Possible to Island a Grid Tied Solar Array ?

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In spite of many of the above replies, many in the sailing cruising community are doing fairly well with their pv powered sail boats , some using electric motors instead of diesel power. Much simpler way of life than the norm however , small refrigerators etc. and some making do to do, but they get by. And of course on occasion most resort to shore power after longer periods of cloudy skies and inclement weather. Well equipped pv boats have run months at sea using the sun as the primary energy source, other than the wind that pushes the boat thru the water.
Covid lockdowns at sea have proven the actual extents to which one can survive without utility power in other cases most notably at Columbia and Panama while at welcoming safe remote island harbors for those unable to land at other locked down ports of entry near civilization.
 
The solar PV systems on boats invariably use batteries and then DC powered equipment. The battery provides the necessary stability to maintain the voltage when available PV changes.

One can certainly go this route and build a full off grid PV system.

Again: the grid is _not_ necessary for a PV system, but it is specifically part of the design of a grid interactive PV system.

-Jon
 
The planet is not, and will not be in trouble.

At issue is if we are changing the planet in a fashion which will benefit whatever will follow humans rather than for the benefit of humans. When I was a kid and the fear was atomic war, then the joke was that we would be clearing the world for the cockroachs. If we follow the _natural_ path, we will change the planet in some way that we cannot tolerate, and something else will come along to take our place. This happened with the algae that created our oxygen atmosphere; trying to _prevent_ this sort of change is quite human centric and un-natural.

An additional issue is if we will change the climate in ways that are not politically desirable. I firmly believe that some of the disinformation directed at the US from Russia is done with the goal of thawing Siberia. The world (and humans) will survive if Siberia thaws, but the US will be placed in a severe economic disadvantage relative to Russia.

-Jon
 
winnie said:
I get on the order of 4-4.5 peak sun hours per day, so that means that 1 kW of installed capacity makes about 4 kWh per day.

I think it is a pretty good bet that solar would pay off for you in your lifetime.

-Jon
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In 69 months with 4250W of panels, I've generated 30.35 MWh. I have a little shade and less than optimal angle and assume I'd have gotten perhaps 36 MWh with better conditions. That supports your about 4kWh/kW/day results. On Duke Energy with our relatively low rates, and including the rebates available in 2015, I calculated a ROI of about 7 years. Without those, ROI would be about 13-15 years. The government estimates (SS life expectancy) I'll (70.6 now) live another 14.1 years.

So given ONLY that, yes, but not by a large margin. Higher power costs would help you.

The caveat I'll offer is that your benefit requires you to remain where you are; moving the installation won't be cheap.
 
SG-1 said:
Just threw that in for the true believers. You know the ones making millions on the scare mongering.

When i was in grade school the problem was the coming ice age, aka global cooling. Guess we fixed that problem !
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Don't get me wrong, I believe we are contributing to our demise with our actions and inactions. It's just a little quirk of mine, when I see "save the planet" :). The planet will be here long after we have been extinguished.
 
macmikeman said:
In spite of many of the above replies, many in the sailing cruising community are doing fairly well with their pv powered sail boats , some using electric motors instead of diesel power. Much simpler way of life than the norm however , small refrigerators etc. and some making do to do, but they get by. And of course on occasion most resort to shore power after longer periods of cloudy skies and inclement weather. Well equipped pv boats have run months at sea using the sun as the primary energy source, other than the wind that pushes the boat thru the water.
Covid lockdowns at sea have proven the actual extents to which one can survive without utility power in other cases most notably at Columbia and Panama while at welcoming safe remote island harbors for those unable to land at other locked down ports of entry near civilization.
Click to expand...
For most people who are using PV on their boat, it makes up a very small part of their energy production. Most of it comes from a gas or diesel-powered generator. If someone is doing hairshirt sailing, only powering lights and really small loads, they can get away with PV. There is just very little room for PV modules on a boat, if you get 2 or 3 you are lucky. That is not powering an electric drive, watermaker, refrigerator/freezer, and other large loads.
 
