Grid Tie Micro Inverter that plugs into house AC outlet...

There are a couple of these for $200+. You hook up the red (+) and black (-) wires of your 12v solar panel to it and then plug it (the inverter) into any house AC outlet. And, supposedly, when the sun is shining, you're offsetting your electrical usage! That simple!

My big question is: Can you set this thing up without having any permits or paying the city any fees for such a setup? In other words, can you (legally) start reducing your electric bill, without anyone knowing about it?

A neighbor down the street has a massive solar array in her back yard and showed me her electric bill. Her bill wasn't much smaller than ours... maybe $20-$30 less. But I noticed that SSEVC (that's who we have, here in Sierra Vista, AZ) is CHARGING her for net metering! She pays a fee to be generating electricity and yet only got a $20 credit on one of her bills! Her panel array is huge (at least 14' square (if not bigger), I'd guess)... I know it generates more than $20 of electricity in a month! It HAS to, doesn't it?

Well, anyhow, that's my reason for asking... if I can offset my electric bill by even 150w (that's just where I'd start at), while the sun is shining, it's a great deal to me. But... if the city (and/or the electric company) has to have their cut of the action (no matter how you're doing it), it totally takes away the incentive for doing it at all!

Comments

  • Seven
    Seven Solar Expert Posts: 292 ✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...

    I don't think it is legal. I know it is dangerous,possibly deadly if there should be a power outage and someone was working on the system, and should not be done. It wouldnt make too much of a difference in your bill because you wouldn't be supplying any power except to loads that were running at your house during the day. Any excess power generated would be lost.

    Others will chime in with better answers.
  • jcgee88
    jcgee88 Solar Expert Posts: 154 ✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...
    Luposian wrote: »
    There are a couple of these for $200+. You hook up the red (+) and black (-) wires of your 12v solar panel to it and then plug it (the inverter) into any house AC outlet. And, supposedly, when the sun is shining, you're offsetting your electrical usage!

    Can you set this thing up without having any permits or paying the city any fees for such a setup? In other words, can you (legally) start reducing your electric bill, without anyone knowing about it?

    There is a detailed debate as to the merits and technical challenges
    of one particular such device at:

    http://forum.solar-electric.com/showthread.php?t=8977

    The company listed in that thread, Clarian, at the time was targeting
    early 2011 to release a product. A visit to their website shows no
    updates since initial marketing splash in 2010. I would assume that
    that delay attests to the difficulty of getting UL approval and some
    kind of generic approval to plug into the grid without utilities' consent.
    Luposian wrote: »
    A neighbor down the street has a massive solar array in her back yard and showed me her electric bill. Her bill wasn't much smaller than ours... maybe $20-$30 less. But I noticed that SSEVC (that's who we have, here in Sierra Vista, AZ) is CHARGING her for net metering! She pays a fee to be generating electricity and yet only got a $20 credit on one of her bills! Her panel array is huge (at least 14' square (if not bigger), I'd guess)... I know it generates more than $20 of electricity in a month! It HAS to, doesn't it?

    Several things...

    1. A 14' x 14' array would be about 12 PV panels, or on the order
    of 2.7 kw. Such an array would generate something like $400
    worth of electricity per year, or roughly $35/month. It is believeable
    that after deducting any SSEVC service fee, that her array would
    yield only a $20-30/month credit...especially if it were a winter month
    bill that she showed you. During winter, my PV array produces half
    as much as it produces in summer.
    2. It is also possible that her PV array is not producing as much as
    theoretically possible. She might have shading issues, or perhaps
    her array is not perfectly south facing. Either of the latter two
    issues can reduce harvest by 10-20%.
    3. Your house and her house may have entirely different power
    consumption. That means that her bill being "only" $20 less
    than yours may be out of context. For example, prior to my PV
    array's installation, my next door neighbor's bill was double my
    own, even though we are in like houses. This was because I did
    a lot of conservation measures and he has done none. You
    should ask to see her bills before she installed the PV array, for
    true apples to apples.
    4. Lastly, there are monetary incentives other than the monthly
    savings that you may not be aware of. These could include
    the Federal tax credit, a cash rebate from the local utility, and
    cash generated from sales of solar renewable energy credits
    (SRECs). In my own case, such sources represent 30X the
    value of my annual power production.

    John
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...

    I've never seen a legal, UL/CSA listed plug in the outlet inverter system. There is a reason that you wish to have the utility and the permit authority involved in grid tie PV. That is to ensure the safety of you, your house as well as the the utility.

    Icarus.

