Looking to go Off Grid

Celeste

hi! Cheers! Thanks for reading my question.

My dad is building me a house. We had always intended to be off-grid but he couldn't resist hooking me into the grid cause it was already run by the previous landowner. So, currently we have purchased a "switch" that will allow us to stop using the grid and then use batteries.

The house (which is sealed up as of last week!) is in a place where is very sunny in Summer and very windy in Winter. So I think solar/wind together, with majority of power in summer from solar, and majority in winter from wind.

We have room for about 25 roof mount 250 watt panels, and can set up probably around a 4 or 5 kW wind turbine.

I think we have calculated that our usage will be about 1500kWh per month, but that is what we use NOW, so could really be smaller with some energy awareness.

I've seen a few independent hybrid controller systems to incorporate both wind/solar and even a generator.

Anyway I am a total newbie, but want to do this and think I have a reasonable amount of funds to get a properly functioning system.

THanks for all input,
Celeste

BB.

Re: Looking to go Off Grid

My advice:

1. Do not spend one dime on any solar equipment at this time.
2. You have Grid Power to the home--Use it for now.
3. Instrument your home/appliances. Something like a whole house monitor + a Kill-a-Watt type meter for plug-in appliances. Depending on what you get and your budget--A few hundred dollars or a bit more (more options, more measuring points).
4. Look at your home. Insulation, double pane windows, weather stripping, heat recovery ventilator, high efficiency heat pump (A/C and Heating), LCD/LED lighting, picking Energy Star Appliances, etc. etc.... It is almost always a better investment (if you ever sell) and less expensive to conserve power than it is to generate power yourself (solar, wind, etc.).

Once you have done 1-4 and logged your results (kWH per day/month, by season) and done pretty much all of the conservation you can justify (remember, with pure off grid power, you are spending around $1-$2+ per kWH for electricity--Or about 10x as much as you will pay for grid power--So any conservation you do will pay off emensly in allowing you to use less power and "down size" your off grid power system).

Next, you need to ask what you need off grid power for when you have perfectly reasonable (and cheap) utility power).

Do you want emergency backup (hours, days, weeks)? Are outages rare occurrences or almost daily afternoon power failures?
Do you need all power when the grid is down or can you live with a reasonable subset (i.e., no A/C when utility power is down).

The cost of power, roughly:

• $0.10 to $0.20 per kWH: Grid
• $0.15 to $0.35 per kWH: Grid Tied Solar (no batteries, no back power)
• $0.45 to $0.75 per kWH: Hybrid Solar (Grid Tied when utility is up, off grid when utility is down)
• $1.00 to $2.00+ per kWH: Pure off grid solar (battery bank+inverter+panels+charge controllers+back up genset, etc.)

Not all utilities allow Grid Tied power--You have to check with your's.

Just to give you an idea--A very well insulated/efficient home with basic electrical lights, washer, tv, water pumping, etc... can be around ~100 kWH per month.

To generate ~1,500 kWH per month--is a pretty large system. And lots of maintenance (battery replacement every 5-15 years, inverter/charge controller replacement every 10+ years, backup genset maintenance--if used, etc.). To generate 1,500 kWH per month 9 months of the year could run around $100,000 to $200,000 just for the initial install (really wild guessing here--Just to set you expectations).

Where will the system be installed (roughly, nearest major city/region to look up the amount of sun you will get).

Personally, I am not a big fan of wind power (lots of maintenance, variable/unpredictable output, very site specific--if the wind is not "unpleasant" to live with--then you may not have enough wind to be useful).

-Bill

Photowhit

Re: Looking to go Off Grid

I think Bill caught all the high lights...

Since it's a new place be very careful when picking out your new appliances, will this be a total electric house? 1500Kwh is a lot of energy! Where are you located? Did pop - pop for 6" well insulated walls? R40 in the roof? This will help your long run costs. Earth contact would make for cheaper heating and cooling...

