From Oklahoma

[Steve76]

Thanks for the add. We are in the process of designing a new house for the family. We had earlier intentions of building to net zero (or close as practical) with some renewable energy. This has changed now that we have the quote from the utility to provide grid connection. We have an existing 2000 foot over head line extension that has been off line since the 1970s. We were quoted over $15k to bring it up to current standards and extend it another 500' to the point of service connection. We are now contemplating putting the funds toward an off grid application instead. A little background on myself: I currently hold a master mechanical contractor and commercial electrical journeyman ratings with the state along with various industry related energy management and building performance certifications (and incidentally, an Advanced Class amateur radio ticket for the past 25+years). I work in the DDC automation, building commissioning, and energy management industry. That being said, I have the background and access to equipment to build our own control system for all things energy related on the build. We are at least a year out on breaking ground, so I'm gathering as much research and evaluation information as I can. I would ask to not go into the economics of the system. We are not basing our decision solely on whether or not it makes for positive cash flow. Our family is looking at the greater picture of environmental concerns, energy security, social stability, weather damage, ect.

[SunEagle]

Hello Steve76 and welcome to Solar Panel Talk.

Sounds like you have a lot of research to do before you jump into an off grid system.

Leaving out the economics for a minute (but that can be a show stopper for most and you did bring up the cost of a grid connection), an off grid system is not very green due to the usage of batteries and fossil fuel for a generator that is a must due to extended periods of poor weather.

Also batteries is not a good solution to energy security because they do not last very long and can get more expensive as the system ages. A whole house generator using bottles gas is much more reliable and provides a lot more watt hours then an expensive battery system.

Weather damage is something that most pv system do not survive from. High winds and wind thrown debris can create a lot of headaches for the panels.

IMO if someone was concerned about the environment they would stop using any type of equipment that pollutes which includes any type of battery chemistry.

So there are my thoughts. Welcome to the mad house.

[Steve76]

Thanks for the thoughts. No matter what the outcome of our final decision on electrical supply, the primary design elements will be geared toward high efficiency building practices and low consumption building systems. This will provide the lowest base line power consumption regardless of source.

[SunEagle]

Thanks for the thoughts. No matter what the outcome of our final decision on electrical supply, the primary design elements will be geared toward high efficiency building practices and low consumption building systems. This will provide the lowest base line power consumption regardless of source.

Sounds like a good plan. If you use power efficiently then your need to generate and rely on it less. Best way to save money and the quickest payback is to conserve energy usage.

[DanS26]

Two things I would consider:

1. Go back to your POCO and ask if there is anything you could do to lower the grid tie connection....ie clear the right of way, etc.

2. Since you are in the design phase make sure your roof angles and orientations are solar ready.......IF you ever decide to go that route.

[Sunking]

Thanks for the add. We are in the process of designing a new house for the family. We had earlier intentions of building to net zero (or close as practical) with some renewable energy. This has changed now that we have the quote from the utility to provide grid connection. We have an existing 2000 foot over head line extension that has been off line since the 1970s. We were quoted over $15k to bring it up to current standards and extend it another 500' to the point of service connection. We are now contemplating putting the funds toward an off grid application instead.

Howdy neighbor and fellow OKIE. Last thing you want to do is take anything off-grid, especially in Oklahoma. You are asking for a 1000% rate increase for the rest of your life and a new part time job with no days off. Not to mention very limited power. The batteries will cost you more than the utility upgrade and those batteries need replaced every 5 to 6 years. Additionally requires you to have a generator to perform required monthly battery maintenance and a power source for those cloudy rainy spells of 2 days or more. We are not talking about a small gasoline portable generator. we are talking one large enough to fully charge your batteries in 8 hours or less, plus run your home. Something on the line of a 10 Kw or larger with diesel, NG, or LPG tanks.

I know Oklahoma well, worked for PSO for 10 years, and in Oklahoma you will need air conditioning 6 months or more out of the year. Last thing you want is batteries and Air Conditioning.

Additionally electricity in OK is dirt cheap making Grid Tied almost impossible to ever achieve break even point. OK does have Net Metering laws in place today and is mandated on the utilities, But rest assured it is going away very soon now that Nobama and democrats were thrown out of power.

So do your homework, or else you might just regret your decisions.

[Steve76]

I definitely have to emphasize the word "considering" when it comes to the idea. This is one of the downsides to my personality, if there's a technology, system, network, ect that I don't have a sufficient working knowledge of I will research it to death for months on end. Usually this serves me well in my line of work since people pay me to solve their problems. The whole renewable energy world has always fascinated me. Unfortunately, I've never had an opportunity to delve into it. On the other side of the fence, I'm not unrealistic either. My personal curiosity has to be balanced with the reality of the real world (much to my dismay...). We'll see where this leads. At the least, I'll say I've done my due diligence and explored the option(s). As far as generators are concerned, I actually have several. Ranging anywhere from small Honda inverters, Miller pipeline rig, and an older 25kw diesel rig.

