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-   -   Anyone working toward Off Grid (https://ecorenovator.org/forum/showthread.php?t=4760)

randen 04-21-16 07:45 AM

Anyone working toward Off Grid
 
I would seem that the technology is now available for Off grid systems. I'm wonder if there are any Eco-renovators out there working toward this amazing goal.

Solar P/V has become quite affordable and the supporting equipment, inverters etc. have become more reliable. And now the Tesla Powerwall the best tech in electrical energy storage is here.

The other side of the equation, the consumers of that electrical energy have become very efficient. LED lighting, appliances, and heat-pumps.

The methods for home construction and materials have gotten better. The passive house designs requiring such a small amount of heat is another step in the right direction.

I'm just wonder if eco-renovators are working toward the goal??

Randen

gasstingy 04-21-16 01:27 PM

I've looked closely at my energy consumption and my family could do off-grid for about 9 months of the year. However, our local weather patterns for those other three months would have me doing a massive amount of generator running.

What I am planning to do long-term is put in a battery storage system and a Sunny Island and partially power my home from solar. When the weather isn't agreeable, I'll still have the grid. When the utility power fails, if in the low solar production winter months, I'll run very minimal load and heat the house with natural gas instead of the heat pump.

oil pan 4 04-22-16 06:15 PM

It's a waste of money to go off grid when there is a perfectly good power line right outside of your house.

The tesla power wall is an over priced toy for the rich, just like almost everything else they make.
It's not the best, it is the newest and just because some thing is new doesn't automatically make it better than what was in use before. I find the people most impressed by the power wall don't have any idea what the existing tech is like.

The best is still low voltage DC modular charger and inverter systems powered by lead acid.

NiHaoMike 04-23-16 01:30 PM

It can make sense where the service fees are high. One example of that would be some parts of College Station, TX where the service fees were on the order of $40/month. Not sure if it's still that expensive now that there are "off grid in a box" devices that are nearly ideal for college students.

gtojohn 04-23-16 01:31 PM

My cabin project is off grid. Currently thats just a 5400 watt honda. PV panels bought but not on the roof yet. Same with the hot water panels. Composting toilet purchased but not installed. Haven't bought batteries yet either, that won't be until the end. I've been too busy to make any progress on the cabin this winter. Good news is the lake is backed up into our cove, we have about 6-8ft of fresh water in the creek and I found sulfur spring water on the property. I've been focusing on other parts of self sustaining like permaculture, digging rain water catchment ponds, wildlife habitat and food sources. If it were just me off the grid wouldn't be difficult. My wife's power requirements are much higher and her comfort directly effects my own. I don't think I can afford to take her off the grid with me ;) Funny thing is her best friend since kindergarten could totally do it, just depends how you're raised.

oil pan 4 04-23-16 02:07 PM

$40 a month is a deal compared to going off grid.

In a nut shell to go off grid you need to first save as much electric power as possible.
Then you need to convert most if not all your heating needs to natural gas or propane or solar thermal.
After that figure out how much power you use per day. Then install 2 to 4 times that in panels and size the battery bank for about 4x what you use in a day. Get an inverter and not the cheap ebay ones to power your largest demands.
After all that you will still need to buy a backup generator.
Typically start up costs are usually starting well over $20,000.
Then once you think the setup just might break even the inverter or charge controller will suddenly quit. And you have to replace the batteries at some point, between 5 and 10 years if you are lucky and 2 to 3 years if you are unlikely.

MEMPHIS91 04-23-16 05:52 PM

I find that most people who are looking to go off grid either don't understand all the is involved (money, batteries, no sun for days, etc.) or that do it as a worst case scenario as in grid down. For me, I have been planning going off grid for a very long time. It is not about saving money, its because I want security that my power company is not capable of providing.

NiHaoMike 04-23-16 06:44 PM

The requirements can be very low for a student. It helps that heating is rarely even needed in College Station and that the usual fall/spring semesters miss the hottest days of the year. Hot water in many apartments there are also included in rent.

