An Educated Move Off-Grid: Page 3 of 4

Beginner

Inside this Article

Off-grid PV system
A high-tech off-grid system now provides electricity for the twentieth-century farmhouse.
Twentieth-century farmhouse
This twentieth-century farmhouse was originally built by an Amish family; it was formerly electricity- and plumbing-free.
Usage of energy-efficient appliances
Energy-efficient appliances play a critical role in reducing the electrical loads in an off-grid system.
Batteries for energy storage
Two 48 V strings of Trojan L-16-RE batteries provide energy storage for the McDermott home.
OutBack inverter and two MidNite Solar charge controllers
The balance-of-system components include an OutBack inverter and two MidNite Solar charge controllers.
Generac EcoGen 6 kW propane generator
The Generac EcoGen 6 kW propane generator is designed and warranted for off-grid use with an RE system.
Pole-mounted solar-electric arrays.
Much of the 21-foot lengths of the mounting poles are encased in concrete to handle the wind loads on the large arrays.
PV module mounting
Mounting the PV modules.
Olde English Babydoll lamb.
The McDermotts’ off-grid life also includes this Olde English Babydoll lamb.
Teresa inspects her beehives
Teresa inspects her beehives and checks for honey. Notice the solar-powered electric fence used to keep out pesky black bears.
Off-grid family
Off-grid family Mark and Teresa McDermott with their son Dylan and daughter Laura.
Off-grid PV system
Twentieth-century farmhouse
Usage of energy-efficient appliances
Batteries for energy storage
OutBack inverter and two MidNite Solar charge controllers
Generac EcoGen 6 kW propane generator
Pole-mounted solar-electric arrays.
PV module mounting
Olde English Babydoll lamb.
Teresa inspects her beehives
Off-grid family

Going with a Pro

I contacted several different NABCEP-certified solar installers. I had a good idea of what the complete system would look like and what equipment was available, so this was kind of a test for the two I sought bids from.

I hired Four Winds Renewable Energy (FWRE) out of Arkport, New York, which was only a few minutes’ drive from our property. Not only had owner/installer Roy Butler been installing off-grid PV systems for decades, but he also lived off-grid. After Roy did a site survey, we took his proposal and tweaked it a little bit to arrive at our system design: a 4 kW PV system with a 740 Ah battery bank and a 6 kW backup generator. FWRE would order and install the equipment for about $30,000. New York state does not offer any rebates or tax incentives for off-grid systems, although we did qualify for the 30% federal tax credit.

Site Prep & Installation

To keep costs down, I took responsibility for hiring an excavator for the pole holes and the wiring trenches, repairing the yard after the trenching was finished, preparing the basement wall for mounting the balance-of-system components, and the rough AC wiring between the generator and the inverter. I was also responsible for selecting and installing the generator and its fuel supply—a propane Generac 6 kW EcoGen, which is the only generator designed and warranted for off-grid use with a renewable energy system.

We started the installation the first week of September. It probably would have taken less time to install if I hadn’t been there, but it was important to me to watch and learn as much as I could about the installation and how all of the components worked together.

Setting the two 6-inch, 21-foot-long steel poles for the pole-mounted system was a critical step. They had to be lifted into place with the backhoe and set in 24-inch, 6-foot-long concrete form tubes. Since the arrays presented a large surface area for wind loads, plenty of ballast was needed to keep them in place.

While the concrete was curing around the poles, we installed the BOS equipment. The inverter, charge controllers, battery box, and batteries were all wired, connections torqued, and parts labeled.

Strong, Silent Energy

A couple of days later, the first array was installed and was charging the batteries. Our new system sounded like nothing—it was dead silent. No generator noise, just a dull hum from the battery box fan. A day or two later, the second array was online. The backup generator was delivered, and we installed that and wired it into the system for those stretches of little to no sun, and for enough energy to occasionally equalize the batteries (an intentional overcharging of the battery bank to remove imbalances between individual batteries).

The first thing we did was plug in our refrigerator. It’s funny how some things get taken for granted, like having a refrigerator instead of buying ice every day and living out of an ice chest, as we did before installing the PV system. I remember my wife saying that if all we could ever supply electricity to was the refrigerator, it would be OK with her.