I have been exploring solar for myself, and have come across more of value to the OP's question about island operation. As has already been discussed, a regular line interactive inverter cannot do this, because it _must_ protect the grid from export during a power outage, in the same way that a transfer switch must separate the home from the grid in order to operate on local power.

A properly designed inverter can certainly operate in 'island mode' with proper separation from the grid. This will almost certainly require energy storage to function well.

I am pretty well biased against energy storage because I am in a location where the grid is quite reliable and where we have 'net metering', which means energy storage has a poor to negative ROI. However I have been giving it a closer look.

1) Tesla provides a very good price for their PV installation, but _requires_ that you include a powerwall in the package. To make this attractive they identify a number of energy storage incentives available in some areas. (The big one is where you join a program that allows the POCO to use your battery to support the grid; the POCO pays a pretty significant amount for such capacity _if they use it_, but I think this incentive might be oversold because if the POCO doesn't use the capacity you don't get paid. ) In any case if you have energy storage incentives than having such might be worth while, so this got me looking closer.

The incentive program has a list of inverters/batteries that are eligible, and so I started looking at a few of them. Here is the incentive info:

Battery Storage Demand Response | Eversource

Home batteries can help you store your clean solar energy or simply provide backup energy in case you need it. Learn more from Eversource.
www.eversource.com www.eversource.com

In particular I found the Sol Ark 12K inverter interesting https://www.altestore.com/store/inv...verter-pre-wired-systems-p41381/#SOLARK12KOUT

This unit is an all in one that includes the PV connection, the utility connection, the battery interface, and a small number of backed up circuits. In the event of a grid outage the system stops feeding power to the grid (anti-islanding) but will continue to power your 'backed up' circuits from the PV array and the battery.

This inverter is more expensive than one that is only grid interactive, and you also need to pay for the batteries. IMHO it is only worth it if you have a very unreliable grid thus needing backup power frequently or if you have incentives that pay for the energy storage. But it does look interesting in that the actual batteries are separate from the unit and you can adjust to battery capacity and chemistry to suit your application.

If any of the PV professionals have comments on this system I'd appreciate hearing them, but this might get to close to a DIY discussion :)

-Jon
 
winnie said:
I have been exploring solar for myself, and have come across more of value to the OP's question about island operation. As has already been discussed, a regular line interactive inverter cannot do this, because it _must_ protect the grid from export during a power outage, in the same way that a transfer switch must separate the home from the grid in order to operate on local power.

A properly designed inverter can certainly operate in 'island mode' with proper separation from the grid. This will almost certainly require energy storage to function well.

I am pretty well biased against energy storage because I am in a location where the grid is quite reliable and where we have 'net metering', which means energy storage has a poor to negative ROI. However I have been giving it a closer look.

1) Tesla provides a very good price for their PV installation, but _requires_ that you include a powerwall in the package. To make this attractive they identify a number of energy storage incentives available in some areas. (The big one is where you join a program that allows the POCO to use your battery to support the grid; the POCO pays a pretty significant amount for such capacity _if they use it_, but I think this incentive might be oversold because if the POCO doesn't use the capacity you don't get paid. ) In any case if you have energy storage incentives than having such might be worth while, so this got me looking closer.

The incentive program has a list of inverters/batteries that are eligible, and so I started looking at a few of them. Here is the incentive info:

Battery Storage Demand Response | Eversource

Home batteries can help you store your clean solar energy or simply provide backup energy in case you need it. Learn more from Eversource.
www.eversource.com www.eversource.com

In particular I found the Sol Ark 12K inverter interesting https://www.altestore.com/store/inv...verter-pre-wired-systems-p41381/#SOLARK12KOUT

This unit is an all in one that includes the PV connection, the utility connection, the battery interface, and a small number of backed up circuits. In the event of a grid outage the system stops feeding power to the grid (anti-islanding) but will continue to power your 'backed up' circuits from the PV array and the battery.