And while it could well be considered cheating as far as truly going off grid goes, a good number of students already spend much of their time on campus. One could just charge a battery pack while on campus and use it to run LED lighting and some basic electronics at home, no solar panels needed. Back then (about 6 years ago), LED lighting and lithium batteries were a bit expensive to justify doing that, but now they're practically dirt cheap.

Kramer 04-24-16 06:24 AM

Batteries seem to be the most expensive and the least reliable part of an off grid solar system. It might be more practical to look for individual loads that can be taken off grid without batteries or expensive grid tie inverters. Well pumps, pool pumps, Hot water and HVAC systems seem like good candidates. Each could have its own set of panels, motor control system and if needed, energy storage other then batteries. Then, eventually the lighting, and other low wattage loads could be put on a small battery bank with the grid as a backup charging option. Save the mains power for heavy, occasional loads (e.g. vacuum cleaners, power tools)

randen 04-24-16 08:46 AM

I would agree with Kramer regarding the reliability of lead acid batteries. However the new chemistries of lithium are becoming available. I've seen some you-tube video where some people have installed lithium packs liberated from a Nissan Leaf and showing some excellent results coupled to their solar PV.

For the reliability the manufactures are warranting the batteries for eight years and this would be a very conservative time frame as I'm sure they would not what to be supplying new batteries seven years out. I have read the Tesla Roadsters produced in 2008 has a lithium pack that showing some very good life as measurements of 90% of the capacity remains.

As more and more electric vehicles meet their demise with trees, poles or other cars, a lot of lightly used batteries will be available to the eco-renovators for a lot better price than Lead-acid.

Randen

MEMPHIS91 04-24-16 11:20 AM

Randen, I am for sure looking to go the way of an lithium car battery. I'm on the edge of my seat waiting for the price to get better and more and more cars are produced/wrecked a little.
The only way I have found to be able to go the lead acid route is used cell tower batteries or forklift batteries.
For me running the HVAC system is only a must in the summer when my solar hours will be much higher. I use wood heat in the winter, but of course if I have a large enough system I should be able to use the up and coming geothermal system on the sunnier winter days saving my wood burning for only the coldest of nights.

oil pan 4 04-25-16 01:51 AM

The prices on lithium batteries are not going experience any dramatic fall in prices.
When I built my 8 cell amp20 LifePo4 battery in 2012 then expand it by 4 more cells last year the price of the cells was almost the same price I paid 3 years earlier.
I believe the price actually went up in that time.

MEMPHIS91 04-25-16 05:11 AM

I have a general question, let us assume someone is looking more toward the worse case scenario idea. And getting new batteries every decade or 2 is not possible. Which type battery would last the longest? I know the nickle iron batteries are great but their charge rate sucks. Would lithium be the next closest thing?

stevehull 04-25-16 07:03 AM

Memphis - the perfect battery is not yet on the drawing boards. What we have today are essentially elegant capacitors. They store charge for a bit, but they lose it internally. The input output inefficiencies will always be there - and even if they are each 95% (very high), you still lose double that as you must come in at 95% and they go out at 95%.

Then there is the aging issue (that you mention). There are only so many life cycles on a battery.

I maintain the best "battery" is actually available - the grid.

A self contained battery (totally off grid) will require some 30-50 kWhrs per day minimum. For those of us in the south, where air conditioning is dominant, then double that. All the chemistry I read about is interesting, but my estimate is that it will take a generation (human) or so to further develop.

Fuel cell technology will likely be a better participant in this as very rapid gains are observed - especially in the many kW situation. Is a natural gas line to your home "off grid"?

The other day I was looking at a physical situation to describe what a mega Whr was. It was hard until I was stopped at a train crossing while a train went by. Turns out that a diesel locomotive is about 1 mW at full output. So that engine, pulling a long trainload of cars for one hour is about 1 mWhr.

I mention this as 33 kWhrs per day (minimal consumption) for a month is about one mWhr. A tremendous amount of energy.

Yes, I know that many here can survive and do quite well on less than 30 kWhrs/day, but will the average Joe/Suzy and family do so? My experience is that they want their electricity sucking appliances AND they want it now at the flick of a switch.

Yes, we can scrounge packs from smashed up Volts and Bolts and that is what people on this forum love to do. I have a friend doing exactly that right now (and am helping him test each cell as it comes out). But internal losses, aging/cycling problems and input output inefficiencies make this maybe a solution for a couple years.

