Looking to go Off Grid

ggunn · October 2012

Re: Looking to go Off Grid

Celeste wrote: »

The house is ICF. About 60% buried - southern exposure has windows. Heating is taken care of by hot water heated by outdoor coal boiler which we use to heat the 6000 sqft greenhouse in the winter. Triple pane windows. No expense has been spared, also a foam roof.

Its very windy - average wind speed over 20 mph. http://www.usa.com/rank/wyoming-state--average-wind-speed--city-rank.htm

It's not really a money saving project. It's more of an independence project. I guess there is the issue of not really having another thing I WANT to do with my money. I want to have this.

One question you will have to answer is whether you are prepared to pay 10X or more per kWh for your electric power than you would if you were buying it from the grid. That's what it will cost when you get down to it. If that's what you want to do with your money, that's your business, but if it were my situation, I would look at grid tied PV before trying to go totally off grid. If the grid is available, with the right size system you can still make all your own electricity but use the grid to store it until you need it for a fraction of what an off grid system will cost you.

Another thing to consider is that if you keep the grid as a backup, even if you never use it, the utility is still going to charge you for staying connected. The only way to stop paying them anything is to disconnect at the pole and let them take all their equipment away. But then, you'll take the risk of running out of energy if you have too many cloudy days or have unexpected demand. You can buy more equipment for insurance against that, but nothing is 100%; how sure do you want to be that you will never run out? 90%? 99%? 99.9%? How many 9's do you want to buy?

Eric L · October 2012

Re: Looking to go Off Grid

One question you will have to answer is whether you are prepared to pay 10X or more per kWh for your electric power than you would if you were buying it from the grid.

Using current off-grid equipment prices, that "10X or more" number should already include a very high reliability rate for power. I carefully tracked all my battery-based system costs, and have subsequently carefully tracked production. Even after de-rating the production numbers for system inefficiency, the average production, when multiplied by my .08/kWh rate, yields a base cost for my pv-supplied power of 1.8 times more than utility power when averaged over 20 years. (If anyone is interested, I posted some details of the system and costs in post #36 of this thread -- by the way my average daily production has subsequently gone up significantly since adding my hot water heater to the system.) This is with a roughly 95% observed reliability. Of course I will have ongoing costs of batteries and other equipment to replace, so that 1.8 times cost rate will almost certainly rise, even if utility rates rise. But I could replace the whole system five times over and still not be paying 10X more!

So yeah, the OP needs to "do the math", but whose math? I'd suggest looking at people who have done it recently, using current prices.

Cariboocoot · October 2012

Re: Looking to go Off Grid

Eric, what's the utility rate where you live? That makes a big difference in the factor between grid price and off-grid price. Around here 'only' 10X more for solar would be a lucky thing, what with the equipment prices being high and the utility rate being low. But I've yet to see a place in North America where off-grid solar electric is cheaper than utility power. Although that day may be coming!

Eric L · October 2012

Re: Looking to go Off Grid

Coot, it's about .08 kWh (here's the exact rate). Sadly, unless things have changed, these guys (Alabama power) have no true net metering for grid tie (even though they have something they call 'net metering'). They just buy at wholesale and sell all power back to you at retail. If there had been a better grid-tie arrangement, I probably would have done it at the time. But now, in hindsight, I'm very happy with the way my system has worked out.

Cariboocoot · October 2012

Re: Looking to go Off Grid

Wow. You must have got some deal on your system to be able to compete with a grid price so low! Ours is about $0.10 per kW hour. Last Summer I duplicated my cabin system on paper and found I could buy about 25% more kW hours per day now than I could back in 2008 for $2,000 less. Even so it worked out to about $0.75 per kW hour based on estimated lifespan of the equipment, full-time power usage, and included battery replacement.

In some places now grid-tie actually makes economic sense without any tax credits or rebates. Slowly but surely solar is becoming more practical.

Photowhit · October 2012

Re: Looking to go Off Grid

Eric L wrote: »

So yeah, the OP needs to "do the math", but whose math? I'd suggest looking at people who have done it recently, using current prices.

Eric, I don't think your doing a real system evaluation. Your still using grid rather than having extra capacity in your battery bank and likely a larger array (I did go back and read)

If you put in replacement costs of the L-16 batteries (about 7 years) and electronics at 10 years (and figure for true off grid if you'll need more battery bank and array) I think you will get bigger numbers.

