Napabill: Now that we know from your picture you have 250W panels, all you need do is count 'em up and we can get at Shadows's question. For example, if there are 25 panels, then you are at the 6.2 number you gave (6.25kW, that is). But if they really did give you a MW number, then it would indeed had to have been some estimate of yearly production, rather than instantaneous capacity.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
-
On today's TMC Podcast, we ask the question "What is the Tesla Cybercab?". Join us on YouTube live at 1PM and participate in the chat.
Solar energy questions and answers
- Thread starter gene
- Start date
-
- Tags
- Energy Environment Policy
@Theshadows, I am getting ready to have a 14 kw system installed next week. We are using the new Enphase M250 microinverters and LG 290w panels. Any issues that you know of with LG panels? I noticed that you use 260w panels, but I was given the impression by my install company that 260-285s are quickly getting phased out to the 300w range panels. Not sure if that is manufacturer-specific.
Any "must-do" things for me to check over during the install? Thanks.
Any "must-do" things for me to check over during the install? Thanks.
simplesolar
Member
Just a little trivia about wineries in Napa....Starmont Winery is a relatively new facility there, that is 100% solar powered. Don't know their total capacity, but it is very impressive. They don't do tours yet, but we happen to know the assistant wine maker quite well and we got a private tour.............VERY IMPRESSIVE............and state of the art. They also have a great chardonnay!
InTheShadows
Active Member
I have never used LG panels so I can not speak for them. We have installed enphase inverters before. We no longer install them unless you, the customer, want to pay a huge premium on them. The premium is to cover the warranty work we will have to do in the future.
Panel sizes are increasing as a way to reduce total costs. Each panel still needs to be installed on a racking structure. A 300w panel thus reduces racking cost over a 250w panel by (theoretically) 20%. It also reduces labor. A 10kw system with 300w panels is 7 less panels to install, cutting labor, wiring, and racking.
we install both, the larger wattage panels are utility scale and weigh more and are harder to handle. You usually can't get as many on a roof because of their larger size. They are usually only larger in the length dimension so they don't take up more racking. But larger panels are not as flexible in the same square footage on the roof.
simplesolar
Member
Agree with on the enphase. I try to avoided it as well unless our client request it or the roof has alot of shading issues. Enhpase causes more trouble than not just too much stuff can go wrong. LG typically has decent quality stuff, I would say its up there with the rest besides sunpower, which is more efficient.
Last edited:
InTheShadows
Active Member
I don't. Sma just released their micros and I have talked with them about it and the reason they just now released them is because of the enphase problems. Sma said they wanted to cut the components in half to reduce the mean time between failures. I will talk with them in the next few months to see about getting a few demo units to test at my place.
simplesolar
Member
no micro inverter unless you have to (shading, tricky roofs, early adopter). Use the money saved and put it in your pocket.
JPP
Active Member
napabill et al: I had my SolarCity 16kw (....yes, 63 panels) completed 2 weeks ago with the Canadian Solar panels (like yours). As noted, my understanding is that there are more efficient panels (e.g. SunPower), any many cheaper, but I assume that SC went with these based on price/performance. Note that I did not purchase or lease my system, but chose the Power Purchase Agreement. Since SC owns the system, and has to maintain it, guarantee it (output/uptime), fix it, etc, I would assume that they have a pretty good idea of what to use. Also note that my panels are east-west mounted (no good south roof). Thus every panel has its own module clipped to the back that monitors/adjusts output and allows each string of panels (10-15 per string) to optimize output as the sun shifts. The modules are SolarEdge, and they require the use of individual SolarEdge inverters that communicate with the modules. For my system I needed 4 single inverters (microinverters would not work), with disconnects, load centers, etc. (see photo of work in progress):
Here is the finished install (with S charging):
FWIW, the SC install crew was extremely professional, and very safety oriented. They drew up a full set of plans (16 pages) with not only electrical calcs, but wind/load calcs for the roof. All legal, approved by the building department and PG&E. They use special low profile mounting brackets, and the panels are all black with black frames, and a bottom edge black skirt. They even painted out any visible conduit on the roof--really clean install. They were there for the final inspection and sign-off of the permit. Now I am just waiting for PG&E to swap my meter so that I can backfeed the grid instead of just running the meter back to zero. YMMV.
