PV system question for MtnDon

[Arky217]

I just found out what it would cost me to put my retirement home that I'm building on the grid. And now I'm wondering if I should go with my original plan for a PV system.

My location is western Arkansas and the distance from the house to the utility line is 1000'.

The power co. wants $8400 to install the line.

If I pay up front, they will credit me $3500, which leaves an up front payment of $4900.
Otherwise, they want a minimum monthly payment of $140 for 5 years.

By that I mean if I use $5 worth of power, I still pay $140.
Or, on the other end, if I use $145 worth of power, I pay $145.

If my electric usage was going to be close to $140, then that would work out fairly well, but based on the house I now live in, I anticipate the electric usage to be between $40 and $60 if I go on the grid.

So, either way, if I paid $4900 up front and used $60/month for 5 years, that adds up to $8500 or if I pay $140/month for 5 years, that's still $8400.

So, I wondering how much of a PV system I could put in these days for $8500 ?
And could I count on the batteries lasting about that long ?

I know, of course, that I would have to have a large enough system to supply my anticipated power usage.
But I could limit the power usage that I currently have severely if I needed to.

For instance, I will heat with wood, cool with passive underground tubes, use low wattage lighting, cook with propane, and hot water from the wood stove heat in winter and solar heated tubing in summer.

My biggest concern is running a refrigerator/freezer full time.

For large intermittent loads, I have already have a generator.

So, PV or grid for this situation, which sounds more reasonable ?

Thanks,
Arky

[MountainDon]

My quick and dirty answer is we spent $8K for our PV system instead of $55K for a grid connection.

We could not run an electric refrigerator without taking away a big chunk of our 'cloudy day' cushion that we presently have. As things are we can go through three cloudy days before I start to worry about the batteries. A very rough approximation is that an electric energy star fridge would more or less double our power use. If that was the case I would want to double the storage capacity and likely the PV module capacity. The present charge controller and inverter have sufficient capacity to cover the extra needs. More batteries for certain. More PV modules, maybe as it might work out okay to just need an extra day or so to replenish the extra battery capacity if and when it was used.

I do not like to have to depend on being there to monitor the batteries and make the decision to run the generator after a cloudy day or two. I also not like the generator at all, would rather do without unless for something exceptional like doing a lot of welding.

If we could have been grid connected for for $5K I'm not sure what I would have done.  I think I might have gone to a grid connect setup. There are outages in the mountains, though not normally longer than half a day, so I might have considered a small set of batteries and an inverter/charger system. Not sure though.  

For us, going PV was a no-brainer simply because of the cost of the required underground grid connection.

If I think of additional comments, I'll be back.

[Arky217]

Thank you sir for a quick reply,

Wow, $55,000; that would certainly be a no-brainer for me as well.

For someone trying to do PV on a shoestring, it seems the fridge is a real thorn.

By the way, how do you get around that ?

Really though, I think I'm actually leaning toward the grid.
At least, I'll have unlimited power usage, for the first 5 years anyway.

If so, I plan on putting in a heat pump and not having to cut so much wood.
(It's only going to get harder as I get older (66 now))

Also, then the Missus can have all the electric gadgets she's used to.
(I guess you really can't put a price on anything that helps keep harmony in your marriage)

Thanks,
Arky

[MountainDon]

For someone trying to do PV on a shoestring, it seems the fridge is a real thorn.

By the way, how do you get around that ?

Propane fridge. It works well, no issue with that. But ti me that is a bit of a crutch. It is not renewable like PV/wind electric would be. Some day I might like to increase the battery capacity and go electric for refrigeration. Maybe I'll think about that when the golf cart batteries need replacing.     Maybe by then electric fridges will be even more improved as far as energy use goes?

[Squirl]

I know this was directed at mountaindon or mtndon? 

I hope you don't mind me joining the conversation.  A quote of 8k was the price break point for me, but I was already leaning toward off grid anyway.  The basically "free" power for the first five years of the installation changes the equation a little.  One factor that I looked at was long term price security.  Paying upfront for your power helps protect from price shocks in energy markets.  Also energy prices tend to outpace inflation or any other investment in today's market.

Mtndon has a unique factor that many have not faced and that is having to put his panels a few hundred feet from his house.  This can be a design challenge that can cost a slight amount more.  There are many fixed or sticky incremental costs.  Many systems need one inverter no matter how many panels and batteries you add.  Charge controllers handle a range of power and you may be able to expand the system size for a few dollars by maximizing panels.  Shipping a pallet of 4 panels can cost the same as a pallet of 6. Upsizing an extra KW to handle a fridge load may only cost a small marginal amount more such as adding two panels and upsizing the bank, say $800.

Although the work involved with maintenance, such as batteries, may be more of a deterent with age.  Also in retirement, you may find you self at home all day using your electricity.

[OlJarhead]

Using an energy star fridge that does not have a freezer can help.  We ran ours all summer long without issue (though our battery bank is a bit small) and had no issues at all -- but we have a lot of sun too.

My system ran roughly half of what you're looking at and I'd say you're in the ballpark for a serious possibility (sorry to hijack the thread if I am).  Here is how I see it:

You can get 8 Surrette 400ah batteries giving you 1600ah's of power on a 12vdc system or two banks of 800ah's each, 8 solar panels in the 200-210watt range two give you 1600watts or two banks of 800 watts, two 60amp MPPT controllers and two inverters (one modified and one pure) and have a system capable of running most anything you'd probably want within reason anyway -- and all that for about what you are looking at (~$3400 in batteries, $1500 in charge controllers, $1500 in inverters and ~$2500 in panels).  You'd wire the modified up to one side of the AC panel and pure to the other and intentionally choose which outlets went to which type of power (some things just have to have pure and some things don't).  That way you would actually have two systems which would allow you to dedicate, for example, one to run things like a fridge and freezer but nothing else, and one that runs the lights etc (non-essential) saving you from using too much power during a party and killing the batteries you need for the next three days to keep the food from spoiling

Of course you have other costs associated with all of this but my point is that it's possible to do what you want for around the price of the Grid Tie In BUT and here is a BIG BUT you will not have the power you think you'll have and a good solid generator backup WILL BE required if you want to live off grid and aren't seriously hard core.