1500 KWh is not a practical amount of energy to think about storing for more than a 24 hour period (even that, the thought is scarry... 2000Ah 48V battery for a 50%DOD for 24 hours of no charge?) Look into a grid tied system! since it's a new home, it might even be a nice 'pilot' project for a utility that wants to show it's willing.

So is the roof area with the room for panels south facing?

How about heating with wood? it's cabon nuetral and you can do an outside wood heater and use big logs and tie into your inside central distribution, or a pellet stove...

Celeste

Re: Looking to go Off Grid

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.

I guess the question I should be asking is what is possible. They are marketing wholesalesolar dot com a 500 kWh per month system for around 20k, that's with batteries and cables and controller etc. A 4kw wind turbine could run about $20K as well, and surely some additional batteries upping that to 30k. OK, so then maybe I would be getting 400 kWh per month. One can run a fridge freezer, lights and entertainment on that? I have accepted that I will have to hang my clothes and diapers to dry.

Celeste

Re: Looking to go Off Grid

Oh, 1500 kWH is our current monthly electric bill. SO that is 50 kWh per day. So I think we would want to be storing 150 kWh? I'm not terribly well versed in the conversion from watts to kwh..

Photowhit

Re: Looking to go Off Grid

Don't spend money yet! Talk about what the system they are selling has. People here can evaluate it.

Wind is tricky. I wish I knew more about it but if you have 20 mph avg and have the space to put up tubines, knowing they will need to be taken down from time to time for servicing... maybe.

I've lived off grid and hope to do 13Kwh a day next summer, we have sun with our heat and I will do a minimal reserve system, I have gotten good enough deals and will do the install myself, and it will be roughly $13K if I had to do it with out bargain shopping, likely $20+ if someone else was doing it, I don't know what the system your looking at has, mine will have 6.5 Kw array, a 800Ah 24V battery, 120/240, 2 charge controllers, 4000watt inverte,(planning and price given reflects that, I was cut back to part time so likely go with what I have) all wiring, fusing, grounding...

Your talking about a system 4x as large... if your shooting for 50Kwh a day (1500Kwh a month) and likely adding to that wind, if you want to prepare for 3 days with out sun or wind, add a battery bank the size of a room (I did not say small room)

Photowhit

Re: Looking to go Off Grid

Celeste wrote: »

Oh, 1500 kWH is our current monthly electric bill. SO that is 50 kWh per day. So I think we would want to be storing 150 kWh? I'm not terribly well versed in the conversion from watts to kwh..

If you looked at a 'normal' system, you would want 3 days no wind or sun storage down to 50% or the battery capacity, more than that and the battery might be damaged. So storing 150Kwh or a battery of 300 Kwhs, the math looks something like this;

300,000 Wh /48v = 6250 Amp hours The largest 48V battery I could find was 1600Amphours it's neartly 4000lbs and you will need 4 of them, The near wholesale price is $8300 each Here.

To service such a large battery bank, you would want to be able to charge at a rate of @ 10% of capacity, 625 Amps at 48 V = about a 30,000 watt array BEFORE rerating to @80%. These are scarry numbers.

So, as suggested, check out what you actually use, conserve and see what you actually need, sounds like pop did some really smart things, the house might use very little energy, is there need for AC where your at? I would guess you have a deep water well that will use a good bit of power, and lots of it if you have a huge green house?

Celeste

Re: Looking to go Off Grid

OK, you are making me laugh. That number is what we use now - I have two children in cloth diapers that I put in the dryer.... Not sure what that amounts to, but surely it isn't small. SO to say, we can adjust our energy consumption drastically. We will also buy all LED light fixtures. I ordered an energy star fridge and a propane stove. Is a microwave even a option? My dad has specialized in building energy efficient homes longer than I have been alive, so we have designed the home to need less energy to heat. I did convince him to let me have a swamp cooler, although he kind of called me a wimp for acting like 78 degrees was too hot in his house when it was 102 outside... Anyhow, thanks for making me think.