NOT trying to be a wet blanket, but I maintain we do already have a "battery" - and a very efficient one at that.

Steve

MEMPHIS91 04-25-16 08:30 AM

I do understand your point. I've read similar articles saying the same thing. But I will stick with my original question, in a worst case scenario what is the best battery currently available (or at least soon to be) that would provide a reasonable amount of storage. (75-100+kWh) of power with NO grid.
I am a conspiracy kind of guy. And its no secret that the grid is a mass thrown together money pit, that gets harder to maintain and even harder to power without robbing the next generation of clean air, unpolluted water, and at safe areas to live in without radiation poisoning. What we have now will not last, I hope for everyone that it last your predicted one generation to find a different means of storing or making power, but in all my research I believe we will see a mass grid down scenario long long before that.
It would be wise at least on my part (since I believe what I do) to prepare the best I can for that to happen. I could care less about cheap electric bills. I want security. And yes that might come with having to deal without a few comforts when it happens.

jeff5may 04-25-16 09:10 AM

Quote:

Originally Posted by MEMPHIS91 (Post 49848)
I find that most people who are looking to go off grid either don't understand all the is involved (money, batteries, no sun for days, etc.) or that do it as a worst case scenario as in grid down. For me, I have been planning going off grid for a very long time. It is not about saving money, its because I want security that my power company is not capable of providing.

This security you speak of does not come easily or economically. To provide backup power for when the grid is down is one thing; to provide complete independence from the grid is another. It takes a well-rounded and thorough approach, as well as lifestyle changes. Whether or not your entire family (living in the home) is willing to make these changes (or not) will bear heavily on your system requirements and backup capacity.

A recent line of commercials illustrates this idea with the usual American blatant disrespect: the "settlers" being portrayed in the DirecTV ads. This attitude of making do with what is available is a mentality that many people will no longer accept. Although your family will not have to go to the extreme "homesteader/settler" methods being ridiculed in the commercials, they will need to implement some changes in that direction in order to reduce your raw energy consumption. Simple acts like hanging clothes on a line outdoors, washing them in cold water, and washing (and drying) dishes by hand really add up in savings. Make sure everyone involved is willing, or design your system larger if not.

As you are detailing in your ground-source/water-source heat pump projects, these two methods (direct and water heat exchange) are a large part of retaining comfort while reducing energy demands. When used with some sort of thermal (hot and/or cold) store, your heating and cooling needs can be buffered or time-shifted to reduce or eliminate comfort control from taxing your battery storage. Again, not simple or cheap, but highly effective. Naturally, the insulating and envelope strengthening you are doing further increases the effectiveness of comfort control systems and reduces your thermal energy needs. These comfort control improvements are essentially invisible to occupants not concerned with the details of how they operate, working behind the scenes to satisfy demand.

For a completely off-grid home, using the raw voltage your PV panels produce without conversion is the most efficient way to use that power. Having some low-voltage DC lighting that runs off a panel or two is also a great indicator to those less energy-conscious occupants as to when they can use high-drain equipment without taxing your battery bank. When the lights are on, at least some portion of the consumption will come directly from the panels; when they are off, they know they are using battery power to dry their hair or whatever. This "psychological" habit change can mean the difference between a battery bank draining overnight or not.

jeff5may 04-25-16 10:43 AM

Quote:

Originally Posted by MEMPHIS91 (Post 49868)
I have a general question, let us assume someone is looking more toward the worse case scenario idea. And getting new batteries every decade or 2 is not possible. Which type battery would last the longest? I know the nickle iron batteries are great but their charge rate sucks. Would lithium be the next closest thing?

Like Steve and Randy have stated, there is no such thing as a perfect storage battery. For one, they burn generated power on the way in and out, to the tune of 10 - 20 percent round-trip loss. For two, their charge rate and capacity are limited: there is a finite number of charge and discharge cycles a battery can provide before it is spent. For three, batteries have a finite shelf life: if they are not used, they will slowly discharge and lose capacity naturally with age.

