Mothballing Solar Electric Panels

[gfsch]

PA is not the sunniest winter climate around. PVWatts shows 176 kWh for a 3.57 kW system in Erie for Dec.
I'd suspect snow cover on the array and/or some long shadows could knock that down to 120 kW without too much trouble.

My output for December and annually:


Year December (kwh) Annual Mwh
2014 140 Partial year
2015 148 4.4
2016 160 4.53
2017 101 4
2018 146 3.62
2019 144 3.8
2020 120 4.19

The panels are roof mounted and I don't clean the snow from them. Sorry, I can't get the table to format correctly

[gfsch]

In your original post you said POCO net meter can read how much power is being used even if you are generating it. What kind of net meter is that? If I follow an electron from the solar panel to your electrical panel to your stove, it never crosses the net meter. My net meter reads watts taken from the grid and watts going to the grid in two different displays. You need these two numbers and the enphase watts generated to figure out your power usage for a given period of time. I reconcile all my numbers monthly to follow my power company billing.

Based on your comment I reanalyzed generation. You are correct the meter only sees what I sent back. What I didn't realize is how much I sent back. I sent back about 1.2 MW in 2020. In all but 3 instances I used it that day, but if I go with the Envoy S metered, I lose about 26% of my generation.


Thanks Good Catch!

[J.P.M.]

[QUOTE=SunEagle;n422331]

I now understand what you are talking about. I guess I would think that 14 panels would generate more than 120kWh in a month so they must be low wattage or not pointed South. /QUOTE]

might. PA is not the sunniest winter climate around. PVWatts shows 176 kWh for a 3.57 kW system in Erie for Dec.
I'd suspect snow cover on the array and/or some long shadows could knock that down to 120 kW without too much trouble.

[gfsch]

I now understand what you are talking about. I guess I would think that 14 panels would generate more than 120kWh in a month so they must be low wattage or not pointed South. .

I have 255 Watt Solar World panels and they are pointed due south. I just don't get much sun in December.

The problem I see is that you paid for that system so why not use it in some way instead of just letting them go to waste..

I am trying to salvage as much as I can out of this. I installed the panels as a lark. I realized I was in the 0-2% ROI when I installed them. This net metering just destroyed any hope of a positive return. One of the reasons my electric is so cheap is I am about 60 miles from the Marcelles shale and we get relatively cheap natural gas.

I guess overall your POCO just does not want any co-generation connected to their grid so they hit you up with a hefty penalty for each kWh you purchase..

Actually, I think the utility wants the generation. Our state required them to cut usage by 3%. Solar panels are an effective way of meeting the goal. The costs are the result of deregulation. I have to go out on the open market and buy my electric from a list of suppliers. This is the $.045 and $.093 cost I quoted in my first post. Only one of the 20+ suppliers is offering net metering. The utility gets another $.068/kw to deliver it.

Still I am not really sure what the POCO would pay for every kWh you send them. But if it only comes to $3 per month it sounds like you are better off with no solar connected to the grid.

I only had 3 days last year when I went net negative for the day. It looks like they gave that back to me. Ie just subtracted it from my usage the next day. The $3 is my SREC credit. I can sell green credits in Pa for $25/MW. I get to use the electricity and get the green credit for what i generated. .12MW times $25=$3. Net metering is relatively new and when I got my rates I unplugged my panels and now am looking at alternatives. If it makes sense, I'll abandon them.

Thanks
Greg

[bob-n]

Right. If you block it going back to the grid and don't use it, you lose it. Some people are really obsessive and only run their heavy loads (electric dryer, electric stove, car charger, etc.) when the sun is shining to try to get as much handled by their own power source as possible.

[gfsch]

If you have an Enphase Envoy and CT clamps later versions can be programmed for Zero Export.
As far as other suggestions it would depend on your consumption and which rate plans are avalaible within the Net Metering arrangement.

Thanks Ampster. This may be a good alternative. My system is 5 years old so my Envoy does not have monitoring capability. I would have to upgrade. Getting information on the Envoy S metered is difficult but I'll check for more tomorrow. My concern is that it looks like the utility is monitoring constantly. My system generates about 4.5 MW annually and 1.2MW of that is back-fed into the grid. If I block the 1.2 MW from going into the grid I suspect I will lose that generation.

[bcroe]

It sounds like one way out, is to generate all the KWH you need, buy none. That is
happening here, net metering bridges nights and seasons without any purchases.
Bruce Roe

[SunEagle]

Thanks guys. I'll start with the easier ones first. Pa is deregulated. I will pay $.093 for the generation and about $ .068 for the distribution or a total of $.161 per kw. The teaser rate is $.045 for generation for 3 months, so you have to keep renewing. This is the rate I took now. The annual no nonsense rate is $.068/kw. Again you have to add the $.068 distribution charge to these, but that rate is fixed so it doesn't effect my analysis.

For example. I purchased 2210kwh in December and my panels provided 120kwh for a total use of 2330 kwh usage. 2330kwh @ $.113= $263.30 is my cost with the teaser rate. I am being forced to net metering which means I will buy 2210@.161= $355.81. I get a .12 times a $25/Mwh solar credit of $3. I am out $89. Again this is with the teaser rate, but even with the annual rate I am out of pocket $36 for December and this isn't going to be my worst month. When I looked at the entire year with the no nonsense rate I am out about $250. I am trying to figure out how to keep these on-line without being scalped or whether i can jump in and out of the net metering rate for specific months.

