I am going solar

You're right. #2 is Gross which matches #1.

#3 shows two figures, but I wonder if it doesn't move up the generation side if we use the energy. That's an interesting question versus transmission loss....

The way that we get billed is the electric company goes to our meter and records both figures and finds the difference. Then the find the difference between generated KWh and used.

So I am unsure if the generated KWh report goes up only if we can't use the energy...that I really don't know. But then why two separate figures?

 

It simply can't measure the generation you use promptly, because this portion never goes through this meter. The meter can measure only what passes through it. The portion you use does go through meter #2 but is intercepted before reaching meter #3.

As a retired electrical engineer, and the designer / installer of my own system, I'm quite sure of it. But go ahead and ask your installer.

Does your utility credit your generation at the same price per kWh that you purchase energy from them? If not -- in some states, they pay for your generation at wholesale prices, then sell it back at retail -- then they need to know the two separate figures.

In my state, my generation goes back to the utility at the same retail price, so a meter showing a single figure will suffice. My meter won't work with the other pricing scheme, but your meter will work with either system.

 

My solar installer knew that the figures would be different but didn't know why. Then again the electric company is the one that installs the net meter.

As for stuff that goes back to the grid, it's the same exact price it's sold to me at, always. So if electricity rates go up, so do my over generation rate

 

Well my friends with the PV Solar system, I'm reading your comments of the multiple electrical meters and the way you think the electrical providers calculate your consumption and the overage they will receive back to their poll.
In my case, Long Island, New York; LIPA (then PSEG) replaced the only meter I have with a digital one ( capable of wireless NET metering). This meter is all the time in negative numbers, what it means, I have a large overage of energy production in a bank and being used wen I do not produce any energy for obvious reasons, like in the middle of snow storms. I still have almost 1000 KW in reserve from previous months.
The only monthly payment they take is wire distribution and maintenance fee for $12.00.

Inferno, where a you located at?

 

I am in mass

We have a standard $6 customer fee which my over generation can cover...

 

The two different figures might be just the way that meter manufacturer designed their net meter. If you're curious, you can find the model number printed on your meter and google to find a manual online; there might be some clues in there if it's designed that way with a specific use in mind.

I have a smart meter, so I can see hourly usage (although typically subject to a 24-48 hour delay before it is visible online) from my electric meter. If I'm generating 1 kW, the utility's net meter will read maybe -0.8 or -0.85 kW (for my normal not-home usage, anyway). The other 150 or 200W are being used in my house, as others have said. I have no separate production meter other than what the inverter itself reports (which is also fed to the internet so I can see hourly numbers - though without the 2-day delay).

If both your electric meter and production meter have instantaneous readouts, you should be able to prove to yourself that the difference between the two is your usage; look at them both and note the instantaneous reading. Then, turn on something that uses a lot of power - like a hairdryer. You should see the difference between the two increase, by approximately the power rating of whatever you turned on. If they don't have instantaneous readouts, there are other ways you could prove it - like turning off all your circuit breakers except the one to the solar panel - but that would be rather annoying to do. I suggest just trusting us that it's working correctly, and the utility isn't robbing from you.

 

Ugh so I type in my model number and find this: https://www.itron.com/PublishedContent/1-210+c_SmartMeter-web.pdf
It's actually an Itron Watthour Meter CL200

My question is, if the net meter is only recording what I 'overgenerate' at a given moment, why does it need to switch back and forth from showing generation versus usage. The electric company records both figures then subtracts them from previous figures to see how much I used and generate. So far I've generated 1400 according to my production meter, my net meter says I produced around 1030 - so now it's a 27% difference. What gives? :O

However SRECs are being paid on what my production meter says...Is there a trick in MA to make you think you're earning SRECS when they might be screwing you on the electric company side by only counting 75% or so of what is generated according to your production meter? Anyone else have this issue?

 

Well that certainly bodes well for my East/West only panel situation.
Thanks!

 

As I pointed out yesterday, that sort of meter exists because some areas have price structures where production and consumption are priced differently, not to the benefit of the home solar producer. My simpler meter cannot handle it correctly, your's can.

Why your utility selected that fancier meter, when a simpler model would have been sufficient, is a separate matter. Maybe they also serve an area with the other price structure and want to minimize the different parts in their warehouse. Or maybe they are hoping to get future legislative approval to convert you to that other system, and want to be ready to implement it the same day the governor signs the bill, without having to visit every home to install new meters. Either way, it doesn't matter right now.