Whether or not you accept the fact, any available storage battery available today will need to be replaced (regardless of usage) over the course of a decade or two. How much loss of original capacity you are willing to accept is the main factor that will determine your replacement time frame. Over time, the replacement cost is pretty constant: if you install a larger bank to account for the loss of capacity, your replacement will be less frequent, but you will have more batteries in your bank.

Like the others have said, the power utility is essentially a low-loss, infinite source and sink of generated power for a single family home (when it operates). With most modern inverter-driven systems, insertion losses are close to an order of magnitude less when feeding power into the grid compared to the losses of charging a local battery bank. The economics of grid-tying vary with the individual power company and their pricing structure, and are worsening as the general public gains the ability to generate their own solar power. Those of us who did grid ties maybe five or ten years ago got better deals than someone wishing to tie in today. Even so, the savings of needing to maintain a much smaller (backup-sized) battery bank are substantial. You will eventually have to decide whether to pony up big bucks to support your ideal to be grid independent (and the bank it requires), orto save the investment and use the grid for storage.

Kramer 04-25-16 10:43 AM

I live in the South as well, and AC accounts for about a third of my usage. I want to build an ice storage system that i think will be much cheaper more robust then any battery bank. My idea is to put a few hundred partially water filled soda bottles in a tank and then fill in the voids with a glycol mix. My thought is that this way the expanding ice will not damage the tank or any piping since the bottles will be able to move freely as they freeze. Then, I just pump the glycol from the tank, and then through indoor evap coils (now converted to glyco/air heat exchangers) as needed throughout the day or night. The only need for batteries would be to power the coolant recirc pump. The AC compressor and condenser fan can run only when the sun shines.

jeff5may 04-25-16 11:06 AM

Kramer,

The type of system you describe is known as phase change material (PCM) based thermal storage. It is highly effective at leveling your load for comfort control. There are PCM's available besides plain old water, and some of them even sequester more heat (or cold) than water does. More importantly, the various PCM's have been designed to absorb and release their latent heat in whatever temperature range you may require. There are a few threads on the forums where these methods are discussed at length, and some members have shared their experiences in using these materials to acieve goals such as you describe. When and if you experiment with and/or implement a PCM-based solution, be sure to detail your experiences with us. Projects like you speak of have made this site the robust source of information and inspiration that it has become.

I wish you luck in your pursuit of this method.

oil pan 4 04-25-16 03:27 PM

Quote:

Originally Posted by MEMPHIS91 (Post 49868)
I have a general question, let us assume someone is looking more toward the worse case scenario idea. And getting new batteries every decade or 2 is not possible. Which type battery would last the longest? I know the nickle iron batteries are great but their charge rate sucks. Would lithium be the next closest thing?

The cheapest battery that will last the longest and has a good shelf life are lead acid AGM.
Good shelf life high mobility but at high cost are LiFePO4.
Batteries that kind of last forever are nickel iron. But they are expensive, big and have almost no mobility.

oil pan 4 04-25-16 03:59 PM

Quote:

Originally Posted by Kramer (Post 49881)
I live in the South as well, and AC accounts for about a third of my usage. I want to build an ice storage system that i think will be much cheaper more robust then any battery bank. My idea is to put a few hundred partially water filled soda bottles in a tank and then fill in the voids with a glycol mix. My thought is that this way the expanding ice will not damage the tank or any piping since the bottles will be able to move freely as they freeze. Then, I just pump the glycol from the tank, and then through indoor evap coils (now converted to glyco/air heat exchangers) as needed throughout the day or night. The only need for batteries would be to power the coolant recirc pump. The AC compressor and condenser fan can run only when the sun shines.

I don't think that will work very well.
I use glycol coolers and splits at work.
For example a 5 ton split condenser has 1/4 line feeding liquid refrigerant going to it.
The 5 ton glycol cooler needs 36gpm and has 1 inch lines going to it.