THe system wholesalesolar sells includes for $10,171.00

18 240-watt Astronergy Solar Solar Panels

6 MC4 10 AWG - 50' Cable Extensions

1 MidNite MNPV-12, 12 Position Combiner Box 150V

1 4 Star Mini-Magnum MS4448PAE Power Center

1 Outback FM80 & Breakers installed on Mini Magnum Center

UL Listed breakers and cables

1 Midnite MNSPD300 Lightning Arrestor

1 Wiring Diagram

and battery banks Surrette Battery Bank 48VDC 1,200 Ah 24 Surrette 6v, 400 Ah S530 Battery Cables and Float Hydrometer for

$9,055.00

But my question really is, how do I combine this system with a wind turbine.

Celeste

Re: Looking to go Off Grid

My husband did a pretty nice table of what we will need, so hopefully I can find that tomorrow to post what we envision actually using. Waiting 6 months to monitor consumption and adjust doesn't seem like an option right now for us. The money has to be spent on something soon.

waynefromnscanada

Re: Looking to go Off Grid

50 Kwh/day and thinking of going off grid? WOW! Perhaps if you were using 5 Kwh/day, but NOT 50!
Even 5 Kwh/day is a big off grid system. Major change in way of thinking is required.

solar_dave

Re: Looking to go Off Grid

So at 1500 kWh a month your most cost effective way to do solar is by grid tie. We have a 12.5 Kw name plate rated system and can produce 2200 kWh in May and 1300 kWh in December, we have excellent solar potential. You will have to double at least your solar and add the cost of a huge battery bank to cut the grid off. You will also have the expense of a large generator to maintain that battery. Grid tie in effect uses the utility as your battery eliminating the expense and hassle of a battery bank.

BTW off grid is much more work in battery maintenance over time, plus if you mess up you will be buying batteries again at a huge expense.

Ralph Day

Re: Looking to go Off Grid

Hi Celeste
Been there, done that. I was off grid for 6 years, like yourself because we wanted to be. It was quite a learning experience. When we installed the 10kw fit system (feed in tarriff) we put another service in to use the utility like a multi billion dollar generator. That works well. If I want to charge batteries, I just flip one breaker, if I need to use the generator I flip 2 breakers (and go out, start the generator...).

The power used to charge and cover loads costs: Generator...30cents per kwhr minimum. Utility...6-14cents per kwhr depending on time of day. Our daily loads are still in the 6.5-7 kwhrs per day range, utility usage averages 3kwhrs per day in a given billing period. Solar and wind pick up the majority of the loads averaged over a year.

If utility is there now Grid-tie, put in a generator panel and have a backup genset for any outages. Especially if your daily loads are 50kwhrs/day. With propane for cooking/hot water/clothes drying you could cut your loads by more than half, but that puts you way above off grid living (unless you have wind turbines like tulips around you). Otherwise you're looking at a crippling amount of pv and generator run time...and there will be generator run time, 24/7 if your loads stay at 50kwhr/day.

Good luck. TAke some time to research, reduce loads before you spend a huge amount of money on this.

Ralph

peakbagger

Re: Looking to go Off Grid

The economics dont make a bit of sense. If someone has a fat checkbook and doesnt know what to do with it, have them set up a college fund for the children.

One option may be to go half way, install a grid tie system and set it up so that in the future you can switch it to off grid. The advent of the Xantrex high voltage charge controllers means that if you design it right you can go grid tied initially and then in a few years when new battery technology trickle down from the emerging electric vehicle industry if it makes sense you can make the switch.

In the meantime even though you are on grid you could simulate being off grid by only using the power you generate each day to run the house and determine the limitations to doing this. To make the simulation even more realistic, plan on having to "buy" a new battery bank in about 3 years and then plan on 10 to 12 year schedule.

A grdi tied system makes a lot of sense and that is why most systems are grid tied. For a feeling of security install a a breaker panel with a transfer swtich and buy a generator.

