how much cost to grid-tie?

veloman

10 MW
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Austin TX
I have the inverter, PV panels or wind turbine. How much would it typically cost to have an electrician make the connection from the inverter to the house 120vac? I have no idea if its $200 or 2000.
 
I could, but it wouldn't be legal. Needs to be done by a licensed electrician. Also need a permit I think.

I put an ad on CL and seems like almost none of the response will give me a number. One said 2700. Seriously? Im not doing anything that will take more than a few yrs payback.
 
veloman said:
I could, but it wouldn't be legal. Needs to be done by a licensed electrician. Also need a permit I think.

I put an ad on CL and seems like almost none of the response will give me a number. One said 2700. Seriously? Im not doing anything that will take more than a few yrs payback.
$2700 is a deal if the electrician takes care of the permits and everything. If not, it still might be a deal especially if he throws in the conduit, wiring and boxes, etc.

Solar can pay back quick these days due to lower panel costs, etc. To estimate pay back add up the electric portion of your bill over a year. Now divide that into your solar system cost whatever that is. That's roughly your payback. Even if you get a small system since your smaller electric bill will stretch you out to about the same timeline.
 
I may have 500w of DIY panels. That might save me $5 a month. So no, it does not make sense to have a 30yr payback.

Im not buying a full normal size 4kw system. I just have some homemade panels.
I'll just keep charging my ev batteries with them. That's all.
 
You might check into that solarcity thing; if it's available in your area (I can't access the map (or most other things) on their site).

I tried to contact them but have never received a reply.
 
veloman said:
I may have 500w of DIY panels. That might save me $5 a month. So no, it does not make sense to have a 30yr payback.

Im not buying a full normal size 4kw system. I just have some homemade panels.
I'll just keep charging my ev batteries with them. That's all.
People way underestimate how much electricity cost them. It's easy to do. Where I live electricity costs about 15 cents per kwh. BUT, what people don't realise is that the very smallest of loads over a long enough period of time will add up to MANY kwh's. I can't put my finger on it but it could be caused by power factor or harmonics, etc. In my experience, the smallest of wall warts, plugged in all the time costs $5 per month. Everyone with a cell phone pays $5/month to keep it charged. A little bigger wall wart like for a wireless router costs $10 per month. My 7 watt porch light with photo cell costed $10 per month. Your electric bike charger would be $10 minimum unless you never ride it and never plug it in.

Now go around your house and add up all those wall warts. Then go around and add up all your devices that have internal wall warts (transformers). That would be anything with stand by mode or a digital clock, etc. I would say multiply each one by $5 or $10 depending on their size.

Now you take your 500 watts worth of panels and install them and guess what? You can easily offset half of your electric bill (the daytime half). More so in the Summer and a little less in the Winter.

Just for fun take your standard electric oven with digital clock. The digital clock will cost you a lot more than the large hungry heating elements in the oven. The heating element is only on a brief period of time plus, resistance heating tends to have the best power factor (closer to one) vs. the digital clock and it's transformer which has a lousy power factor and runs for many hours. While your panels can't really power the inexpensive to run heating elements in your oven, they can very easily power your very expensive digital oven clock!
 
veloman said:
I may have 500w of DIY panels. That might save me $5 a month. So no, it does not make sense to have a 30yr payback.

Im not buying a full normal size 4kw system. I just have some homemade panels.
Hi,

As soon as you have it set up, you can start looking for deals on free or cheap panels (prices are constantly going down).
 
edcastrovalley said:
BUT, what people don't realise is that the very smallest of loads over a long enough period of time will add up to MANY kwh's. I can't put my finger on it but it could be caused by power factor or harmonics, etc. In my experience, the smallest of wall warts, plugged in all the time costs $5 per month.

I don't know what the actual cost would be, but I do know that all the various vampire draws around my house would add up to 500 - 1000 wh a day, if I actually left them plugged in (which I don't, partly for that reason, and partly out of fire paranoia).


The data below is probably not useful for comparison with anyone else here, but:

Presently, as an example, I only use around 3-4kwh / day on days I don't need to run the water heater (haven't got my solar water heater back online yet) or cook. (on those days it can go up to 5-7kwh). If I have to use the clothes washer, same thing. If I have to do a combination of things, it can go up to 10-12kwh. I'd guesstimate my average is around 6kwh/day right now.

My actual energy cost is only about $15; the other more-than-half of my $33 bill is service charges and fees and taxes. (for Nov and Dec, anyway).

