I read a topic somewhere on here where Dana was talking about PV dropping to around $2 a watt by 2017 and I decided to hit up ebay again to check pricing. I have been watching it for about 2 years now, maybe longer, and the return on investment isnt great. Coupled with the power companies hindrances it just hasnt made sense. However, this new pricing scheme is interesting.

http://www.ebay.com/itm/BrandNew-10000W-10KW-24V-Solar-Panels-Home-Power-Generator-Free-Ship-Worldwide/131027189194?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D22780%26meid%3D6989750387617481995%26pid%3D100033%26prg%3D9830%26rk%3D2%26rkt%3D4%26sd%3D201089172140

So they come from China so I would expect some efficiency loss but all in all they probably come from the same Chinese factories that the 4x priced US panels come from. This means I am paying some US company $20k to import something. With this price point I would be looking at solar at under $10k at my house. I could get a cheaper inverter and just go with that until such time where the enphase type get to a similar pricing model. So I would be looking at $6400 for panels and about $1500 for inverters. Then probably another $200 - $1000 for mounting. Free shipping to the closest US port means I could take a trip down to Norfolk for a day and bring it back in a $25 budget rental truck. I would be looking at a much faster pay back then one of the Lowes 10kw systems. That is not to mention the thermal load that the panels would take off of the attic being placed above the roof, with air space, and blocking the sun from striking it.

I think you are missing a big point, Dana is talking about a complete system  costing under 2$ per watt, that is panels, mounting, micro inverters, disconnects, installation, permits.  Today, the costs of the panels are just a fraction of the system cost.   I don't think you are going to get the rest for 4 K. 
Cheers,
Eric

How big is your roof? 10KW is a lot of panel area! 
When you are ready, you should check out http://www.ecobusinesslinks.com/surveys/free-solar-panel-price-survey/
The kit price survey is probably more useful than just the panels.  The kits include mounting hardware and inverters.  Current kit prices are about $1.50/W with string inverters and about $1.89/w with micro-inverters. You'll need to add shipping and installation costs.

Yeh was looking at the micro inverters. They are more efficient but they cost more than just two or three normal inverters. That being said I was finding some for $115 a micro inverter as opposed to the more expensive pricing I have seen before. As for the install I would be doing it. Everything I found before the cost of a 10k kit is around 20-30k.

Permits? I will not be asking permission to put the panels on the roof I own. When getting the addition done, I had the inspector do a breaking and entering on the structure. I was at work one day, the builder wasnt there, and the inspector came out and let himself in. Yep, he opened the door too the garage, then opened the door to the house, climbed the stairs and tooled around in the addition for an hour. When I asked him something about it he said he could get into the one of the doors because it was locked. Of course that door went to the master bedroom of my house. Very nice man and he probably did it like that because he has always done that but it would have been very bad if I was home and had no idea who he was. The work crew had not been there in days and I would have recognized them. From what I could tell from surveillance video he never even knocked and announced. I can not stress how dangerous this was enough. So long story short, no more permits on small items like decks or water heaters and so forth.

You'll almost certainly need permission to hook up your home-brewed PV system to the power grid. If your system isn't designed will and puts out enough line noise or unstable output that it affects others on the local grid (or worse, causes power outages or ruins the power company's equipment) you could be on the hook for a heluva lot more than just the cost of a professional installation by a licensed bond solar contractor. It's one thing to play PV-hacker for off-grid, but highly inadvisable for grid-tied PV. This is not a water heater swap or a mini-split installation- this is an electrical power generator, and there are plenty of directly-lethal &/or fire-hazard ways of screwing it up.

Complying with all the relevant code & utility requirements is not a trivial thing, and part of the reason it's still $4/watt instead of $2/watt in my neighborhood. When it becomes more mainstreamed and both the code inspectors & utilities have it down to a well-trodden path it makes a big difference. That's why grid tied PV costs homeowners ~$2/watt or less in Austin TX, where the city owned & operated local utility is gung-ho on solar, and ~$3.50/watt in most of the rest of TX.

A 10kw system will take about 1000 square feet of roof area. Micro-inverters are an up-charge, but have pretty high reliability and will optimize the output on a per-panel basis (one weak panel won't bring the performance of the rest of the string down), and won't likely need replacing every 15-20 years the way a centralized inverter would. But unless you take the class and get the licensing it'll probably be both cheaper & better to hire a pro than to buy a bunch of hardware that may or may not be compatible or code-compliant for your application.

