If he sees this post, perhaps our longtime solar user Nords can help out with his voice of experience on this subject.
Thanks, Sarah. Busy thread.
We went almost completely DIY with used panels. We had to use an electrician for the permit and the net-metering agreement but now I do all the work on my own.
Extreme home improvement: DIY photovoltaic array - Military Guide
Here's the math:
Extreme home improvement: the finances of your residential photovoltaic array - Military Guide
We installed just over 3300 watts between 2004-2007 for just under $16K (plus sweat equity) and got back over $9K in federal/state tax credits. Our sweat equity paid for itself by late 2010.
(
BTW renting [a power-producer agreement] might be just as cost-effective, although it has its own issues. This is a guest post from one of our own forum members:
The Bright Side of Solar Power Purchase Agreements - Military Guide )
Here's an update on those posts:
In 2011 we renovated our familyroom and elected to remove our system to add more reflective insulation to our south roof. When we reinstalled our array I bought a modern flashed-mounting system with two rails. It was cheap and easy to install, but it also gives us more flexibility in swapping out panels or expanding for more capacity. The images in those linked posts show our old configuration while the photos below show the new layout. The larger panels are 115 watts (10 years old) and the smaller ones are around 50-55 watts (20-25 years old). If I rebuilt the system with 2015-tech 350-watt panels then it would take up about a third of the roof space.
We went with a string inverter in 2004. The microinverters are fairly new but the bugs seem to have been worked out. An early problem was that panels were rated at 315+ watts while microinverters topped off at 270-300 watts. That might have been fixed but it's important to make sure that the microinverter is big enough to not just clip off the panel's power output. For larger arrays, it's also important to compare the price of the microinverters to the price of a large string inverter. The microinverter may be more efficient (I'm skeptical of the magnitude of the difference) but it might still be more expensive even after the efficiency is included in the price comparison.
A few months ago our 10-year-old Xantrex 3000-watt grid-tied string inverter died. It was $2500 new. The problem was in the AC side, it kept blowing its output fuse, and I couldn't find the fault. For $2861 we bought a SMA Sunny Boy 4000-watt grid-tied string inverter. The tech difference is amazing-- not just more capacity but better DC-->AC conversion circuitry, two MPPT trackers instead of one, eight strings instead of two, a modern display/interface system, and even a better DC connection box.
Can you direct us to this system?
I would love to do solar but would really like a hybrid system that can be used in power failures also.
Best of all, this Sunny Boy has a small "Smart Power System" feature with limited off-grid abilities. When HECO goes down I can shut off the inverter's grid circuit breaker and flip the switch on the SPS receptacle. The inverter puts out up to 1500 watts at 120V AC (sunshine permitting), which is enough to run an aquarium air pump and the AC pump on our solar water heater. It might even run the fridge, although a fridge compressor startup surge will hammer the inverter's ability to maintain a 120v output. When HECO comes back up, I can turn off the SPS receptacle and shut the inverter's grid circuit breaker again.
$2500 in 2004 dollars for the Xantrex is about $3300 in today's dollars, so we technically spent 15% less today for the Sunny Boy. It's the equivalent of upgrading from a 1980s PC XT running DOS to a multi-core Win7 machine with a SSD and extra RAM.
For a hybrid system that can be used in power failures, the configuration is a bit different. Most house back up is via battery. The plant I'm looking at has AC right from each panel, so batteries is going to require that AC be converter to DC, then back to AC again. Lots of hardware and overhead expense. Also, batteries are not cheap and must be replaced within every 10 years. Tesla is building a house battery system, but 10kw is over $3,000 and not anywhere near cost effective.
With that said, there is a split system that saves the final DC to AC conversion to a central inverter, still using the MPPT and the DC to DC converter at the panel and saving the line losses.
Here is a 5kWh system that does that;
16 Panel SolarEdge / SolarWorld Grid-tie System - Wholesale Solar
The panels are built in Oregon, starting at the silicon level on up.
The kit price is $9,111. You would have to add sales tax and shipping depending on your location to the FOB which is Lake Shasta, CA.
With a sales tax of 7% and an average shipping cost of $500, you could expect to pay $10,250. Subtract the Federal tax credit of 30% and it's a net cost of $7,175. Figure in incidentals; permits, conduit, etc. of maybe another $500, and hire an electrician to lend you a hand for the two days to install, $1,000 and you are still under $10,000 for a 5kWh plant that will reduce your utility dependance by 8450kWh per year. (Based on a latitude of 38 degrees, panels facing 180 from North and a tilt of 22 degrees.)
Compare that generation to your own use and see where that puts you. That link has tabs for other options and sizes for solar kits.
