Net Metering to Distributed Generation Program.

[+3 Golfer]

I am sure the city council cares - not. This is a downside for those who have taken advantage of subsidies and incentives. The vast majority that haven't used those financial aids are not too sympathetic. On the site solar is the big thing but in the real world - different story.

That's probably true - city council would likely rather look good to the vast majority for political reasons and may not even be the same that promoted Solar.

IMO, the 13 solar owners in the City have one card to play - "begging for mercy" - grandfather the "Solar 13" at little extra cost to the rest of the City's electric customers. Spread say $7,800 ($600 *13) a year over all customers say $3.00 / year additional for the mistake of the previous council. Can the current council in good conscience ask 13 residential customers to pay around $600 per year more so that other customers might save $3.00 a year?

[russ]

IMO, the 13 solar owners in the City have one card to play - "begging for mercy" - grandfather the "Solar 13" at little extra cost to the rest of the City's electric customers.

That would be quite fair

[jschner]

I'm working on the formal proposal to the city for first, grandfathering existing customers and second, making changes to the DG program. In the mean time I asked for clarification of the meters needed and formulas.

Here is my email:

Tom,

Thanks for taking the time last night to answer questions.

Real quick two things were not explained enough to help us understand fully.

First, the two meters. I understand there are single meter customers out there but I need to understand my situation better which is probably most of the solar customers. I currently have two meters. A production meter that shows how much my solar produces and a use meter whatever you call it that spins forward and backwards that shows my overall house net use after solar.

Other than not being wireless, are those meters sufficient to operate under the new DG program? If not please explain why and what the difference is in the way the meter reads. If they are sufficient, then I really need is to be able to understand the example given in the spread sheet.

Second, the example bill. It is still not fully clear. I would like to give you three scenarios and hopefully you can create three tabs on an excel sheet or send me three separate bill examples.

For ease of understanding I assume starting at 0000 on both my meters for all three examples. That would represent the new monthly "true up" in the DG program correct?

Example #1 starting at 0000 and 0000, after 30 days the meters read: Production meter = 1000kWh - 2-way meter = 0kWh

Example #2 again starting at 0000 and 0000, after 30days the meters read:Production meter = 1000kWh - 2-way meter = 200kWh

Example#3 Starting a 0000 and 0000, after 30days the meters read: Production meter = 1000kWh 2-way meter = 9800kWh <---spun backwards.

I'm sure you can understand why the three examples. What I need to understand in your spreadsheet is how these numbers are plugged in because the example is not clear. The example given in the Nov 15th Agenda shows "300" and "530" and you mentioned last night that represents the customers monthly 830kWh personal usage.

These calculations are at the heart of the matter really. And maybe I'm wrong in my understanding of them? So you don't have to explain everything in words, if you don't mind, please plug my examples into three separate spreadsheets and send all three via email if you can.

I'm pretty sure with these three examples I can figure it out and understand the numbers a lot better.

Thank you very much,

Jim

Jim –

The net meter does not tell us how much, in total, was taken from the utility and how much, in total, excess solar is put back into the grid; it only tells us by the meter reading at a point in time compared to the next meter reading the results of traffic for the time period.

For example:

On a two lane road with a north and south bound lanes there are 100 cars passing a given point going north. At the same point there are 12 cars travelling south. So the total traffic is 112 passing the point with 88 more cars heading north. The City’s net meter only tells us there are 88 cars going north.

The existing meter is insufficient in providing a true picture of activity.

From the DG perspective

Example #1

· Assumes 0 kWh energy provide by the utility; Charge to solar producer is $14.50

· Assumes total solar production = total household consumption perfectly during all 720 hours in a month

· Solar production 1,000 * $0.0865 = $86.50 paid to household

· Household has $72.00 credit on bill


Example #2

· Assumes solar production is greater than household consumption by 200kWh

· How many kWh went to the household from the utility? Charge to the household; $14.50 plus toll from any kWh heading to the household; total charge unknown

· Solar production 1,000 * $0.0865 = $86.50 paid to household

· Unknown charge less $86.50 is presented on the bill

Example #3

· Same answer as example #2

From the Net Meter perspective

· Example #1

· Household billed $14.50 for the current month



Example #2

· Household billed $14.50 for the current month

· Household billed 200 kWh times $0.1437 = $28.74

· Total monthly charge is $43.24



Example #3

· Household billed $14.50 for the current month

· 200 kWh held off book for 12 months; if the carryover is still there after 12 months than 200 kWh * $0.0341 = $6.82 paid to household

· Total monthly charge is $7.68 the month of 12-month settlement

I hope this helps. If not, keep asking away.