    PS if you are trying to save the dollars equivalent to ~ 150 watt, maybe $.01 per hour for may be 6 hours,, or $.06 per day I would surely bet that I could find 150 watts of energy savings that would save more than $.06 per day. Water heater blanket, heat traps on water heaters, turn off a light or two, change a few more bulbs to LED/CFL, turn down the heating t-stat 1 degree F, or turn up the A/C t-stat the same 1f, water saving shower heads, air dry you dishes, wash your laundry in warm or cold water, air dry your laundry,, and on and on and on.

    Your 150 watts of PV might cost ~$500 installed with an inverter. What would it cost to do some if not all of the above? Nearly nothing.

    T
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...
    Luposian wrote: »
    A neighbor down the street has a massive solar array in her back yard and showed me her electric bill. Her bill wasn't much smaller than ours... maybe $20-$30 less. But I noticed that SSEVC (that's who we have, here in Sierra Vista, AZ) is CHARGING her for net metering! She pays a fee to be generating electricity and yet only got a $20 credit on one of her bills! Her panel array is huge (at least 14' square (if not bigger), I'd guess)... I know it generates more than $20 of electricity in a month! It HAS to, doesn't it?

    There are several things to consider here: Perhaps her bill is only a little lower than yours because she uses a LOT more electricity than you do (I don't know this, it's just a possibility.
    As they say the first step in going solar is to reduce your power consumption, many people just don't get that.

    There are some things you still have to pay for even with net metering. You still have to pay the fee for the meter and you still have to pay the Taxes and surcharges for energy used at night, even if it's energy you banked during the day. A couple of these fees (REST for example) while based on a percentage of energy use are capped at a low level, my REST fee dropped from $3.49 (capped) to about $3 winter & $2.25 summer when I installed my array.
    So basically there are about $20-$25 worth of fees you have to pay even if you generate all of your own power

    The SSVEC Net metering fee is only $2.70, not a lot of money considering how much time and money they have spent reprogramming their billing system to allow net metering. They have only been doing Net metering for a little over a year and don't have many net metering customers. However, it looks like they have worked most of the bugs out now.

    I live out in Hereford and my 3.45kw array mounted on trackers produces more power than I use right now.
    At this time of year I only use about 490-500 kwh a month and my array produces about 700 kwh a month (this time of year). Since September the only month I used more than I produced was December and that was only 4kwh extra. With net metering I just pulled that out of the 600 kwh I had banked.

    Now there are a couple ways you can zero out your bill. You can install an array that is up to 25% larger than you need. On an annual basis, if you push more kwh to the grid that you pull, SSVEC will pay you about 4 cents per kwh for the surplus. The rising costs of diesel will drive up the delivered costs of coal soon and since all of our power is produced by a coal burning power plant up in Tucson, that means they will start tacking the "Whole Sale Cost Adjustment" onto our bills soon. A couple years ago that cost adjuster made up almost 50% of my bill. If you produce more power than you use when the "Whole Sale Cost Adjustment" is in effect, you get a CREDIT for that instead of a charge.

    Finally if you want to install solar, SSVEC currently has about a 4 to 5 year waiting list for the 50% rebate. However they also offer another program that not many people know about or are taking advantage of called a "Performance Based Incentive" that can pay back up to 60% of your costs, the PBI is available NOW, no waiting and PBI customers get paid FIRST, the 50% rebates are only available if the money hasn't been spent on PBI.

    The problem is that the PBI pays back monthly in small amounts over 10-20 years depending on which program you chose.
    I chose the 15 year program so I earn 18.7 cents per kwh that my array produces produce. It doesn't matter whether I used this power immediately or export it to the grid, I get paid for every kwh produced. They have to install a second meter just to measure your arrays output and originally they were saying that they would have to charge for the second meter, but I was only charged once on the month they installed it.
    My PBI payment is about $130 a month, they automatically subtract any fees I owe (basic meter fee, net metering fee, taxes and tarrifs, etc.) and if there is at least $100 left over they cut me a check. Otherwise they bank it and wait until the next month.
    I haven't paid an electric bill since my array went only and most months I get a $100 check, or every two months get a $180-$190 check.
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...
    Luposian wrote: »

    A neighbor down the street has a massive solar array in her back yard and showed me her electric bill. Her bill wasn't much smaller than ours... maybe $20-$30 less. But I noticed that SSEVC (that's who we have, here in Sierra Vista, AZ) is CHARGING her for net metering! She pays a fee to be generating electricity and yet only got a $20 credit on one of her bills! Her panel array is huge (at least 14' square (if not bigger), I'd guess)... I know it generates more than $20 of electricity in a month! It HAS to, doesn't it?