MEMPHIS91 04-25-16 04:53 PM

Yep I could not agree more with everything ya'll have said. I'm not trying to disagree, just trying to really answer Randens question by saying YES I am thinking of going off grid, even though it means BIG changes. And large expense. And large head ache. And probably a mental breakdown every time someone turns on a light, or watch a dvd for longer than 10 minutes at a time.
My question still remains, what would be the best (not perfect) but best with todays market, battery system to achieve that goal. Assume I was handed a $100,000 check (me installing myself of course) and could ONLY spend it on solar.

oil pan 4 04-25-16 05:29 PM

Well you are going to need a backup generator.
The best batteries are true deep cycle lead acid wired for 24 or 48v.
Use MPPT charge controller.
Don't put in one large too big to fail charge controller or inverter, because it will quit some day. Use smaller charge controllers and more than one inverter. Large inverters tend to be very inefficient on very low loads and gobble up far more power in stand by mode. Smaller modular inverters and charge controllers will make upgrades easier so you aren't ripping out everything and replacing it all during an upgrade.
Go one size up from what is recommended for DC wiring.
Switch over all heating loads to direct combustion.

Kramer 04-25-16 07:53 PM

Quote:

Originally Posted by oil pan 4 (Post 49887)
I don't think that will work very well.
I use glycol coolers and splits at work.
For example a 5 ton split condenser has 1/4 line feeding liquid refrigerant going to it.
The 5 ton glycol cooler needs 36gpm and has 1 inch lines going to it.

Is the glycol used to cool the ambient air or to cool the condenser? We have AC systems at the power plant where I work which use glycol to cool the condenser, however since the glycol is cooled by a cooling tower it is close to the outdoor temp. Since it is warm to start with, it takes a lot flow to remove much heat from the condenser. Not much delta T. For my idea to work, the water flowing through the evap would be near 0C. This is not as cold as the refrigerant for which the unit is designed, however, the entire evap will be liquid filled unlike with refrigerant which is undergoing a phase change in the evap. Sorry Memphis91, I'm getting off topic.
The Fe-Ni seems interesting, I think it would be cheaper if produced in volume.

oil pan 4 04-25-16 09:55 PM

That was 2 different units.
I was trying to say is there is no way enough glycol can be pumped through the tiny evaporator inlet lines.
The glycol where I work is cooled down to near freezing with ammonia refrigeration.
The glycol to air heat exchanger is huge compared to phase changing refrigerant.

oil pan 4 04-25-16 11:58 PM

For going off grid try to eliminate heating that uses forced air ductwork.
In Japan they like those little kerosene space heaters.

Kramer 04-26-16 12:01 AM

I have a few larger heat exchangers, sounds like they might be a better choice since I won't get the benefit of the phrase change. Thanks for the advice. I used to spend some time in the Taos-Red river area. Is that close to you?

oil pan 4 04-26-16 12:42 AM

The red river area is about a 4 hour drive north from where I live.
Its actually kind of nice up that way.

jeff5may 04-26-16 07:00 AM

OK, so I'm going to try to address the issue of space heating/cooling, combining the off-grid requirement of Jake (Memphis), the phase change storage of Kramer, and the advice of Oil Pan.

It should be possible to install enough solar panels and a small and efficient enough heat pump to satisfy cooling demand with the solar power gathered during the day. The most effective way to do this would be to install two heat exchangers indoors: one that feeds directly off the refrigerant loop, and one that feeds off the cold store. Another intermediate brazed-plate exchanger could be installed that fed off refrigerant and exchanged heat with the cold store. Both the refrigerant-to-air (DX) and the refrigerant-to-glycol (BP) should be TXV metered. When the house calls for cooling demand, the air handler would cool the house air quickly and efficiently. When no cooling was being called for, the BPHX would extract heat from the cold store. The outdoor unit would run constantly as long as the cold store was above a certain destination temperature, let's say -5 degC. Once the cold store froze solid, the outdoor unit would not run unless there was cooling demand called for indoors.

At night, the outdoor unit would not run. When cooling was called for, glycol would flow through the second indoor HX then through the cold store. A large enough cold store would stay at or very near 0 degC all night. Due to the reduced heat load, the cold store would only need to be massive (not supermassive). When the sun came up in the morning, the outdoor unit would start charging the cold store for the next night.