Here is the finished install (with S charging):
FWIW, the SC install crew was extremely professional, and very safety oriented. They drew up a full set of plans (16 pages) with not only electrical calcs, but wind/load calcs for the roof. All legal, approved by the building department and PG&E. They use special low profile mounting brackets, and the panels are all black with black frames, and a bottom edge black skirt. They even painted out any visible conduit on the roof--really clean install. They were there for the final inspection and sign-off of the permit. Now I am just waiting for PG&E to swap my meter so that I can backfeed the grid instead of just running the meter back to zero. YMMV.
OK, so as this is the Q&A thread, here is one of mine (not relevant to our Alaskan, off-grid business, of course):
How can one "negotiate" the size of PV system to backfeed to one's elec. co.? There must be some parameters that come into play. For sake of argument, let's say a house has a 400A service, single-phase, naturally. Does one's historical consumption (month-over-month/yearly/etc) factor in? Can different utility's rate structure alter the cost-benefit of sizing a panel bank to approximate the house's expected consumption? Can one actually receive more from a utility than "approximately a $0 check", so to speak?
I guess that was more than a single question, but all are closely linked.
How can one "negotiate" the size of PV system to backfeed to one's elec. co.? There must be some parameters that come into play. For sake of argument, let's say a house has a 400A service, single-phase, naturally. Does one's historical consumption (month-over-month/yearly/etc) factor in? Can different utility's rate structure alter the cost-benefit of sizing a panel bank to approximate the house's expected consumption? Can one actually receive more from a utility than "approximately a $0 check", so to speak?
I guess that was more than a single question, but all are closely linked.
simplesolar
Member
Here in California, unless you live in cities with Feed in Tariff, your option of cashing out excess kwh is at $0.03. If you live in Hawaii, I believe its $0.22 kwh for 20 years, which is awesome. Not sure about the east coast.
Thanks very much for starting this thread. I am building a house and plan to install a PV system with netmetering. Some of the production will be used to charge my Ford plug-in hybrid and the MX I have reserved. I have already learn a lot from this thread. I am sure that I will have plenty of questions as soon as the roof plans are done and I get specific installation proposals.
Regarding the ability of HOAs and other entities to restrict solar panel installation, we need to check the law in our various jurisdictions. Florida is usually a Neanderthal state (not to insult the Neanderthals). However, Florida Statutes § 163.04 limits the restrictions that HOAs and other entities can impose on energy devices based on renewable resources, including solar installations. Restrictions cannot impair their effective operation.
InTheShadows
Active Member
Some states have solar access laws which prevent HOA's and municipalities from preventing people from getting solar. Dsireusa.org is a great place to check. Some of their info is outdated so the incentive programs they have listed may not be available anymore. They also have the laws that will help everyone with HOA's.
That last sentence is a little ambiguous: are you saying Sunpower panels are more efficient than the others, or less efficient? It's too late for me (I have 30 Sunpower panels on my roof), but I'm curious...
The answer varies sharply from state to state, and even utility to utility. I don't know of a good site that's consolidated this info, so you should check directly with your utility.
In general there are two approaches to take:
1. Net metering. In net metering you can run your single household meter forward when you draw power or backward when you inject power. Over some period, usually in months or year, you receive a payment for any net injections. The payment rate is usually you would it cost power for the utility, which can be quite low in some areas or quite high in others, like Hawaii.
2. Feed-in tariff. Under a feed-in tariff, your solar is separately metered. You pay for the power you use exactly as you do today, but you were paid a set price for the solar you deliver. You are paid for the solar energy at a premium rate, often several times above the cost of bulk power off the grid.
If you have a feed in tariff available, then installing as much solar as you can is often the best strategy. Under a net metering approach, however, you probably want to size your solar array to more closely match your own load.
Similar threads
