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Comment by jvdvegt | Hacker News Reader

So, with about 10.000 kg of these in my basement (2MWh capacity), I should be mostly self-sufficient? Nice! (4MWh electricity usage per year, with solar panels producing slightly more)

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I don't think it's feasible to store your summer excess long term like that. It would be cheaper to add more panels to produce enough power in the winter and having enough battery capacity to last you a few days in case of bad weather.

i use between 1 and 2 MWh a month... Do you live underground and not have anything electronic? 1000KWh is 1MWh. I guess if one has all natural gas appliances and no need for air conditioning it's possible to get down to 333KWh a month.

i have owned and ran computers that used more than that a month, for goodness' sake.

This is a family of 5 in the mid-Europe. We don't use electricity for heating or cooling, and we're still burning gasoline to drive around. These are pretty normal numbers around here.

Between 1 and 2 MWh per year isnt that unusual.

For example in Germany the average per person per year is 1.3MWh.

that's 100KWh per month, which is ~3KWh per day. that's the equivalent of leaving a 100W incandescent bulb and a 100W equivalent LED bulb on for 24 hours a day.

You're telling me that the AVERAGE usage in germany is 1.25 incandescent bulbs 24/7?

my LAPTOP uses more power than that!

Why would you need storage for half of your annual electricity usage to be self-sufficient? It seems like you could achieve that with far, far less battery, perhaps combined with slightly more solar.

Our panels produced a mere 60kWh in december. We've got 6 months where we use more than we produce. Storing 50% was a quick estimate as for what we'd need. Anybody got better numbers for that?

These numbers are easy to compute myself. For the 6 months my panels did not produce enough electricity, we used a total of 2.1MWh from the grid. So my 50% guestimate was actually spot on :)

Well there you go :)

If you have the land for it, you might find it mildly more cost effective to ground-mount solar panels at a steeper angle to optimize for wintertime production, which would allow you to shrink the battery. Installing 10000 kg of batteries in a home isn't something likely to ever be super easy.

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