In heating mode, the same strategy could be used. When the sun was shining, the outdoor unit could charge heat into the store while no heat was being called for by the house. There are two factors that make this setup less effective for heating, though. For one, the store would not change phase, so the amount of heat it could sequester would be much less. For two, a balance point exists where an alternate heat source would be more economical to run. At the high end, it becomes inefficient to charge the heat store above a certain temperature. At the low end, the outdoor heat exchanger becomes ineffective at gathering heat from chilly outdoor air. Outside of this range, it is wiser to burn wood or natural gas to meet heating demand. During a cloudy cold spell, it might make sense to level the load out by burning backup fuel, diverting the reduced solar power to the battery bank.

Another need that could be satisfied with this type of system that was not mentioned is domestic hot water (DHW). Jake has built a heat pump water heater, and has proven that a small (dehumidifier or refrigerator) amount of capacity can serve his family and a house full of guests without running out of hot water. A small heat exchanger (desuperheater) could be rigged at the compressor outlet that served only the DHW tank. This HX would not rob an excessive amount of heat from the rest of the system, and would self-regulate at a temperature that would not yield scalding hot water.

A major goal of this type of rig would be to not run off of battery power at all. Space heating and cooling is a huge load, and would lay waste to precious battery power that would better be saved for lighting, ventilation, and electrical infrastructure.

randen 04-26-16 08:18 AM

The solar panels 10 kw's worth should be showing up this week. 4 kw's will be covering the pergola the rest 6 kw's will rest on the flat roof. The first order of business will to have the 4 kw pergola interrupt the grid supply and power the home while the sun is available.

My summer usage is about 20 kwh per day. As we head into the winter the geo-thermal units (3) starts to really flex their muscles and 100 kwh per day. Now I must qualify this as I'm also factoring in my business usage running a machine shop and running a geo-thermal (DIY) there as well.

I have a spread sheet on my usage in 2009 the price was $0.13 /kwh and we had been notified April 1st the price is now $0.26/ kwh Doubling in seven yrs. Without going to deeply into the math and ROI its going to workout nicely by installing the solar.

Now batteries I see some anecdotal information. I'm currently working with large format Nimh that were manufactured in 1999. Under load testing they are shown the have still a 80 to 90 % of their capacity remaining. Now yes they do have some internal losses during storage. How ever Lithium batteries have not demonstrated this loss during extended storage. These chemistries are completely different and light yrs better than Lead-acid.
Better yet you can actually buy them now and they are not pie in the sky just around the corner technologies. I can go down the scrap yard and buy 20 kw's of battery out of a volt or leaf and put them to work. If I treat them properly in a residential type charge discharge they will last for decades.

Randen

Kramer 04-26-16 10:44 AM

The hybrid system is and interesting idea. What I had initially imaging was a compressor consuming all the solar energy available and basically functioning as a solar ice maker. This would be paired with a hydronic air handler. Of-course the ice storage would need to be able to absorb all the power on the sunniest day beyond what is consumed by cooling during those hours. A couple tons of ice, perhaps about 500 gallons for a large system. With a hydronic system, zoned cooling could greatly reduce night time demand.

I don't see it working to well in the winter without supplemental heating since the solar power and heating needs peak at different times.

Also, an alternate use would be needed at times when HVAC demand is low. It would pair nicely with a geothermal system since it could be used to recharge the ground loop when not needed.

jeff5may 04-26-16 01:29 PM

Well... humm...haww... nobody ever said too much about a ground-source exchanger.

That changes everything...please tell me why.

MEMPHIS91 04-26-16 06:38 PM

Great ideas! I live in probably one of the most prefect places ever. So my case is different than most. In my case I can run the AC when the sun is up and curse through the night without any AC. Also as mentioned the hot water heater only has to run during the day too (as long as the sun shines for that day) Not the mention the hot water heater is now doubling as a small AC/dehumidifier when it runs.
Lights and a very few other appliances would be the only thing really needed at night. (assuming bright days)

Kramer 04-27-16 02:02 PM

Quote:

Originally Posted by jeff5may (Post 49914)
Well... humm...haww... nobody ever said too much about a ground-source exchanger.

That changes everything...please tell me why.

