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Powerwall 2 Installs in Hawaii

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Aloha all. Sorry I didn't see these questions earlier. I put in a request to my HECO person if they are willing to accept calls.

This may seem quite surprising, but there is a cadre of people within HECO who really are interested in figuring out the right way to use solar and batteries to complement the grid. There is a significant study going in Hawaii which myself and two of my neighbors are participating in. Since Hawaii leads the nation in solar penetration, we are actually on the cutting edge as a community.

The problem with high solar penetration is it creates a high voltage situation on the neighborhood circuit / transformer. Aka when he sun is really high and there are no clouds, everyone's solar is at max output and often people aren't home so consumption is low. Net result is a lot of power flows back into the grid.

So, the notion is that advanced inverters can be tied into an advanced control system which is responsive to high voltage on the neighborhood circuit. The advanced inverters allow for curtailment during this time period of ultra high productivity. I'm not real hot on this curtailment aspect, but the pilot lets me get my solar faster than replacing the transformer in my neighborhood, and I can always opt back out, so, I'm in for this pilot.

However, what's most interesting is the battery pilot. In this pilot, the notion is to allow the batteries to absorb peak production and thereby prevent this high level of back flow onto the grid thereby also preventing this high voltage situation. The conundrum for me is that since I have NEM, effectively the grid is my battery so, there is less justification for multiple PW2's. Thus, PW2 quantity is really equal to runtime when the power is out. With battery technology being relatively new, it does make some sense to not buy too many batteries right now if one believes next year another big upgrade to the PW will occur.

The cool thing about the Tesla PW2 is when you install a system, you also get a gateway. The gateway is super smart and super capable. It can mimic the sine wave of the grid. I posted previously in the PW2 thread on this, but basically, when the grid goes off-line the PW2's kick in and the gateway cuts the house off from the grid and can mimic the grid. The mimicking of the grid sine wave allows your solar to boot back up and essentially then you're running off solar (if during the day).

There's more in the PW2 thread, but hopefully this answers people's questions.

I'm quite impressed though with HECO for trying to find advanced solutions for high solar penetration and I am working with them very closely to try to get this figured out.
 
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Jeffrey, very interesting. I too am NEM. You said, stay tuned. Where? How please?

Akikiki, I meant I'd post regularly...which I haven't! But seriously, my solar phase 2 is in the process of installation, so there hasn't been a lot to post until this week.

Feel free to PM me or I'm happy to meet with you and PapaFox and dpodoll for coffee one day if you like so we can all discuss.
 
So I ended up not pulling the trigger on PV + powerwall 2, back in 2017, when customer grid supply was paying $0.15/kWh, and now I’m kicking myself because the current customer grid supply plus only pays $0.10/kWh. But since the federal tax credit begins to phase out in 2020, here I am again, re-contemplating solar systems.

Question for the group: any experience with Tesla (solar city) for installations in Hawaii? They get awful yelp reviews, but since Tesla recently announced price cuts on their solar panels, I’ve requested a quote from them.

Also, can anyone with powerwalls confirm whether an owner can put the system in storm watch mode manually, or are you at the mercy of Tesla to switch it on?
 
One more question: does anyone regret getting battery storage in Hawaii?

I’m looking at two or three powerwall 2 configurations. While I don’t think I’d be able to fast charge my Tesla from the batteries, I’m pretty sure I could slow charge my Leaf overnight, which would really reduce my reliance on the grid...
 
I'm also considering Tesla to expand my current system due to the price drop. I had a quote in hand for a system (additional panels + 1 powerwall) from another installer, and the Tesla system was $8k cheaper.

Also, the federal tax credit drops 4% on 1/1/20. Your installation must be "started" by 12/31/19 to claim the full 30% credit.
 
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I'm not ready to add Powerwalls to mine. But I am working on a panel upgrade that will remove 26 200 watt panels of 36 and replace with 25 330 watt panels. 25% of my Enphase microinverters have failed in the past few years. They no longer cover the labor for the replacement, so I am getting away from Enphase. I'm also removing my Enphase microinverters and replacing with a Solaredge single inverter. This will bump my system from 5.72 kw to 11.2 kw and still be approved by HECO under my existing NEM agreement - while we are still getting the 30% fed & 35% state tax credit. Gotta get what we can while the bennies are maxed.

Anyone thinking of a panel upgrade should contact HECO and ask them for a most recent copy of your NEM approval letter. If yours follows the pattern, you will find that when HECO approved your system, it was approved for 1 kw (nice round number) more than was installed. Get your copy. This gives you some flexibility in your decisions. Also, its your house that has the NEM agreement, not your account. If you sell your house, the NEM agreement stays with the system. The letter documents your proof.

Hmm, makes me wonder. If I sold my house, and removed my system, maybe if I bought a house in the same part of the grid, I could install (move) the system to it and retain the original NEM agreement. Comments?
 
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Akikiki, Do you mind sharing the cost of that Solaredge inverter? How about the removal of the microinverters and wiring up the new inverter? I'm in a similar boat because I have those wretched Enphase microinverters that keep failing. Seems to me that with the addition of the panels you could also get some credit on a battery if you included it. The thing about the battery is that it would allow you to still harvest solar power in the event of the grid going down. Without a battery, your house solar panels would be of no use until the grid came back up. Thoughts?
 
Papafox, I've sent a request for the installed cost of a low end and my sized Solaredge inverter to my contractor. You are welcome to contact her directly, if you wish, as your home installation will vary depending on build and panel configurations among other things. Creative Energy (in Kailua), [email protected] 262-2137.

You notice I mentioned optimizers too? One optimizer replaces one microinverter. Solaredge's explanation of an optimizer.

