Depends on your where you live and the orientation / angles of your planned panels.
Sizing your Solar or Wind Alternative Power System
Sizing your Solar or Wind Alternative Power System
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Solar Carport
- Thread starter shark2k
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- Energy Environment Policy
Thanks TEG. Looks like it is not really feasible for me to pursue it. Given my roof size it would be a stretch for me to get 20% of my power from solar at the max and the cost would be way higher than I am paying now - like doubling my electric bill so I guess it is a no starter. Totally bummed.
I am hoping they will continue to come down in price and I am sure they will. But it will have to be a SUBSTANTIAL reduction to make it worth while. I would double my electric bill for 25 years before I would even break even on the deal and see ANY return. I have a townhouse and the roof is small but I also use very little electricity as well. I only use 17,000 Kwh / yr. @ an average bill of $135/ month. The largest panels I could put on my roof would yield about 20% of my current usage. Therefore a 20% savings on my bill of about $25/ month. Financing the system would be about $180 / month. The math just kills it !!!! Perhaps these new PV cells that can just be printed in high quanity will be cheap enough to turn some of that around. Also I assume that installation would be easier and cheaper to boot. here is keeping my fingers crossed.
AntronX
Member
17MWh/yr is 47KWh/day, that's not very little... You need to half that before PV will make sense. Get solar water heater tank, that investment pays off in 3 - 5 years. Take steps to reduce your cooling/heating energy use.
Actually I am thinking of going with a tankless hot water heater. I have a VERY small house for the area and I know many people that have electric bills that are easily 3-4 times what mine is. Let me look back and see if I am mixing units or something odd. My bill is VERY small for an all electric house @ $135 / month. 
I checked my usage again and this makes no sense to me. I used 16,617 Kwh in the past 12 months and averaged 45Kwh/ day. So I am falling into the category that you mentioned BUT NONE of the numbers work out for cost. It would take me 25 years to recover the cost of the system AND on top of that all of the time after that I am only saving like $25 a month so I would still have a $110 bill every month with the PV panels. What am I doing wrong !?!?!?!?!?! I would love to do it if it makes any sense at all to do it .....
SByer
'08 #383
Possibly. As we got estimates for our system there was an interesting knee in the curve where the payback time was minimal - and for us it was one of the larger systems. The system we're getting installed is an 8.1kWH system, with an estimated payback time for us of about 7.6 years (that includes the federal and CA discounts). But that payback doesn't include estimated increased equity in the house, which is actually pretty significant. The payback time is only an estimate of course, and can change based on how much you can adapt your electricity use to the TOU metering. A bunch of stuff we'll be able to move out of peak hours. I'd say if your electricity use doesn't put you into the higher rate tiers, then solar probably still doesn't make sense.
Also note that the tools for doing shading and production analysis are getting really sophisticated. They take a bunch of 360-degree fisheye pictures with a known orientation from multiple locations, trace the outlines of things that will cause shade, and the software can compute out production based on roof angle, orientation, that shade line, and time of year.
I think PV solar is just one tool in what should be an arsenal of being more efficient. I'll also be looking into putting in a thermal radiant barrier and whole house fan this summer as well. What works for what situation is going to be all over the place.
Also note that the tools for doing shading and production analysis are getting really sophisticated. They take a bunch of 360-degree fisheye pictures with a known orientation from multiple locations, trace the outlines of things that will cause shade, and the software can compute out production based on roof angle, orientation, that shade line, and time of year.
I think PV solar is just one tool in what should be an arsenal of being more efficient. I'll also be looking into putting in a thermal radiant barrier and whole house fan this summer as well. What works for what situation is going to be all over the place.
see we don't have tiers of power here. one rate. $0.055/kwh and that rate changes a little bit in the winter or summer - i am not sure which - to a slightly higher rate maybe like $0.06 or so. So I guess that would effect it as well. I like the idea of saving 20% on my electric bill since that is the max I can do but makes no sense if the payment on the system is like 100% of my old bill.
AntronX
Member
Kevin, i punched in your location into first solar calculator i found on google, and to power your needs 100% you will need 12KW system that will pay for itself in 25 years. Thats roughly $65K after incentives. You really got to figure out how to conserve energy so you can realistically make it on solar. Last thing you wanna do, is to waste your expensive solar electricity on heating water, drying clothes, space heating and inefficient appliances.
Electricity is cheap because the true cost is subsidised by thousands (if not millions) of years of solar energy condensed into energy rich fossil fuel that humanity will burn through during only 200 years or so. If we had to run our society on energy captured in real time, it surely would not cost 5.5 cents per kilowatt hour.
