This math checks out but the way you present the units is deeply confusing. It's not your fault though, I blame watt-hours.

You use 8kwh==28.8MJ of energy per day. 28.8MJ/7MW turbine is about 4 seconds, as a watt is a joule per second.

I found his units to be significantly more clarifying than yours. There's nothing wrong with having units of time (or distance) in both the numerator and the denominator, depending on the context. For instance, the Hubble constant is commonly expressed in km/s/Mpc, and astronomers purposefully don't cancel the units of distance.

In this case, there are two distinct timescales involved: the scale on which the energy is used (an hour or day) and on which it's generated (a second). It's ok to keep track of those separately.

There's nothing "wrong" with the units, besides that it is easy to get confused, evidenced by GP calling the turbine "7MW(h?)".

If you want to compare, however, you will have to convert to common units, and I at least find it easier to use watts and joules than watt-hours/second and watt-hours. By all means convert to stationary-bike-hours and big macs or whatever unit at the end but calculations are easier in the SI units.

Hubble's constant is expressed like that because it is a nice unit for the math.

> In this case, there are two distinct timescales involved

Three really: seconds, hours and days.

8 kWh per day = 8 Joules per second ⋅ hours per day ~= 330 Watts

Sometimes you even get four time units in one go. e.g. "I averaged 8 kWh per day last year"

It's madness.

My home uses 72 kWh/day (16-20 of that is charging a Chevy Volt), so even at my extreme usage, it's less than two minutes to provide my daily power needs. These are amazing:

https://www.siemensgamesa.com/en-int/products-and-services/o...

For comparison, that's a bit more than the electric consumption of all fourteen 90 years old houses on our street combined. Would cost roughly 650 USD a month over here.

Unless you are running an extremely energy intensive commercial operation at home, there's a lot of low hanging fruit to be picked. Get an energy audit yesterday. That could hugely benefit all of your comfort, your wallet and the environment.

That's....huge.

For reference, I use 30kWh/day but I live in an 80 year old all-electric house (heating, water, cooking, ...) where temperatures go down to -30 degrees celsius and winters last for 6 months. Plus both my wife and I work from home so the heating and lights etc. are on all the time. And I still think it's way too much !

Why are you using so much power? Do you use electric for everything including heat and cooking?

Over 4000 sq feet, three stories, mid-atlantic. I need to have an energy audit done though; it's still a lot.

That’s a _lot_. That would cost you 5k euro a year here! Do you have a good sense where it’s going? Unless there’s something obvious, you might want to get the meter checked.

It's the kind of figure that suggests someone has tapped the supply and has a cannabis farm next door.

8-9 tons of A/C split across three units. High ceilings. All windows, some of them quite large, are on the east and west side of the house. They are double-paned, but still. We have shutters but they are mostly open because we like the light. I work from home, and we home school our kids, so the house is always occupied.

We don't keep the house exceptionally cool. 78° during the day, 74° on the second floor at night just before bed.

I really need to try and track things down a bit better. I've got two sub-panels and it's a lot of circuits to track it down. I can start by monitoring the obvious things though: A/C units, refrigerators, dryer. I recently replaced two of the A/C units, but around the same time switch from natural gas dryer to electric and that seems to have been a wash.

Power comes from a nuclear plant less than 10 miles away, so at least it's clean? :-(

If I've done my math right on the A/C units, they pull a combined 8500 watts. It would only take them each running on average 15 minutes per hour to eat up 52 kWh per day.

Two 14 SEER units, one 3.5 ton, one 3 ton, and a 10 SEER 2 ton unit.

1 ton = 12,000 BTU.

(6.5 x 12000) / 14 + 2 x 12000 / 10 = 7971 watts.

The air handlers have 1/5 HP motors, call that another 150 watts per air handler, so we're up to 8500 watts at least.

52 kWh / 8.5 kW is a little over 6 hours, or 1/4 of the day.

To use less power and still have a comfortable home, I'd have to insulate it better and switch to smaller and more efficient A/C units. The units are sized properly according to:

https://asm-air.com/airconditioning/what-size-central-air-co...

Yeah, that seems entirely crazy to me.

I was like "That seems high" so I checked my usage meter and it say 112kWh. OK then. Then I notice it's set to monthly.

So that's about 4kWh per day. It will be a bunch more in winter, and your place is much bigger than mine, but still - that number seems kinda crazy huge to me.

That is awful.

8 KWh/day is very impressive. How did you get it that low?

The common advice (in Denmark) is to buy energy efficient electrical appliances. Fridges, washing machines, dishwashers, and led lights are labelled[1] so consumers can decide for themselves.

School kids are taught (well, at least I was) small habits such as boiling just the amount of water that you need, cooking with the lid on, turning off the oven 5 minutes before the meal is done, etc.

These energy saving habits are motivated by taxes on energy consumption.

The average household in Denmark use 4.4kWh/day per person (1600kWh a year) and the current recommendation is to be aiming at 1000kWh/year[2].

[1] https://en.wikipedia.org/wiki/European_Union_energy_label

[2] https://sparenergi.dk/forbruger/el/dit-elforbrug (in Danish)

I guess it's all relative! I'm not home much of the day, live in a newish condo with LED lights, and heat and cooking use natural gas. 8 KWh feels like a lot to me as it's enough electricity to power an oven for several hours each day.

Is it low? My last bill said I averaged 5kwh/day last month, my February bill averaged 7kwh/day. That's gas heating and hot water though.

I have a smart meter in my apartment.

A few weeks ago I was on holiday. Usage was 2.5kWh per day, about 100W, which is the fridge and a low power PC (NUC).

Otherwise, it's 3-6kWh per day, and depends whether I did laundry and cooked or not.

District heating and water.

Mine is 7kW a day; smallish house, LED lighting, gas heat and stove (though electric oven). I believe a good bit of that is the drier, tho.

Have you looked into heat pump-powered dryers? They cost a little more up front, but seem to be much more energy-efficient.

Due to space/kitchen layout constraints, I've got an integrated combo washer-dryer; I don't think anyone currently makes a heat pump one.