I just ran another calculation for an 8kW system in the Tampa Bay area all facing South at a 20 D angle using the standard setup through pvwatts. For some reason the results seem lower than the last time I ran the calculation so maybe there is a lower efficiency value being used now then when I ran it before.
Anyway this time it resulted in a multiplier of about 1500 hrs for each kW installed for the 8kW or about 12000kWh for the year (which would be about 82% of my yearly usage). The last time I ran the numbers the multiplier was closer to 1700 hr for each kW of DC installed. But maybe pvwatts has modified its formula.
So for the OP's usage of > 25000kWh per year I would expect the need for a system in excess of 17kW. That is a pretty big system which can make the payback much longer to get the last 10% of the total usage covered which is why a lot of people figure a system to cover 80 to 90% of their usage.
Based on my earlier calculations for savings at $0.12/kWh it would take over 10 years for the system that cost ~ $2.00/watt to pay for itself.
As for the question about self installs in Fl? It seems some localities allow it if certain rules and codes are followed. I am not sure about the OP's location but I can tell you that I will not be able to do the entire installation up in the Brooksville area. But then again I will have a different POCO then the OP's.
-
You may be under the incorrect thinking that, for example, a 10 kW PV system will only produce 10,000 kWh/yr. Closer to reality, a 10 kW system will, over the long haul, with an equator facing azimuth and an 11.3 deg. (20 % roof pitch), produce something like ~ 15,000 or so kWh/yr. average in your area +/- ~ 10 % for seasonal weather variations, shading effects and a few other things.
Depending on what your local costs are, an installed, turnkey system at, say, $3.00/STC Watt (SunEagle ??) will set you back ~ $30,000 X .7 = 21,000. Don't know if FL allows self installs (SunEagle ??), but a good ball park cost might be ~ half as much than for a turnkey installed system. NOMB, but sometimes self install runs into problems because DIY'ers are often very uninformed about how PV works and local code requirements, even though they consider themselves experts. Just sayin'.
Depending on what you pay for power - and as a respectful suggestion only - look before you leap, and do not assume you understand not only how much, but also and equally importantly how you are billed for what you use, and also how those numbers may change in the future - and they will . This is important. Sizing and deciding go/no go on acquiring PV is more involved than getting and installing a garage door opener.
Before the sizing, look at what you will pay in time and treasure for the resulting bill reductions made possible by a PV system of varying sizes, and how that reduction will change as system size is varied. Some (but usually too few) folks actually do all that homework and find (decide) the upfront cost of PV is not worth the amount of money it will save in electric bills, vs. what else they could do with the money/time. Others ( probably most) are reactive to high, self induced electric bills, and/or have a woodie for their power co. (POCO for short), rather than being proactive about lifestyle choices like conservation measures before PV that are much more cost effective, and can produce further savings by reducing subsequent PV size requirements (and so costs) still further. Reduce your use as much as your lifestyle allows before PV. PV is the most expensive way to reduce an electric bill. Therefore, intelligently, it should be the last thing done if saving money in the most cost effective way is a priority.
Suggestions:
1.) Download and read "Solar Power Your Home for Dummies", a free net download for an older version, or ~ $25 for an updated hardcopy in bookstores or on Amazon.
2.) After the read, get familiar and run something called PVWatts. It's a modeling program that estimates long term average output. read the help/info screens a few times and do a few runs. You'll probably quickly zero in on a size. A little homework on rates and how PV system sizes can change what your bill is in a non linear way may help you see that the common idea of the uninformed that a 100% or worse, more off set of an electric bill is a no brainer is actually a financial fallacy for many if not most situations. Still a choice - but often not that of the smart money.
Welcome to the neighborhood and the forum of few(er) illusions.
Take what you may want of the above. Scrap the rest.Leave a comment:
-
You can check out what a pv system can produce by going to a website called pvwatts.nrel.gov that can run a calculation for your area. That will help you size your system to cover X% of your usage.
Next you need to check with your local permitting office to find out how much of the installation you can perform yourself.
Based on a lot of previous information the state of Florida (at least most cities and counties) require a pv installer to have a specific Contractors license and Solar qualification to install any or most of it.
Finally you really need to check with your POCO to see if they allow a home owner to connect the system to their grid. They usually require someone with an electricians license but it may be different for your area of Riverview.
Once you have checked out the above and have determine what you can and cannot do for the installation, then you can start to determine where to get the parts or who to get to do the install.Leave a comment:
-
-
Hello Suneagle, you're not far from me, I'm just south of Tampa in Riverview.
If my calculations are correct my usage of 2120 Kwh's a month a 12-15kw system would just break even, No? I don't want to oversize my system.
Are there any parts wholesalers in our area? I'm thinking about doing the whole job myself.Leave a comment:
-
Hello Cessna TPA and welcome to Solar Panel Talk
I am also a Floridian currently living in the Clearwater area of Tampa Bay but will soon be up in the Brooksville area.
My first thought about building a pv system much larger then I would need might not make sense due to the cost of the system and the possible low payback my POCO would pay me for any excess power.
You might want to check with your POCO again to see if the price / kWh stays the same if you are a co-generator at 10kw or a much larger generator at 25kw. IMO when someone starts to be a big co-generator you start to compete with the POCO and they will find a way to not make it as profitable to you compared to a small system.
Leave a comment:
-
Hello From Sunny Florida
Glad to be your newest member, having been on car & motorcycle forums in the past I know there will be a wealth of information on here.
I've just begun to start my research and planning for a grid tie solar system for my home. My usage is 2120 kWh a month and my back roof faces south with 1000+ sq ft of roof space at a 20% pitch.
My electric company have different categories of solar installs. Teir 1 under 10kw A.C., teir 2 above 10kw to 100kw which from what I've read the only difference is the requirement of 1 million dollar liability insurance ($39 more a year) and a $250 applications fee. I'm thinking about a 12kw-15kw system but when I've talked to 2 solar installers they both Immediately said they can do above 10kw but recommend staying teir 1. I explained I was fine with the extra insurance and $250 fee. But they still pushed the smaller system. I felt they were not telling me the whole story. Any thoughts why?
Leave a comment: