Solar Quote Oahu Hawaii

[shaka]

Ok, I limited my choices to the following systems below. I plan on having Vendor 1 to install my solar hot water system. Another thing is they need 1K deposit to be put in the HECO NEM queue. Vendor 2 has been pretty responsive after we met. No deposit needed to be added to the NEM queue. Also my neighbor an installer with the company.

Only difference between the Systems 1 & 2 for Vendor 2 are the inverters.

Your advice is greatly appreciated!

Vendor 1

System 1
8.37kW
(31) Solarworld 270
(31) Enphase M250 Microinverters
Price Per Watt - $4.00
Total Price - $33,480.00
Price after Federal & State credits - $13,718.00

System 2
8.25kW
(30) Solarworld 275
(31) Enphase M250 Microinverters
Price Per Watt - $4.00
Total Price - $33,000.00
Price after Federal & State credits - $13,550.00

Vendor 2

System 1
7.95kW
(30) LG 265
(2) SolarEdge 3800
Price Per Watt - $4.01
Total Price - $31,895.06
Price after Federal & State credits - $11,902.56

System 2
7.95kW
(30) LG 265
(30) Enphase M250
Price Per Watt - $4.04
Total Price - $32,128.34
Price after Federal & State credits - $13,317.20

[russ]

Did you still need HECO approval to use the batteries? One of the companies I got an estimate from said HECO still needs to approve your battery backup.

Battery backup means grid tie

[wwu123]

Just had another estimate today with a guy that matched an LG270 with an Enphase M215. The PTC for LG270 is 245.1w which is well over the 225w max that I've read others clip at with this inverter. Am I missing something here or is this a bad combination?

My crude understanding is the PTC is only achieved under the test conditions but also when the sun is perfectly perpendicular to the panel's flat plane (i.e. "straight above"). 225/245 = 0.92 which means you'd only clip if you came within 23 degrees of the panel's vertical axis. So if for some reason you could only mount your panels facing straight up on a flat roof, at your latitude 21 deg you'd only be clipping for a few hours on a few days in June. Or if you were tilted but on a north, west, or east roof, you might not come within 23 deg to clip significant through the year.

But if you're south-facing tilted towards your optimum of around 21 degrees, it seems you'd be clipping during peak generating hours mid-day for significant periods of the year.

[shaka]

In reality, they can't stop you from going off grid. HECO tried a couple years ago to keep people from doing just that, but they failed. Not sure about Ewan, but they already stopped issuing permits for Waianae for grid tie application PV.

Did you still need HECO approval to use the batteries? One of the companies I got an estimate from said HECO still needs to approve your battery backup.

[bcroe]

Power management problem

There is no way else to do it currently for my area. They will not
issue permits or interconnect agreements. We can start talking about the efficiency of the
systems all day long, but the utility has a real problem with all the extra generation occurring.

The only time that the transfer switch would need to operate is when the battery falls below a
threshold. Just like using a gen autostart to recharge the batteries.

So I think you are saying, you are going for an essentially off grid system. If all your energy
flows in and out of batteries, the cost is going to be even more than your electric rate. If a lot
of PV power will flow directly to the load, the battery costs are reduced, but your power
management problem balloons. I was hoping to see details of equipment, loads, numbers.

You could simply use a battery charger to maintain a minimum level, no need to transfer.
Bruce Roe

[silversaver]

Just had another estimate today with a guy that matched an LG270 with an Enphase M215. The PTC for LG270 is 245.1w which is well over the 225w max that I've read others clip at with this inverter. Am I missing something here or is this a bad combination?

It might clips depends on your orientation, pitch or shade.

[shaka]

Just had another estimate today with a guy that matched an LG270 with an Enphase M215. The PTC for LG270 is 245.1w which is well over the 225w max that I've read others clip at with this inverter. Am I missing something here or is this a bad combination?

[Naptown]

Not having thought all the way through this it is most likely possible.
You would need to use something like a Xantrex XW series inverter set to load shaving (not in sell mode)
The only issue I haven't worked around is keeping the battery sensor from reading the higher voltage when it is in charge mode and keeping it off till the batteries reach at least absorb state.
Opportunity loads could be introduced also like the diversion on a wind system to preheat water when system is producing more than is being used.
It is going to be expensive no matter how you look at it.

[boostinsteve]

Using a transfer switch twice a day sounds difficult. Can this be done without
batteries, or at least with very few batteries? Is it all automatic, equipment for
this sort of service available? Inverters on all the time waste a lot.

Its a huge power management problem. Without a grid tie, a LOT of PV energy
may not get utilized when available. I am imagining your whole load system
being designed around the time of day. Perhaps the primary problem is getting
through each night; here its a matter of getting through winter. Bruce Roe

There is no way else to do it currently for my area. They will not issue permits or interconnect agreements. We can start talking about the efficiency of the systems all day long, but the utility has a real problem with all the extra generation occurring.