Thanks for being an active participant. I truly appreciate the discussion.

Tom M.

I get what is happening here. My examples were not exactly right but it did clarify things. They need to change my meter and want to track ALL incoming and outgoing power by the minute to my home instead of by the month and buy my exported power at the lowest rate and sell my power back to me at full retail rate. Negating all the reasons why they promoted solar in the first place and the fact that in a year I only use 426kWh net. Anything else you guys can see in these examples?

While I'm producing power in excess, are my neighbors not using that power at the full rate while the city is sourcing that much less? It appears the city will be double charging for power here. I'm still trying to wrap my head around that.

[Ian S]

I'm working on the formal proposal to the city for first, grandfathering existing customers and second, making changes to the DG program. In the mean time I asked for clarification of the meters needed and formulas.

Here is my email:



I get what is happening here. My examples were not exactly right but it did clarify things. They need to change my meter and want to track ALL incoming and outgoing power by the minute to my home instead of by the month and buy my exported power at the lowest rate and sell my power back to me at full retail rate. Negating all the reasons why they promoted solar in the first place and the fact that in a year I only use 426kWh net. Anything else you guys can see in these examples?

While I'm producing power in excess, are my neighbors not using that power at the full rate while the city is sourcing that much less? It appears the city will be double charging for power here. I'm still trying to wrap my head around that.

I think Tom misunderstands Example 2. He claims "Assumes solar production is greater than household consumption by 200kWh" when shouldn't it be "assumes solar production is less than household consumption by 200kWh?" In any event, I think you are right about needing a meter that tracks instantly - and separately - the kWh's going into and out of the home. That's the type of meter we have here in Phoenix (APS); in fact it also tracks instantly and separately the peak kWh's going in and out. APS then does an on-bill subtraction to give the off-peak kWh's going in and out. APS doesn't bother at all with the production meter at least for billing purposes.

[+3 Golfer]

jschner, are you saying that the City is going to sum energy coming into the meter and energy going out of the meter for the billing period? So, apparently the city is replacing the net meter with one that accumulates IN +Flow (delivery to customer) and OUT -Flow (excess generation purchased by City). You pay for energy coming in at $0.1437 / kWh and you get credit for energy going out to the utility at $0.0865 / kWh. Actually that's not as bad as I thought in that your generation on an instantaneous bases does offset usage at the $0.1437 rate. It's your excess instantaneous generation that gets paid at the $0.0865 rate. Problem is how does one estimate what that might be and how it affects the Solar 13? If this is the case, you want to shift load into your high production hours (especially on clear days).

However, this is not what is in the resolution presented to the Council. It clearly shows that the old Net Metering = Co-metered (Delivery minus Generation). What is in the Council resolution is IMO significantly more costly to the Solar 13 than the instantaneous in and out metering because one can offset load with generation. Actually, this is fair. The only question is what is the power delivered to the City worth. It appears they give credit for purchased power cost and RECs in the rate - seems fair. I believe the resolution needs a lot more clarity on this. If the resolution is based on instantaneous accumulated in and out meter readings then your original estimate / interpretation of $600 / year hit is likely significantly overstated.

[inetdog]

Actually, whether or not the classic net metering and the IN vs. OUT at separate prices come anywhere close to each other depends very strongly on whether or not the user has large local loads during the peak production hours.
Consider two hypothetical users:
1. Nobody home during the day, and all of the housekeeping (dishwasher, showers, cooking, A/C, etc.) take place in early morning or late evening. If this user sizes the system to offset 100% of total load power, he will end up paying a little less than 1/2 of his original (no-PV) bill.
2. Retired person who occupies the home during the day and runs the A/C, etc, and is careful to schedule cooking, washing, etc. during solar production hours. With the same size system as above, that person will have a close to zero bill.

With classic net metering, both of them would have a zero bill.