I have run into many people who were formerly off gird and the majority of them welcomed the day when a grid connection was availlable.

Eric L

Re: Looking to go Off Grid

The economics dont make a bit of sense. If someone has a fat checkbook and doesnt know what to do with it, have them set up a college fund for the children.

But he didn't say he wanted to do it for economic reasons. He said this:

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.

I think it's perfectly reasonable to spend some income on hobbies/discretionary purchases/luxury items, and if the OP considers renewable energy with an eye to off-grid living to be such a discretionary purchase, what supposed to be wrong with that?

That said, completely agree with what everyone's saying above that energy use has to come down by a large factor (of 5-10) for off-grid to be viable.

BB.

Re: Looking to go Off Grid

We need to wait for the OP's power estimates... The 1,500 kWH per month was for their current home energy usage, not the new one.

-Bill

Celeste

Re: Looking to go Off Grid

What we expect to need in the New house in kWh per month

refrigerator - 50
freezer - 50
coffee maker, blender, mixer, juicer, computer, satellite dish, lights, vacuum etc - 150
deep well water pump - 50

So that is a total of 300 kWH per month.

This are the changes we assume - no furnace or furnace fan, no clothes dryer, no hair dryers or irons, no hot water heater (using solar water heater), will be buying all new appliances with energy star, no microwave, What other changes would I need to make to make this a viable option for us?

The people at wholesalesolar really think that 18 panel system will give 500 kWh per month.... Are they wrong? We have a lot of sunny days in Wheatland WY, and LOTS of wind, yes, in this area of the country wind turbines are popping up like tulips. From Casper to Douglas which is 40 miles there is almost a solid line of them....

Going to look at a neighbors house who is grid tied...

BB.

Re: Looking to go Off Grid

Ok, we can start with numbers:

Using PV Watts for Cheyenne Wy, fixed array, tilted to latitude, with 18*250watt panels (4,500 watt or 4.5 kW of panels):

"Station Identification"
"City:","Cheyenne"
"State:","Wyoming"
"Lat (deg N):", 41.15
"Long (deg W):", 104.82
"Elev (m): ", 1872
"PV System Specifications"
"DC Rating:"," 4.5 kW"
"DC to AC Derate Factor:"," 0.520"
"AC Rating:"," 2.3 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 41.2"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:"," 7.2 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 4.14, 309, 22.25
2, 4.93, 328, 23.62
3, 5.67, 419, 30.17
4, 5.86, 397, 28.58
5, 5.82, 390, 28.08
6, 6.24, 389, 28.01
7, 5.96, 376, 27.07
8, 6.12, 391, 28.15
9, 6.20, 395, 28.44
10, 5.40, 374, 26.93
11, 4.46, 311, 22.39
12, 3.79, 278, 20.02
"Year", 5.38, 4356, 313.63

So--That is a pretty good match for what you are looking for. 278 to 419 kWH per month. A bit larger array would be a good idea if 300 kWH per month of actual, minimum, power usage.

These are 20 year average numbers (+/- 10% variation is very likely)--You should not plan on using 100% of estimated power every day. Some day swill be more, others less. If your base load is ~66-75% of estimated power per day--You will be fine.

Of course, there will be times of bad weather (typically during winter) where you will need a backup power source (grid, genset, etc.), or you have to use less power.

In general, we recommend avoiding electrical heating devices (electric cook tops, water heaters, etc.)--But for a larger system, some use of microwave, coffee makers, etc. can certainly be supported.