Yes, you are correct about adding batteries qualifies for fed/state tax credits, if you are adding or removing/installing panels. Removing and adding new panels, mine qualifies as a new installation and tax credits will be in effect. However, according to my contractor and tax person, removing Enphase and adding Solaredge is not eligible for tax credits.

I agree with you ref batteries. I want to do batteries. I waiting on some improvements in batteries tech. What specifically? I don't know. I do trust the advice and options of my contractor. She's not interested in selling me a battery backup system - yet. That's enough for me to recognize that I need to wait. Once my upgrades are complete, I am plug and play battery ready.
 
Papafox,

The SE inverters range from $1100 to $2000 depending on the size depending on system size/requirement, this does not include the pricing for upgrading the warranty to 25 years which is between $500 - $1000 depending on the inverter. Optimizer pricing varies on which optimizer is used which is between 320-400 which is dependent on the module wattage; pricing is between $75-$125. This doesn’t include the Red/Black PV wire or gateway(ZigBee) for monitoring.
 
Thanks Akikiki. I have spoken with Nikki and she gave me a quick quote. My system right now is close to my total electrical needs, though, so I need to look at alternatives too. Enphase offers a legacy microinverter replacement program with nice discounts and 7th generation microinverters, and so I might consider that approach.
 
Yes, I have read up on that Enphase replacement program. Read slightly between the lines. You will notice they leave themselves an out. There's a point when they will no longer pay for the labor when replacing the component. That's exactly the same place we are now. They warranty and provide a replacement for the M210 microinverters that are failing frequently. I believe we could jump ahead 5-7 years and we will see the same pattern then that we do today. They will warranty the newer microinverters used on replacement microinverters program, but not the labor. Current labor per failed component is $150. What will it be in 5-7 years? $225-250? Not me, getting rid of Enphase stuff while I can.

I current PV production is adequate for my uses. But while I can, while tax credits pay 65 cents on every $1, I am going to increase my production 40-45% to future proof my house for the next family that will live here and make my house more price-worthy.
 
Anyone go with Tesla/SolarCity for their systems? I’m trying to get a quote through their online configurator, and it’s showing some wacky numbers for Hawaii. An 8 kW PV system, for example, says that it will generate an average 19 kWh per day, in Hawaii, but closer to 30 kWh in most other states, including cloudy regions like the pacific NW. Because of this, it’s recommending a 12 kW system with 4 powerwalls for my home, which I know is ridiculous based on quotes I got from local providers. If I downsize it to a comparable sized system to the ones that the local guys recommended, Tesla is much cheaper per watt, which is why I’m still tempted to go with them, in spite of their awful yelp reviews.

Was hoping someone here might have some experience with them?
 
I would go with your common sense approach. Get what makes sense to you, and since it's scale-able, you can go back and add to it later if your own estimate it turns out is not enough. But the sooner you do something to offset/stop paying so much to HECO, the sooner you gain some independence. Especially while the fed tax credit is at 30 in 2019.
 
@Akikiki , I've decided on a unique solution to my microinverter dilemma. The cost of having someone replace one or two inverters at a time is too expensive, and I wasn't in a financial position to just start from scratch on a new solar panel layout on my roof. The answer? My warranty is still good for another 8 years or so on the microinverter hardware and the system is still performing well. I've decided to replace the defective microinverters myself. Enphase is okay with the plan and I've just done another RMA to get all remaining microinverters functioning.

My roof is painted white, is one story high and fairly flat, so there's little risk in doing the work myself. I need a helper with panels that need to be removed for changing the inverter, but with practice one can get it down to little over half an hour per panel.

As for batteries, I'm thinking that once Tesla incorporates Maxwell's technology in their PowerWalls, we could see nearly double the longevity of the batteries, so I may just wait for that next generation of PowerWalls. On the other hand, if we get hit with a hurricane and those powerlines running over the Koolaus get knocked down we could be looking at months before power is restored, and so a couple PowerWalls sooner might make sense.
 
Thanks guys. I’m still waiting to hear back from them, after submitting an order through their website. I think my dilemma might be that I need a system size between 8 and 12 kW, so I’ll either be under or oversized with Tesla. Hopefully I’ll find out soon.
 
@Akikiki , I've decided on a unique solution to my microinverter dilemma. The cost of having someone replace one or two inverters at a time is too expensive, and I wasn't in a financial position to just start from scratch on a new solar panel layout on my roof. The answer? My warranty is still good for another 8 years or so on the microinverter hardware and the system is still performing well. I've decided to replace the defective microinverters myself. Enphase is okay with the plan and I've just done another RMA to get all remaining microinverters functioning.

My roof is painted white, is one story high and fairly flat, so there's little risk in doing the work myself. I need a helper with panels that need to be removed for changing the inverter, but with practice one can get it down to little over half an hour per panel.

As for batteries, I'm thinking that once Tesla incorporates Maxwell's technology in their PowerWalls, we could see nearly double the longevity of the batteries, so I may just wait for that next generation of PowerWalls. On the other hand, if we get hit with a hurricane and those powerlines running over the Koolaus get knocked down we could be looking at months before power is restored, and so a couple PowerWalls sooner might make sense.

Wow. DIY. Wow. I wish for you the best. I'm sure you know, I just want to remind you. Document the serial number of what comes off and what goes on where, so your array can be updated. (I'd also take a picture of each.)
 
Wow. DIY. Wow. I wish for you the best. I'm sure you know, I just want to remind you. Document the serial number of what comes off and what goes on where, so your array can be updated. (I'd also take a picture of each.)
Aikikiki
you can just do the documentation and pics when you are up on the roof helping p fox with his panels.