I'm true off grid and only need the larger battery bank in summer, and we normally have heat with Sun so I'm only at about a 24hr reserve and I'm at about 26 cents a differed KWh (not what I will produce, but what I would not have to buy from the power company) I did not include the costs of equipment I had on hand, but did not include about $2500 in tax credits either. I truely can't imagine a cheaper off grid system or situation at this point, heck I paid 26 cents a watt for some of my array, and have a very minimal battery that will meet my needs. Here's the thread on my costs and evaluation.

I also admit that I have a very unique system and utility costs making mine a somewhat practical situation. I will have to be aware of cloudy summer days with heat, it actually happened this summer one one day, and I'll need to minimize my usage.

Eric L · October 2012

Re: Looking to go Off Grid

Eric, I don't think your doing a real system evaluation. Your still using grid rather than having extra capacity in your battery bank and likely a larger array (I did go back and read)

If you put in replacement costs of the L-16 batteries (about 7 years) and electronics at 10 years (and figure for true off grid if you'll need more battery bank and array) I think you will get bigger numbers.

I agree, except for the part about it not being 'real'.

I did say above that I expect the cost to increase due to replacement costs; my point was that it's nowhere near the 10X grid power cost.

Looking at your post, I think I did a cost breakdown similar to yours (I know in my case it's a simple, perhaps simplistic, calculation):

4100 watt system @ $2,79/watt installed (I give a partial price breakdown in the link, and have also explained here how I built the mounts for around .30/watt). = $11,439.

I'm getting at least 11 kWh/day usable out of my system: that's after discounting for efficiency losses. The production number at the controllers has been averaging closer to 13 recently since making some upgrades (hot water, especially), but I went conservatively with 11. So, 11 X .08/kWh (grid cost for me) X (365 X 20 years) = $6,424. $11,439/$6,424 = 1.78, which I rounded up to 1.8.

As I said, I'm well aware that, as you point out, this is not the total cost, and I'm also aware that a true off-grid system would need a generator with AGS at the least, and/or a bigger bank, which would also be a cost, to get reliability closer to 100%.

But I don't see how factoring all that in would get it anywhere near 10X the cost of grid power, even with my very low electric rates.

By the way Photowhit, I see you have Classics too. If you haven't already, check out this idea for using them to heat hot water, which is working out great for me.

Photowhit · October 2012

Re: Looking to go Off Grid

Well part of the 10x explaination is found in figuring 11KW/day generation, vs off grid if you want/expect to use 11Kw a day, year round, you must build a system that will withstand winter storm/cloudy periods of serveral days, so you must store a significant portion of what you generate. So to use 11 Kw hours per day you would need a much larger array and battery bank, or a genny. At this point you have a 360 amp 48V battery, that's about (48x360=)17,280 Watt hours or less than one days reserve to 50%DOD, typically we/I would suggest 2-3 days reserve...

In 10 years of off grid living, I have only use solar with out a back up gennerator.

FWIW - Your system does work out to be very economical for having a nice back up power and reducing reliance on the grid. I like you mounting system, looks very nice/professional!

I'll check out your hotwater link, I had a nice suggestion over on the Midnite forum but it involved using a DC element and my array is too far from my water heater, I haven't decided what I will do this winter, I was given a small 6gall point of use water heater but if I do a point of use I'll likely go with a 10 gallon version (Ace has some nice ones that already have 2" of insulation) and just replace my current unit. I might run that off an aux function relay to turn on, with a 1 hour timer...

A lot up in the air, I'm cut back to part time and will go back to full time in January. I'll stay grid connected until I make my Christmas trip to Moma's in Florida, which might be in January, I'll have 180 hours of vacation to start using then...

I should have said a real off grid evaluation.

icarus · October 2012

Re: Looking to go Off Grid

"The money has to be spent on something soon."

Ready, fire, aim?

It seems that if you don't have a real handle on your likely loads, you are quite likely to make an expensive mistake. Especially since you have the grid power available, it seems you can do your best to conserve, all while monitoring your rel world usage. For example, a dryer is a huge load on a battery system. Consider a propane dryer,, but even that comes at a fairly hefty electrical load. If you are washing diapers in hot water, why not line dry them?

Just random thoughts,

Tony

BB. · October 2012

Re: Looking to go Off Grid

From my nominal usage with a natural gas drier and a washing machine (natural gas hot water)--I average around 0.26 kWH per load (0.26kWh for washer and another 0.26kWH for drier to run the motors--excluding the cost of natural gas). These are not standard Induction Motor washer/drier sets--So your results may vary.

-Bill

Eric L · October 2012

Re: Looking to go Off Grid

I'll check out your hotwater link, I had a nice suggestion over on the Midnite forum but it involved using a DC element and my array is too far from my water heater, I haven't decided what I will do this winter, I was given a small 6gall point of use water heater but if I do a point of use I'll likely go with a 10 gallon version (Ace has some nice ones that already have 2" of insulation) and just replace my current unit.