Battery bank size... Assuming 48 volt system and 300 kWH per month (assuming 1-3 days of storage and a maximum of 50% battery discharge for longer life):

• 300 kWH / 30 days = 10 kWH per day
• 10,000 WH per day * 1/48 volt battery bank * 2 days of "no sun" * 1/0.50 maximum battery discharge = 833 AH @ 48 volt battery bank

Looking at a 5% to 13% rate of charge (rule of thumb) for a battery bank:

• 833 AH * 58 volts charging * 1/0.77 panel+charger derating * 0.05 rate of charge = 3,137 Watt array minimum
• 833 AH * 58 volts charging * 1/0.77 panel+charger derating * 0.10 rate of charge = 6,275 Watt array nominal
• 833 AH * 58 volts charging * 1/0.77 panel+charger derating * 0.13 rate of charge = 8,157 Watt array "cost effective maximum"

So, depending on how much "extra solar panel" you will want--Using your location and basic numbers, a 4,500 watt to 6,275 watt array would seem to be a nice fit (I am using all the digits like 6,275 so you can repeat my math, and see where the numbers are coming from).

Personally, I am not a fan of wind (expensive, lots of service required, and unpredictable output)--I would suggest designing the system as above with solar array... And then, if you will want to try wind turbines, you do your research and install one to help reduce generator run time during cloudy weather.

-Bill

Cariboocoot

Re: Looking to go Off Grid

I have somewhat of a unique perspective on grid vs. off grid because I'm both, depending on where I am at the moment.

Your present usage of 1500 kW hours per month is three times what we (two people) use on grid. It's twenty times what we use off grid. Big changes are indeed necessary to make the switch. Here's three suggestions:

#1). Get a Kill-A-Watt meter and measure the things you use now in real life operation. Otherwise you are just guessing and that is a painful and expensive mistake to make.

#2). Get rid of the electric coffee maker and anything else that uses electricity to heat.

#3). For off-grid power management think in terms of daily Watt hour use, not monthly. Your power comes in batches every day, not a continuous supply 24/7. And always have a back up generator for when it doesn't come at all.

On the plus side, a good refrigerator and/or freezer will use less than 50 kW hours per month. This will also depend on what the climate is like and how often it gets opened. Ours at the off-grid site is 16 cu. ft. and uses about 36 kW hours per month. Likewise the well pump could be less as some are more efficient than others.

"An 18 panel system" doesn't mean anything; panels come in different sizes.

300 kW hours per month is 10 per day, which is still quite hefty for off-grid. To achieve that you'd need about 5kW of panel on the roof, and that's a lot of panel. For some idea of what you can expect in your area you can use the PV Watts site: http://www.nrel.gov/rredc/pvwatts/grid.html

As others have said, this project makes no economic sense whatsoever. You already have grid. If you want to go solar go grid tie. It could even be profitable.

But no matter what your power source, identifying power loads and reducing them as much as possible is your best bet.

icarus

Re: Looking to go Off Grid

If your reasons for "going off grid" is either to be "green" or to save money,, it is a false choice. If your motivation is self sufficiency then that is a different argument. Bottom line, if you have the grid available, and you either wish to be "green" or (ultimately" save money, then grid tie is your very best alternative. The net power from grid tie comes at about 1/2 the cost with twice the efficiency.

As a piece of advice, I would consult with local PV installers and your local utility to see what the net cost/benefit of grid tie is lieu to be over time.

Tony

mtdoc

Re: Looking to go Off Grid

Or you can go with a "Grid Interactive" or hybrid system using Outback or Xantrex inverters. You'll have the benefit of Grid Tie to make up for any deficiency in RE production and still get the benefit of some self sufficiency. You'll suffer efficiency losses compared to grid tie and you'll still pay quite a bit more than a pure grid-tie system but you've stated that this is not a financial decision. On the other hand you will be able to enjoy the financial benefits of net-metering or RE production incentives if they're available where you live. If you decide to go this route I would look at the Outback Radian Inverter - given your projected relatively high loads.

BB.

