NYSERDA

[mmmmmdonuts]

I have a 23kW residential solar system right now in New York state. The residential limit is 25kW I believe for NYSERDA unless you are on a residential farm then it is 100kW. I have quite a bit of load as I have two geothermal units (8 tons), and everything else is electric. My electric use is around 40MW a year give or take depending on how cold it gets in the winter.

I guess my question is there anyway to add more solar to make up the difference? I am looking at cutting my energy usage but some things are challenging to get much more efficient as I already have a heat pump water heater, etc but I do plan on adding an electric vehicle in the next year or so.

I have thought about doing some sort of battery system and peg the output of a converter right around 2kW. Realistically at peak output is only for a few hours in the afternoon, so I could discharge power in the evening. It could also serve as a battery backup.

Thoughts? Or is it way to expensive or am I missing a better option?

 

[Brucey]

I have a 23kW residential solar system right now in New York state. The residential limit is 25kW I believe for NYSERDA unless you are on a residential farm then it is 100kW. I have quite a bit of load as I have two geothermal units (8 tons), and everything else is electric. My electric use is around 40MW a year give or take depending on how cold it gets in the winter.

I guess my question is there anyway to add more solar to make up the difference? I am looking at cutting my energy usage but some things are challenging to get much more efficient as I already have a heat pump water heater, etc but I do plan on adding an electric vehicle in the next year or so.

I have thought about doing some sort of battery system and peg the output of a converter right around 2kW. Realistically at peak output is only for a few hours in the afternoon, so I could discharge power in the evening. It could also serve as a battery backup.

Thoughts? Or is it way to expensive or am I missing a better option?

Can you add some mobile ground mounts i.e. panels on trailers? Would seem to bypass a fixed ground mount system and the 25kWP limit?

 

[Brucey]

Sorry misunderstood. Looks like the limit is 25kW per electric meter for grid export. Seems like you could potentially add a second meter and get to 50kW?

 

[mmmmmdonuts]

I thought of that. It is a $20 connection fee per month for another meter. The only logical place to put it to is about 1/4 mile from the road (Garage) so I am sure it would cost quite a bit.

 

[Brucey]

I thought of that. It is a $20 connection fee per month for another meter. The only logical place to put it to is about 1/4 mile from the road (Garage) so I am sure it would cost quite a bit.

It's not clear to me if you could add a bunch of DC coupled panels as long as they were for self consumption and not additional >25kW grid export?

 

[mmmmmdonuts]

This what I am not sure of. My DC side is currently rated just over 26kW so I think they only care at the meter but I am not 100% clear on that.

 

[Brucey]

My local town code also mentions a 25kW limit for panels so just watch out for a possible restriction there as well.

 

[HarryN]

Perhaps you can aim some of the panels to face morning, mid day, and late afternoon sun positions?

In California, peak power demand is from roughly 3 pm - 8 pm, but most solar panels are facing in a direction that produces essentially nothing during this period. Instead we have a glut from ~ 11 am - 2 pm. The value of electricity is also different during these time periods here.

The houses in my neighborhood that have gotten solar recently vs in the past do have solar panels facing more directions.

Since solar panels typically output less than 50% in the winter vs summer, maybe you could have some extras that are active in the winter but shut down in the summer?

For my own use, I am even considering just having panels that are vertical mounted facing west and east, skipping panels on the roof entirely. Still just kicking around the idea, but don't feel stuck in a rut just because it isn't for everyone.

 

[Brucey]

Perhaps you can aim some of the panels to face morning, mid day, and late afternoon sun positions?

In California, peak power demand is from roughly 3 pm - 8 pm, but most solar panels are facing in a direction that produces essentially nothing during this period. Instead we have a glut from ~ 11 am - 2 pm. The value of electricity is also different during these time periods here.

The houses in my neighborhood that have gotten solar recently vs in the past do have solar panels facing more directions.

Since solar panels typically output less than 50% in the winter vs summer, maybe you could have some extras that are active in the winter but shut down in the summer?

For my own use, I am even considering just having panels that are vertical mounted facing west and east, skipping panels on the roof entirely. Still just kicking around the idea, but don't feel stuck in a rut just because it isn't for everyone.

For that configuration you may be able to use bifacial panels so you hit both sides as the sun moves over. Seems like the way to go to maximize summer production but winter would pretty much require something south facing imo.

 

[mmmmmdonuts]

I have thought of possibly doing an opposite east west facing I just don't know if it pays. As it is I have 76 panels that are ground mounted facing due south. In order to maximize my solar production overall my inverters have extra panels installed on them so they seem to peak out longer but I am not sure how much this helps. This was my output for today. I have wondered batteries to handle the peak loads and charge during the day and discharge on the off solar hours.

 

[Brucey]

So your average util is around 111kWh per day? Do you send a lot back to the grid during the summer? Do you even out over the year or have a deficit?