If this bothers you -- it concerns me not one wit, as that is what I expect -- then consider performing the tests Macman suggested. Increase the house load sharply while the PV system is producing, and the gap should widen. Cut the house load sharply while the sun is out, and the gap should shrink. Shut off everything in the house for a day (at the breaker panel, so no phantom loads are missed), or for as long as you can tolerate having the fridge and freezer turned off, and the gap should vanish. Give or take some rounding error.

 

The usage number on your net meter will measure what you use at night, or in the early morning and late evening, when your panels aren't producing enough to meet your demand at that moment. The production number on your net meter will be the amount of excess electricity; what you're not using in your house.

The meter is incapable of calculating both what you're using and producing at the same time - it only knows the difference between what you're producing and what you're using. This is because the meter can only measure what goes through it - and anything that gets produced on your roof and goes straight into your house doesn't go through the meter at all. So when the difference between what you're producing and what you're using is positive, they add that amount to your production number. When the difference is negative, they add that amount to your usage number. (Compare that to my meter - when the difference is positive, it's added to my usage, when the difference is negative, it's subtracted from my usage. There's only one number. Sounds like your utility wouldn't be confusing you so much if they had installed that type of meter instead...)

At the end of the month, they can see how much the production increased, how much the usage increased, and then take the difference of those to figure out if you (overall) used or consumed more power that month. It doesn't sound like they're using the two separate numbers for any particular reason.

The spec sheet you linked suggests the capabilities that separate out generation from usage can be used for "green-credit electricity programs for consumers who own renewable energy facilities or participate in vehicle-to-grid systems."

One case where the utility might do something like that would be the city I used to live in, when solar was starting to grow, probably 10-15 years ago. They wanted to boost the amount of solar they bought, so they offered to buy 100% of your production at ~35¢/kWh, and then sell back what you use at the usual 13¢/kWh rate. One way of measuring such a thing would be to install two meters; one on the solar that always runs backwards, and one on the rest of the house that always runs forwards. Another way would be to use just a single meter like you have - but they would no longer be able to buy 100% of your production, because you'd be using some of it before they could measure it.

So if you had some sort of a deal like that where the generation was a different price than the usage, your meter might be cheating you a little bit, just because it can't measure generation by itself. But since they're the same price for you, it doesn't matter if what the net meter says production was is lower than what your production meter says - that "missing" 27% shows up by way of a 27% lower usage number on the net meter.


In my case, production and generation are also equal value - though only if I produce fewer kWh than I use over the course of a year. If I have excess production, they buy it at wholesale prices of ~4¢/kWh (instead of retail, where I pay them ~17¢/kWh). I made it extra-complicated by switching to a time-of-use rate. So I earn credits at retail rates - but if my total credit at the end of the year is negative, they'll only pay me if the actual kWh usage is also negative (and they pay per kWh, not what the retail credit is). More likely what will happen is that I'll produce about as much as I consume, but due to the higher rates when I produce, I'll have some extra retail-price credits. That way, even if I use 10% more kWh than I produce, I'll still owe nothing for usage, because that extra 10% will be covered by producing during the peak hours. If that makes any sense at all.

 

Do yourself a favor and have a couple of new extra chain saw blades on hand before you start- that ash heats em up and dulls them quick like you're trying to cut through steel. I cut down a white ash that was only about 12-14" across at 3 ft up from the ground. I actually thought there was something wrong with my saw because it simply stopped cutting after a few inches. I went through a couple of blades on that "small" tree.

 

If they are good enough trees you may even get paid to get rid of those trees.

Otherwise I would vote to install a wood stove and burn the wood. There are credits for buying compliant wood stoves in MA with less submissions to the environment. You would also save on heating tremendously. Wood + Solar - a good way to stay away from oil and coal. Of course at that point you might consider buying cords of wood...But the wood stove we have more than paid for itself in a couple years especially when oil was much higher

 

Are they as difficult to cut down with an axe?

 

I had to gigantor Black Oak trees removed before the PV installation, basically the same job than your offers but I paid $1100.00 in Long Island.
Keep getting proposal, your best one still seems to steep.

EDIT:
Try to donate the wood to minimize the cost; put an add in craigslist to have the wood taken away.
Not all wood is good for lawn mulch and the chips should be chemically treated.
Termites L O V E wood chips, try to keep them away as far as possible from your house.

 

^^ Hopefully those fallen trees are letting into the house net useful energy in the form of light and heat, otherwise the value of PV is taking a hit. I was thinking enviro and not money.