Photowhit,

Definitely check out what that guy is doing then. Short version: "Waste not hi" mode in Aux 2 signals the relay to use almost all (and almost only) whatever surplus power there is from the panels after loads and whatever is needed for to maintain absorb and float (it does nothing until absorb is reached). The relay varies voltage to the AC element according to the signal. It's really looking like a dream come true for maximizing production for a battery-based system. My batteries are completing their charge cycle normally and all surplus after loads is being shunted to the heater element, up to the max wattage of the element. I still have a voltage bug to sort out (discussed in the linked thread), but that may just be due to my small battery bank and even if I never fix it this is still a huge improvement.

My situation, by the way, is similar to yours; my water heater is almost 200 feet from my batteries, so DC was not feasible. With this set-up, a few hours a day of surplus power gets our tank to 160 F which can last us several days. It's like adding an extra 'thermal battery'.

Once you see what's going on, consider buying an old electric water heater with the bottom element connected using the waste not hi function plus the relay.

ChrisOlson · October 2012

Re: Looking to go Off Grid

icarus wrote: »

For example, a dryer is a huge load on a battery system.

It would be very hard to run the typical electric clothes dryer on batteries alone unless you had really good incoming wind and solar power to offset the draw on the batteries. We have an electric clothes dryer in our off-grid home (because my wife won't allow propane in the house). We don't use it in the summer because we use the clothesline. But we use it all the time in the winter and run it with the inverters, but with generator support. It pulls 4.8 kVA and the generator typically runs for maybe an hour and burns .4 gallons of gasoline to dry a load of clothes. So with gasoline at $4/gallon it costs us $1.60 to dry a load of clothes. But it's a heck of a lot cheaper than driving to a laundromat and sticking coins in a commercial dryer.
--
Chris

Photowhit · October 2012

Re: Looking to go Off Grid

Line drying just makes sense in most of the counrty, I line dry year round and use the spare bedroom in the winter, even jeans will dry in 24 hours most of the time, and it adds moisture to the air during the winter when all but open gas needs the extra moisture.

I use to live in North Florida, and it was so humid you could almost never line dry line. Your clothes were more likely to mildew...

ChrisOlson · October 2012

Re: Looking to go Off Grid

We have the dryer vented into the laundry room with a filter screen on it to catch any lint. So all the heat and moisture created by the clothes drying process is not wasted and is exhausted to the room where it is used to heat and humidify the house in the winter as well as dry the clothes.
--
Chris

niel · October 2012

Re: Looking to go Off Grid

i tried that venting of my electric dryer indoors through a filter. it works just fine, but i found it adds too much humidity too fast. when several loads are done it started to create mold in some areas so i stopped doing this. line drying is better as it is more gradual and does not consume electricity. i do not push my other half to line dry as it would take up far too much room in the house to do it in the winter. winds blow the clothes away sometimes outdoors and dust and dirt also get blown onto clean clothes that it sticks to readily when they are wet.

waynefromnscanada · October 2012

Re: Looking to go Off Grid

niel wrote: »

i tried that venting of my electric dryer indoors through a filter. it works just fine, but i found it adds too much humidity too fast. when several loads are done it started to create mold in some areas so i stopped doing this. line drying is better as it is more gradual and does not consume electricity.

My finding as well, even with one wash. The humidity load was way too much all at once, water running down the windows, everything that's the least bit cool in the house gets damp.

icarus · October 2012

Re: Looking to go Off Grid

I would convince my wife that propane, when properly installed is perfectly safe. There are issues with propane settling as a liquid in Ghent of a large leak, ( plus the normal gas leak issues) but that can be mitigated with proper design. In addition, LP detectors, coupled to shut offs, seismic shut offs etc are all available.

Somewhere I read that the here are more deaths from electrical fires than from gas fires,,(that, however, is an example of stats being misused since nearly 100% of US houses are wired for power, significantly less have gas, either natural or LP).

Tony

ChrisOlson · October 2012

Re: Looking to go Off Grid

We had a water heater valve malfunction and fill the house with gas back in 1990. My wife was coming into the house and had just turned the knob on the door and cracked it open when the house exploded. The entry door was insulated steel with no window in it and opened into the house. It blew back shut and held against the door jamb and she did not get burned. The east wall of the house blew completely out, along with the roof. The part where my wife was standing on the front steps held by some miracle.

She's 10 years younger than I am and was only 20 at the time and was pregnant with our oldest daughter.

