Additional solar panels

I have not expanded my solar installation but I seem to recall an article or email from my solar company talking about it. (I can't seem to find it at the moment, unfortunately.) IIRC they basically said you can't typically just add panels (and a bigger inverter); the new system would be separate. Some of that might have to do with how the incentives are managed here in MA, though.

Probably your best bet is to call your installer and ask them the question - they'll know more of the specifics for your area.

 

The federal solar property credit isn't a one time credit, so that would still apply at the least. Everything else varies so much state to state and utility to utility that you'll need to talk to your local installer. (Incentives in MA have changed completely in the last year, and any new panels have to be treated as a separate system)

 

We added panels to our PV array after we bought our Clarity.

In Washington, as in Massachusetts above, we needed a separate generation meter because the incentives have changed. The output of the two arrays is then combined before going into our service panel.
The 30% federal tax credit should apply.

We also had them add a 240V circuit to a NEMA 14-50 outlet for a level 2 charger, which they did for $350 -- getting a permit for the new circuit would have cost over $200, so it was a no-brainer to have them do it. Our service panel is in the garage, so running the circuit was simple.

 

The solar system we had installed seven years ago has a micro inverter on each individual panel, so ours would be easy to add to. Having a micro inverter on each panel ensures that the whole system doesn't lose efficiency if there is a problem with one panel.

 

Adding solar panels is doable if you have the ground space. However, if the original wiring and inverter are sized for the original system, you would not necessarily realize any savings in materials and labor costs when adding more panels. You might ask the installer about converting your current panels to use micro-inverters because that does make it easier to add panels in the future and it ensures maximum output for the system as panels get shaded, etc. as well as to account for different output of different panels. It might not be too much more cost, if you have to replace the original inverter anyway. In any event, it's a complex question to add panels, but for sure doable. Go for it! It feels great to run a PHEV on solar

 

Our initial inverter turned out to be too small for our system (installer underestimated the efficiency of the panels). We upgraded the inverter and as long as they were working on the system had them install two additional panels. So our system was able to have more panels added.

I believe it may depend on the type of system you have. Ours is a SolarEdge with Optimizers. Perhaps a system with micro-inverters would be a different story.

I too agree that the solar tax credits are not a one time thing. We will be able to claim the upgraded inverter and two panels this year.

 

You'll want to do some research for your specific electric utility company on what adding solar panels might entail. You may lose grandfathered rates and terms and be forced to switch to newer TOU plans, which may make the overall system less beneficial. Eg. SCE had very nice Net Metering rates for solar systems installed more than a couple years ago, whereas all new installs in the last couple years are on NEM 2.0, which also requires a TOU plan.

 

Our SolarEdge had enough capacity to add an extra 10kwp (we had 6, and now have 10 - so there's still capacity left to grow). We still had to go through all the rigamaroll with permitting, SDG&E, etc. So it was like getting a whole different system in that respect. However, the system itself expanded without issue. We have a battery coming as soon as LG starts cranking them out again. So that will be another "goaround" with permitting and the PoCo. We don't get any state or local rebates in this part of CA anymore (except for the battery via SGIP), but the 30% federal tax credit is still in play (for both the add-ons and the battery - if it ever gets here). YMMV in NY, but as long as your inverter has extra capacity, it should not be a big deal to expand your system. Also, as mentioned above, you may hit a speed bump with net metering if NY is in that arena. Because of all the permitting needed here in CA, the PoCo knows when you are up to something with your system, and they're keen to reset your billing option - particularly as they relate to time of use schedules and NM 2.0. However, within 5 years, even the grandfathers will be on TOUs along with everyone else, and they'll probably be charging us in 15 minute increments - an "instantaneous demand rate" system is where they'd really like to be.

 

We just completed adding 7 panels with micro-inverters to our 5 year old 12 panel set on a separate inverter. The two arrays are combined with a unit called a "combiner"! Had immediate increase in power generated. At same time had a Tesla Powerwall installed awaiting signoff by SCE to commission. With the system fully online I will be able to operate during a power outage due to a Gateway panel that monitors the incoming/outgoing power. Some local vendors claimed this would not be possible or allowed by SCE. Wrong on both counts.

