Questions on 25kW Residential Cap in NY

[bcroe]

Very cool. I'm at 38 degrees lat. Out of my 80 Micro Inverters, I had 20 fail on me so far. I raised a stink with the vendor, and they send me 80 more. So I have 60 'free' 250W inverters to play with. I'll pick up a pallet of panels and a bunch of treated 2x4's and have some fun!

So if I wire each pair of E-W panels to a single 250W inverter, I'm wondering what Watt rating panels I should get? 290W or so? Maybe something like this?

http://www.renvu.com/Solar-Products/Mono-Poly-Crystalline-Solar-Modules/UPSOLAR-290W-All-Black-Mono-PV-Module-60cell-35mm

Also, my inverters uses the standard MC4 connectors, so I'm hoping someone makes a MC4 "harness" that allows me to connect 2 panels in parallel (that is what I want as opposed to series right?) to each inverter, and then connect multiple inverters in parallel to form a string.

I would start with 250W panels; tilted for most daily hours, there won't be much (if any) clipping. Evil Bay will sell
you 2 into 1 adapters for parallel; I use them here as taps for my voltmeter. In the end it will be your design, keep
us informed with pictures and results. Put a spacer between treated wood and aluminum panels, which don't play
well. I use a rectangle of linoleum with a hole for a SS bolt. At 42 degrees lat. here. Bruce Roe

[pclausen]

Very cool. I'm at 38 degrees lat. Out of my 80 Micro Inverters, I had 20 fail on me so far. I raised a stink with the vendor, and they send me 80 more. So I have 60 'free' 250W inverters to play with. I'll pick up a pallet of panels and a bunch of treated 2x4's and have some fun!

So if I wire each pair of E-W panels to a single 250W inverter, I'm wondering what Watt rating panels I should get? 290W or so? Maybe something like this?

http://www.renvu.com/Solar-Products/Mono-Poly-Crystalline-Solar-Modules/UPSOLAR-290W-All-Black-Mono-PV-Module-60cell-35mm

Also, my inverters uses the standard MC4 connectors, so I'm hoping someone makes a MC4 "harness" that allows me to connect 2 panels in parallel (that is what I want as opposed to series right?) to each inverter, and then connect multiple inverters in parallel to form a string.

[AzRoute66]

I so love that graph.

[bcroe]

Exactly. I was just posting the above reply where I put that down as an
alternative option. So how did you determine the optimal angle for the E and W facing panels?

Your app may be more difficult with micro inverters. To use the same inverter plant, you would need to
tie 2 or 3 panels in parallel tied to a micro inverter. Need the paralleled panels all be the same size,
they aren't here? Using strings here, I don't have a clearcut micro design. Maybe 2 panels tilted east
and west could be optimized for a micro. Here is an experiment with varying tilt of panels facing E, S,
and W. The sum of the E and W panels has about the same peak as the S panel, but much more over
the rest of the day. Bruce Roe

PVm17Jn16.jpg

[pclausen]

You might back up to my 28 June post on this thread. My system can only deliver 15KW, but it
may exceed 3000 KWH summer months. Adding panels to catch the rising and setting sun
won't increase your 20KW peak, won't require more inverters or plant, but will extend the
length of your productive day. Bruce Roe

Exactly. I was just posting the above reply where I put that down as an alternative option. So how did you determine the optimal angle for the E and W facing panels?

[pclausen]

My current system consists of 80 panels with micro inverters. 6 strings totals, each going to a 20A breaker in a sub-panel in my shop located some 200' from the service entrance.

Somewhat dated schematic of my setup (doesn't include the 24 panel ground mount that was added about 1 month after I first went online):



Here's the 400A service entrance to the house:



I'm feeding the shop 200A sub-panel through the old 400A meter base at the shop (I used to have separate 400A services, one to the shop and one to the house). Here's the pass through at the shop:



Nothing is currently connected to the PV Subpanel tabs. As stated above, all PV connections are via 20A breaker in the shop sub-panel on the other side of the wall shown in the above pic.

