Hacker News Reader

Comment by adrianN | Hacker News Reader

You need a pretty big property to be self sufficient, or a very reduced lifestyle. The typical American consumes about 10kW of primary energy at all times, on average. That's hundreds of square meters of panels.

View on HN

Your math is incorrect. 10k at all times per person x 2.6 people per household x 24 hours x 365 days would be 228k kwh per year per household.

In fact it's 10-11k kwh per anum. Many developed nations use 5-7k and don't live greatly reduced lifestyles.

http://shrinkthatfootprint.com/average-household-electricity...

It's hard to calculate the exact size due to multiple factors but the following source says a 2 kw system can use as little as 150 Sq feet. In some places you could generate enough to power your house in 3 hours or an American house in 6.

Presumably solar and power storage will keep getting cheaper. https://us.sunpower.com/blog/2019/07/16/how-much-solar-power...

I'm not talking about electricity alone, but about primary power consumption. That includes heat and fuel for your car, and also all the energy consumed by domestic industry. It's about 2.5155×10^13 kWh, or 81,800 kWh per person (in 2009)[1]. You're of course right that just electricity is much easier.

[1] https://en.wikipedia.org/wiki/Energy_in_the_United_States#Pr...

It's always a red flag when "primary" energy comes up. Something like 3/4s of that primary energy will be wasted as heat while being converted into useful energy, and so renewables have a 4x advantage just by their very nature of directly making electricity.

(They also have a 4x advantage even if generating heat is the actual purpose, but for different reasons.)

Sure, if you take that into account you still need several kW of average energy production. Unless you live in a very sunny area that's a lot of panels. Panels in Germany for example get about 10-15% of their peak rating if you average over the year.

Hah, no way. A little back of the envelope calculation shows that if that claim was correct, my electric bill would be 10 times higher than it actually is ($25 per person in reality, versus $250 per person in your world). Nope.

https://news.ycombinator.com/item?id=21788298

And a small turbine and a wood furnace for heating.

No, just good insulation and a heat-exchanging ventilation system. See Amory Lovins's banana trees in Snowmass, Colorado.[0]

[0]https://mountaintownnews.net/2017/11/21/amory-lovinss-long-s...

That's super interesting for a 40 years old home, around here homes from that time sometimes don't even have double-glazed windows. It's too bad that there are no details being provided, but other articles[0] give more information and aside from the house being covered in solar panels it doesn't look too alien (save for the very bendy walls) at least until you find out the walls are 40cm thick and the greenhouse is absolutely integral to the concept.

I really like that the greenhouse uses permanent water fixtures (a waterfall, brook and pond) for both ambience and humidity control, I've been thinking about this sort of things and how to heat responsibly: mixed wood / pellet furnace was about my best idea, and apparently the Lovinses still have a backup wood-burning stove though their 2009 "v2" renovations allowed them to get rid of the gas-fired stove and heater.

One of the things which I find more interesting is how diametrically opposite they went for one of the directions: opening up the house using efficient glass panes, where I was thinking more towards burying it, in a more extreme version of turf houses. But that makes sense if you want to produce your own electricity using solar panels, you couldn't maintain a proper turf cover then.

[0] https://grist.org/climate-energy/amory-lovins-high-tech-home...

Reply on news.ycombinator.com