the gap.

Obviously, the holes were covered over when not being worked on but it wasn't as air tight as compared to buttoned up and fully insulated as usual.

My power consumption is usually 30 to ~75% of that depending on weather and activity.

Also relevant, houses aren't boiling a kettle and running their oven 24x7, so this is more like worst-case peak load and will be spread across different houses. Having some kind of battery storage closer to the houses will help a lot - the tidal generator can run fairly constantly and fill the battery, and the houses can draw in short bursts from the battery.

Yeah. I always feel that the solution for clean and abundant energy globally is to start with better energy grid management (and storage). There's already so many fit-to-all-geography solutions available. It's just that current grid is used to supporting lines centralized around big energy plants and not small producers.

I also always feel that there's a lot more to take down from energy consumption per household by simply making more efficient devices (especially for heating and cooling). It's possible that modern AC/heaters are already close to the peak electrical efficiency, but I guess even better producer standards for things like insulation, thermal conductors or precision sensors could still squeeze something out of the nation-wide usage.

There is synchronized kettle use and toilet use around televised sports games.

So advertising is one of the biggest factors in determining the required grid capacity? Perhaps we should charge them for it.

Minesto CEO is quoted in local Faroese news saying 800 households:

https://kvf.fo/greinar/2024/02/09/drekin-framleidir-nu-strey...

https://kvf.fo/greinar/2024/02/09/minesto-og-drekin

> The current national average (through Q2 2022) of homes powered by a MW of solar is 173.

https://www.seia.org/initiatives/whats-megawatt

I think 100 households per MW in milder climates is very conservative.

Anectdata: I have a ~150 square meter, 50 year old house heated by electricity and heat pump. I live I Norway, and where I live winter temperatures usually don't get lower than -12C. I have 2 EVs that are driven around 50k km a year combined, charged at home every night, simultaneously.

I peak out below 15kW (1h average). That number is deliberate since I get a higher tariff if I go above 15kW. I have some minor smart house installations that most significantly cuts power to my hot water heater if I get close to 15kW, but even without that I would rarely get above 15kW, and never above 20kW.

Average power this January was 4.75kW, December was 4.96kW, August was 2.25kW.

(Edited for typo)

(What’s a geyser?)

Water heater for bath/showers

From top of my head: my grandma used to have one. There was always a little flame running for safety in case of leaks, but when she used hoy water, I think the geyser just heated it on the go, instead of preheating a reservoir.

Could be wrong though.

A device for heating water on-demand, usually a gas burner with a spiraling water pipe surrounding/above it. As opposed to a boiler, which pre-heats water and stores it for later use (and also needs to keep reheating the water as it cools if not used).

Spanish wikipedia is the only with a picture of the internals: https://es.wikipedia.org/wiki/Calentador_de_agua_circulante?...

In the US, this is called a tankless water heater.

I’m not sure where in the world calls them geysers, but I agree it’s not a term you’ll hear in the US!

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