When we built our new house there is no gas allowed. There is no amount of convincing that can be done.

I agree that while propane is mostly perfectly safe, when accidents happen it makes you wonder. A lake home not far from us exploded two summers ago and pieces of the roof went into the lake. We heard the explosion at our place when it went. A young girl lost her life in that explosion.
--
Chris

waynefromnscanada · October 2012

Re: Looking to go Off Grid

Unfortunately with gas leaks, the results, even if no one, or few are killed, are dramatic and unusual, attracting the media's full attention in the same way that according to the World Health Organization, 5 MILLION people world wide, EVERY YEAR, die as a result of tobacco use, yet the media remain silent. But let a plane go down in Outer Mongolia, and the media spread it around the world with great efficiency. With electrical fires however, "everyone" has those, so unless the fire is HUGE, it's ignored.
BTW in my firefighter training, we are told of a simple way to tell if it was NG or LPG that caused the explosion. NG being lighter than air, usually makes it's way to the upper stories of the house and when the explosion takes place, often blows the walls out at the top. With LPG being heavier than air, pools at the bottom, blowing out the lower sections of the walls before the roof falls down on the basement. I know there are many variables, but they tell us this is often what can happen, depending on the strength of the bang.

ChrisOlson · October 2012

Re: Looking to go Off Grid

In our case it was my fault. That water heater valve had been having problems for six months. The pilot would go out and it would not shut the pilot off unless I tapped on the valve. Something was stuck in it. The warning signs were there. But we were young, just married, didn't have money to replace it, and we lost all our belongings. The house did not burn. It never caught on fire.

I think modern appliances with electronic ignition and whatnot are a lot safer than what we had back then. But that didn't make any difference to my wife. When we had the LP generator she made me put the LP tank out back of a row of pine trees where she couldn't see it. She's very happy now that we replaced that generator with a gasoline one and the tank is gone.
--
Chris

ChrisOlson · October 2012

Re: Looking to go Off Grid

waynefromnscanada wrote: »

My finding as well, even with one wash. The humidity load was way too much all at once, water running down the windows, everything that's the least bit cool in the house gets damp.

I can't say that we've had that problem. We heat our house with a wood/coal fired central forced air furnace and it can tend to get really dry in our house in the winter time. The laundry room is next to the furnace room in the basement and there is no cold air return on the furnace blowers. I think the moisture laden air from the dryer gets pulled in by the furnace blowers and distributed thru the house in the heating ducts.

Our house is also quite drafty and not well sealed like a lot of new houses are. But we don't mind that either - neither of us has even had a common cold in over 10 years. We've had guests that come over and they have a cold and blow toxic spit all over the place and we still don't get sick. Some people have told us that's BECAUSE our house is drafty. We leave one basement window cracked open a slight amount even when it's sub-zero temps outside for fresh combustion air for the furnace because the draft in the stack is always pulling air out of the house. That might help too, I don't know.
--
Chris

Celeste · October 2012

Re: Looking to go Off Grid

Pretty sure we will not be having a clothes dryer. The wind and dryness of Wyoming are wonderful for line drying. And although it can be a bit harsh in the middle of the winter, I have always found cold wind very "cleansing" for the psyche and soul.

I hear all the issues about real life usage and such, but this is a house under construction. I can't do this in my current home as it is heated differently, we have different appliances, and different needs. I wish I could live in the house first and then decide how to make a floor plan. But, the real world requires that I make the floor plan and then live in it. I can use other peoples tried and true floor plans combined with my own judgement and taste to get a likely good fit. I could live in the house first and see what we use while grid connected, and perhaps that is the best idea. The question on that will be whether my dad is willing to let me do that. He wants to purchase these products asap.

We will be going today to look at the grid tied home.

ChrisOlson · October 2012

Re: Looking to go Off Grid

Celeste wrote: »

Pretty sure we will not be having a clothes dryer. The wind and dryness of Wyoming are wonderful for line drying. And although it can be a bit harsh in the middle of the winter, I have always found cold wind very "cleansing" for the psyche and soul.

Line drying in the winter outside just doesn't work. You can hang the clothes on the line and they freeze. They can hang there for a week and bring them in and stand them up in the corner. Before we bought the clothes dryer my wife used to have a line in the laundry room where she would hang the clothes near the wood furnace to dry them in the winter. But that got old after awhile. Nothing like going out to dinner and my wife's little black mini-dress smells like wood smoke.
--
Chris

Photowhit · October 2012

Re: Looking to go Off Grid

ChrisOlson wrote: »

Nothing like going out to dinner and my wife's little black mini-dress smells like wood smoke.