The stuff loses value on the shelf, given the rate of price deflation on both panels & inverters. (Although there has been a modest uptick in panel pricing in the US recently, that is a temporary condition.) Buying a bunch of stuff online right now may even cost more than a professionally installed system 24 months from now, depending on how hot your local market is.

Whats the best way to figure out how many watts you need for a new design?

Posted By TLP on 19 May 2014 04:21 PM
Whats the best way to figure out how many watts you need for a new design?

It starts with figuring out what your design goals are. (Annual Net Zero Energy, Net Zero Electricity, off-grid complete independence?)

For grid tied installations you can use tools like PV-Watts to estimate your capacity factor (average annual AC-kwh production per rated DC watt) for a particular site. 

You then have to take a WAG on how much the annual consumption of the new place will be, which is heavily influenced by occupant behavior. The family populated with video game addicts playing 8 hours/day in front of big screen TVs with the air conditioning blasting (even in winter) is going to have a different use profile than the retirees who prefer reading books by lamplight in cool rooms wearing sweaters.

In my region PV typically deliver  DC to AC capacity factors of 11-12%.  My family of 3 would need about 5-6kw to get to Net Zero Electricity with an ideally pitched roof with minimal shading, but that's without using much power for the primary space heating. Net Zero Energy would be much tougher, given the not-so-superinsulated nature of the 1920s vintage construction. (Though it has seen much thermal  improvement during my tenure there, with more on the planning books.)  But the imposed physical constraints of shading factors & roof geometry are that about 2kw  at most would fit in the most-optimal roof area, and it would run at a capacity factor of about 8%, thus it's not a priority.  When it hits a buck a watt I'd still do it though.

From what I understand, at least here, the power company checks the equipment when they swap the meter out and sign you up to the smart meter or second meter depending on the metering type you do. The cost was not bad when I checked into it. So, while I might not technically have a permit for something mounted to my roof, they will be making sure the equipment is up to par and capable before being attached to the grid. That isnt to say there arnt people that probably use the micro inverters that plug into a regular 110v receptical and hook to a couple of panels. I am also sure that people probably put in a system with the power company doing the sign off and then expand later without it getting signed off. Neither I am interested in doing. I would definitely use a decent inverter like an enphase micro inverter.

On the topic of the cheap inverters that plug directly to an AC outlet, how is that even safe? House has a panel box which has it's individual circuits protected by a circuit breaker. Now you are adding something in the middle of the circuit that provides power to the circuit. Wouldnt it in theory then be possible to pull more current through the wire than the wire would be capable of handling and not stopped by the breaker?

From what I have read on solarpaneltalk, the plug and play inverters are very dangerous. Not UL listed. If there is a fire because of it your homeowners policy will not cover.

Chris

The system grounding, racking grounding etc. all have to be up to local-code snuff, and local codes on that DO vary. Like I said, take the local course (even if you don't actually get the license) or you may end up paying in any number of ways. There is a lot of PV & inverter technology available for purchase on the internet that may not pass legal or utility muster in your location, (and even if it does the installation methodology matters.) If you end up electrocuting a fire-fighter who shows up to deal the fire started by a bootlegged rooftop array you could conceivably be looking at criminal charges.

The "system in a box" plug-in devices skirt most of the code issues by virtue of not being hard-wired. That's not to say that it's safe or sane to just plug them into whatever panels or circuit that happen to be handy.

Posted By Dana1 on 21 May 2014 02:19 PM
The system grounding, racking grounding etc. all have to be up to local-code snuff, and local codes on that DO vary. Like I said, take the local course (even if you don't actually get the license) or you may end up paying in any number of ways. There is a lot of PV & inverter technology available for purchase on the internet that may not pass legal or utility muster in your location, (and even if it does the installation methodology matters.) If you end up electrocuting a fire-fighter who shows up to deal the fire started by a bootlegged rooftop array you could conceivably be looking at criminal charges.

The "system in a box" plug-in devices skirt most of the code issues by virtue of not being hard-wired. That's not to say that it's safe or sane to just plug them into whatever panels or circuit that happen to be handy.

I can assure you that there is no "criminal charges" involved in this so please dont spread that internet rumor. Not that I would ever ever want to hurt a fire fighter much less burn down my house. That being said our fire fighters here are the best and I have nothing but respect for them. I would only go with enphase inverters and would possibly take a course in how to install. I have no issues with this. I have issues with the extent that permits are used as local revenue. Also, the mini inverters that plug into wall sockets really bother me. I see more and more of these and I dont how they could ever be safe. I could totally see some home owner running 12/3 romex to their attic with a 15 amp breaker and daisy chaining five to ten of these together. This could definitely put more than 15 amps on the wrong side of the breaker. In this case I am sure they would deserve whatever they got but it would most likely be a hefty civil fine which would make them wish it had gone "criminal!"