Re: Looking to go Off Grid

I will add here--The 0.52 (52%) efficinecy for off grid solar gives you the PV Watts results above... The same Grid Tied system would be ~0.77 efficient and cost 1/2 to install... So, same PV Watts for Cheyenne (4,500 watt array, fixed tilt, etc.) but GT would be:

"Station Identification"
"City:","Cheyenne"
"State:","Wyoming"
"Lat (deg N):", 41.15
"Long (deg W):", 104.82
"Elev (m): ", 1872
"PV System Specifications"
"DC Rating:"," 4.5 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 3.5 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 41.2"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:"," 7.2 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 4.14, 467, 33.62
2, 4.93, 493, 35.50
3, 5.67, 626, 45.07
4, 5.86, 596, 42.91
5, 5.82, 590, 42.48
6, 6.24, 589, 42.41
7, 5.96, 571, 41.11
8, 6.12, 590, 42.48
9, 6.20, 593, 42.70
10, 5.40, 563, 40.54
11, 4.46, 469, 33.77
12, 3.79, 420, 30.24
"Year", 5.38, 6566, 472.75

So, yes, a Grid Tied system will generate a lot more power for a lot less money--With the requirement that you have a utility grid and you will not have emergency solar power if the grid power fails (unless you go with a Hybrid Inverter + battery bank--The efficiency of GT but the cost of off grid system--may make sense or not to you).

Also, you have to talk with your utility company--There are some utilities that do not support GT connected solar power systems, and others that have very poor metering regulations that don't save you very much money on power costs.

-Bill

Vic

Re: Looking to go Off Grid

Hi Celeste,

Wholesale.. may be OK, but the sponsors of this great site are top-notch folks and have packages systems as well. They have been in the Solar biz for decades and give great service and advice. For example:
http://www.solar-electric.com/ofsokiforho.html

Have dealt with Wholesale once before, but did not appreciate the manner inwhich they charged CA Sales Tax, so do not do biz with them anymore .. FWIW. Not to nag at you. And welcome to the Forum.

The only moderating thing that I will say about the Electric Coffee Maker, is if it is used in the morning to MAKE coffee, and shut off after the 3-6 minutes required to MAKE coffee, then it uses very little power, and to me, is a great convenience. The ultimate OG system will be fairly large, and the caffine extractor will be a very, very small power consumer. Even a Microwave, if used when excess power is available is not such a bad idea IMHO. BUT, do agree, conserve, conserve, and then conserve a bunch more! Good Luck, Vic

Photowhit

Re: Looking to go Off Grid

I'm not a coffee drinker, so I'm not aware of the costs, but others here have made the point of using the coffee maker to make the coffee, then pour it into a thermos or aeropot(?) to keep if hot. Makes some sense to me.

Microwave is fine so long as your not cooking whole meals in it, I think it fits well with off grid solar, I have one in my cabin and use it often, even when I only have 4 golf cart batteries. I'll make popcorn or re-heat meals rarely does it run more than 4-5 minutes.

If you do 'Go off grid' you'll learn to load shift doing things during the day, so you don't have to store energy to do them. I even run a toaster oven off mine from time to time, and will more as an opportunity load during the day (I work 2nd shift). I do this when the batteries are near or fully charged. Unlike the microwave, I don't use this when the sun isn't shining. It sounds like your pop built a very tight house, you'll want a CO2 alarm in your kitchen with the gas appliances.

I think even large freezers are using around 1Kwh a day, is this an old freezer you moving over? Your water pump might be low if you have a big green house to feed, but I'm on county water and don't know the ins and outs of water pumping. You might set this up with a large water tank in the green house, so you can fill during the day and store water rather than energy.

FWIW - The prices given aren't too bad, we as a group are a pretty thrifty bunch and would buy the pieces and save some money, but a quick look I could see with in 15% of the electrical things, We have had some people coming to the forum with issues with the Rolls-Surette(?) batteries and even with this smaller capacity bank, you would have 3 strings of batteries, fewer is normally better. I would go for single cells in the Rolls or move over the a forklift/Traction battery.

Not sure why the money is burning a hole in your pocket, I use to play pool for a portion of my income, and would always feel that way after a big 'score'. usually I would go out for breakfast and go home and pay bills or put the money in the bank...