First it's nice you have a wife that still wears/can fit into a "little black mini-dress"...

...but second, and more important(?) you should have no wood smoke or smell in a house heated with wood, if you do something is wrong! It always surprises me when I see people who leave their door open to wood heaters thinking it's warming the house, that cools the house! and wastes wood, as you have greater combustion, but you must draw in more air from outside, cold air, and the heat? it's going up and out...

If fact, many/most new wood stove/furnaces draw their air from outside via a seperate line. Be careful, we need all our forum members! Do you have a CO detector?

ChrisOlson · October 2012

Re: Looking to go Off Grid

Yes, we have a CO detector. What happens is that when we open the fire door to fire it a little smoke leaks out every time you slide a piece of wood in because it pushed the smoke flap open at the top of the fire door. That smoke will suck right into wet clothes that are nearby and "enhance" them with somewhat of a woodsy odor.
--
Chris

Photowhit · October 2012

Re: Looking to go Off Grid

So this is a furnace, can you open the damper before you fire the stove? My wood stove would just draw fine, I'm not in the great white north, but I've had a fire going in my house for as much as 6 weeks at a time, I only open the damper when I'm cleaning out ash, it really helps then!

BB. · October 2012

Re: Looking to go Off Grid

If you still have access to the AC electrical--"home run" cables back to the AC mains panels instead of "daisy chaining", for example, all of the bedroom/living room/etc. outlets together. Similar with ceiling lighting (hopefully, you have CFL/LED/etc. type lighting for low power usage).

Basically, if you end up with a "mixed" power option--You can have some items that are battery backed (i.e., the outlet near the nightstand for clock/radio/cell phone charger/reading lamp and the other outlets are no "backed up" (vacuum, electric heater, large room lamps with quartz halogen bulbs, etc.).

Then back at the main panel area, you will have two sets of panels. Your main panel connected to the Grid/Utility power (electric water heater, electric drier, A/C or Heat Pump, etc.), and a second "sub panel" that can run your smaller/minimum AC Inverter Loads for when you are on emergency power.

In any case--You really need to work on conservation and be open to options...

For example, we talk about electric water heaters as being something you would never even think of running on an AC inverter--They just are not very efficient.

However, these days, there are stand alone "heat pump" based water heaters (think of a A/C system that works backwards, takes heat from the inside air and puts it into the Hot Water tank) that are 2-~3x as efficient as resistance heating. I think we have a couple people here that are using "Hybrid" water heaters on off grid power systems (they turn off/disconnect the AC backup heating element--so it takes quite a while to reheat the water). There can be more cost effective than running a propane water heater these days.

Heat pump water heaters start becoming less efficient as the room air temperature falls below ~55 degrees F.

Here is one thread talking about them:

Is this hard on my Geospring waterheater?

Anyway--Energy usage is highly personal... Some folks use 1,500 kWH per month, I may use around 200-300 kWH per month, and others here use way less than 100 kWH per month. Climate, personal choices, all matter in terms of power usage.

We try not to get into the politics of why/why not, and just focus on practical solutions that met your needs.

-Bill

ChrisOlson · October 2012

Re: Looking to go Off Grid

Photowhit wrote: »

So this is a furnace, can you open the damper before you fire the stove? My wood stove would just draw fine, I'm not in the great white north, but I've had a fire going in my house for as much as 6 weeks at a time, I only open the damper when I'm cleaning out ash, it really helps then!

Photowhit,

Per your previous comment, "First it's nice you have a wife that still wears/can fit into a "little black mini-dress"...
I suppose we all take our spouses for granted after awhile. But my wife not only still fits and wears the authentic original little black mini-dress, she looks absolutely fabulous in it. I probably don't tell her that enough.

Our furnace does not have a damper on it. It has one of those catalytic recombuster outfits that burns the particulates in the smoke. There's a thermostatic draft under the grates for the firebox. There's also a top draft that lets fresh air into the smoke before it goes into that catalytic thing. There's a flame baffle in the firebox so direct flame can't get into the catalytic section of it and burn it out. We have to turn off the bottom draft to open the door because that makes it draw on the door opening instead of the draft opening. But some smoke going around that flame baffle in there collects near the top of the firebox. There's a smoke baffle at the top of the door opening that's hinged and that helps keep the smoke in the firebox, but some still leaks out when you shove a piece of wood in it.

We can't burn some types of wood in it - pine or box alder is two types. The pitch in pine gives off some kind of fumes or gas that makes that catalytic thing glow and it will burn it out if you burn pine in it.
--
Chris

Looking to go Off Grid

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