AC solar panels: One step closer to DIY solar?
Start-up GreenRay Solar has raised money to finalize development of a solar panel that puts out household-grade alternating current, a technology that backers say will make solar power more accessible to homeowners.
The Westford, Mass.-based company said that it has raised $2 million from the Quercus Trust and 21Ventures, which will allow it to start production of its solar panels in the fourth quarter this year. Since its founding three years ago, the company had raised $3.5 million in state and federal clean-energy grants.
A microinverter and solar panel.
(Credit: EnPhase Energy)GreenRay's AC Solar Module will turn out electricity that meshes with household alternating current and voltage. Solar panels put out direct current, and then an inverter, typically placed in a home's basement or outside the house, converts the direct current to alternating current.
Instead of a large inverter for many panels, there are a number of companies developing microinverters that do the DC-to-AC conversion right on the panel.
This design simplifies installation and offers a number of other benefits, said GreenRay CEO Miles Russell. Cutting out the single inverter is safer because installers are dealing with lower voltages.
Microinverters also make an array deliver more reliable performance, say advocates. When one direct current panel is shaded, that drops the performance of all the panels connected to it. Also, it's easier to gather data on an array's performance, Russell said. GreenRay's panels will transmit performance data over the wires and transmit it to the Web via a gateway, he said.
Does this mean that installing solar panels is a do-it-yourself job? Russell said that very handy people could install GreenRay's 200-watt panel, but they are electrical appliances so require typical safety precautions and inspection.
"The do-it-yourself moniker is more of a long-term objective. You could imagine them at a Home Depot and they could be installed for an extra fee," he said.
Another advantage of AC solar panels is that a person could install only a few, rather than a full array, without the cost of an inverter. On the other hand, microinverters do add cost to a solar panel, which is one reason that microinverters have not been commercialized in the past.
Martin LaMonica is a senior writer for CNET's Green Tech blog. He started at CNET News in 2002, covering IT and Web development. Before that, he was executive editor at IT publication InfoWorld. E-mail Martin. 
PV panel to Charge Controller to batteries to INVERTER to AC breaker box. OMG that's so hard school children will never figure it out. All this will do is create one more weak link and make more money for the mfg's though replacement parts (all those small "micro-inverters" add up to big money .vs a full size inverter that will last AND only costs $500-$2000)
Solar is SO easy already, initial cost is the only thing stopping people from using it. I have a house in Alaska (not using solar due to lat. and trees) and a house in Hawaii (solar ONLY) and I installed the whole system and I knew nothing about PV systems before I started.
Ooooh. FEAR THIS! DYI is DANGEROUS! "bwrobertson2", arent you licensed electrician yourself by any chance?
I have no problem with a rule that township inspector must inspect the installation for safety after the installation, but I have a lot of greef against rules that require "licensed somebody" do do things. These rules for "licensed contractors" were unfortulately put into law not for your safety but by decades of lobbying of various profession groups with goal of keeping prices for their services high and to skyrocket prices for competition for entering the market (high price of entry). Such licensing rules exists not only for electrical installations but for plenty of other professions as well, such as plumbers. Last time I had to do plumbing job in my home I had to hire licensed plumber to do it, even though I had very good references for somebody else who would do the same job for third of the price. And guess what, the licensed plumber was not doing the job himself, his company consisted of a few people without license who actually were doing the plumbing, his license was just legally covering it. The state rules are such that you have to work for licensed plumber/electrician/whatever company for a couple of years before you can get the license yourself. There are cases where it makes sense, but in most cases it doesn't. Some people are capable of doing job right after few weeks of training, some people can be trained for decade and still not able to do the job right. What is needed are good set of exams for giving such licenses instead of requiring skillful people to work as slaves for years before mercifully given a piece of paper (license) by state.
Because of such laws - we (USA) are going to face huge shortage of installers which will keep price of solar installation hight and therefore amount of these installations low (much lower that what it could be if the market wasn't "regulated"), even as price of solar components drops.
Sorry, but the system is corrupt and we pay the price. If Obama & Congress is serios about solar and energy, the first thing they should do is to revisit such laws.
Yes I am a licensed Master Electrician, but I don't make the rules I just follow the national electrical code. :)
Whether you like the laws or not in order to get into your meter you have to call the utility. But the utility won't do anything until they are notified by the State electrical inspector. Guess who's the only person who can notify the inspector? A licensed electrician.
I AGREE with you that it's a corrupt system, but it's called Socialism. So goodbye DYI. The day of DYI electricians is over. If you try to get around inspection, you will be sitting in the dark. Inspectors in my state have more power than you can possibly imagine.
Maybe if, somehow, these microinverters were less expensive and/or more dependable than what's currently on the market, that's cool, but I still think a single unit would be simpler in the long run.
I'm mainly hoping for advancements in PV cell efficiency and reduced manufacturing costs, in the next few years. I'm on a pretty reliable grid, so I've only just experimented. When I move to a more rural location, I don't doubt I'll be taking advantage of solar and other energy resources.
We had a windstorm in 2006 that cut power to the region for several days. The power company appealled to the state and got an exemption to charge for the power that was not actually delivered. That rate increase was meant to be temporary for one year... it's now 2009 and it's still there.