...So my suggestion is go out to eat! Think long and hard, please don't jump into anything. I'm NOT saying you haven't thought a lot about it, only that your just now getting some real numbers to look and think about.

Ralph Day

Re: Looking to go Off Grid

refrigerator - 50
freezer - 50
coffee maker, blender, mixer, juicer, computer, satellite dish, lights, vacuum etc - 150
deep well water pump - 50

A good energy star fridge will run at about 1kwhr per day. A freezer, depending on size 1kwhr per day. deep well pump...mine considerably less than that...just under .6kwhr for a week. I measured with a Kill a watt meter for a week and that's the result. See the figures at the link provided (if that's ok with the moderators).

http://www.greenpowertalk.org/showthread.php?t=6640&highlight=Booster+pump+submersible

I think your 150 kwhr/month is high for all the other stuff. At 7kwhrs per day my total would be 210kwhr per month. You're getting there. A Killa watt meter (or equivalent) will help greatly on figuring out the actual loads you'll incurr.

Ralph

BB.

Re: Looking to go Off Grid

I will also add that placing many of the electronic stuff on power bars that you can switch off when not in use can also save significant amounts of power (switching off entertainment systems/dvr/sat rcvr/internet comm/etc., using laptop vs desktop computers, etc.) can save over 1/2 the power used (in many cases) vs being left on and/or in "standby".

-Bill

Celeste

Re: Looking to go Off Grid

As stated above our estimates are pretty high, I think we took into account the 70% rule on this side of the calculation. I think 300 was what we calculated for high month. But as stated by PPs we probably need to go back and do a high usage day...

The numbers will take me some time to go over and understand, and thanks so much for posting them.

I am very much liking the sound of waiting for technology from auto industry batteries to develop.... As I said we are going to look at a neighbor who is grid tied with wind. I guess I now have to read up on this stuff... grid interactive..hybrid inverter..grid tie. Could you guys post some links, or the title of a book I should read?

What kind of generators are used for backup and how are they integrated?

The following is posted for those interested in my motives... BEWARE :0

I am eager to invest in something that will in the future be worth what I pay for it today. Electric rates in Platte county have gone to a little over 15cents per kWh. (average according to http://psc.state.wy.us/htdocs/dwnload/Ratecompweb.pdf) Just a point that the cost of electricity isn't static and it is going up at an exponential rate, we haven't yet felt the full effects of the EPA shutting down 30% of the coal fired power plants last year. Economic effects take a bit to "trickle down". in addition to shutting down the nuclear disposal units greatly increasing the cost to run nuclear power plants. I am betting on a few more rather steep electric rate increases in the next few years. Ah but, that is just a guess... and perhaps we can consider this a "high risk" investment, likely to be a loser, but possibly will be a winner. If we have to look at this in economic terms. Green - I AM using a coal boiler to heat the house, so "green" I think I would not be considered. I have a little bit a paranoia about the gvmnt and I want some independence from their "grid"... Inflation is likely to hit this country even worse than it is now, and I am also concerned that what I can buy now I won't be able to buy in a year.

Celeste

Re: Looking to go Off Grid

And thanks for pointing this out http://www.solar-electric.com/7waofsoposyw.html - seems like a nice system and thinking these guys will also tell me if that Outback inverter will take input from a generator or wind turbine... Thanks again all of you! Oh wait, I have that backwards right? The controller woudl take the input??

BB.

Re: Looking to go Off Grid

We have all thought about what will happen next here...

Off grid solar tends to be expensive to maintain too... Batteries may last 5-8 years/8-15 years/20+ years -- Depending brand/model/class of battery you purchase.

Inverters/charge controllers/other electronics have about a 10+ year life (on average)...

So, you still have a fair amount of exposure to variations in pricing/availability of the equipment to make your power.

Pure grid tied is, basically, just an inverter that connects to your AC main panel and takes electrical energy (solar panels, wind turbines, etc.) and takes the electrical energy and "pumps" it into your AC lines--Which slows down, or even can turn your meter backwards during the day (and runs forwards at night).

