Solar on Roof

Leo Voisine

Member
Messages
5,703
Location
East Freeetown, Massachusetts
Has anybody done solar on the roof?

I want to hear:

The good Stuff

The Bad Stuff

The in between stuff

Company - Happy? - Never again?

Savings? Yes - No?

Payback period?

Are you glad you did it?

Would you do it again?
 
The new house will have solar, so much research has been done. Snow not an issue here but a certain consideration in certain climates.

That said, talk to at least three different companies. Beware of apples and oranges considerations. Because I will be doing a new install on a new house, I have a few other choices. The biggest one is powering most things, especially lighting, with 12volt fixtures.

For a retro fit, write down your goals. Don't know what they might me, talking to the solar companies will help. Each goal has a cost. Itemize them. In the end, how much less do you want to pay the grid supplier and how much are you willing to spend to get there?

Lots of internet resources available. Lots of BS on the internet as well. Lots of snake oil solar salesmen as well. Depending on your community, I would look for the longevity of the company, and kinds of jobs they have done. Talk to their customers. While it is fun to gather information here, you will want a local opinion. In driving around, when you see a solar installation that appeals to you, stop and talk to the home owner. Nothing like from the horse's mouth information from your own neighborhood.
 
...and what about snow on the panels?

When you get snow on the panels your electricity production goes down. There's not much else to say, Jim. If you are ambitious you can get outside and sweep off the snow (from the ground) with a long-handled broom.

My brother used to live in Trenton, Ontario (near Kingston) and he swept his solar panels a few times, but after that he just shrugged and waited for it to melt.


Leo, I can't really address any of your questions, as the situation here in Ontario is so different from elsewhere due to the MicroFIT program that the provincial gov't set up to subsidize this sort of thing. I can tell you that my brother was well satisfied with his original installation in Trenton and is planning to do another one at his new house, but probably in a few years due to the costs associated with moving + building a new house.

The good here in Ontario is that the MicroFIT program meant subsidized prices for the electricity they buy from you. It also meant that you don't have to fuss with batteries and so on, as your power just goes straight out to the electrical grid so the power company tracks it all for you. It is a well established system so a lot of the bugs in terms of hookups and monitoring and gear have all been worked out.

I think his payback period was going to be 5-7 years and his income pretty much matched what he had predicted (he tracked local temperatures and sunshine percentages which helped with calculating expected income.) But remember that this was 4-5 years ago that he put it in and prices on gear has changed, and the MicroFIT program rules have also changed.

...art
 
I haven't installed any because we live in a dark hole and the amount sun we get (especially in the winter) really did not pencil out.

That's basically the bottom line, you need to look at the specific location and see what the expected yield is and then look at what local incentives there are and do the math. There's no one size fits all. There are some tools floating around on the web that aren't bad for helping to figure this out (although most are at a rather coarse granularity unless you pay $$'s, the more reputable installers will run the payware version for you). Google Earth actually has a daylight simulator that takes into account the terrain that you can play back for days in the past that's actually pretty close - but doesn't deal with cloud cover which can be a huge factor. As to cloud cover, high clouds you still get some power (decreased) but low clouds/fog shut you completely down (a buddy up in WA has solar and his winter yield is close to zero a lot of time due to fog) so its hard to really get a solid number.

There are several different types of panels out there. All of the older ones would shut down the entire panel if a single cell was occluded which is not good if you have intermittent shade (birds, tree shadows, leaves, dust, blob-o-snow, etc..). Some/many (haven't looked real recently but they were getting more common ~2 years ago) newer panels continue to deliver full power for the non-occluded cells and generally yield a lot better. Anyway, look closely at the proposed panel technology and see what the performance characteristics are because they're not all the same.

On the financial side the price/(panel/watt) has been on a pretty continual drop and I'm betting that will continue for the next 5-10 years (based on known but as-yet-unreleased innovations in manufacturing and design). This means that you basically need to figure in the time value of money versus the expected payback and the ongoing decrease in costs in your calculations. With interest rates where they are, the cost of the panels is decreasing faster than the value of stored money appreciates (confused yet, I sure am :D). Mostly its pretty simple if you just BUY the panels and the system, where it gets weird is if you do one of the panel rental deals. A co-worker did one of those through solar-city (who did do a nice job on the install and were reportedly easy to work with), basically the way it works is he pays his residual electric bill to them and they pay the power company. Some of us did the math and figured that if he sold the house at ~5~ years in he was actually at a net liability (that is it would be cheaper to have bought the panels new at 5 years than to continue paying back the rental cost), now the odds of most purchasers figuring that out is pretty low.. but it was an interesting exercise (this was of course at the relatively low local power rates and his specific utilization). My friends in HI are seeing something like a 2-3 year payback because of the crazy power rates there, you're a bit higher than us (~12c/kwh vs ~7c here) but no where near there (40+c/kw).

