Solar Panels that don't save any money?

[Marvin]

I have recently installed 2 * 7 panel arrays on separate inverters, a total of approx 5KW. This feeds into the house fuse board.

Wanting to keep an eye on how effective they are I installed a "watts clever" wireless power monitor. This meter can monitor 3 phases so i hooked up Phase 1 to the mains power just after the meter and Phases 2 and 3 to each solar arrays just after their inverters.

Wonderful device I could see the power each panel array was generating and it actually agreed with what the inverters were reading.

HOWEVER Phase 1 seems to be showing the full house load, and what's worse the mains meter agrees with this as it's metering shows about the full house load as well. And what the mains meter sees is what I get billed.

Even when I turn the solar grid off Phase 1 does not increase to compensate for the power not being injected by the solar system.

This is very strange, any ideas?
The diagram is attached.

[trbizwiz]

What is your utility saying about the metering? If you turn everything off in your house is the meter turning backwards? What are you readings with the main breaker turned off so you have only solar inflow with no draw?

[Mike90250]

The new digital meters, only count UP. 5 KW in, 8KW out = 13KW bill.

You utility has to install a 2nd meter at the array, to caculate it's power.

Arent't smart meters nice ?

[trbizwiz]

Do you think they do this to discourage people from hooking up Harbor freight grid tie equipment with out their permission. This way if you grid tie with out permission, they get paid extra, and the individual has incentive to stop doing it.
I get the impression, utilities aren't crazy about grid tie systems anyway. Not even those which are well designed and engineered.
Missouri has a law that private utilities have to pay $2 per watt to any subscribers who want to install a solar array. It has to do with an initiative that requires private energy providers to sell at least 15% renewable energy. Well prior to the law going into effect they commissioned a wind farm in the south west to purchase a block of power from them. They contend that because they are already buying renewable power they are not subject to the law and refuse to pay out for solar. They are being sued right now. So it will be interesting to see how this comes out.
Sorry about the tangent. Not really related, other than being about a utility and their desire to buy renewable.

[Marvin]

Just waiting for a sunny day. Can;t turn the entire house off or I won't be able to see what's going on. The meter is wireless and needs a PC to view the datae
I have tunred off big chucks of the house Phase 1 shows the lower demand but still what it shows is not the difference between the house demand and the solar power generated.

Secondly I can not turn off the grid. The inverters will automatically shut off once the mains goes away. This is so my generated power does not sneak back out onto the grid should there be a blackout and fry a lines man. Tis the law i believe

[Marvin]

Mike not sure what you mean by this.
The new digital meters, only count UP. 5 KW in, 8KW out = 13KW bill.

The new digital meter I had installed counts import and export KW.
Are you saying if I consume 5KW off the main grid and export 8KW from my panels I get a 13KW bill? i.e. I get billed for the power I export?

[Sunking]

I get billed for the power I export?

That is exactly what he isw saying. The new meters will count all power as use. In order for them to count what you generate, you have to have a contract. Upon that point they will program the meter to run NET METERING.

In addition if you connect a grid tied system illegally without a contract, the meters will detect it and reoprt. At that point the utility has every right to disconnect your service.

[trbizwiz]

Secondly I can not turn off the grid. The inverters will automatically shut off once the mains goes away. This is so my generated power does not sneak back out onto the grid should there be a blackout and fry a lines man. Tis the law i believe[/QUOTE]


What I meant was turn of the main breaker box not your transfer switch. I assumed your solar was joined into your system somewhere between your primary breaker box and your transfer switch. With the breakers all off and the transfer switch set for grid power to come in you should be able to see how your meter reacts compared to how your solar monitor reacts.
I do see your point about needing power for the monitor. Bummer. You should definately ask your utility about this though.

[Mike90250]

What I meant was turn of the main breaker box not your transfer switch. I assumed your solar was joined into your system somewhere between your primary breaker box and your transfer switch. With the breakers all off and the transfer switch set for grid power to come in you should be able to see how your meter reacts compared to how your solar monitor reacts.
I do see your point about needing power for the monitor. Bummer. You should definately ask your utility about this though.

Nope, grid tie won't work that way. you have to have grid present for your local generated power, to go to, otherwise, it overvoltages, and shuts off. Or detects no grid and shuts off, or in pulse test, detects no low impedance grid and shuts off. It does MANY different tests, to be very sure the grid is healthy, before it will start up and "sell".

[russ]

When you read some of these posts you can easily understand why the utility gets concerned over what the homeowner connects to their grid.

An important bit of knowledge is knowing what you don't know!

[Marvin]

Thanks Mike that's what I was trying to say. If you turn the grid off the inverters are designed to shut off. There must be a healthy grid before the inverters will fire up.

BTW: The connection was done legally.

Given that I am monitoring the power on the output side of the meter I am expecting to see a reading of. The house load minus the power generated by the solar arrays. eg. If the house load is 1000W and the panels genetate 700W I am expacting to see a reading of grid supplied power of 300W. Is this a correct assumption?

[Mike90250]

Yes, you should see the meter slow way down. If the house load is low enough, the meter should reverse.

And sometimes the power company gets it wrong 'cause the meter reader can't figure it out.

[Marvin]

Mike

Thanks for restoring my sanity.

I think I'll rip the cover off the fuse area to make sure there isn't anything weird happening in there.

If I can't sort it out I'll go back to my solar installer and tell them they haven't installed the system correctly as it's not saving me anything. (I haven't paid them yet either, so they might be interested)

[Marvin]

I ripped the covers off and the system is wired correctly as per the attached diagram but still misbehaves. We had enough sunshine two days ago to be generating several times the power required to run the house yet virtually nothing was feed into the grid and the meter showed most of the power I consumed came off the grid. Most annoying.

The Solar installers said they would come back out and have another look. I'm thinking the issue may be more sinister and be something like an inverter running our of phase or at a slightly different frequency to the grid.

The saga continues

I have attached an updated wiring diagram.

[Marvin]

For those of you following this thread. It is looking very much like the grid supply has a issue. Looks like the is a massive power factor issue. Or even a metering problem.

Maybe this weekend I will measure it myself and see what's happening in this area.
Time to dredge out my old osciloscope I guess. Wonder if it stil works after 15 years of storage.