Dont worry, if I do this I will do it right even if I dont pull a permit per say. Even if I have to hire a licensed electrician to check behind me and sign off on something.

a licensed electrician is not likely to "sign off on" anything that's not permitted

Licensed electricians won't risk their license for anything that's truly against local code. Most general electrical contractors are still getting up to speed on the particulars of PV installation. If using a local electrician to look over your shoulder, don't count on any insider knowledge about the DC side of it or the grounding structure issues unless they have actually been installing this stuff.

Criminal charges would only come into play if you actually killed or injured somebody with a bootlegged un-inspected sub-standard non-code installation. There are various levels of criminal negligence that might come into play in such a situation. For property-damages-only it seems unlikely to exceed those thresholds, but electocuting a firefighter with a mis-installed bootleg PV installation isn't the same as an idiot smoking in bed causing a fire that injures or kills a firefighter: Smoking in bed isn't against anybody's regulations (as much as some people would like to regulate that), but a bootleg grid connected power generator clearly is. Taking the course, pulling the permit and doing it all above board would give you a LOT of legal protection (and probably steer you away from some of the less-obvious hazards.)

I agree that plug-in systems with no safety ratings have a lot of potential for problems when installed by the ignorant & unwary. The more idiot-proof you make a product, the more creative the idiots become.

So looking at the consensus I think I am convinced... It might just be simpler to pull the local permit for this one. Leave the non permitted stuff for small decks and sidewalks, tankless water heater, or maple syrup spout (yes they require a permit to put that plug in your tree to get it here.) 

Hooking up an electrical device incorrectly would never rise to the level of gross negligence in order to get a charge. Now, if you use your solar PV array to pump 220v electricity into your fence in the backyard (the nazis did this because electricity was cheap and they didnt have to waste extra wire to hook up lighting on the fence) to keep out deer, zombies, child molesters, or whatever else and someone were to get fried on it trying to put out a brush fire you might just reach the threshold. Either way that argument is neither here nor their the point is to make sure it is done right whatever route you go. I would have to be absolutly sure of a setup before risking my families safety in the structure to begin with. I would not want anyone to get hurt, ever, no matter the penalty.

Even if solar stays at the prices it is now electrical costs will be still rising in another 5 years. I know that this winter alone I saw a $50 spike in my bill each month in just a moderate rate increase. If the VA rate ever rises to a level close to some areas of NY or NJ I could see even more poeple going with these systems. It becomes more and more attractive when building a home to take out the extra mortgage at the time and never pay an electric fee. From all the math that I have done it is in many cases cheaper to pay the bank than the utilities.

FWIW I got a quote here in VT - That does not include any VT incentives (which are low or already spent for 2014 and seem to be getting lower by the year) , but includes fed tax credit @ 30%. Does this "$2/watt" figure we talk about include the fed tax credits... and if so, at the 30% present level or the 10% 2016 (?) level.

24*260 watt panels installed= 6.2kw = $18k (post 30% credit) = $2.88 installed.

That is just the first place I talked to, So I don't know if it's the lowest price.

we're doing a 8.7 KW roof mounted system in NH; have quotes for $17-18k after all rebates. Not bad for all your electrical useage, hot water, AC & heat for 25 -30 years+.

we're doing a 8.7 KW roof mounted system in NH; have quotes for $17-18k after all rebates. Not bad for all your electrical useage, hot water, AC & heat for 25 -30 years+.

Bob, how much acreage does an 8.7 KW system take up on the roof? In other words how many square feet of panel area?

I think there are 37 panels covering about 650 SF of roof. The supplier is looking at adding a few more panels to completely fill the roof. Panels are approximately 39"x65" each.

Posted By Jelly on 25 Jul 2014 11:12 AM
Bob, how much acreage does an 8.7 KW system take up on the roof? In other words how many square feet of panel area?

It depends on the panel efficiency.  Commodity silicon panels run about 10-11 peak-watts-DC per square foot, but 20%+ high efficiency panels are more like 14-16 watts/ft². 

So, with commodity panels 8.7kw takes about 800 square feet.

With high efficiency panels 8.7kw takes about 600 square feet.

You typically pay a ~30-50 cents/watt premium for high efficiency panels.