I can easily see a difference of more than $60 per month for user A under the new plan as long as their no-PV bill was more than $150/month!

[silversaver]

2 meters system: you are not sure if the power generated send to the grid is growth or net after consumption. That is why I told him to check. If he has to sell ALL to POCO then never mind, $0 saving. If the power send to the grid is net after consumption, try to do all the house keeping during solar production.

[+3 Golfer]

Actually, whether or not the classic net metering and the IN vs. OUT at separate prices come anywhere close to each other depends very strongly on whether or not the user has large local loads during the peak production hours.
Consider two hypothetical users:
1. Nobody home during the day, and all of the housekeeping (dishwasher, showers, cooking, A/C, etc.) take place in early morning or late evening. If this user sizes the system to offset 100% of total load power, he will end up paying a little less than 1/2 of his original (no-PV) bill.
2. Retired person who occupies the home during the day and runs the A/C, etc, and is careful to schedule cooking, washing, etc. during solar production hours. With the same size system as above, that person will have a close to zero bill.

With classic net metering, both of them would have a zero bill.

I can easily see a difference of more than $60 per month for user A under the new plan as long as their no-PV bill was more than $150/month!

Definitely depends on usage during periods of generation but the max hit for jschner (which is what this thread is about) is calculated in post 1 at about $600 / year (not as I misstated $60 / month) based on his actual load and actual generation. It won't be $150 / month. Also, "modern" dishwashers, washers, dryers have timers. Usage on weekends is generally different than weekdays. One can put a timer on their water heater and delay morning water heating load until high generating hours. You don't have to be retired to shift load.

There is really is no basis for the "a little less than 1/2 of his original bill". The worst case is 1 kWh of usage paid at $0.1437 and 1 kWh of generation sold at $0.0865. So, the No-PV bill is $0.1437. The with PV net bill worse case is $0.0572. 572/1437 = 40% worse case which is a lot less than 50% and the 40% assumes no offset of instantaneous load with instantaneous generation which there will be some.

[ButchDeal]

Definitely depends on usage during periods of generation but the max hit for jschner (which is what this thread is about) is calculated in post 1 at about $600 / year (not as I misstated $60 / month) based on his actual load and actual generation. It won't be $150 / month. Also, "modern" dishwashers, washers, dryers have timers. Usage on weekends is generally different than weekdays. One can put a timer on their water heater and delay morning water heating load until high generating hours. You don't have to be retired to shift load.

There is really is no basis for the "a little less than 1/2 of his original bill". The worst case is 1 kWh of usage paid at $0.1437 and 1 kWh of generation sold at $0.0865. So, the No-PV bill is $0.1437. The with PV net bill worse case is $0.0572. 572/1437 = 40% worse case which is a lot less than 50% and the 40% assumes no offset of instantaneous load with instantaneous generation which there will be some.

How is there an offset of load with generation in a dual meter system? The generated power must go out through the one meter then back in through the other to get to the instantaneous load.

[Sunking]

How is there an offset of load with generation in a dual meter system? The generated power must go out through the one meter then back in through the other to get to the instantaneous load.

Not how it is connected. Your service connection is the common point between the two meters. If your panels are generating more than you are using, excess power goes back out through the POCO meter.

[ButchDeal]

Not how it is connected. Your service connection is the common point between the two meters. If your panels are generating more than you are using, excess power goes back out through the POCO meter.

Yes I understand the selling of excess but in a Gross metering (dual meter) system, all generated power is sold.
2.gif
In this case at a reduced rate. All consumed power is purchased from the grid, there fore if you are consuming your own power you are selling it at one rate and purchasing it back at a higher rate.

If it is wired this way there is no way to use the generated power locally, it all goes to the grid.

[+3 Golfer]

How is there an offset of load with generation in a dual meter system? The generated power must go out through the one meter then back in through the other to get to the instantaneous load.

There won't be any offset if the City is going with what appears to be in the proposal that the Council adopted.

But jschner says the City is going to track "ALL incoming and outgoing power by the minute to my home instead of by the month." So, my premise is that the generation stays behind the interconnection point. Otherwise, the City could simply read the generation meter and buy all generation and compute his monthly usage = generation meter change for the month + net revenue meter change for the month. But based on what jschner says, I'm led to believe that the City still going with net metering but the net is instantaneously (not monthly). The instantaneous Out and Ins will be accumulated for the month.