An insulated soil bed could be used instead or along side of ice as a cold storage mechanism, or it could be located after the indoor air coil. The water/glycol could be pumped through pex coiled within the soil. It wouldn't need to be that big, just an extra buffer for when solar power is exceeding AC demand over a longer stretch of time.

Redmohawk 05-17-16 01:33 AM

You want mass , in a small volume , your not going to move it .

Stone is cheap , immersed in glycol will work just fine, fill a tank with stone insulate and away you go.

Redmohawk 05-17-16 03:35 AM

Started an intro thread today , will start linking my future projects to them as I go .

Total independence from grid and some self sufficiency food wise along with income from home planed.

http://ecorenovator.org/forum/introd...html#post50122

Robaroni 05-17-16 06:14 AM

Hi Guys,
I've addressed this before here so please excuse my redundancy. I'm sort of a prepper myself and my original thoughts, ten or so years ago, were that I would go autonomous and completely turn off the grid. After living with PV, off and on grid, I've modified my original thinking.
The best solution is to have an off grid/intertie system. This way the grid keeps your batteries charged an when the grid fails the batteries take over and run your house. You get to sell energy back and still have fully charged batteries when you need them and even LA batts can last a very long time.

With that said, if you still want to go completely off grid you will need more than just PV because batteries, regardless what kind, simply won't cut it. I have about 10Kw's of PV, this summer (hopefully!) I'm putting in wind and micro hydro.

You have to look at your land in its entirety and extract every bit of power you can from it. If you live on a 100 x 100 lot you're not going to make the power you need and your best option is the off grid/ intertie system. I can tell you this after building battery boxes, an off grid only system and an off grid/intertie system. And I have 16 acres with a stream and good wind I've monitored for several years.

Wind compliments PV and microhydro trumps them both ( sorry for the trump word!). Microhydro is the best because you get power 24/7 and your batteries only come into play for surges like motor starts. Even if the stream doesn't provide all the power you'll need it will get a boost from PV and wind if you calculate your system right.

That's the way you have to figure and look at it. Land is power, we've forgotten that with the advent of fossil fuel but, as most of you know, fossil fuel is not our friend!

Rob

creeky 05-17-16 09:00 AM

I've been living full time off grid for five years now. I love it. So here's a few things I've learned.

ONE: Build it: Solar.
It's easy. And cheap. (this could also be called ignore the trolls)
Yup. Even a humble fella like myself can stumble through a solar build. It's cheap. I built my starter system for $5k. I've grown to around $8k and I have an electric everything. Except my stove and some hot water. I have propane for that. By choice on the stove. I prefer cooking on a gas stove. I also have plans for solar augmented hot water. But, at less than a 40 lb propane tank for hot water every year. No rush.

TWO: Don't be afraid to grow
I've grown my system. It was a pretty bare bones 1 kw system when I started out. I've added a second kw of panels and a second controller. Put in a better inverter. Added a battery charger. An ATS. All as I learned I needed them.

THREE: Buy modern stuff
This means Lithium batteries. If you can get/jury rig a Volt or Leaf battery. Huzzah! But lithium is cheap compared to the alternatives. So even some nice big fat expensive Lifepo4 1000 ah with a bms will pay you dividends for many a year.
Again, this could be called ignore the trolls. I don't know why. But mention any battery chemistry but Pb and the rocks start to shake.
It also means look to Europe. Inverters and chargers from Europe are currently (ha. never gets old) the way to go.

FOUR: be flexible.
Yes, living off grid on a humble solar system like mine means I have to wash dishes in the dishwasher (electric hot water) when the sun shines (tho that will change when i get my lithium battery pack).

FIVE: It's easy.
Really. There are so many folks who have been doing this for so long. You'll find a plethora of quality info online. I have discovered "bokashi" for making my waste management (composting) easy. Building "perfect walls" to keep house heating costs down (combo wood/propane). "Texas cool roofs" to lower cooling needs.

SIX: Experiment
Perfect for us experimental types. I've been running a variety of experiments. Most very successful (texas style cool roofs before they were popular. now on rev C). Solar. Perfect wall. Wow. Some less successful. Pole style building on clay soil? Ha^%@#.