So I have the infrastructure in place to add another 20kW worth of solar to the taps show above. I'd mount another dedicated panel outside next to that 400A meter base at the shop.

So this is the plan I'm currently on with my POCO:



And my other 2 choices are:



And:



I'm not sure what they mean by Demand Charge per kW on the larger power service plan, but the usage and energy charges per kWh are certainly better than the other 2 plans.

Depending on what I can and cannot do within my current installation, it might make sense to re-install a separate 4000A service to the ship, move some of my miners down there, and do separate solar arrays for that meter. My original plan was to keep both 400A services and tie the solar into the shop service, but since my primary service was at the house some 200' away, and given my generally very low usage at the shop, the solar had to be tied to the house service. So I had to dig up the 500MCM that was running from the shop to the house and run it up to the house instead.

I suppose another option would be to just leave everything the way it is, and setup a bunch of East and West facing panels, and connect those to a regular inverter. This way my mid day peak would stay the same, but I would add move production before and after high noon, and keep doing that until my mid-day peak reach, say 28 kW.

I'm mining various alt coins (ZCash, ZenCash, Eth, etc) and holding some and converting some to BTC. I'm running GPU rigs exclusively right now, but plan to add some ASIC miners as well.

[bcroe]

I currently have a 20kW system which matched pretty closely what my consumption was. I in-fact was starting to build up a "bank" with the POCO (I have a net metering agreement with them). But then I got into crypto coin mining and currently have about a 8 kW draw 24/7 from my mining rigs, plus everything else in my house.

My POCO (State of Virginia actually from what I understand) has a 20kW limit for residential systems. But, given that I'm always shaving 8 kW off whatever solar production makes it to the meter, I figured I'd be safe going to a 28kW system, at least, without them ever figuring it out.

Before mining, I was making and consuming about 2,800 kWh a month. Now I'm still making about 2,800 kWh, but my consumption has jumped to almost 10,000 kWh. So is the POCO really going to care if my peak delivery back to them goes above 20 kW at high noon each day?

You might back up to my 28 June post on this thread. My system can only deliver 15KW, but it
may exceed 3000 KWH summer months. Adding panels to catch the rising and setting sun
won't increase your 20KW peak, won't require more inverters or plant, but will extend the
length of your productive day. Bruce Roe

[peakbagger]

I expect that you would be talking to the utility interconnect group. They may be amenable to installing protective current relaying to trip the system off line if it exceeds the rated backfeed current. It usually means a couple of calibrated utility grade meters connected to the utility breaker. It may cost you tens of thousands of dollars as you will need an interconnect study which is oriented towards large power generators. In general once you go commercial the utility gets considerably more difficult and expensive to deal with.

What you are getting into is that many utility substations were not designed to have generated power entering the station, they were designed to distribute power from the grid and may not be equipped with protective relaying to ensure that power being independently produced. Your inverter is supposed to be designed to prevent exporting when the grid id down but they cant trust your equipment. They may need to upgrade their substation ad may require you to install something called Direct Transfer Trip which is something you really dont ever want to deal with (lots of bucks). Regulators "twisted the arms" of the regulators to make small solar simple to connect but the trade off was there would be an upper limit on output and unfortunately it looks like you want to trip the limit so you get to deal with the commercial side.

[cebury]

Before mining, I was making and consuming about 2,800 kWh a month. Now I'm still making about 2,800 kWh, but my consumption has jumped to almost 10,000 kWh. So is the POCO really going to care if my peak delivery back to them goes above 20 kW at high noon each day? I suppose I can discuss converting to a commercial account with them, but that will only drop my gross kWh rate from $0.07 to $0.04 and the base fee each month is higher and there is this thing they call peak load that will start taking in.

Yes. When will they notice? Dont know. There are technical reasons the limits are in place. They arent going to trust your promise that you will always consume the extra 8kw of juice from your larger 28kw system. They have to ensure their infrastructure supports your system and wont negatively affect quality or reliability down the line. Just as I am sure you realize you cant just add extra panels to make 28kw. Your inverter will need upgrading, your wires will need upsizing, service panel changes, or you will need two independent systems. If your intention is to go larger, like 35kw, that is not trivial even though its only a 10kw upgrade.