We have to wait to see what the City is really proposing.

[+3 Golfer]

One other thought, does the City have the authority to require a solar owner to rewire his once approved metering to put the generation meter outside the interconnection point? Who pays for this? Probably need another service panel with generation on a breaker. What right does the city have to gather data from behind the interconnection point (except possibly annual generation for RECs).

jschner have you reviewed the agreements you have with the City? Give Tom this example.

Load is 1 kW continuous for 720 hours in month (billing period) or 720 kWh.

Generation is 3 kW continuous for the first 300 hours of the billing period and zero thereafter or 900 kWh.

Is the energy part of bill:

(720 * 0.1437) - (900 * 0.0865) = $25.61 ==> this is effectively have two interconnection points, one for generation and one for usage.

(420 * 0.01437) - (600 * 0.0865) = $8.45 ==> this is accumulating all instantaneous energy for the billing period into two buckets IN+ and Out- at one interconnection point.

Someone check my math.

[jschner]

I still need to get clarification but my original thought scenario #1 was they will be buying 100% of my solar production at $.0865 and charging me for 100% of my household usage at $.1435kWh. That is how I arrived at $600 annually. If they did that, it also adds in price tiers.

Now I'm wondering if they will change my meter and track just ALL my inflow kWh such as during the evening and cloudy days and just charge for those kWh and not what I use during production hours?

And are they buying ALL of my production or just my exported solar production that outflows through the new meter? I'm sending another email shortly.

Playing with those scenarios:

I average about 10kWh of use when solar is not operating. 14kWh to 17kWh when it is operating. (stay at home wife). With that, hat would be about 300kWh a month of inflows in the evenings. We get a lot of sun here so toss in about 50kWh of inflows for mostly cloudy days. 350kWh monthly average plugged into the first half of the example:

14.50 + (350*.1435 = $50.23) + (2.85% = $1.84) = $66.57 avg.

Scenario #2 If they buy 100% of my solar production at $0.865
Winter 600kWh = $56.23 My bill = $14.67
Summer 900kWh = $77.85 Credit $11.28

Scenario #3 If they buy only my exported solar then that gets even more complicated.
Winter 600 - 350 = 250kWh exported $66.57 - $21.63 = I pay $30.28
Summer 900 - 350 = 550kWh exported $66.57 - $47.58 = I pay $18.99

So now I need to clarify which of the three ways they are going to charge. If it's the later two ways then the impact is not as great as I first thought. Any other scenarios I might be missing here?

Also, right now under Net Metering they bill me for the $14.50 + $0.41 public benefit even when my solar produces more than I use during the month. In their new DG program examples they include those two things into their calculations.

I'm going to try to nail this down. Anything you guys think I should ask here?

[jschner]

One other thought, does the City have the authority to require a solar owner to rewire his once approved metering to put the generation meter outside the interconnection point? Who pays for this? Probably need another service panel with generation on a breaker. What right does the city have to gather data from behind the interconnection point (except possibly annual generation for RECs).

jschner have you reviewed the agreements you have with the City? Give Tom this example.

Load is 1 kW continuous for 720 hours in month (billing period) or 720 kWh.

Generation is 3 kW continuous for the first 300 hours of the billing period and zero thereafter or 900 kWh.

Is the energy part of bill:

(720 * 0.1437) - (900 * 0.0865) = $25.61 ==> this is effectively have two interconnection points, one for generation and one for usage.

(420 * 0.01437) - (600 * 0.0865) = $8.45 ==> this is accumulating all instantaneous energy for the billing period into two buckets IN+ and Out- at one interconnection point.

Someone check my math.

On my house all they have to do is remove the net meter and plug in the 2-way usage meter. I imagine it has two meters in one, inflow and outflow. No rewiring needed. Plus my net meter is not wireless so they physically have to send a guy to my house right now.

I have read the agreements. I'll see if I can figure a way to post the PDFs.

to be honest I'm not sure what you are asking here? I think Tom is looking at daily inflow and outflow of kWhs and whatever that is in a month's time is how they will charge me. It's still not all that clear yet but I think we are getting closer.

Thanks a bunch!