To qualify this:  My neighbor has been off grid for 30 years (neighbor at the cabin that is) and runs a solar array of ~500watts with a tracking system he created.  He has ~1000AH of battery bank (currently he's using caterpillar batteries) and a generator back up system.  He runs everything anyone else might run except that he does things differently.

1.  In the winter his generator runs Friday through Sunday night.
2.  Laundry and any other big job involving power is done on the weekends only.
3.  He's replaced his batteries a few times and his generators at least 3 or 4 times.

Like I said, it's doable but requires a commitment to cut power usage significantly -- if it were me I'd start with my monthly electric bill and see what the total watt hours used is.....3000kwh would mean you better get the grid tie in -- assuming you plan to do pretty much the same stuff as you do now.....1000kwh and you might be a serious candidate for an off-grid system

Just my 2c

[Rob_O]

My .02...

Run for the grid and don't look back.

I plan on putting in a heat pump and not having to cut so much wood.
(It's only going to get harder as I get older (66 now))

Also, then the Missus can have all the electric gadgets she's used to.
(I guess you really can't put a price on anything that helps keep harmony in your marriage)

Propane fridge. It works well, no issue with that. But ti me that is a bit of a crutch.

Although the work involved with maintenance, such as batteries, may be more of a deterent with age.  Also in retirement, you may find you self at home all day using your electricity.

My neighbor has been off grid for 30 years (neighbor at the cabin that is) and runs a solar array of ~500watts with a tracking system he created.  He has ~1000AH of battery bank (currently he's using caterpillar batteries) and a generator back up system.  He runs everything anyone else might run except that he does things differently.

1.  In the winter his generator runs Friday through Sunday night.
2.  Laundry and any other big job involving power is done on the weekends only.
3.  He's replaced his batteries a few times and his generators at least 3 or 4 times.

[Native_NM]

Based on the math, the grid is the better option, especially at your age.  If you are trying to be green, there are other options besides solar...

If you are in an area with enough wind, check out the new Honeywell wind turbine with the micro-inverter.  I saw one installed specifically for refrigeration (medical) use on the web.  In high-wind areas they can crank out 1500Kw at 120V AC.  An Energy Star fridge can operate on as little as 275KWH/year. 

http://www.honeywellstore.com/store/products/honeywell-wt6500-wind-turbine-with-blade-tip-power-system.htm

My buddy in north Arkansas complains about the frequent power outages in Arkansas due to storms and ice.  A wind turbine, in the right area, will generate power 24/7, eliminating the need for batteries.   Generators are great if you have a) enough fuel to run them, or  b) the roads are passable, and c) the gas station has not run out or has the ability to run the pumps. 

[MWAndrus]

One option for a fridge in an offgrid system is something like the chest freezer conversion: http://mtbest.net/chest_fridge.html
I have read stories from multiple people who have done this, and it seems to be a pretty low energy way of keeping food cold.

[Pritch]

Based on the math, the grid is the better option, especially at your age.  If you are trying to be green, there are other options besides solar...

If you are in an area with enough wind, check out the new Honeywell wind turbine with the micro-inverter.  I saw one installed specifically for refrigeration (medical) use on the web.  In high-wind areas they can crank out 1500Kw at 120V AC.  An Energy Star fridge can operate on as little as 275KWH/year. 

http://www.honeywellstore.com/store/products/honeywell-wt6500-wind-turbine-with-blade-tip-power-system.htm

My buddy in north Arkansas complains about the frequent power outages in Arkansas due to storms and ice.  A wind turbine, in the right area, will generate power 24/7, eliminating the need for batteries.   Generators are great if you have a) enough fuel to run them, or  b) the roads are passable, and c) the gas station has not run out or has the ability to run the pumps.

Thread creep, but that Honeywell turbine looks cool! 

[considerations]

"A very rough approximation is that an electric energy star fridge would more or less double our power use."

I don't know what your "living needs" are, but I'm running an electric fridge and an electric freezer. Both of them are very small, under the counter size, about 4.5 or 5 cuft each. They both surge on at 200 or so watts, then drop back to 85 and 80 watts respectively, when running....and they are not on all of the time.  After today, they will be stacked in a cabinet frame made for them. 

For me it turned out to be a good solution, a household of one.

[Squirl]

This is a pretty recent thing for me so I will elaborate on my previous post.

I recently decided to expand my system after viewing the winter sun hours and talking with a few locals with solar.
I was going to go with around 1 KW of panels.  I went to expand that to close to 2kw. So to do this I ordered extra panels when they came on sale.  That cost $670 extra.  The shipping on the pallet was the same whether I only bought a few or extra panels.  To deal with the extra power, I have to go with a larger charge controller ($100 extra, $700 vs $600) and a go with a larger DC combiner panel ($30 extra, $100 vs. $70), extra fuses (3 extra at $11 each), extra battery bank capacity of 5.2 KWH for $600, and I will probably need extra mounting hardware for $200.  The additional wiring should be a nominal cost.  So for around 40% increased cost, I'll get around 100% more power.