The kit I am interested in with USA built micro inverters and panels is found here, but I'm needing it customized for an 18 panel solution and that falls between their 15 and 20 panel kits;
Enphase Energy Expandable Gridtie Solar Power Systems
The neat thing about this option is that you can start with a starter kit and just buy panels and microcontrollers to build it out. Plug-n-play. Everything is contained in each panel.
I think the reality of grid-tied vs off-grid is a little more nuanced, and so are the other factors in buying a system.
For example, PV panels are a commodity. We have the Chinese solar-panel industry to thank for crashing prices to under $1/watt, and their industry is paying the price for that overbuilding. Instead of buying the latest & greatest, try eBay for last-generation panels or factory seconds. You'll get a huge discount over buying used/dinged panels just as you would for buying a used car.
"American made" might be important for morale, but there's little difference in panel output or lifespan. Much of the R&D is American, and it's far more cost-effective to outsource the manufacturing. I don't worry about finding American-made oil or American-distilled gas for my car, and I don't worry about what country makes my PV panels.
Buying off-the-shelf arrays (with installation) is ridiculously easy. (Hawaii alone has over 200 PV installation businesses.) Installing your own system is within the capability of an electrically-safe DIY homeowner, but you'd still need a construction permit and an electrician's signature on a net-metering permit.
But if it got to the point of custom-configuring a retail system then I'd simply buy my own panels (eBay or local supplier), buy my own inverter(s), and find an electrician willing to do their part (at an hourly rate) while I take care of drilling holes in a perfectly good room. I'd even connect the panels & inverters with wiring and connectors made up from our local supplier... but these days that might also be available in pre-fabricated lengths sold online.
I understand that solar panels are a popular asset with potential house purchasers so you can consider that they add value to your home for potential re-sale.
It's just a feature. Some homebuyers can do math and will pay extra for the PV system, while other homebuyers just like the kitchen appliances and won't appreciate the PV system. They might even argue that it's a maintenance liability.
I would not install a PV system expecting to raise the value of my property. Buy (or rent) a PV system for the financial payback.
The info about the panels with the mini-inverters is pretty cool, and the relatively low cost per watt these days.
I wonder if it might make sense to build your system to something well below 95% of your present usage. Given the current rate structure, you save the most money by reducing your use over that present low base rate of 200-300 kwh. The payback period for the "extra" panels that replace energy now sold for 13 cents per KWH must be fairly long. Now, that's all present rules and politics, but given present California proclivities and demographics, it might be a safe bet to assume there will continue to be a lower rate for the first few hundred kwh while the "fat cats" pay higher rates. Also, it might be fair to guess that there will be continued improvements in A/C efficiency, appliance efficiency, etc, so having fewer panels might make sense even down the road. If there's a cutback in the net metering generosity, one obvious option would be "no sales back to the grid that exceed the customer's use." If that happens, any money spent to buy capacity beyond your (possibly lower future) needs is wasted.
Environmental laws, special rate programs, court rulings: So many of these factors are artifacts of your political system, not market forces. That makes the future very hard to predict.
Lots of folks said that about oil prices, too.
Again, thanks for the info, and good luck.
I've given up trying to predict electricity prices. Hawaii's prices fluctuate with the price of oil, and we don't have time-of-day metering (yet). Inflation has been unpredictable, too, and when oil prices start to rise then the alternatives (LNG, biofuel, PV, wind, OTEC, even geothermal) start to enter the competition.
Tax credits have been on the brink of expiring at least three times in the last decade. Maybe they'll be extended after 2016, or maybe not.
I think it's reasonable to factor the CPI into energy prices (and maybe the opportunity cost of buying a PV array instead of a nice blue-chip dividend stock) but otherwise you subtract the tax credits and do a straight payback calculation.
As you've pointed out, it's far better to reduce your consumption than to raise your generating capacity.
Most net-metering agreements only reimburse the owner for what they use. (HECO carries our excess production over a rolling 12-month period.) If you make more than you use then you'll eventually give it away for free. If you become a wholesale producer then it's an entirely different price (a fraction of retail) with extra tariffs, and for homeowners it's not worth the price.
We use all the usual tactics: solar water heating, tinted double-pane low-e windows, wall & roof insulation, EnergyStar appliances, line-drying our laundry, tradewind cooling, CFLs & LEDs instead of incandescent bulbs. I even have SSDs in our household computers instead of spinning-platter hard drives. However our biggest energy-efficiency improvement has been launching our daughter from the nest. Today our biggest indulgence (by far) is a DVR and an aquarium air pump. When my spouse eventually upgrades her CRT TV to a Smart TV then our energy use will probably drop again.
Doesn't that assume that you have no maintenance expenses, and that the panels maintain the same level of efficiency over that 25 years? Is that likely? Most of the electronics I purchased 15 years ago have already been retired, and those don't sit out in the elements 24/7.