SEVEN: The benefit list is long. And goes well past energy use
One of the best things about living off grid is the extra time you get. I deliberately set out to build a lower overhead lifestyle. I spend my money travelling. Meeting people. Writing. Doing art. Surfing the web. Cooking. Being active. My quality of life has gone way up.

To sum up. Off grid is awesome. Go for it.

Robaroni 05-17-16 10:54 AM

Creeky,
It depends where you live. The hardest thing to do is to heat and cool. Heating in Northern US climates like mine where it can get to 20 or 30F below means that you need alternative heating methods, you can't do it on PV alone. It's the middle of May now and we had a frost two nights ago with several days of overcast. There's no battery that can cover that. You can burn wood sometimes but if the outside temp gets too high you'll get a back draft.

Living off the grid means greater expense for batteries and a shorter life. Why not let the grid charge your batteries and only use them when the power goes out?
I'm over $500.00 ahead on my electric bill and I use it to my advantage. In the winter I use electric heat to supplement my oil and reduce costs while my batteries don't get overworked. What are you gaining by not letting the grid work in your favor?

As for time, being off grid doesn't save you time or give you any extra time. In fact it takes more time to live off grid. And it's not a breeze either when those batteries get low on an overcast day and that genset has to kick in.

I guess you're in England and Europe is easier for you as far as inverters but there are good inverters in the States. Outback, like mine for example which are very highly rated.

I agree that you can start slow and build but you still have to know where you're going as building for off grid involves different equipment than off grid/intertie. What you want is flexibility and that means land. Can you put in a microhydro? Probably not, how much land do you have? Enough for a windmill that will actually accomplish something? That takes real estate, you can't put up a windmill on a 1/4 acre lot, well you can but you can't get it high enough to do real work.

Sure you can shut off the grid but you'll have to spend more on other resources to heat, cool and cook.
Rob

creeky 05-17-16 11:34 AM

I'm about a mile from hydro. No intertie option. Putting in just the poles to run the grid in would have cost $35k. I have six acres. I'm north of you in Canada. The wind maps show this is a poor area for wind. Not to mention turbine maintenance. My creek by the property is too slow for useful hydro.

So as for heat and cooling. Situating your building(s) for shade is a good idea. Building properly insulated structures is key. I use around 500 lbs of propane and 1 face cord of wood per year. When I expand my system I plan on putting in an ASHP.

I do use a small electric a/c unit in my studio. The only building that gets too hot (not as good insulation/strong west late day sun exposure).

I have never had trouble with back draft using my wood stove.

Batteries. Pb is dead. Lithium is the new standard. Talking about anything else is not time efficient.

I'll point out that most people say off grid electric is too expensive. And then they use absurd comparisons. Ie., my electric is .07/kw. Not taking into account the electrical system/grid hook up costs that are on their mortgages. Because if they can't see it, it doesn't exist right?

Due to heavy cloud in the late fall I use a genset. Two years ago I used $50 in gas. This year was more, but I was building. So $80? Big deal. A season for one week of truck use. Last year I went from Jan 3 to Oct 16 without any genset use. I run the genset a max of 2 hrs maybe twice a season. I expect this to drop with a lithium battery pack. Usually an hour in the a.m. suffices. And that is typically/rarely more than one or two days a week.

Again. I actually live off grid. So, from 5 years experience: Once your systems are built they are completely reliable.

For ex. I emptied my composting toilet facility last fall for the first time in 4 years of use. It took me an hour. Cost. .25 in diesel using the tractor to move the material to a secondary composting area. (Note: Now no trace of the material remains. Completely returned to the earth.)

My electrical grid has been up and running for 3.25 years without interruption. It's funny, as many people "in town" know I'm on solar, they delight in telling me about the latest grid interruption. Two years ago the "big game" was interrupted for 20 minutes by a grid shutdown. I saw the whole game. Many laughs were shared.

Because I don't have the overhead costs of living on grid (taxes, mtg etc) I have a great deal of "free" time. And living in a rural area where I get to do some light farming and kayak, hike, fiddle fart. I'm in terrific shape. My life is wonderful.

You make your own decisions as to consumption. I traded excess material consumption for time. This makes me happy.

Now, this is my experience. Results may vary.


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