500W of panels wouldn't offset much of my usage, even if that is 500W *actual* power delivered thru most of the day, rather than just at noon. (and I'd expect it's really a lot less than 500W even at noon).



Summer is different, as I have to use the window A/C unit to cool the curtained-off bedroom for the dogs (and myself, but they can't handle it; I mostly don't want to), so usage goes way up then. (though the solar water heater offsets that some as I pretty much never use electricity to heat water at that point).
 
amberwolf said:
Summer is different, as I have to use the window A/C unit to cool the curtained-off bedroom for the dogs (and myself, but they can't handle it; I mostly don't want to), so usage goes way up then. .

Hi AW,

Why not use a swamp cooler?
 
MitchJi said:
Why not use a swamp cooler?
The landlord took the existing one out during the fire rebuild, and wants me to use only the house A/C. (which I don''t use because he's never put any fuses in it, but I couldn't afford to run it anyway, so I use the window A/C)

Before the fire, I had a small one that sits in a room as a piece of furniture, and it worked sort of ok, but the humidity rises very quickly, until it no longer cools, and the humidity itself means it feels hotter than it actually is. Worked better outside, to cool an open shed as a shaded work area. Needs higher volume of air moving thru, and fresh outside (though hotter) air as a low-humidity source to cool...like the main one the landlord removed and scrapped. :(

I've intended to build one, but havent' got all the parts yet. I also thought about building an evaporative pre-cooler stage for the window A/C unit; not sure if it would end up making it enough more efficient to make up for it's own power usage.

I only need it down to 80-85F, so it doesnt' take much most of the time, but there are times it's gotta drop it by 30F or more, if it's an outside-air-source evap cooler that feeds into the house directly.
 
I don't know why we are debating the potential of a 500w panel. Math does not lie. Best case scenario that provides 75 kWh per month which cost about $7.50. so if I spend 2700 to grid tie, that would take 30 yrs to break even.

As for vampire currents.... Yes they shouldn't be ignored, but its unrelated to this topic. I don't leave my charger plugged in (have it on an on/off switch). $10 month would be a third of the household use... You are picking these numbers out of the sky. 100kwh? That's 3.3kwh a day or 130 watts as a vampire current? Hmmm..... I tested a handful of ebike chargers and they are 5-10w vampire current.

I love solar, but I don't think its worth more than a couple hundred $ to grid tie with 500w of panels. I actually only have 200w of panels built so far.
 
if you are the homeowner then you are legally able to work on your home wiring. it is so simple i am always staggered when i see how people pay exorbitant fees to do such simple work.
 
edcastrovalley said:
People way underestimate how much electricity cost them. It's easy to do. Where I live electricity costs about 15 cents per kwh. BUT, what people don't realise is that the very smallest of loads over a long enough period of time will add up to MANY kwh's. I can't put my finger on it but it could be caused by power factor or harmonics, etc. In my experience, the smallest of wall warts, plugged in all the time costs $5 per month. Everyone with a cell phone pays $5/month to keep it charged. A little bigger wall wart like for a wireless router costs $10 per month. My 7 watt porch light with photo cell costed $10 per month. Your electric bike charger would be $10 minimum unless you never ride it and never plug it in.

Now go around your house and add up all those wall warts. Then go around and add up all your devices that have internal wall warts (transformers). That would be anything with stand by mode or a digital clock, etc. I would say multiply each one by $5 or $10 depending on their size.

Now you take your 500 watts worth of panels and install them and guess what? You can easily offset half of your electric bill (the daytime half). More so in the Summer and a little less in the Winter.

Just for fun take your standard electric oven with digital clock. The digital clock will cost you a lot more than the large hungry heating elements in the oven. The heating element is only on a brief period of time plus, resistance heating tends to have the best power factor (closer to one) vs. the digital clock and it's transformer which has a lousy power factor and runs for many hours. While your panels can't really power the inexpensive to run heating elements in your oven, they can very easily power your very expensive digital oven clock!

For the record this is largely bullshit.
 
edcastrovalley said:
The digital clock will cost you a lot more than the large hungry heating elements in the oven.....very easily power your very expensive digital oven clock!

Rule of thumb of energy usage in a US home is 30% plug loads, 30% HVAC, 30% hot water. I measure/monitor in my own home and it's 20% plug loads, 50% HVAC and 20% hot water. YMMV: LP/Natural gas, holidays, company and weather all move that balance around. I can't agree with edcastrovalley's science, I agree with his end-game conclusion: that even a little bit of solar panel ends up being helpful.