This is one reason that the roof of a dwelling is not an optimum place for a solar array. I'd feel better about putting a solar array up there if I had a metal roof (50+year life). Another option is an outbuilding/shed that can be put where there is the least shade/best angles for catching the sun, and can have a metal roof.
"Maintenance expenses"?
I have never cleaned the cover glass on our PV panels-- the rain does that (even for bird poop). I've never done any maintenance on the hardware or wiring itself. Our system has seen hurricane-force winds, hail, torrential rain, vog, and (of course) lots of sunshine. The aluminum frames and the cover glass look fine. I wish I knew what killed our Xantrex, but it wasn't a lack of maintenance.
Most manufacturers show projected panel performance of 20-25 years before output starts to roll off. (The tech changes every 5-10 years so it's difficult to predict the reality.) Our 25-year-old panels are starting to show signs of rust under the cover glass, and I'll probably replace five or six of them with one 300-watt panel (from Craigslist or eBay).
A rooftop of PV panels will actually prolong the life of a shingled roof, but even so you might reasonably expect to get 20-25 years out of your average roof.
Thanks for the info....
So, solar cannot work without a line charge... so if there is a power outage then you do not get any benefit of having solar
I guess unless you get off the grid that is....
Does that mean all solar just connect up to the breaker box?
As others have mentioned, a grid-tied system is cheaper but it needs the electrical utility's voltage before it'll run. Some modern inverters will do both (with limited capacity). However even an off-grid inverter on its own will struggle to maintain steady household voltage if a large surge load (fridge, air conditioner, vacuum cleaner) starts up. A large bank of batteries can help an off-grid inverter maintain house voltage under almost any startup surges, but that also gets more expensive.
Our house feed from HECO is a 100-amp breaker. The same bus bars have a 20-amp breaker (next to the 100-amp breaker) that feeds our inverter's output into the house and grid. Electrical code also requires a manual disconnect, but grid-tied inverters have their own circuitry to shut off when the grid goes down. Our Sunny Boy SPS receptacle is wired directly to the inverter and won't come on unless I flip a switch on the receptacle. That switch turns on the receptacle and also electronically disconnects the inverter from dumping power into the circuit connected by the 20-amp breaker.
I am seriously tempted now to get just one panel and one microinverter, spend 1 hour to wire them up then to record the power output to see what kind of output I can get over a day of summer, a month, a year. It's as you say, an interesting hobby. And if it looks promising, I can scale it up.
Here's the cost: 1 250W panel ($275 new, $180 used), 1 microinverter ($155), a 110/220 1kW transformer ($45), hardware ($10). Total: $380-$485.
The transformer is needed because I want to plug this into a normal wall outlet of 110V, while the microinverter works with 220V output. This allows me to use a common Kill-a-Watt to log the power output.
Better yet, I think you could monitor the microinverter over its powerline network interface.
The 800 pound gorilla hiding in the closet though appears to be this, and I do not have an answer for mind you. Lets say that a significant number of people "go solar", but still stay connected loosely to the grid. Average daily power consumption need from the Utes goes down significantly. However, PEAK maximum backup power from Utes is still necessary if not mandated. This would cause a tremendous increase in cost per kilowatt as peak backup power is expensive in itself to maintain. If successful meaningful battery backup power is not invented the costs for maintaining the grid will still be fixed and at a higher cost.
I don't think we would immediately see the death spiral of Utility company viability because the grid will still be needed. So I wonder if the costs will just be shifted to higher monthly connectivity fees, thus negating a big savings in going solar?
Yeah, that's an issue.
I think PV tax credits will come under more attack from the states, and eventually even from the federal govt. The subsidies helped jumpstart an industry and drive prices from $10/watt down to $1/watt, but further subsidies are arguably of little impact.
HECO is already whining about us slimy net-metering customers not paying their fair share for the grid. However HECO's CEO earned nearly $6M last year, so I have a difficult time feeling guilty about my own selfishness. I've also watched HECO waste millions on flawed engineering analysis and dubious reliability/redundancy upgrades, so I'm skeptical that our grid-tied vampire behavior is worse than their bureaucratic and operational inefficiency.
In other words, they need to fix their own house and run it more like a business (and less like a government agency) before they come after us little guys.
Our house was net-metering agreement #26, and today Oahu has tens of thousands of net-metered installations out of more than a million customers. In other words, they're hysterical about fewer than 5% of their customers. If HECO adds a feed-in tariff then I'll grudgingly pay it. But first I'll do the math and compare HECO's price to the long-term cost of lead-acid batteries or Tesla PowerWalls.
Electricity is a commodity, and I'm not going to pay for infrastructure any more than cell phone users want to pay for a landline telephone. Even our local landline phone company has figured out that its customers will still pay for IPTV and fiber-optic Internet access. Maybe HECO will come up with a similar business model that extracts the last penny out of their infrastructure.