I would dig into the billing for commercial Peak Load because that may affect you more than you realize, not sure for your state.

So which crypto coin minjng you doing? Bitcoin?

[pclausen]

Sorry for resurrecting this old thread. I'm in a similar pickle. I currently have a 20kW system which matched pretty closely what my consumption was. I in-fact was starting to build up a "bank" with the POCO (I have a net metering agreement with them). But then I got into crypto coin mining and currently have about a 8 kW draw 24/7 from my mining rigs, plus everything else in my house.

My POCO (State of Virginia actually from what I understand) has a 20kW limit for residential systems. But, given that I'm always shaving 8 kW off whatever solar production makes it to the meter, I figured I'd be safe going to a 28kW system, at least, without them ever figuring it out.

Before mining, I was making and consuming about 2,800 kWh a month. Now I'm still making about 2,800 kWh, but my consumption has jumped to almost 10,000 kWh. So is the POCO really going to care if my peak delivery back to them goes above 20 kW at high noon each day? I suppose I can discuss converting to a commercial account with them, but that will only drop my gross kWh rate from $0.07 to $0.04 and the base fee each month is higher and there is this thing they call peak load that will start taking into account.

[aleenoor]

My suggestions to the OP:

1. Can you get a 2nd separate service for your castle ? say your in-laws / servant / peasant accommodations ? That way you can you can get 2x 25kW systems.
2. If above doesn't work, I would take a serious look at reducing your consumption. Its always cheaper to use less. Upgrade HVAC, Pool Pump, W/H to be more efficient. Upgrade the heck out of insulation / windows etc
3. Another option is to add an off-grid system on top of your 25kW grid tied system. Move predictable day-time loads like pool-pumps, water-well etc. to the off-grid system with a smallish size battery backup.

I would find out if 25kW limit is on the AC size of DC size. If it is AC, then by all means, get a 30 to 35kW DC system with an AC output limit set at 25kW. Your system will exceed 25kW 1% of the times so not much will be lost.
Good-luck.

[peakbagger]

I think the key thing is net metering access. If you want to go bigger you become a merchant plant and I guarantee you the utility is not going to pay you a lot for any surplus and will mostly likely charge you a demand fee on top of any power you need to buy when you are importing. Odds are you need to shell out for a PE to sign off on one line and interconnect application. The utility will probably also decide that they are going to have you pay for upgrades to their system in order for you to interconnect. Heck if they want to be cruel they can hit you up with the cost and cruelty to put in a Direct Transfer Trip and a 3VO protection upgrade to a nearby substation.

Homeowner PV regs usually set up a "sandbox" for the little guys to play in where everyone plays nice, once someone wants to leave the confines of the sandbox, the gloves are off and the cost and complexity to do an interconnect increases exponentially. Some solar friendly states have solar friendly rules for intermediate systems so you may get lucky but doubt you will find a utility that will net meter al large system. Then again Mass seems to do it via SRECs to big developers.

[GRickard]

Here you are allowed 30kw per meter. Theoretically, if you were to put in a second service for just your HVAC loads, that may allow you to put 25kw on each meter. Extra kwh however will not transfer between accounts. Check your POCO's net metering tariff.

Greg

[bcroe]

Here in the Wild West the PoCo cares about the inverters & AC wiring that feed into their system; over
panelling is not a concern. Your results may vary. Bruce Roe

[J.P.M.]

Looks like NY State law sets the 25 kW limit for net metering, and the standard permitting guidelines are based on DC size, which pretty much kills all the more creative approaches discussed here. It may be worth verifying with the specific AHJ and Poco, but it doesn't look good.

If the OP is willing to forgo net metering, a larger system could be installed, but it is hard to see how that would be cost effective.

Similar to what Jflorey2 writes, I'd size the system right and then use inverters and system design that limit output to the grid at 25 kW or less. Not sure how cost effective or cost ineffective that might be, not to mention increased maint. hassle/PITA.