The only time that the transfer switch would need to operate is when the battery falls below a threshold. Just like using a gen autostart to recharge the batteries.

[bcroe]

Power management problem

The only way we have found a good resolution is moving the
house to off grid, and using a transfer switch to isolate from Heco, and use the off
grid system as the primary source, Heco as the secondary source.

Using a transfer switch twice a day sounds difficult. Can this be done without
batteries, or at least with very few batteries? Is it all automatic, equipment for
this sort of service available? Inverters on all the time waste a lot.

Its a huge power management problem. Without a grid tie, a LOT of PV energy
may not get utilized when available. I am imagining your whole load system
being designed around the time of day. Perhaps the primary problem is getting
through each night; here its a matter of getting through winter. Bruce Roe

[boostinsteve]

Yup, I live in Ewa Beach. I'm not too sure if my association will even let me have a battery system. Will HECO even let you off the grid entirely? I gues if you use them as a secondary it's ok?

In reality, they can't stop you from going off grid. HECO tried a couple years ago to keep people from doing just that, but they failed. Not sure about Ewan, but they already stopped issuing permits for Waianae for grid tie application PV.

[shaka]

Are you out here on the Leeward side of the island? I am in Waianae and can tell you it is getting extremely difficult to get the permits. I was one of the last few that got the permit very easily.

I am working with a couple of PV companies, and Heco on a good resolution, but to be honest, it isn't looking good. The only way we have found a good resolution is moving the house to off grid, and using a transfer switch to isolate from Heco, and use the off grid system as the primary source, Heco as the secondary source.

Yup, I live in Ewa Beach. I'm not too sure if my association will even let me have a battery system. Will HECO even let you off the grid entirely? I gues if you use them as a secondary it's ok?

[Volusiano]

I've been thinking to still target the solar hot water and the pool pump, as you suggest. I'm just not sure whether the dealer network is mature on variable speed pool pumps. I'd like to take it further and take the pool pump off-grid with three solar panels and a DC pump, just let it run whenever the sun's out with enough insolation - seems like one way to circumvent the utility PV restrictions, and there's seems like a solar supply company that sells panels and parts. Sadly the solar water pumping forum here on Solarpaneltalk seems hostile to any discussion of directly driving pool pumps.

That's a good idea to isolate the pool pump and the solar hot water from the grid.

By the way, there are only a few companies that make variable speed pump -> Pentair, Hayward, Jandy... You can google them up and research them. Many states, AZ especially, don't even allow new pool construction to use single speed pump anymore. So most new pumps sold in the market nowaday are either dual speed or variable speed anyway.

If you have water features in your pool like an in-floor cleaning system or big water falls, you may need the high speed pump to do the job. But variable speed pump like Pentair is 3HP and capable of running at full speed 3450 RPM 2550 W anyway. The beauty is for the rest of the time when you don't need to activate that water features, you can run at the lower speed and conserve.

[wwu123]

Tell your sister to get a variable speed pool pump if she doesn't have one already. I used to have a 3HP single speed pool pump and it easily consumed 30% of my overall usage (and I have everything on electricity, no gas in our 'hood). It consumed 2550 W when running at 3450 RPM. After I switch to a variable speed pump, the new pump consumes 260 W when running at 1400 RPM. That's a whopping 90% reduction in energy. OK, I have to run it 2.5x as long for the same water turn-over, but that's still a 75% energy reduction for the same turn-over.

I've been thinking to still target the solar hot water and the pool pump, as you suggest. I'm just not sure whether the dealer network is mature on variable speed pool pumps. I'd like to take it further and take the pool pump off-grid with three solar panels and a DC pump, just let it run whenever the sun's out with enough insolation - seems like one way to circumvent the utility PV restrictions, and there's seems like a solar supply company that sells panels and parts. Sadly the solar water pumping forum here on Solarpaneltalk seems hostile to any discussion of directly driving pool pumps.

[boostinsteve]

Yup! before September it was relatively easy to get solar installed. Now they changed the rules because of the solar saturation. You have to get approval from HECO to get solar installed now. The companies I talked too said that only 10% of the people have gotten approved. Most have been waiting since September. I am also pricing solar hot water systems so at least I can get savings immediately instead of waiting in limbo land for HECO.

When I used to live in the Bay Area I would never have thought of getting solar but now that I moved to Hawaii electricity costs arm and a leg here.

Are you out here on the Leeward side of the island? I am in Waianae and can tell you it is getting extremely difficult to get the permits. I was one of the last few that got the permit very easily.

I am working with a couple of PV companies, and Heco on a good resolution, but to be honest, it isn't looking good. The only way we have found a good resolution is moving the house to off grid, and using a transfer switch to isolate from Heco, and use the off grid system as the primary source, Heco as the secondary source.