Guesstimate my solar power potential

7,118

10. Ivan Seeking

12,539
Staff Emeritus
How did you come up with 2KW? If you know that's the number, it's a fairly easy problem. 2KW during daylight hours, or 2KW continuous?

11. Danger

9,878
Hello, beaked one.
I'm with Rhody on this one. I can honestly say that I don't know anyone who has an air conditioner (aside from those which are included in vehicles as standard equipment). For heat, I would actually go with black ABS or PVC piping as opposed to photovoltaic devices. You apparently live in a climatic zone that is not normally conducive to penguin longevity. Wanna trade?

12. Pengwuino

7,118
Oh I just vaguely guessed at it. I remember Chi saying his house was fully powered by a 7 kW system and he sounds like he doesn't use much electricity in the first place so I figured 2 might be a non-stupid guess. I should actually check the bill!

So when people say they're giving you a 2kW system, what does that actually mean? I mean, is that how much it will produce in direct sunlight? Does that only apply during summer when intensity peaks? Does it include variables like roof slope? Is it some kind of average? AHHH!!!

Yes, we live in an area that regularly tops high 100s and low 110s during the summer. Even the biggest swamp coolers can't handle it.

13. Ivan Seeking

12,539
Staff Emeritus
The panels are typically rated according to their maximum output. You have to derate from there according to angle, panel temp, and so on.

I would look closely at the break point for the high price, how much you need to reduce power, and during what hours. The rates can even vary with the hour of the day, but I don't know if this applies to you.

14. Pengwuino

7,118
PG&Es site says we're on a plan where they do not charge based on the time of day. So during the summer it looks like we're using 1000 kWh into the $.33/kWh tier (yes, our bills can hit nearly$800 on a really bad month). Maybe a 3kW system would be able to keep us out of that super high range as much. Our winter electricity usage drops to around 1kW during the day since we have a gas heater, so going beyond 3kW would seem to be adding more cost with no benefit to be gained during the off-months.

I really can't figure out jack from solar company websites. It's always "Enter your monthly bill and your area code and we'llt ell you how much you can save :D" with figures such as how much the actual stupid system they're installing costs if you buy it upfront or what the generation would be or anything.

15. Danger

9,878
And here I be, up to my *** in snow. It's currently -8°, which Dave mentioned a while back is considerably warmer than the point at which we Canuks have to put on a hat when we go oot and aboot. It's T-shirt weather.

16. Ivan Seeking

12,539
Staff Emeritus
So it sounds like you need to reduce your usage by at least 35 KwHrs per day. You would want to do a formal check on the losses, but just shooting from the hip, you are probably into a 10KW panel, or so. Then you need to figure out how to apply it in an independent mode. When I feel like thinking harder, if you haven't worked this out yet, I'll check back. Right now my brain is still fried from running budget numbers.

17. Pengwuino

7,118
Holy chit, 10kW? :-/ Why so much?!?

18. Ivan Seeking

12,539
Staff Emeritus
35 KWHrs per day over say 6 Hrs effective, is 5.8 KW. Then factor in additional losses due to angle and temp, and system losses after that.

19. Pengwuino

7,118
Sadface. I read that systems are around \$7/W. So that's like.... ridonkulous.

20. Ivan Seeking

12,539
Staff Emeritus
I would take a hard look at getting a deal like Chi has, where you pay a fixed amount every month and have a complete system.

Obviously the negawatt [saving energy] approach is the place to start. You guys are total power hogs.