This inverter is more expensive than one that is only grid interactive, and you also need to pay for the batteries. IMHO it is only worth it if you have a very unreliable grid thus needing backup power frequently or if you have incentives that pay for the energy storage. But it does look interesting in that the actual batteries are separate from the unit and you can adjust to battery capacity and chemistry to suit your application.

If any of the PV professionals have comments on this system I'd appreciate hearing them, but this might get to close to a DIY discussion :)

-Jon
Click to expand...
We have those incentives also, but in reality they are little more than a carrot on a stick. Peak demand is tough. Very few (if any) of ours manage to export during peak demand times. After all, everyone’s AC is running during the hottest part of the day..

A lot of what we see being installed now is battery backup to a specific circuit(s) refrigerator, living room, bedroom. That’s about it. And the run time is hours. So a major event will stop it unless the solar during the day manages to power the circuits AND charge the batteries.

Basically what I’m seeing installed is a huge UPS..
 
winnie said:
I have been exploring solar for myself, and have come across more of value to the OP's question about island operation. As has already been discussed, a regular line interactive inverter cannot do this, because it _must_ protect the grid from export during a power outage, in the same way that a transfer switch must separate the home from the grid in order to operate on local power.

A properly designed inverter can certainly operate in 'island mode' with proper separation from the grid. This will almost certainly require energy storage to function well.

I am pretty well biased against energy storage because I am in a location where the grid is quite reliable and where we have 'net metering', which means energy storage has a poor to negative ROI. However I have been giving it a closer look.

1) Tesla provides a very good price for their PV installation, but _requires_ that you include a powerwall in the package. To make this attractive they identify a number of energy storage incentives available in some areas. (The big one is where you join a program that allows the POCO to use your battery to support the grid; the POCO pays a pretty significant amount for such capacity _if they use it_, but I think this incentive might be oversold because if the POCO doesn't use the capacity you don't get paid. ) In any case if you have energy storage incentives than having such might be worth while, so this got me looking closer.

The incentive program has a list of inverters/batteries that are eligible, and so I started looking at a few of them. Here is the incentive info:

Battery Storage Demand Response | Eversource

Home batteries can help you store your clean solar energy or simply provide backup energy in case you need it. Learn more from Eversource.
www.eversource.com www.eversource.com

In particular I found the Sol Ark 12K inverter interesting https://www.altestore.com/store/inv...verter-pre-wired-systems-p41381/#SOLARK12KOUT

This unit is an all in one that includes the PV connection, the utility connection, the battery interface, and a small number of backed up circuits. In the event of a grid outage the system stops feeding power to the grid (anti-islanding) but will continue to power your 'backed up' circuits from the PV array and the battery.

This inverter is more expensive than one that is only grid interactive, and you also need to pay for the batteries. IMHO it is only worth it if you have a very unreliable grid thus needing backup power frequently or if you have incentives that pay for the energy storage. But it does look interesting in that the actual batteries are separate from the unit and you can adjust to battery capacity and chemistry to suit your application.

If any of the PV professionals have comments on this system I'd appreciate hearing them, but this might get to close to a DIY discussion :)

-Jon
Click to expand...

There is no meaningful financial ROI for home battery systems unless you are one of the few that can get them with heavy government subsidies. Most people that buy home battery systems are doing it for comfort and convenience reasons particularly for blackouts.

Virtual power plant (VPP) programs like Connected Solutions are pitched to PoCo's as cheap replacement for gas peaker plants but to consumers they are being pitched as a great way to prevent blackouts and get paid for doing it. However, the reality is that there are quite a few reports of unhappy Connected Solutions participants experiencing blackouts with empty batteries that were drained by the PoCo's and some have stopped participating. The basic premise of VPP programs getting lots of home battery owners as participants seems questionable.
 
