Cost of off grid systems

Seminoob · April 2018

I'm familiar with solar & wind. I did it in NE Arizona, but didn't have enough bucks to do it right. That was years ago. Prices have improved. I might try it again in Southern Colorado, but need to know roughly what it will cost me. Not too sure about panels made in the orient. My last monthly electric bill said I used 370 kwh. That's about average. Maybe that will help you answer this question. I forgot to say it would be a hybrid system using wind, solar and a gas driven battery charger.
Thank you

Estragon · April 2018

VERY roughly, ~$10,000 each for panels, batteries, generator, and electronics etc., so ballpark 40 grand. LOTS of variables/choices/trade-offs though.

Figure 5-10yrs for batteries, 10 or so for electronics, 20 for generator, 25 for panels, so maybe $3,500/yr. + fuel etc. That would be in a $0.75/kwh order of magnitude power cost.

Photowhit · April 2018

You are in one of the better areas for solar, averaging 5.5-6 hours per day. That said it is doubtful you will be less expensive that the grid. Do you have particularly high grid energy cost?

You would average about 4 hours in Dec, What does your energy profile look like? Do you heat with wood? Gas?

Seminoob · April 2018

The grid energy cost is about about $70 per month in this location. The kwhs were a little higher in January / February at 400. We use propane gas but due to our income (low income senior couple) we get help with that + the furnace is very efficient. I'd like to heat with wood but heard you can't get insurance if you have a woodstove. In any case we are thinking about selling out and moving to a different county that's quieter. Large portions of it have no electric and those properties are cheaper.

Seminoob · April 2018

Estragon said:

VERY roughly, ~$10,000 each for panels, batteries, generator, and electronics etc., so ballpark 40 grand. LOTS of variables/choices/trade-offs though.

Figure 5-10yrs for batteries, 10 or so for electronics, 20 for generator, 25 for panels, so maybe $3,500/yr. + fuel etc. That would be in a $0.75/kwh order of magnitude power cost.

I disagree about the panels. There is a solar installer in the county we want to move to. He said he could sell me eight 300 watt panels for $2700 but I would probably need more.

mcgivor · April 2018

Off grid living is entirely different to grid, energy efficient appliances, lights etcetera should be used, a refrigerator will most likely be the single largest load which often determines the size of a system. Conservation is of upmost importance, in order to keep costs down, my monthly average is ~100 Kwh, tropical location. It's definitely a lifestyle change but not an uncomfortable one, just need to understand where the energy comes from as well as how much reserve is available. Off grid means you are the utility so having a sound understanding of how things work is extremely useful, unless you put everything in the hands of others, which obviously adds to the expense, even then knowledge is invaluable.

Dave Angelini · April 2018

It is in my opinion not a matter of money but more a matter if the place is worth the work and effort.
If you love the place you should do the things that make it happen.
Some call it providence !

Photowhit · April 2018

Seminoob said:

The grid energy cost is about about $70 per month in this location. The kwhs were a little higher in January / February at 400. We use propane gas but due to our income (low income senior couple) we get help with that + the furnace is very efficient.

While I agree somewhat with Dave, It is likely the off grid solar would take a considerable investment up front and cost more over time.

@Estragon was throwing around some rough numbers. For me to run solar for 400KWhs in winter it would require a huge array and battery bank. I think you have a better chance but it will still be difficult. Don't give up your gas heat!

Since we are talking about a place that doesn't exist and we don't know the loads, it will be hard to give 'real' answers.

A 13 KWh daily load with much of it run off a battery bank, The numbers would be pretty big. With 4 hours of direct sun light to work with to produce it we commonly use 50% total losses through the system. So you would need to produce 26 KWhs a day with 4 hours of sunlight to stay even (battery based systems most be larger!) so 26 Kwhs ÷ 4 hour = 6.5 Kw array.

If you start with a 6.5 KWh array and understand that, that works for days when you have 4 hours or more sun, a single cloudy day, means you will need to store that 13 KWhs of energy plus and additional 50% for 2 nights So call it 20 Kwh's of available storage. Why do I say available storage? Because you don't want to draw down a lead acid battery bank below 50% in general. It shortens the life of the battery bank. So 13 x 1.5 x 2 = 39 Kwh's of storage. That's a pretty large battery bank. This is a start, go to go, I'll follow up tomorrow some time.

noradawn456 · April 2018

To determine which of these options may be best for your home or business, you must first understand some basics, as well as the pros and cons of each system.

Estragon · April 2018

> @Seminoob said:
> Estragon said:
>
>
> VERY roughly, ~$10,000 each for panels, batteries, generator, and electronics etc., so ballpark 40 grand. LOTS of variables/choices/trade-offs though.
>
>
>
> Figure 5-10yrs for batteries, 10 or so for electronics, 20 for generator, 25 for panels, so maybe $3,500/yr. + fuel etc. That would be in a $0.75/kwh order of magnitude power cost.
>
>
>
>
> I disagree about the panels. There is a solar installer in the county we want to move to. He said he could sell me eight 300 watt panels for $2700 but I would probably need more.

Yes, you would need more unless your consumption can be reduced considerably. As I and others have noted, there are lots of choices and trade-offs. In the end though, off-grid battery based solar will be more expensive than almost any grid power if it's available nearby.