 

Curious about this notion of "forced to switch to newer TOU plans". I actually did get a call from my local utility (LADWP in L.A) regarding switching to TOU. They seemed to imply that it would be more cost effective for me with my solar panels. I was not sure I understood exactly what they meant and haven't done anything so far. Are there downsides to TOU? I thought that if you could program your car charging, clothes drying etc at night it could be a real cost savings.

 

Wow, it’s really different for you guys in California. All I had to do to install a 9.2kW system was to get an electrical inspection from my city passed. No restrictions on size, or anything else. I’m now grandfathered in with net-metering for 25 years. (My non-progressive money grubbing utility is trying to do away with that)
According to my solar installer, in my area, it’s very easy to add my last two panels with regards to government and utility. No permit needed (wiring approved at first inspection for the added power) and no permission of utility needed since with optimizers on every panel, it’s just plug and play on the roof with nothting changed elsewhere.
Adding panels, electrically speaking, depends on the size of wiring going to the inverter and the capacity of the inverter. If you go past the inverter’s capacity you will get clipping and lose efficiency; in effect negating some of the power gained by adding panels.
My roof, wiring, and inverter allow me to add two more panels and they are on order.
So in coal country I don’t get any state, local, or utility rebates but I do get net-metering and no restrictions on what I install.
In Feb, the 2 added panels will bring me up to 9.9 kW and will cover 100% of my power needs (car and house). And I sized it so that the small yearly degradation in PV efficiency will be offset when I have to replace my old inefficient AC with a heat pump in a few years. I’ve calculated that I will be able to zero out calendar year energy usage for the next 25 years. And my whole system (StorEdge and Panasonic panels) is warranted for efficiency and replacement for 25 years. Will add battery back up when battery prices come down. ROI is 10 yr due to $0.10/kW low rates and no rebates other than Federal.

 

KKen,
EVERYTHING is a giant regulatory hassle in California. More regulations here than any state in the country.

 

You need to check closely their rates and how you actually use electricity. We're on a TOU plan with Edison that has three rate periods...On Peak, Off Peak and Super Off Peak. On and Off Peak rates are higher than the two-tier TOU, but the Super Off Peak (10PM - 8 AM) is really cheap. Plus, for each KwH within the baseline, they credit back 8 cents. So, it costs us 5 cents winter and 4 cents summer per KwH to charge our Clarity. We use more total electricity than before the Clarity came along, but the cost is sometimes less in a month than on the old TOU rate. We have a small solar array (2K) and we really minimize our electric use during the day, particularly during the 2PM - 8PM On Peak period.

Only you can figure what would work best, but looking forward, everyone in Commiefornia will be forced onto a TOU before too much longer (3-5 years).

 

This is a complex question that is very site and utility specific. For example, if there are large loads you can't time-shift and end up paying more per watt for those, is there any overall savings? My utility pushes TOU hard because they would like to cut down the peak usage on summer afternoons and they figure the more customers that shift loads to night the better. BUT, it's not necessarily an overall cost savings for the customer because they also have to maintain their income stream. You'll have to get deep into usage and rates for your situation to figure out what's best, especially if there are "newer TOU plans" that may or may not benefit the customer bottom line. And, your solar panels may or may not help with the TOU issue.

 

We have contracted to have another 7.5KW of solar panels installed on our garage in May to augment the 3Kw of panels we already have on ground mounts in our yard. This will primarily benefit the Clarity, so to speak, but the power will be available for general use in our house too. We are taking advantage of the last year of grand-fathering into net-metering with our utility and the last year of the full federal tax credit for solar.

 

It is obvious that the energy consumption of the air conditioning system with the parallel use of
solar panel to run air conditioner will decrease. In addition, the use of thermal energy from the Sun can expand the scope of absorption refrigeration machines operating on safe working fluids - water or brine. The main advantages of a solar-powered air conditioner are the absence of energy costs, quick payback, versatility, and simplicity.
Of course, it has its cons and pros.