    See attached for massive! ;)

    Really the right way to go about an incremental add system is to pull the permits, wire the system for final sizing, use micro inverters and talk to the code guys about what they will require to add to that system. None of that is cheap, the code guys may require a new permit at every add of panels/inverters and that is an additional expense you will have to deal with.

    One of the problems with "plug-in" inverters is that they can over load the line they are attached to. Just think of it this way, 15 amp breaker can pass in 15 amps on a 14 gauge wire to the circuit, then you add a plug in inverter to the line say another 15 amps, now you have the potential to load a 14 gauge wire rated for 15 amps up to 30 amps with out a breaker trip. Surely that is a potential fire from an over heated 14 gauge wire. If a fire did happen, your insurance company could deny your claim because of your actions.
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    Re: Grid Tie Micro Inverter that plugs into house AC outlet...

    Those cheap grid tie inverters like to over heat and cut off when you try to run them any where near rated capacity.
    In factory configuration they are only good for about two thirds what they are rated for.
    I have to modify them with a big CPU fan and add some air vents before I can even think about running them any where near capacity.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • LjTonight
    LjTonight Registered Users Posts: 1
    I have two 1400w inverters with anti-islanding protection, which means when the power goes out they shut off keeping the linemen safe while working during an outage. I have five 230w solar panels connected to each inverter and since I have installed them my bill has made such a change that the light company sent someone out to check my meter and I would guess to see if I'm stealing juice, I went from up to $315 bills during the summer to $180 Highest and as low as $65 during winter, I didn't pay the light companies fees for net-metering as they come standard here, I live in Louisiana the downfall from that is whatever I put in the grid after what I use they keep but I can log onto myentergy.com and see what I'm using a day even by the hour I can even compare bills from last years to now there's another option to look at your bill projection for next bill as the month goes by when ever you log on it also shows how much I'm putting into the grid, if your neighbor had a $20 credit on her bill that's electricity she put into the grid and didn't use during that month when her meter was read,i look at like this if I put 7 kwh in the grid during the day in excess when night comes the first 7 kwh i use is free lol.. you would have to see what her bill was before the PV system was installed there are a lot of different size solar panels that can be put in a 14' area if her bill was just $20 to $30 less than yours she must be burning a lot of juice or you could be burning a lot. since we installed ours were more mindful of turning things off when not in use, we've changed all lights to led we only wash when the sun is up we changed porch lights and nightwatchman lights to solar-powered. You will definitely see a big difference in your bill with those plug-and-play inverters just make sure you get anti-islanding protection, I bought used solar panels 3 years ago and there still as good as new, I'm getting ready to switch to a used Solaredge SE3800H I think they're the best most efficient system on the market, I'm going to install it myself but this time im getting the permit and paying the electric companies one-time fee of $100 because this system will put a lot more juice into the grid that I want to get back I lost 1855 KWH put into the grid last year, with the new system and 10 more 250w panels it's gonna be a check from the light company instead of a bill.  you asked that question in 2011 did you ever install a PV system if so how did it work out?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Welcome to the forum LjT,

    There is a good chance that much of your energy savings are because of your conservation measures... It is not hard to cut 50% off a power bill if this is the first time you have done conservation...

    Just as a sanity check, we can do some quick math... 2,300 Watt solar array, guessing around Baton Rouge LA, facing south array:
    http://www.solarelectricityhandbook.com/solar-irradiance.html

    Baton Rouge
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 60° angle from vertical:
    (For best year-round performance)

    JanFebMarAprMayJun
    3.41
     
    3.95
     
    4.76
     
    5.23
     
    5.35
     
    5.07
     
    JulAugSepOctNovDec
    5.14
     
    5.11
     
    5.02
     
    4.85
     
    4.03
     
    3.54
     

    Use June as a typical summer month:
    • 2,300 Watt array * 0.77 panel+inverter deratings * 5.07 Hours of sun per day * 30 days per month = 269369 WH per June = 269 kWH per month of June (long term average
    • 269 kWH per month * $0.20 per kWH (pure guess) = $53.80 per June average energy bill reduction
    Lots of guesses on my part... But it would appear that a large amount of your savings was your conservation measures (usually our "first suggestion" on the road to solar).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • WebPower
    WebPower Registered Users Posts: 73 ✭✭
    If you use inverters plugging them into an outlet, realize that normal electric meters are absolute value. It runs the same way even if you are feeding power back to the grid. You will be billed for that negative power.
    9000+W grid tied IQ7 22 panel rooftop and 6 panel ground combination with 1 additional IQ7 connected to 500W wind turbine+200w solar+2 IQ7s with 300W+600W on the RV grid tied when it's in the driveway.