 

[mmmmmdonuts]

I generate about 29MWh (29,000kWh) per year from solar (gross not net). What I attached is my inverter outputs.
Basically my solar acts like a bank for the power in the summer and in the winter when my geothermal is really kicking in takes the power out of the account. From November to April give or take I use what I banked from the summer. My overall net usage is somewhere around 36MWh with about 35-40% being geothermal for the year give or take but I am looking at getting my first EV soon possibly so it is only going to go up.

 

[HarryN]

For fun I will just throw out some crazy ideas to ponder and see if any of them make sense for your location.

- Since your winter heating is coming from ground loops, is there any way to pump heat / power into the ground during the summer ?

- If the EV will be mostly in the garage to charge, is it possible to set up a dedicated PV / battery system there that does not feed power back to the grid? A 2 kW output charging system might be viable using just 4 x 100 amp-hr batteries fed by as much solar as you can put on it. (assuming that you are charging it during the day time. )

- In my particular case, I am not really worried about electrical use in the winter, because our heat and hot water comes from natural gas, so what I am focused on is panels mounted on the vertical sides of the house vs on the roof. We had a storm damage our roof about 10 years ago and the water coming in is still too much in our memory to risk putting panels up there. On the other hand, mounting panels on the side of the house seems less risky - maybe this can work for you, if nothing else as a trial to see if you can extend the solar collecting hours?

- It might be that a plug in hybrid could be a better choice for your next vehicle than a pure EV. That way you can use the solar when available and normal fuel when it isn't.

- Solar is good, but sometimes it makes sense to consider wind. The wind still blows at night.

 

[mmmmmdonuts]

Basically here is the diagram I have below. I do wonder about possibly up sizing the inverter(s) possibly? I just don't know how much it buys though. Upsize the 6kW to 7kW and 5kW to 6kW. Max input on my 6kW is right around 6.8kW and
Max on the 5kW is 5.43kW input. With efficiencies I maybe able to get a possibile 400-500W per 6kW system more but most likely only during peak hours.

The other issue is warranty with this. Still have 7 of my full 10 year warranty available on this.

 

[mmmmmdonuts]

For fun I will just throw out some crazy ideas to ponder and see if any of them make sense for your location.

- Since your winter heating is coming from ground loops, is there any way to pump heat / power into the ground during the summer ?

- If the EV will be mostly in the garage to charge, is it possible to set up a dedicated PV / battery system there that does not feed power back to the grid? A 2 kW output charging system might be viable using just 4 x 100 amp-hr batteries fed by as much solar as you can put on it. (assuming that you are charging it during the day time. )

- In my particular case, I am not really worried about electrical use in the winter, because our heat and hot water comes from natural gas, so what I am focused on is panels mounted on the vertical sides of the house vs on the roof. We had a storm damage our roof about 10 years ago and the water coming in is still too much in our memory to risk putting panels up there. On the other hand, mounting panels on the side of the house seems less risky - maybe this can work for you, if nothing else as a trial to see if you can extend the solar collecting hours?

- It might be that a plug in hybrid could be a better choice for your next vehicle than a pure EV. That way you can use the solar when available and normal fuel when it isn't.

- Solar is good, but sometimes it makes sense to consider wind. The wind still blows at night.

A few answers on this. Some of which i have pondered as well.

1) I do use the ground loops in the summer for air conditioning with geothermal. So pumping heat in the summer would hurt them.
2) I have thought of this for charging. And have also found out my job offers reasonably low rates for EV charging at 0.12c a kWh which compared to the over 20c i pay is way better.
3) I have lots of wind energy available and have thought of it. It is windy enough at my house where I don't have mosquitos. There are several wind farms not far away from me either.

 

[Brucey]

Basically here is the diagram I have below. I do wonder about possibly up sizing the inverter(s) possibly? I just don't know how much it buys though. Upsize the 6kW to 7kW and 5kW to 6kW. Max input on my 6kW is right around 6.8kW and
Max on the 5kW is 5.43kW input. With efficiencies I maybe able to get a possibile 400-500W per 6kW system more but most likely only during peak hours.

The other issue is warranty with this. Still have 7 of my full 10 year warranty available on this.

View attachment 193869

Doesn't seem worth it for such a small incremental increase in capacity.

 

[mmmmmdonuts]

Doesn't seem worth it for such a small incremental increase in capacity.

I think I agree with you 100%. I was doing the math while I was posting.

 

[Brucey]

Seems like next logical step is adding battery storage if you have excess production.

 

[mmmmmdonuts]

Seems like next logical step is adding battery storage if you have excess production.

I have been thinking about this for a while even as a system backup at some point to sort of act as a generator. Ideally it would be automatic and last maybe 3-4 hours, but the tough part is how to incorporate everything to be automatic and where to store the batteries.

It would be great if I could tie everything together as a backup and as a power source where I could discharge back to the grid.

Basically in the diagram up top is what I have and then the next two is sort of what I was considering.

 

[zanydroid]

What is the reason you want to scale both kW-AC export and kW-DC?

25 kW export seems like plenty with storage. Size storage for how much you need to shift to nighttime in peak power use season. And then install infinite panels on that.