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April 8, 2008
Roofing / Solar Panels
I may be re-doing the roof on my 20' 0" x 45' 0" brownstone this year. If I do, I'll be looking to incorporate provisions for future installation of solar panels. Is there anybody out there who's done this, or who already has panels and retrofitted existing roofing to provide the panel supports? Do the supports comprise posts coming up from the joists, through the roofing, with pitch pockets or flashings at each post or is it done via steel beams spanning between the party wall parapets? If the former, did you have to reinforce the existing roof joists? Any advice and insight would be much appreciated as would recommendations for solar installers that are based on actual experience.
Thanks.
Comments
The solar panels will be mounted on racks that require pitch pockets, correct. I am currently planning a system about half your size (1.5kW) and it will require about 6 of these pitch pockets.
If you are redoing the roof anyway, these should be no big deal and I would think installing the panels would be an excellent idea. They weigh almost nothing in relation to the live loads your roof can handle already, less than 5psf, so you most likely would not need any reinforcing for the existing joist supports (in a typical roof span brownstone).
Posted by: Smokychimp at April 8, 2008 10:04 AM
Smoky Chimp, I had been doing some research on solar panels and my overall impression (and disappointment) was that unless significant unscreended south facing square footage were obtained the gain wouldn't justify the cost. It seemed like the payback period for other orientations would approach the life cycle of the panels. The panels were also quite expensive. Do you know of any good links or books for furthering my research? Also any leads for more economical panel sourceswould be appreciated.
Posted by: guest at April 8, 2008 10:21 AM
10:21,
If by, "leads for more economical panel sources" you mean that your intention would be to acquire the panels and do the installation yourself, I don't think that's on the cards. In order to get the benefit of the tax rebates and/or tax credits and to be hooked up to the Con-Ed meter so that you get the benefit of the "backwards-running meter" scenario when your using less power than you're producing, I'm pretty sure the entire package has to be bought from a firm that is licensed by the State for photo voltaic installations.
Posted by: johnife at April 8, 2008 10:38 AM
Johnife is correct, you cannot just go out and purchase / install the photovoltaic system yourself, you need to use a NYSERDA licensed designer and installer. Con Edison may cut your supply if you do it yourself as the system is tested by them for safe operation. Using NYSERDA is also the only way you can get the on going tax rebates and start up grants which will pay approximately 50% of the initial cost of the system (thus making it cost effective). The panels alone will cost you approx $1000 each, depending on type, each panel is rated at around 200 kW. Under the NY PSC, you are limited to a maximum size of 10 kW for residential system, net metered is what Con Edison calls the "backwards-running meter" scenario.
There are also several different ways of fixing the panels to your roof. Many systems for flat roofs utilize a floating raft system and ballast weights, therefore no need for any penetration of the roof itself.
Other things to consider are, the photovoltaics should be South facing and not shaded - direct access to sunlight during daylight hours. You may require a structural survey of your roof. You will need to have room availible for the invertor unit and you will also require a lockable fused disconnect switch within 10 ft of the Con Ed meter.
A Dispersed Generation Engineer!!
Posted by: guest at April 8, 2008 12:53 PM
"each panel is rated at around 200 kW. Under the NY PSC, you are limited to a maximum size of 10 kW for residential system"
Huh? Did I read that wrong or does that say that You are limited to only 5% of what they are rated?
Posted by: guest at April 8, 2008 1:20 PM
What is the 'life cycle' of photo-voltaic panels, anyone?
Any thoughts about potential vandalism?
Posted by: guest at April 8, 2008 1:29 PM
Yeah, I think it was a typo; should have said 200W.
Posted by: johnife at April 8, 2008 1:32 PM
1:29,
From FAQs on a solar info site:
"How long do solar panels last?
For a long time: solar panels carry 20-25 year warranties, with life expectancies of 40+ years.
What if there’s a hailstorm? Can the solar panels withstand hail?
Solar electric panels are built with high-impact tempered glass. The solar industry standard dictates that panels should be able to withstand 3/4” hail at 60 mph. One of our solar PV panel manufacturers even performs tests by shooting ice cubes at their panels at 140 mph. If your solar panels do suffer any hail damage, you can claim the damage via your homeowner's insurance policy."