So: THUMBS UP to what veloman is trying to do - it's very worth it. DO IT DO IT DO IT. veloman posed a question that does have a straightforward answer.....)
 
With only 500W of pannels, don't bother hard wiring it into your pannel, just buy a $100-300 grid tie inverter on ebay in your power range and plug it's output into the most convenient wall outlet. Just cutting the end off an extension cord and wiring it up should function as well as any solution for low power levels.
 
The losses in small power supplies (wall warts) have changed over the years. You can get some idea by feeling the temperature of each one after it has been plugged in an hour or so. The warm ones are lossy and expensive to operate, the newer ones are not warmer than ambient and are not consuming much power at all. The really old ones might have been a few dollars a month, the new ones are not.
 
veloman said:
I have the inverter, PV panels or wind turbine. How much would it typically cost to have an electrician make the connection from the inverter to the house 120vac? I have no idea if its $200 or 2000.

Hey veloman:
I've also put out requests for quotes to tie in my own solar panels and grid-tie inverters to my home circuits. Let me tell you what I ended up with:

Electrician:
The "wrong ones" quoted me insane prices over $1000. I did get one $2200 quote ONLY FOR THE INTERTIE WIRING, just like you are asking for. Those guys are trying to make you go away, you granola-eating hippie! :lol: :lol: :lol:

The "right ones" quoted me $200-$500 depending on the parts they perceived were needed. THAT is the order of magnitude of work you are looking for from a licensed electrician.

Some Detail:

1) If you use plain panels and choose grid-tie microinverters (I like Enphase, but I've not bought yet so it could be anything):
http://www.altestore.com/store/Inverters/Micro-Inverters/Enphase-Energy-215-Watt-Micro-Inverter-with-Integrated-Ground-H4MC4-Compatible/p11248/

Then you end up, as you properly surmise, holding a cord that's carrying split-phase 208/220V US power.

2) You will need conduit to an AC cutout box and from the cutout box, you will wire into a 240V breaker position on either your one main panel or your whole-house "sub panel" near the meter base. That's really not much stuff and $200-$500 is about the range of cost we're talking about.

3) There was prior mention of a permit. Two kinds. A construction permit if it's a construction project. But if it's a "flagpole", then, no construction permit. The intertie with your home's AC service can (depending on municipality and local laws) require a permit as well.

4) You do need a pre-energizing inspection by an electrical inspector and the power company. You can get the deets on this by calling your local power supplier. In my case, they require the pre-energizing inspection and will also make me pay $3/month to install a bi-directional net meter. (basstaads!)

I must recommend these websites to you:

My solar porn. Not sure if I'll ever buy from them but the pitchers shure is purty!
http://www.altestore.com

Got a question? Ask Gary, he's either done it or found someone who has!
http://www.builditsolar.com/Projects/PV/EnphasePV/Wiring.htm
I go to this website when I'm feeling like I'll NEVER get solar installed and it cheers me up, gives me hope. Gary's got the answers, man.

Don't know much about these guys but I like their optimism and qualifications:
http://open4energy.com/forum/solar/eaw/solarman_guide_to_home_diy_solar_energy

There IS this thing:
http://cleantechnica.com/2014/03/14/plug-solar-panel-kit-truly-diy/
But I don't know what grid-tie inverter they are using that generates only 120v single-phase and those goobers don't tell you. I'm not at all sure any power company would "approve" this, but if you wanted to go guerrilla, that would be one way to do it. I've pondered going this route for TESTING only, to see what kind of dent one or two panels could make, but not as a final solution. I believe in the necessity of the A/C cutout. (and BTW: I think this is the thing LFP is talking about above. If you can get these inverters off ebay, they might be worth a try...just ensure they shut off if the power goes out....)

ONE CAUTION: injecting single-phase 120v into your home circuits could damage 240v split-phase devices if you lose power. The 120v inverter has to shut off, fast, when power is disconnected or it could burn up the motors in air handlers, compressors or other 240v light equipment.
 
Alan B said:
The losses in small power supplies (wall warts) have changed over the years. You can get some idea by feeling the temperature of each one after it has been plugged in an hour or so. The warm ones are lossy and expensive to operate, the newer ones are not warmer than ambient and are not consuming much power at all. The really old ones might have been a few dollars a month, the new ones are not.