By the last week in September, our new system was complete. There was still much to learn and do—understanding the technical and practical details of a whole new electrical supply system, tweaking the charge parameters to properly charge the batteries, and reminding the kids to turn off the lights! I pay special attention to the batteries, since they are the heart of the system and its most vulnerable part. To date, there have not been any major issues or problems. The array tilt was adjusted to an optimum angle for the winter and left there. I adjusted the array for the summer angle on April 1, and will readjust it again this fall.

Comments (6)

America Install Solar's picture

Congratulations McDermontt's making your home off-grid!

It's odd how most('grid-tied') people try to justify not going Off-grid, like saying "the Packback is very long"!
so the Q. for grid dependent users is...When are you going to 'pay-off' your utility bill?

A. Never

Ian Woofenden's picture

The McDermotts are off-grid because line extension cost was in the $35,000 to $45,000 range. If the utility line is on site and interconnection policies are reasonable, using renewable energy ON-grid makes more sense, because you can use or get credited for all production. Off-grid systems must be designed to have a surplus, and therefore are fundamentally less efficient than grid-connected systems. The payback may or may not be longer for off-grid systems, depending on the cost of line extension.

I think sometimes people say "I want to go off-grid" when they really mean, "I want to power my home with renewable energy". Sensible renewable energy design will most often use the existing utility grid if it's practical. Unless line extension costs or interconnection bureaucracy or costs are high, a grid-tied renewable energy system usually makes the most sense.

Ian Woofenden, Home Power senior editor

America Install Solar's picture

Good sunny day Ian! (hopefully there, if not soon) With most of what you said, I concur.
That's why I promote use of 'biModal' PV systems (On-grid+stand alone operation), customers get the Best of both worlds...hopefully, as you said, if not a interconnection mess!
With a hybrid type PV system costing less (vs. cost a Grid-Tied Only sys. few years ago) installing a Bimodal is the best & makes the most sense, esp. when the grid fails...like 'victums' of hurricane Sandy with 'grid-dependent' PV systems, looking at their arrays but have NO power from their solar investment!!
For those with a stand-alone (i.e. 'off-grid' PV+ some type of back-up power) energy system, they will never have the headache of a 'Sandy Storm' (unless their array and 'back-up power' flies or dies!) or dealing with all the net-metering misinformation, and unfair (by most utilities) 'credit' as a lower than grid retail rate 'paid' for PV owner's true value of their solar investment, which should be equal for kWh delivered.
note: Minnesota has just declared the 'value of solar' sent to the utility grid at over 14 cents/kWh hour!
see:
http://www.ilsr.org/wp-content/uplo...

Stay cool,
It's Time for Solar!

Ian Woofenden's picture

From my perspective, it all depends on the goals of the system owner.

My experience is that when most people find out the increased cost and responsibility of battery based systems, they opt for batteryless grid-tie. But again, it depends on their motivations. If they are concerned about the end of the world or grid instability, certainly battery-based systems will fill their needs better. But most people in the U.S. live where utility outages are rare and short, and paying for, maintaining, and charging batteries for 364+ days per year to plan for a brief possible outage doesn't make sense to a lot of people.

I _try_ to keep my personal viewpoints and conclusions (I've lived off grid for 30+ years by choice) mostly to myself, and present options to readers and clients while trying to discover and help them achieve their own goals.

And then to throw a bit of a curve into the batteryless-with-no-backup vs. more-expensive-battery-based-grid-tie decision, we now have the limited-backup-when-the-sun's-out option, as profiled in HP159:

http://www.homepower.com/articles/s...

It remains to be seen how this limited product will play out in the real world of people's goals and expectations.

Ian Woofenden, Home Power senior editor

Kolapo Olakonu's picture

Hello Mark,
this is awesome, i'm all excited about off grid living and look forward to it. the "inside this article" links however does not contain the cost table mentioned within the main article. Can we see that also?
Thank you
Kolapo Olakonu
Phoenix AZ

Michael Welch's picture

Hi Kolapo. Off-grid living has a lot of benefits, but also more expensive PV systems. Unfortunately, there is not a cost table with this article to illustrate that, and the reference should have been removed during the editorial process. Please accept our apologies.
Michael -- Home Power

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