NW-Bound
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
- Joined
- Jul 3, 2008
- Messages
- 35,712
For a place where electric cost is as high as $0.35/kWhr, it is true that the $1/watt panel cost is a godsend. I can see one would want to cover his roof with cheap panels, and screw the low efficiency of the panels on the east-facing roof.
But, but, but Hawaii is at a lower latitude. In the mainland, I have seen terrible installations that would really hurt the payback.
It is also true that when panels are this cheap, it is absolutely not cost-effective to have a mechanical system that automatically tilts to track the sun through the day. It may not even be worthwhile to lower or raise the panels for the seasonal sun angle.
I just looked up my electric costs. Over the last 12-month period, I use a total of 23,162 kWhr, and paid a total of $2370. So, it works out to $0.10/kWhr, including all taxes and service charges.
As a rough back-of-envelope calculation, I use an insolation calculator that shows that, when averaged out over a year, my location provides the equivalent of 6 hrs/day of maximum solar energy. The above is for a panel that is fix-mounted, and tilted to the same angle as the latitude. By the way, the calculator uses actual measured data to reflect average cloudiness of a location. My location in the SW has the best insolation for the continental US, period.
So, a $1 worth of panel would give me an average of 1W * 6 hrs * 365 days = 2.190 kWhr/year. That's $0.22 worth of electricity/yr, or 22% return. However, it does not include the installation cost, nor the cost of the grid-tie inverter.
The true payback would be a bit more difficult to compute, because I pay by a demand-rate schedule, which is up to more than $0.20/kWhr in the late afternoon in the summer. This is the time where A/Cs are cranking all over town, but also when one would orient his solar panel for maximum output. So, the payback would be even faster.
Being a geek that I am, I would even spend $10K-$20K even without the subsidy to build something to play with, even if I just break even. If I had a large lot so that the array could be built on the ground for maximum orientation, ease of maintenance, and no risk to the roof structure, I would do it. But with my suburban home with a bad orientation of the roof surfaces, I just cannot see it as something worthwhile.
I do have more land, actually a nice south-facing hillside up in my boonies home, but I hardly use any electricity up there to make it worthwhile. Thieves might also cart off all this stuff while I am not up there.
In short, though I just want some excuses to play with this stuff, I do not see myself going further than solar for the MH.
But, but, but Hawaii is at a lower latitude. In the mainland, I have seen terrible installations that would really hurt the payback.
It is also true that when panels are this cheap, it is absolutely not cost-effective to have a mechanical system that automatically tilts to track the sun through the day. It may not even be worthwhile to lower or raise the panels for the seasonal sun angle.
I just looked up my electric costs. Over the last 12-month period, I use a total of 23,162 kWhr, and paid a total of $2370. So, it works out to $0.10/kWhr, including all taxes and service charges.
As a rough back-of-envelope calculation, I use an insolation calculator that shows that, when averaged out over a year, my location provides the equivalent of 6 hrs/day of maximum solar energy. The above is for a panel that is fix-mounted, and tilted to the same angle as the latitude. By the way, the calculator uses actual measured data to reflect average cloudiness of a location. My location in the SW has the best insolation for the continental US, period.
So, a $1 worth of panel would give me an average of 1W * 6 hrs * 365 days = 2.190 kWhr/year. That's $0.22 worth of electricity/yr, or 22% return. However, it does not include the installation cost, nor the cost of the grid-tie inverter.
The true payback would be a bit more difficult to compute, because I pay by a demand-rate schedule, which is up to more than $0.20/kWhr in the late afternoon in the summer. This is the time where A/Cs are cranking all over town, but also when one would orient his solar panel for maximum output. So, the payback would be even faster.
Being a geek that I am, I would even spend $10K-$20K even without the subsidy to build something to play with, even if I just break even. If I had a large lot so that the array could be built on the ground for maximum orientation, ease of maintenance, and no risk to the roof structure, I would do it. But with my suburban home with a bad orientation of the roof surfaces, I just cannot see it as something worthwhile.
I do have more land, actually a nice south-facing hillside up in my boonies home, but I hardly use any electricity up there to make it worthwhile. Thieves might also cart off all this stuff while I am not up there.
In short, though I just want some excuses to play with this stuff, I do not see myself going further than solar for the MH.
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