BB. · April 2018

I suggest that for a full off grid cabin/small home/very energy efficient near normal electrical life--That you aim for ~100 kWH per month (3.3 kWH per day) of average usage. That is a system that does not cost "too much" to install and maintain, and is a system that the home owner can (possibly) install and maintain without needing professional help. Of course, that requires a lot of conservation (the home needs to be well insulated, LED lighting, Energy Star Appliances, "solar friendly" well pump, etc.) and the ability to cut down energy usage during bad weather or startup the backup genset during parts of winter.

A larger system (10 kWH per day or 300 kWH per month) is no longer in the "small" system size (in my humble opinion). It is not to say that a home owner cannot install and maintain such a (larger) system--But if this is your first time--There is a steep learning curve.

Doing several paper designs will help with both the education and understanding, but get you prepared for planning the expenses for such a system.

-Bill

Seminoob · April 2018

Thank you Bill

BB. · April 2018

You are very welcome Siminoob.

Would you like to walk through some theoretical calculations (math is pretty straight forward) for a 3.3 or 10 kWH per day system (or both)? All we really need is the rough location where the system will be installed--And any "special" loads (deep well pump, Heat Pump, etc.).

Here is a handy site to find Average Hours of Sun per day by month:

http://www.solarelectricityhandbook.com/solar-irradiance.html

-Bill

Seminoob · April 2018

mcgivor said:

Off grid living is entirely different to grid, energy efficient appliances, lights etcetera should be used, a refrigerator will most likely be the single largest load which often determines the size of a system. Conservation is of upmost importance, in order to keep costs down, my monthly average is ~100 Kwh, tropical location. It's definitely a lifestyle change but not an uncomfortable one, just need to understand where the energy comes from as well as how much reserve is available. Off grid means you are the utility so having a sound understanding of how things work is extremely useful, unless you put everything in the hands of others, which obviously adds to the expense, even then knowledge is invaluable.

I would buy a gas refridgerator and dependable LEDs for lighting. Some aren't. CFLs are pretty good but use a few more watts. I think the desktop computer would have to be checked with an ammeter to see how much power it's using. It might say 400 watts on the power supply, but I don't really believe that. Someone in Hong Kong might say: Mista Nooby, you get much power wit our parts. All guarantee forever. Prease note, company moves to unknown island dis munt.

706jim · April 2018

I sold my gas refrigerator last year. They are expensive to buy and expensive to run (approximately $1/day on bottled gas). They also do not self defrost so you have to pull everything out of it every few weeks to get rid of the ice buildup around the cooling fins.
And if not externally vented, they can kill you from CO fumes when the chimney carbons up.

I think you would be better off with a mid sized solar/battery system with the lower price of large panels these days.

Estragon · April 2018

IMHO, propane fridges are a good option for an application like an RV or cabin not used all that often. Used weekends over the summer, for example, the cost of propane is minimal compared to a solar setup. CO could be an issue, but a propane range could be too, and solar electric has it's risks as well.

For a more regularly used application, I agree an electric fridge is a cheaper and probably safer choice in the long term.

mcgivor · April 2018

When first starting out I went from a cooler to a chest freezer conversation both of which were like living out of a backpack, seemed everything needed was on the bottom and usually wet. Thought about a gas unit but then discovered inverter refrigerators, they are solar friendly due to efficiency along with low startup current, being that a refrigerator is the largest consumer, it was the best decision I believe I made and a welcome change to the "backpack days".

littleharbor2 · April 2018

When living Off-Grid You'll learn to take advantage of "Opportunity loads" Laundry, Vacuuming, power tools, etc. Can be ran for free, so to speak, when your batteries are nearly or totally full. Mid day and into the afternoon is when you do your chores.

BB. · April 2018

You really need a kill ac watt type energy meter to see what your AC loads really are for your appliances.

https://www.solar-electric.com/kiacpomome.html

If your desk top computer uses 200 Watts (monitor, printer, networking, etc.) for 10 hours a day, that would be 2,000 what per day, or more than a typical full size refrigerator.

A lap top computer may use 20-30 Watts, a big savings.

Bill

cdrichards2 · April 2018

I got a kill-a-watt meter and was surprised to learn my older laptop in docking station with 2 external LED monitors only burned ~70 watts when on. Get a meter; it's good to be able to measure what you are using and set plans around that...

peakbagger · May 2018

Seminoob said:

The grid energy cost is about about $70 per month in this location. The kwhs were a little higher in January / February at 400. We use propane gas but due to our income (low income senior couple) we get help with that + the furnace is very efficient. I'd like to heat with wood but heard you can't get insurance if you have a woodstove. In any case we are thinking about selling out and moving to a different county that's quieter. Large portions of it have no electric and those properties are cheaper.

Sorry to be late to the game. I seriously doubt that you cant heat with wood unless you are in emission non attainment area (highly unlikely). Plenty of folks including myself heat with wood and have homeowners insurance. Generally you need a modern stove and installed by a qualified installer to manufacturers specifications. The other alternative is a pellet stove if there is good source of pellets locally.

Cost of off grid systems

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