I hear you on 'no meaningful ROI' for battery systems unless there is someone else paying for them.

I am curious about the reality of Connected Solutions payments; I see Hv&Lv's point about providing peak power from my personal system if I need power at the same time as everyone else; really it only works if I make sure that I am not using power when the POCO needs it, or if I have a system that optimized production during such peak times.

But trying to keep focus on the OPs question: information about the actual payments for Connected Solutions or other battery subsidies for battery PV inverters might understand the actual costs of having a functional 'island' PV systems, as opposed to having a standard grid interactive PV system which shuts down when the grid is out, and then simply having a generator for backup purposes.

-Jon
 
I have a fish tank at home and about 10 years ago I bought a decent marine battery (for boats I'm assuming) that supposedly can handle deep discharge better than a standard car battery, I think it was about $65-70. Paired that with a cheap inverter ($45) that has two plugs on it and is rated up to 1500 watts. Equally cheap trickle charger for $25, so less that $150 in all. With everything connected it pulled between 150-300watts (150 watt heater goes on and off) and it would keep my fish tank running for almost a week, haven't checked the wattage on my fridge but I'm considering getting another setup like that, maybe a little higher quality. I could keep myself pretty comfy for less than $500 I bet.
 
winnie said:
But trying to keep focus on the OPs question: information about the actual payments for Connected Solutions or other battery subsidies for battery PV inverters might understand the actual costs of having a functional 'island' PV systems, as opposed to having a standard grid interactive PV system which shuts down when the grid is out, and then simply having a generator for backup purposes.

-Jon
Click to expand...

I read one extreme case of a participate getting $4K in one year but he has a huge home battery system that he paid 10x+ for. The other payments I have seen reported are much lower (<$2K). In general, I doubt VPP incentives would make home battery systems financially justifiable.

Regarding OP's question, there are inverters that can produce power from solar during outages even without batteries. I mentioned some in an earlier post (#11) including Sol-Ark. The cost premium of these inverters over grid-tied only variants can be < $1K which is much lower than the cost of a home battery system.
 
analog8484 said:
There is no meaningful financial ROI for home battery systems unless you are one of the few that can get them with heavy government subsidies. Most people that buy home battery systems are doing it for comfort and convenience reasons particularly for blackouts.

Virtual power plant (VPP) programs like Connected Solutions are pitched to PoCo's as cheap replacement for gas peaker plants but to consumers they are being pitched as a great way to prevent blackouts and get paid for doing it. However, the reality is that there are quite a few reports of unhappy Connected Solutions participants experiencing blackouts with empty batteries that were drained by the PoCo's and some have stopped participating. The basic premise of VPP programs getting lots of home battery owners as participants seems questionable.
Click to expand...
As I see it, the grid it going to want to tap your batteries they same time you do. There are other programs I've heard of but have not seen the details on that would tap the battery of your electric vehicle. Double plus un-good!
 
gadfly56 said:
As I see it, the grid it going to want to tap your batteries they same time you do. There are other programs I've heard of but have not seen the details on that would tap the battery of your electric vehicle. Double plus un-good!
Click to expand...

The vehicle would have to have been designed for that function. A normal EV cannot output power.
Supposedly it’s coming next year in the F150 Lightning. There may be some out there now that I’m not aware of.
 
retirede said:
The vehicle would have to have been designed for that function. A normal EV cannot output power.
Supposedly it’s coming next year in the F150 Lightning. There may be some out there now that I’m not aware of.
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There are people who retrofit their EV or hybrid to tap the battery for home power. With a hybrid the cars own electronics starts the motor as needed to maintain battery state of charge within the designed range.
For an EV, you would have to interface with the battery management system to avoid excessive discharge. That should be automatic too IF you connect at the right point.
None of this is manufacturer approved, so kiss your battery warranty goodbye.
Vehicles with a built-in AC power outlet are fair game (like some pickup models,)
 
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