Posted by: johnife at April 8, 2008 1:42 PM
"on going tax rebates and start up grants which will pay approximately 50% of the initial cost of the system"
Is that 50% of the cost of the panels, or of all the materials needed to set up a system, or of all that and installation by approved licensed designer and installer?
Posted by: guest at April 8, 2008 2:25 PM
Sorry, it was a typo. It should have read 200W. For a 2KW system you would need around 11 panels of 200W as you get around 10% loss's in the invertor and asociated cabling.
Regarding the availible grants, this is calculated on a per project basis, depending on the size of the system, how much sunlight the system will receive etc. The approved designers get the rebate (or initial grant) from NYSERDA, not you the customer, you just get a cheaper price for design and installation and the tax deductibles once installed.
Johnife is correct with the stated life expectancies but you would never get these figures under waranty, more like 15 to 20 years.
Posted by: guest at April 8, 2008 3:30 PM
Sorry, it was a typo. It should have read 200W. For a 2KW system you would need around 11 panels of 200W as you get around 10% loss's in the invertor and asociated cabling.
Regarding the availible grants, this is calculated on a per project basis, depending on the size of the system, how much sunlight the system will receive etc. The approved designers get the rebate (or initial grant) from NYSERDA, not you the customer, you just get a cheaper price for design and installation and the tax deductibles once installed.
Johnife is correct with the stated life expectancies but you would never get these figures under waranty, more like 15 to 20 years.
Posted by: guest at April 8, 2008 3:30 PM
just a note here to everyone thinking solar, solar hot water is much more cost-effective than solar electric. everyone who is considering solar should be thinking hot water. it will produce up to 80% of your total hot water costs and it's much cheaper than electric.
Posted by: guest at April 8, 2008 8:41 PM
what is the deal with getting a building permit from the DOB for solar installations? Is that still the case. Check the archives for what I am referring to.
Posted by: guest at April 8, 2008 10:05 PM
Notes on the above comments
-the NYSERDA regulations were just recently changed (I believe last month) and no longer required for the rebate.
-the payback period for the panels depends on a number of factors but the published rule of thumb is 6 years.
-the new code has provisions for solar panel installations but the current building code does not.
-to the engineer's comments the newer inverters don't take up much room and are typically built into the panel frame now
Posted by: Smokychimp at April 8, 2008 10:35 PM
smokychimp,
You're obviously very knowledgeable about this subject. Can we establish direct off-board contact on this? My email address is my user name at panix dot com.
Thanks.
Posted by: johnife at April 8, 2008 11:30 PM
I installed a 6kW system on my brownstone roof in Cobble Hill last year. So far, so good. I used Solar Energy Systems (based in Brooklyn) and had a very smooth experience. The NYSERDA rebate became substantially less generous several months ago, but still definitely worth going through the process. Overall, not a process you I wanted to do yourself. Con Ed makes their approval kind of painful to get, so I was happy to rely on professionals.
Posted by: guest at April 9, 2008 6:21 AM
Smokychimp, you are incorrect, to get any rebate the system has to pass NYSERDA regulations since it it them who give the rebate, has to be installed by an approved installer and meet Con Ed requirements for parallel operation (which are covered by the NY PSC interconnection requirements).
The Con Ed approval is not painful in the slightest if you are using an installer / designer who has a good relationship with the utility and really knows their stuff e.g. how to submit the correct documentation.
Posted by: guest at April 9, 2008 9:05 AM
guest @ 6.21,
Any chance of talking to you about and maybe seeing your installation? See above in my 11:30 post for my email.
Thanks.
Posted by: johnife at April 9, 2008 9:37 AM
I have a dream of getting a collective bargaining agreement together with a group of like minded brownstone owners and doing a bulk bid to these solar providers to try and drive the installation price down. How can the sinatallatio n of a few panels really be $30K? Anyone interested?
Posted by: guest at April 12, 2008 11:56 AM
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