I am grid tied and the electrical company told me I have the right meter to get net metering. My question is the meter says delivering at night and receiving during the day but the meter always goes forward and much faster when I am sending them power. Is this normal? does the electric company just keep track and bill the difference?
digital meter?
- Thread starter scmoore
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svetz
Works in theory! Practice? That's something else
There are all sorts of meters, to know for sure you could look it up on the internet (the model number is usually on the front).
For the meter to spin faster than you normally see it moving should indicate you're producing more power than consuming. For example, if your using 2 kW at night let's say the meter spins 2 rpm. If you're producing 4 kW solar then it should still spin at 2 rpm because the house consumes 2 and you export 2. But, if you're producing 6 kW then the meter should spin twice as fast.
You should know for sure when you get your next bill.
For the meter to spin faster than you normally see it moving should indicate you're producing more power than consuming. For example, if your using 2 kW at night let's say the meter spins 2 rpm. If you're producing 4 kW solar then it should still spin at 2 rpm because the house consumes 2 and you export 2. But, if you're producing 6 kW then the meter should spin twice as fast.
You should know for sure when you get your next bill.
I am grid tied. I read my meter every morning and record the number just so that I can have the data and learn more about my power usage/generation. My meter is digital and counts down when I am making more than I am using. I also have a Sense energy monitor with the "solar" addition. On my phone or on my home PC I can look at usage/generation....right none, daily, weekly, monthly, billing period, and year. It tracks usage and generation separately. If you think something is wrong, you need to get data to back up your complaint.
svetz
Works in theory! Practice? That's something else
You might also find this of interest: Using RF to read ITRON utility meters
Doesn't sound like you have an Itron, but you might be able to do something similar.
Like @DThames, I track my meter readings (but I'm to lazy to go outside and look at the numbers). I use it in a Home brew program along with readings from Envoy Api to get key data and send me alerts if anything is wrong.
Best of all, they can't argue with the numbers cause it's their meter. ;-)
Doesn't sound like you have an Itron, but you might be able to do something similar.
Like @DThames, I track my meter readings (but I'm to lazy to go outside and look at the numbers). I use it in a Home brew program along with readings from Envoy Api to get key data and send me alerts if anything is wrong.
Best of all, they can't argue with the numbers cause it's their meter. ;-)
I am on a rural electric coop. For all of my life there was a "meter reader" person that drove house to house. In recent years, they can read it via the power lines. I assume they piggyback a digital signal on a carrier wave that they can add on. On the power company web site I can see my consumption for each hour of the day. But when I am over-producing it show zero, not negative on the web sight. But on my bill all credit shows up correctly.
svetz
Works in theory! Practice? That's something else
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| That's so cool!  Now I have meter envy... |
I live in Arkansas, not way out in the sticks, but out of town for sure. The electric coop asked some years ago if they offered internet over the power lines who would be interested. It had some major limitations but they could piggyback the internet over the power lines, so I am guessing something like that is built into the meters. We are in the process of getting fiber optic supplied by the electric coop. The fiber is on the pole but not connected yet. I am excited to get away from my flaky DSL.
That's so cool!
Now I have meter envy...
DThams, I live way out in the sticks. Our co-op didn't even send people out we had to enter our own meter reading when we paid our bill. About 5 years ago they put in all new meters that sends the readings to the co-op. Our only option for internet is hughes net and it is pretty bad. Does your meter go forward all the time even when you are sending them electric? I have only had my solar up for 7 days but last Nov. I used 150 KW for the month and in the last week my meter has went up 240 KW. I'm just worried about getting a $500 electric bill and then fighting with the co-op to get it corrected.
74nnn column is my meter reading. Far right column is net change. Those negative (used more than I made) days were very cloudy.
Hedges
I See Electromagnetic Fields!
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Was your rate plan changed?
Maybe you used to pay the same low rate all day, but because you installed PV and selected net metering, the utility company now charges you $0.05/kWh at night but $0.50/kWh during the afternoon. If you generate less than you consume, costs you more than if you didn't do anything.
Where I am, had to change meter. Rates are $0.15, $0.30, $0.45 depending on time of day.
Shut off all branch breakers except for PV and see how reading changes over an hour.
Shut off PV breaker and have all others on, see how reading changes over an hour.
If you have a mechanical meter, direction of wheel should reverse.
If electronic, dashed lines simulating wheel or similar should indicate.
Does your bill reflect consumption went down? or up?
It is possible the meter reads "VA" not "Watts", doesn't account for direction of power flow.
Boneyard42
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I live in a small town and my electricity is provided by the city. I have 60 400w panels and 60 IQ7plus which produce 290wh. My electric company tells me that I produce less than what Enphase says that I produce and they say I use more than what is being reported by Enphase. I thought that I would just be grid-tied and send the excess back to the grid. I was happy to not have a bill. "NOT" I commissioned Aug13 and today I have had a bill every month. So you guessed it I have to add batteries for storage to use at night.
When you are producing more than you are using, does your meter go backward?
Hedges
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Seems like someone's measurement is incorrect. Unless the error is in your accounting, or where Enphase sensors are vs. your understanding.
To measure power, need current measurement and simultaneous voltage measurement, considering phase between them.
Simpler would be if you use a DMM with clamp AC probe, no reactive (motor) loads, and your understanding of which direction power flows. At night so no PV, apply a large resistive load such as space heater but other (automatic) loads off. Run the test an hour or more and note utility meter and Envoy Wh readings. Measure voltage of each leg and current of each leg at the main connection. Daytime, measure again with PV production but all loads turned off, and again with space heater (during an hour when panels are oriented toward sun, to minimize variation). Note utility and Envoy readings.
Compare Wh readings to your calculations.
To measure power, need current measurement and simultaneous voltage measurement, considering phase between them.
Simpler would be if you use a DMM with clamp AC probe, no reactive (motor) loads, and your understanding of which direction power flows. At night so no PV, apply a large resistive load such as space heater but other (automatic) loads off. Run the test an hour or more and note utility meter and Envoy Wh readings. Measure voltage of each leg and current of each leg at the main connection. Daytime, measure again with PV production but all loads turned off, and again with space heater (during an hour when panels are oriented toward sun, to minimize variation). Note utility and Envoy readings.
Compare Wh readings to your calculations.
Boneyard42
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The town replaced both meters with Digital meters, they just flash numbers.
Hedges
I See Electromagnetic Fields!
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Many people alleged incorrect readings from the new "smart" meters.
Utility has said the old meters might have been incorrect, and new are reading correctly.
Digital meters are subject to software bugs. A meter for "net metering" should be calibrated for power flowing both directions. If your utility incorrectly installed a meter not for net metering, perhaps is measures volts and amps, and computes power as scalar not vector product (doesn't acknowledge two different directions for power flow.)
Turn off all your loads. Read the meter and Envoy. After operating PV system to produce power for an hour, read meter and Envoy again.
Turn on loads (ideally something approximately known, like space heater), turn off PV system. Read meter, and after an hour read again.
Compute net use/consumption and see if sign is different for the two cases.
Check magnitude against what's reported by Envoy, and against estimated load.
"Both meters"
One for production from PV, one for consumption by house loads?
Also try to figure out rate schedules. Do they give you a small credit for production but charge a large bill for use?
Do you have time of use rates, higher than before, so if you produce enough to reduce consumption in half some hours (e.g. afternoon when running A/C), the rate is so much higher that bill goes up not down?