GT is very efficient, lowest maintenance, cheapest to install. Requires utility power and will shut down if the grid fails (weather, car accident taking down pole, etc.). Requires building permits and utility approval.

Off grid solar is simply a battery bank that is recharged by whatever (AC Mains, solar panels, wind turbine, AC Generator, etc.). You run your DC loads and AC inverter from the battery bank, and recharge with available power. This is expensive (battery bank is major expense) and less efficient (energy conversion losses, battery charge/discharge cycling, etc.).

Hybrid Inverter is a special Off-Grid battery based inverter... When the Grid is up, the Hybrid Inverter takes excess power from the battery bank (i.e., battery is fully charged) and pushes it back into the grid. When the grid fails, the Hybrid inverter disconnects from the grid and runs the local AC devices. Hybrid Inverters are about the same cost as Off Grid inverters, but can pump excess power to the grid (GT mode) and use the grid like a giant AC Battery bank (turn utility meter backwards during day, forward at night) and still provide AC power when the grid has failed.

The newer/lager AC inverters have become very complex with many options and optional modes.

In general, it is better to define your loads and needs first, then we can help suggest equipment configurations that may meet your needs. Once you understand what we are talking about, then you can do further research and look at variations that my work better for you.

-Bill

Photowhit

Re: Looking to go Off Grid

I'm often asked why I do off grid solar, with the grid running by my house, in truth if I was just starting out and thinking about it, I couldn't/wouldn't do it. I live on less then 20K a year but have always been very independent. When I bicycled into Missouri in 1999 I had been wandering the US on my bicycle for 8 months and had lived off a 10 watt solar panel and 2 - 5 Amp SLA 6V batteries and a dual fuel Coleman camp stove run on unleaded gas. So living on 200 watts of solar and a couple 6V golf cart batteries and wood stove wasn't a big change. Later when I wanted AC after 5 years of living on fans, I still had a break even point of about 12-16 years.

This year or early next I'll take a 16x60 modular home off grid, I'll have no practical break even point and I didn't hesitate...

To me it's the feeling of independence and taking care of those needs myself, I'll romanticise it and say I feel like Tom Bombadil of the Lord of the Rings, the important part of The Lord of The Rings that Peter Jackson missed, he was living independent and parallel to the rest of Middle earth and uneffected by the 'Ring' when he put it on, and it's just another pretty bobble to him. In a simpler vain it's Hulk vs Loki in the avengers, Loki the power company wants to set down the rules as a Demi God but hulk lives by simple rules.I hope you have read Lord of the Rings or watched The Avengers....

waynefromnscanada

Re: Looking to go Off Grid

Photowhit wrote: »

why I do off grid solar, with the grid running by my house, in truth if I was just starting out and thinking about it, I couldn't/wouldn't do it. I live on less then 20K a year but have always been very independent.
To me it's the feeling of independence and taking care of those needs myself, living independent and parallel to the rest .

Pretty much describes where I'm coming from as well. For me, it's an awesome feeling, knowing my home is energy independent, while all around me, others, knowing no other way, have placed the well-being of their lives in the hands of big business. I have been (in my life) where these other folks now are, so it's not like I don't understand their existence, but they have totally no clue about where I am now. They have no clue either about home energy conservation, and there is no end of complaining about their high electric bills.

Eric L

Re: Looking to go Off Grid

As I said we are going to look at a neighbor who is grid tied with wind.

It would be interesting to hear how that's working out and the cost. I used to live nearby in Laramie, and while there was plenty of wind (it's Wyoming, duh), there was also bright sunshine year-round. The PV Watts numbers from Cheyenne that BB posted confirm that solar production should be pretty uniform.

Even with Wheatland's wind, it wouldn't surprise me if, with the current very low price of solar panels, solar would still be the winner on a cost-per-watt basis; especially when you factor in productive lifespan of a wind turbine versus solar panels.