Comparing cost of solar PV to coal power is illogical. But so is thinking that cheap coal electricity will last forever.
Electricity is cheap because the true cost is subsidised by thousands (if not millions) of years of solar energy condensed into energy rich fossil fuel that humanity will burn through during only 200 years or so. If we had to run our society on energy captured in real time, it surely would not cost 5.5 cents per kilowatt hour.
Comparing cost of solar PV to coal power is illogical. But so is thinking that cheap coal electricity will last forever.
Antron,
I have an all electric house with no alternatives available to me unless I put them in myself. I can not use Gas or Propane or Oil or anything else. All I can do is look into solar or wind and I am about 99% sure that the owners association here will not allow wind. If I had Gas or LP heating and hot water I am sure that I could make use of a solar system easily. 25% of my bill was about what I have been saying all along that was my max system because I do not have the roof space to do any more than that. Therefore, the high cost with little to no savings makes no sense for me. I don't mind the 25 year ROI but to do that and still only see a 25% reduction in my bill is rediculous. I am seeing no alternatives that make sense.
I have an all electric house with no alternatives available to me unless I put them in myself. I can not use Gas or Propane or Oil or anything else. All I can do is look into solar or wind and I am about 99% sure that the owners association here will not allow wind. If I had Gas or LP heating and hot water I am sure that I could make use of a solar system easily. 25% of my bill was about what I have been saying all along that was my max system because I do not have the roof space to do any more than that. Therefore, the high cost with little to no savings makes no sense for me. I don't mind the 25 year ROI but to do that and still only see a 25% reduction in my bill is rediculous. I am seeing no alternatives that make sense.
AntronX
Member
Well, that's how it is. Either pay or conserve. Did you look into better insulation? R40 attic? Double, triple windows?
graham
Active Member
Sometimes it is not solely about saving the electric bill. For me, the power in my neighborhood was crummy enough that I used to lose a lot of electronic equipment when the power would bounce.
Now that my solar + battery system is in place to clean my power and prevent interruptions, I have to replace far fewer pieces of equipment. Not to mention, I have the added convenience of never having the power go out (which is worth something as well).
Yes, it was very expensive - but it wasn't solely about trying to break even on my electric bill.
Edit to add: not to mention that eventually I will be able to use it to "gas" my car
Now that my solar + battery system is in place to clean my power and prevent interruptions, I have to replace far fewer pieces of equipment. Not to mention, I have the added convenience of never having the power go out (which is worth something as well).
Yes, it was very expensive - but it wasn't solely about trying to break even on my electric bill.
Edit to add: not to mention that eventually I will be able to use it to "gas" my car
Antron,
I HAVE done all of the small things I can do like insulation and windows etc. I can not get any toher source of power other than electricity and there are very few incentives in this area - only the 30% that the feds offer - so just not realistic here I guess. I do not mind paying a little bit more for the solar power BUT I am not willing to pay DOUBLE for 25+ years just to save 20% on my bill after that. I am not looking for lectures on how to improve I am looking for alternatives that I have not found to make it possible. I WANT to do this IF it makes a modicum of sense......
I HAVE done all of the small things I can do like insulation and windows etc. I can not get any toher source of power other than electricity and there are very few incentives in this area - only the 30% that the feds offer - so just not realistic here I guess. I do not mind paying a little bit more for the solar power BUT I am not willing to pay DOUBLE for 25+ years just to save 20% on my bill after that. I am not looking for lectures on how to improve I am looking for alternatives that I have not found to make it possible. I WANT to do this IF it makes a modicum of sense......
SByer
'08 #383
Kevin, with your ultra cheap electric rates, it's going to be a while before solar PV makes sense for you. While thin-films do lower the cost per watt, they have unknown lifespans. Also, where roof space is limited, small increases in panel efficiency can make a big difference in payback time. All the non-Sun Power bids we got had significantly longer paybacks.
That being said, I also suspect electric rates are going to climb even faster than they have been (6%/yr here in CA) as carbon caps and/or pollution taxes are enacted. And as we get rid of dirty coal (ok, that's redundant - all coal is dirty!), I think that impact will be felt more in the east.
That being said, I also suspect electric rates are going to climb even faster than they have been (6%/yr here in CA) as carbon caps and/or pollution taxes are enacted. And as we get rid of dirty coal (ok, that's redundant - all coal is dirty!), I think that impact will be felt more in the east.
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