I now understand what you are talking about. I guess I would think that 14 panels would generate more than 120kWh in a month so they must be low wattage or not pointed South. If your POCO charges you 48 cents/kWh because you are self generating then I also think you should either use your panels to power a specific load and not be connected to the grid. Or as you first asked, just disconnect and mothball them. The problem I see is that you paid for that system so why not use it in some way instead of just letting them go to waste.

I guess overall your POCO just does not want any co-generation connected to their grid so they hit you up with a hefty penalty for each kWh you purchase.

Still I am not really sure what the POCO would pay for every kWh you send them. But if it only comes to $3 per month it sounds like you are better off with no solar connected to the grid.

[oregon_phil]

In your original post you said POCO net meter can read how much power is being used even if you are generating it. What kind of net meter is that? If I follow an electron from the solar panel to your electrical panel to your stove, it never crosses the net meter. My net meter reads watts taken from the grid and watts going to the grid in two different displays. You need these two numbers and the enphase watts generated to figure out your power usage for a given period of time. I reconcile all my numbers monthly to follow my power company billing.

What are your POCO's net metering rules? Is the net meter balance zeroed out daily, monthly or yearly (mine is yearly)?

[gfsch]

Thanks guys. I'll start with the easier ones first. Pa is deregulated. I will pay $.093 for the generation and about $ .068 for the distribution or a total of $.161 per kw. The teaser rate is $.045 for generation for 3 months, so you have to keep renewing. This is the rate I took now. The annual no nonsense rate is $.068/kw. Again you have to add the $.068 distribution charge to these, but that rate is fixed so it doesn't effect my analysis.

For example. I purchased 2210kwh in December and my panels provided 120kwh for a total use of 2330 kwh usage. 2330kwh @ $.113= $263.30 is my cost with the teaser rate. I am being forced to net metering which means I will buy 2210@.161= $355.81. I get a .12 times a $25/Mwh solar credit of $3. I am out $89. Again this is with the teaser rate, but even with the annual rate I am out of pocket $36 for December and this isn't going to be my worst month. When I looked at the entire year with the no nonsense rate I am out about $250. I am trying to figure out how to keep these on-line without being scalped or whether i can jump in and out of the net metering rate for specific months.

[SunEagle]

Welcome to the forum. Would you really only pay 4.5 cents per KWh? I've never heard of electricity that cheap and I'm curious what the expected ROI would be with prices that low, or even at 9.3 cents. I wouldn't bother with solar at all if we had those prices here.

You don't need to do anything to protect the panels, you should be able to just turn off the feed-in circuit breaker at your service panel to shut down the inverters.

I think the OP is confused concerning what his electricity will cost. I think the POCO will charge $0.093/kWh for purchased power and credit the account $0.045/kWh for the Net metering. As you said I have never heard of a POCO only charging 4.5 cents / kWh anywhere in the US.

I am only being charged about 9 cents/kWh and it is very hard to justify installing a solar system even if I get that 9 cents/kWh back with net metering. My ROI calculations are over 10 years and that is if the final cost of installation is less then $2/watt.

[bob-n]

Are you certain that you understand the complete cost picture with and without netmetering? As sdold said, in most places, those rates would be very unusual. If you're not sure, it may be beneficial to do some more research. For most places that I know, the utility will charge roughly the same for energy you use whether netmetered or normal. If netmetered, they will also pay you some rate for the energy that you send back to the grid. They may charge a slightly higher monthly fee to rent a netmeter compared to a regular meter.

According to one story that I read, the Pennsylvania PUC allows customers to produce up to 200% of their annual consumption and receive retail rate electricity prices for energy they send back to the grid. In your case, if you are not sending significant energy back to the grid, perhaps you may be right that netmetering doesn't help you and may actually hurt you. So Ampster's suggestion of enabling Zero Export may solve your problem. Contact Enphase tech support for advice on how to do this. Then tell the power company that you are not sending them any energy and don't have any need for a netmeter.

As others have said, you don't need to do anything when you take solar panels offline. They won't overheat or overvoltage.

Panels will degrade while exposed to the sun, perhaps 0.5% per year or something like that, but most people consider that insignificant.

[sdold]

The cost of electricity with net metering is 50% to 100% more expensive then net metering ($ 0.045 compared to $0.093 today).

Welcome to the forum. Would you really only pay 4.5 cents per KWh? I've never heard of electricity that cheap and I'm curious what the expected ROI would be with prices that low, or even at 9.3 cents. I wouldn't bother with solar at all if we had those prices here.

You don't need to do anything to protect the panels, you should be able to just turn off the feed-in circuit breaker at your service panel to shut down the inverters.

[SunEagle]

Again I just don't understand what the issue is with Net metering. The POCO will pay you for power generated and not used. Whatever the cost is it still provides some $ towards what you pay them for electricity which will reduce your overall costs. Mothballing a system that you paid for will never get you anything back so why do it. Just go with Net metering and calculate the overall ROI.

[bcroe]

. Is there any way I can block the solar output from going back into the system?

One way to separate your solar from the PoCo, is to feed panel DC output directly into
some of your large loads. That is difficult and time constraining. It is possible to
get heat pumps which allow direct connection of solar panels, usually with a PoCo
backup input. The heat pumps can heat your place in winter and cool in summer,
up to the energy level available at the time. Bruce Roe