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Oh yeah and I hope your roof is in good shape (that is has an expected lifespan past the panels) because now you have a bunch of stuff on it that needs an electrician to remove if you need to re-do the roof. I haven't seen any good number on the impact on roof lifetime but expect there has to be some (you've penetrated the roof seal - that's bad, you have less exposed roof because the panels act as a second roof on top - that's good). No idea, maybe its a wash?
 
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My son is a super fanatical 'greenie'. He has a Tesla, a Prius, a Toyota hybrid SUV and another Tesla on order, and planned to get a solar generator on the roof to recharge the cars. After lots of research he decided not to. If it had proven at all economically feasible he would have done it. For a good system the recapture period can be quite a long time.
If still considering, check out Northern Tools. They sell some systems quite reasonably. Look good in the catalog. :rolleyes:
 
I think like many have said it really depends on were you live out here in Arizona they are all over the place, my brother in law has it on his house outside of Tucson. many of my neighbors have them all are connected to the grid. Most here are installed based on certain saving and I know that my brother in law says his bills are only a few dollars a month. I really have not looked into the real dollars and cents of it for my use since I have no intention of putting on a system but will say that there are solar farms not far from here one real close is reported to produces 19 MW per day. I think that would be one thing I would look at is are there any commercial sites around you If is commercially feasible tan it might be economically feasible but if no one as invested te money into a commercial site ten you might want to ask your self why.
 
You really have to crunch your own numbers. Watch out for any offer that includes a business model that you could not function under. That is; if you couldn't do it for that amount of money, how can they? Example; an outfit down in Dad's area was offering to install solar "free". That's right, no cost to you, the state, county, city and service provider offers and rebates cover everything. In reality you sign all current offers and rebates over to the company to cover initial costs and are personally responsible for any costs going forward due to changes in the power providers plan, changes in your usage over the next decade or so, and so on, and so forth.

SDG&E has a decent controversy going as they want to adjust things since they make less money on solar users. Some discussion reduces what the power company will buy back or at what rate. This takes the polish of the apple or at least presents a less than stable prediction model when compared to that presented by your friendly solar salesman. Other area providers are pondering this as well of course. Do you really think they are behind the curve on this?. Their business model is based on a certain amount of money coming in to operate and maintain the grid. Someone with a $400 a month bill going to a near-zero bill will not support that model. It has to made up somewhere so, the tariff change applications begin to flow.

I'm sure there are many plans where this pays off. A coworker has kids who come home at 2pm, fire up the AC and watch TV, use the computer, leave the fridge door open and so forth. His solar has been in for years and is working for him. His out of pocket cost went from $400-$500 a month down to about $270. This is in SoCal where the sun shines 340 days a year. The sun shines on my roof when I am using power the least (I'm at work) and there is no storage model. The real benefit for me would only be what SCE pays me for my contribution to the grid and that is under discussion for reduction. My bill is under a hundred bucks despite many hours in the shop so I am obviously not a good candidate.
 
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You really have to crunch your own numbers. Watch out for any offer that includes a business model that you could not function under. That is; if you couldn't do it for that amount of money, how can they? Example; an outfit down in Dad's area was offering to install solar "free". That's right, no cost to you, the state, county, city and service provider offers and rebates cover everything. In reality you sign all current offers and rebates over to the company to cover initial costs and are personally responsible for any costs going forward due to changes in the power providers plan, changes in your usage over the next decade or so, and so on, and so forth.

That's the same "deal" my co-worker got.. Like I said above it penciled out to be a liability after roughly 5 years without taking into account some of the other factors you've highlighted here on future variability.

SDG&E has a decent controversy going as they want to adjust things since they make less money on solar users.

Yeah, the main problem is that the connection fee doesn't actually cover the cost of infrastructure for the power company so basically they high usage customers are subsidizing the low usage customers. The other problem is that solar is time of day dependent so the electric co still has to maintain the facilities for the non-sunny periods (and has to deal with higher power generation variability as well). This is starting to be a real problem in some places, and I can see it getting a lot worse if some reasonably priced storage solution comes on market as that will start pushing the high dollar folks off grid which could eventually lead to the cost for the poorer folks skyrocketing. I know in some places they're talking about having the electric co offer a deal on co-storage facilities located at customers houses to buffer the time of day problem (basically you have ~2-3 days of buffer that you can trickle back) - still only really viable in places where the cost of generation is really high.
 
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