GRA
Well-known member
Seeing as how I used to do this stuff for a living, here's my $0.02. One of the first things I used to ask my potential off-grid customers was, "why do you want to go off-grid?" If they answered that they were tired of getting ripped off by their utility and wanted to save money, I'd tell them to forget it, because it wasn't going to happen - they had to be doing it for some other reason (and I'd tell them how to cut down their utility bill through efficiency and conservation). Unless you were paying exorbitant rates, it wasn't cost-effective to be off-grid unless you were typically 1/8th to 1/2 mile beyond a power line, depending on what the utility would charge to extend it and the rates.
I stopped designing and selling off-grid AE systems about 2 decades ago, and some things have changed since then which alter the economics. For instance, at the time, new mono and poly-crystalline PV modules ran about $7-7.50/Watt peak retail, and they're now at or below $1.00/Wp. Battery prices haven't changed much, but inverters have gotten a lot better, with large sine wave inverters available that approach the efficiency of modified square wave. BoS costs seem to be about the same. Efficient, high quality loads like appliances are far more available, and less expensive than they were then: I think I paid $29 for my first compact fluorescent in 1989, and bought some for $0.55 ea. not too long ago; LEDs are starting to come down in price. Energy Star appliances are readily available. So, while it's easier to justify going off-grid now than then, I suspect it's still unlikely to make economic sense if you already have the grid. OTOH, if you're in an area that experiences frequent, prolonged outages, it may well make sense to have some kind of backup.
I haven't kept up with the tech and know next to nothing about micro-inverters, but from what little I do know, if your system uses them and you want to go off-grid, it's like the punchline to the old joke asking the colorful local for directions - "I wouldn't start from here, if I was you." Maybe you could, but it's so inefficient and expensive that it's probably not worth it most places. I suspect it's still a lot easier and cheaper to go off-grid with a system that uses string inverters, but for all I know there's a product out there that makes that not the case. And while automatic transfer switches have been around since then, what may be necessary to meet the requirements of your local utility/codes for safety could be daunting.
Most on-grid homes use a lot more power than the typical off-grid home, because the typical 3-7 days of storage is so expensive. So, for anyone contemplating going off-grid when you have it now, my advice is the same as it was two decades back: First, reduce your demand by getting the most efficient loads you can, and learn to conserve. Only when you've done that should you consider off-grid. And for occasional short term outages, consider getting yourself a generator to run essential loads. It will be cheaper than buying batteries. Of course, if you're doing it for ideological reasons the economics may be less important or irrelevant; most of my customers way back when fell into that category.
I stopped designing and selling off-grid AE systems about 2 decades ago, and some things have changed since then which alter the economics. For instance, at the time, new mono and poly-crystalline PV modules ran about $7-7.50/Watt peak retail, and they're now at or below $1.00/Wp. Battery prices haven't changed much, but inverters have gotten a lot better, with large sine wave inverters available that approach the efficiency of modified square wave. BoS costs seem to be about the same. Efficient, high quality loads like appliances are far more available, and less expensive than they were then: I think I paid $29 for my first compact fluorescent in 1989, and bought some for $0.55 ea. not too long ago; LEDs are starting to come down in price. Energy Star appliances are readily available. So, while it's easier to justify going off-grid now than then, I suspect it's still unlikely to make economic sense if you already have the grid. OTOH, if you're in an area that experiences frequent, prolonged outages, it may well make sense to have some kind of backup.
I haven't kept up with the tech and know next to nothing about micro-inverters, but from what little I do know, if your system uses them and you want to go off-grid, it's like the punchline to the old joke asking the colorful local for directions - "I wouldn't start from here, if I was you." Maybe you could, but it's so inefficient and expensive that it's probably not worth it most places. I suspect it's still a lot easier and cheaper to go off-grid with a system that uses string inverters, but for all I know there's a product out there that makes that not the case. And while automatic transfer switches have been around since then, what may be necessary to meet the requirements of your local utility/codes for safety could be daunting.
Most on-grid homes use a lot more power than the typical off-grid home, because the typical 3-7 days of storage is so expensive. So, for anyone contemplating going off-grid when you have it now, my advice is the same as it was two decades back: First, reduce your demand by getting the most efficient loads you can, and learn to conserve. Only when you've done that should you consider off-grid. And for occasional short term outages, consider getting yourself a generator to run essential loads. It will be cheaper than buying batteries. Of course, if you're doing it for ideological reasons the economics may be less important or irrelevant; most of my customers way back when fell into that category.