+1, agreed. I've seen this evolution take place in my cellphone charging supplies, which are always teeny tiny switchers.
 
liveforphysics said:
With only 500W of pannels, don't bother hard wiring it into your pannel, just buy a $100-300 grid tie inverter on ebay in your power range and plug it's output into the most convenient wall outlet. Just cutting the end off an extension cord and wiring it up should function as well as any solution for low power levels.


I've considered this, but I am wary about it being legal / potentially dangerous. I know some inverters will shut off if the house AC goes out, to protect any lineman working.

JKB, thanks for the links and info.
 
Just tie a low wattage light bulb to the circuit your charging, with no off switch, right at the panel. If anyone still wonders if they have power, they are blind and should not be working with live wires anyway.

You could also make hot water with the excess wattage on a separate heating element and not tie into the grid. Don't think you will over heat a reasonable sized hot water tank with 500 watts of daylight power.
 
veloman said:
I don't know why we are debating the potential of a 500w panel. Math does not lie. Best case scenario that provides 75 kWh per month which cost about $7.50. so if I spend 2700 to grid tie, that would take 30 yrs to break even.

As for vampire currents.... Yes they shouldn't be ignored, but its unrelated to this topic. I don't leave my charger plugged in (have it on an on/off switch). $10 month would be a third of the household use... You are picking these numbers out of the sky. 100kwh? That's 3.3kwh a day or 130 watts as a vampire current? Hmmm..... I tested a handful of ebike chargers and they are 5-10w vampire current.

I love solar, but I don't think its worth more than a couple hundred $ to grid tie with 500w of panels. I actually only have 200w of panels built so far.
If anyone out there wants to try a little experiment but doesn't want to fool around with a grid tied system, try an RV system. Basically a 12 volt panel, a deep cycle lead acid battery, and a charge controller. Then once up and running add a couple of automotive style cigarette lighter sockets and use your cell phone car charger to charge up your cell phones. In 2007, 2008 I was saving $5 per cell phone off my electric bill.

Then take your wireless router/gateway and determine the input voltage. Most these days are 12vdc. Perfect! Cut off the wall wart and attach directly to the 12 volt deep cycle battery. Check and double check the polarity before connecting! If you don't have the guts to do this then post somewhere on here that I'm full of it. Don't worry, I can take it. The rest of you, enjoy the $10 monthly gift.

Next, if you want buy a 12vdc to 120vac (non grid tied) inverter. The pure sign wave variety is best. Now plug in any small but long term load that's plugged into your house. Since my system was in the garage I started there. Eventually I had the door bell transformer, garage door operator, porch light, and a couple others plugged in. My electric bill went from $115 to $50 a month. Now that math don't lie! :mrgreen: The panels used to save this much every month? Just two lousy 125 watt 12vdc Kyrocera's for 250 watts total!
 
To do grid tie correctly, you need to install a PV meter as well as a disconnect for the PV array. You don't want the EMT/Fire/Rescue guys getting shocked when they think the power is out. This is also why you don't want to just plug in your charge controller---->inverter to an outlet. Yes, it will feed back to the Grid, but it will also leaves your panel charged even if you shut off the Utility power for servicing. This is likely why you get quotes for $2700. It's not easy to do properly and to code.

Here is the last project I worked on:

http://endless-sphere.com/forums/viewtopic.php?f=41&t=60512
 
liveforphysics said:
With only 500W of pannels, don't bother hard wiring it into your pannel, just buy a $100-300 grid tie inverter on ebay in your power range and plug it's output into the most convenient wall outlet. Just cutting the end off an extension cord and wiring it up should function as well as any solution for low power levels.
:twisted: :twisted: :twisted:
Sunnyboy700U.jpg

I've had this for a couple of years. A relative gave it to me. It's a Sunnyboy 700 watt, 120 volt AC grid tied inverter and weighs 36 pounds! This is an older model they probably don't make anymore. There are 2 and 3 thousand watt versions in the same size box. I ended up buying four 180 watt, 36 volt panels for a total of 720 watts (nominal) which it handles just fine. I paid $116 for each panel and are mono crystaline. Unfortunately I don't have the wall mounting bracket.

BTW: This has an anti-islanding feature which most grid tied inverters have and will shut down instantly if power is lost on the grid.
 
Enphase seems to be good stuff. We are going to start with our Solar in the spring. My plan is to use Enphase micro inverters so we can add 1 panel at a time.
Most likely be 250-300 watt panels what ever is bang for buck as we have a lot of space. http://enphase.com/microinverters/
 
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