Any power sold back is at a much lower price than what you get charged for power coming in. I think I'd rather keep the power entirely local and only use what I need from the grid as needed.
Unfortunately all this is pie in the sky talk. This sort of thing isn't reality yet.
The rest is crap legislature and/or crap power company policy, in which case getting off the grid would be a pretty good idea, no?
I don't see funding a startup just because it makes a panel with a microinverter-- all the companies will be doing it. Lowering the cost of supporting electronics and installation will become the high priority as the panel manufacturing approaches $1/W while installation & electronics are $3-4/W.
The only real innovations are in cost reductions for any of the three big cost problems: panel, electronics, or installation. Frankly, they all need to come down by at least half and probably a factor of four if rooftop solar is going to get anywhere. Without that, unsustainable gov. subsidies are the only reason anyone can afford to put these installations in. There's no way we can afford a million solar roofs at $15,000 subsidy per. That's $15B, and in case anyone was paying attention, CA is broke.
Until these cost reductions, large utility-scale thermal solar plants are a much better cost bet on solar.
* the initial cost of a PV install is amortized over time (up to 20-30 years, depending on manufacturer). If you intend to keep living in the same house over that amount of time, it pays itself off with enough besides to make the whole shebang worth it. (and if you don't, you can use it as a bump-point in the selling price).
* instead of subsidies, why not incorporate it into the cost of new construction? That way it is a lot more palatable cost-wise (you're paying big bank anyway for the mortgage, so...)
* Economies of scale and of competition are bringing costs down as we speak (the only questions left are quality, output, longevity...).
Solar panels will be a DIY project for some; maybe 15% of the market. Installing solar panels requires designing and installing a system. That means understanding household energy consumption and the output of the power system. Plus, the installer has to get up on the roof, shut off the electricity, run conduit, test the equipment, connect everything to the electric meter, yadda yadda. Therefore the majority of solar panel installations will require a licensed, professional installer.
If you want to do something about this today, then visit a site like <a href="http://FreeCleanSolar.com/installer_loans.php" rel="nofollow">FreeCleanSolar</a> to search a nationwide network of 500 local solar installers. You can also find information about state solar rebates, federal tax credits, solar financing, system costs and the benefits of going solar. The bottom line is that many homeowners and business owners can afford solar power today. If you're paying more than $150 per month for electricity today, then you will pay at least $45,000 for electricity over the next 25 years. Compare this to the cost of installing a solar panel system, and you are likely going to be able to save money.
I don' think so. Lower Amps, sure.
"Cutting out the single inverter is safer because installers are dealing with lower voltages. "
No, you should be dealing with 120/240 VAC @ 60Hz if you're pumping it to household wiring in the US or Canada (IIRC, much of Europe does it straight-up 240VAC @ 50Hz)... no matter where or how many inverters we're talking about here. Most likely 240VAC, since most houses still do the higher voltage for large electrical appliances (e.g. electric dryers, heating, and etc).
...maybe you meant amperage instead of voltage? (IOW, it'll still sting if you get bit, but not be as dangerous as the higher-amperage configs present).
One potential disadvantage I see is that instead of one inverter possibly breaking down, you get to worry about multiple ones (then again, if one dies, the rest don't go with it...)
also it doesn't look like they are syncing anything, it's just one inverter for one panel providing one AC connection to the house. if you get two you will have another connection.
the tech described doesn't seem mind blowing or anything, but it's also not completely wrong.
OTOH, you'd think the inverter(s) would have some sort of sense-match mechanism (though the circuitry would in itself consume some of that power you've been generating...)
They come with 15 year warranties, have the highest rated NEMA enclosures and feature and 100% up-time guarantee. No other solar inverter on the market can touch that. They automatically sync with the grid's waveform and you can simply plug one into another on the roof so you only need to make one grid connection for every 16-24 panels. The best part is that by plugging a monitoring box into your wall socket you can see the real-time production of each solar module from anywhere in the world through a customized website, and they are no more expensive than any other solar inverter out there when you consider all the DC componants you get to eliminate.
As long as solar modules are mounted on the roof where there are major structural concerns from wind, snow and dead weight, and they are producing power, you will need to to have a proffessional installer put them in for you who can complete all of the engineering for the city. I don't see people complaining that they had to call the Air Conditioning installer or the gas guy, but for some reason with solar everyone wants to do it themselves. Right now there is a payback of as little as 5 years in some states for solar when you get to receive state and utility incentives by having a proffessional put in your system.
The ideas that solar doesn't work, the payback is too long, and it's something you should be able to do yourself are things of the past. It is a perfected technology that has an excellent ROI and it is a potentially dangerous piece of equipment that needs a proffessional solar installer to design and install.
- by gerbercon July 29, 2009 12:58 PM PDT
- I am in a quandary re PV.
- Like this Reply to this comment
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(33 Comments)In order to put PV on the roof we would have to cut down 2 mature trees. Our house is an affordable tract housing type built 30 years ago, (in AZ that's old.)
We already have a solar water heater
We use little electricity, that it would take 15 years to payback, even after the credits and rebates
If there was a AC panel that we could say, stake in the backyard, and plug it into the wall socket, and it cost $500 or less, I would get one as an christmas gift and then take it from there.