I do have one question....AC for only 6 months?? It's been closer to 12 lately.

[Sunking]

I do have one question....AC for only 6 months?? It's been closer to 12 lately.

Yeah in Oklahoma sumer can last 11 months. I remember winter of 89. Lakes froze, (extremely rare only once in my lifetime) by Thanksgiving, and did not thay until February. Point is Air Conditioning and Off-Grid do not play well together.

I was born in Shawnee at Tinker AFB, left when young to Las Vegas until 6th grade, came back to Tulsa until I graduated high school at Bishop Kelly, and graduated from OSU. After I got off a Submarine in the Navy did 9 years time at PSO before going to Wiltel which grew up to Worldcom until the party ended in 2003. After that went into biz for myself making a lot more money doing the exact same thing in Texas for 11 years. Now I live semi-retired in paradise of Panama tax free. 2 of my 3 kids live in Tulsa, and my oldest Son took my place at the Engineering design firm. Fun part is he pays me to work there and throws me a bone once in a while. I know OK utilities real good and the politics.

Yep I am a proud half breed Injun and half Redneck SOB they call FBI.

[Mike90250]

Welcome.

My advice is much as was given earlier.
Go with the grid. 2500' of service line is not bad. Have it sized for a LARGE residence, 300 or 400 Amp service. If you ever add solar in the future, you will be thankful for the extra capacity, which costs very little when building new.

Have a generator transfer switch installed, You will want a generator for backup power. Size the service to handle your loads, you can always switch off gear to match the size of generator you install (something like a Honda EU7000 inverter generator, with split phase 240V to interface with standard household wiring) or some giant generac20KW fuel sucking behemoth. Remember, the ice storm that took out miles of power lines, likely took out your PV array too ! Just like the wind blown hurricane debris fixes all the solar panels. And your water source, city or well, can the genset run the pump?

Yes on the Passive Haus thoughts.

Good Luck

[Steve76]

It's good to know that the design criteria I've looked at so far is pretty similar to what has been suggested. The first question I had when meeting with the utility estimator was whether or not I could contribute to the connection labor/material. The additional extension will most likely be underground primary simply for the sake of the driveway layout and to a lesser degree aesthetics. I figured I could at least open the trench with my backhoe, install the conduit and sand bedding along with back filling and compaction, but alas it was a no go. Apparently they have had some scenarios like mine go bad lately, so now it's all done by their guys or approved contractors. The grid connection was also speced for a 50 Kva padmount and a 400A single phase service set at a central location with a distribution rack and branch circuits for residence/shop/agricultural loads. I would love to have 208 dropped for possible machine tools later down the road, but that was going to be a disturbing amount of money to extend the additional phase wires. Another issues that I'm sure added to the cost is the fact that the distribution voltage is scheduled to be upgraded from 7KV to 14KV in the next few years so all new installations have to have dual voltage primary xfrmrs. That was part of the line upgrade cost as well. I will be burden with the insulator upgrades and line height changes for the higher voltage even though it's still only 7KV at the time of connection.

At a bare minimum I will have some version of a transfer switch installed. I'm currently looking at either going with a dedicated service entrance rated manual switch, or a SE ATS with manual override capability. That way I can use one of my portable units for now but be set up to drop in an automatic system with load shedding later on down the road if needed (medical issues, disability, you never know what life has in store for you). In a similar design, I have the manual SE switch now, but also wire the residence with an emergency sub panel to make installing an ATS a breeze at a later date. That way essentials are covered but I still have the capability to back up the entire system including shop and misc agricultural loads not tied to the residence.

Another design factor I have been weighing is the aspect of building the solar system for 3 phase with the conext XW+ or similar equipment. Comparing this with the even more astronomical line extension starts to ease the $ pain. This is a bit of a pie in the sky dream, but I'm still looking at every possible angle. It's easy to do with pencil and paper (ok, CAD) but not so easy with brick and mortar. Realistically I'll add a rotary phase converter if I every get to that point.

Along with the centrally located padmout and distribution rack, my plans are to put the well house at the same location. This will make for something of a central power/utility building for the property. The well house will be large enough to accommodate inverter(s), battery bank, ect if that were ever needed. It also provides a central location for all connections and would have all the power gear and batteries located away from other structures (yes I'm a bit paranoid about fire). That being said, I would go will all ground mount equipment. I just have a personal issue with putting equipment on my roof. I guess that comes from years of working on other customers stuff and how inaccessible equipment can be. In my experience, routine maintenance will only get done if it's a routine action. Climbing on top of a building is rarely considered routine. Also, I've built enough pipe and cable/sucker rod fence in my day (anybody that's lived around the patch knows my pain), so welding up some poles or racks could probably be done with the scrap I have laying around.

Anyway, thanks for the input so far. Like I said, I have at least a year ahead of me. It'll be a great education no matter what the final design is. I've learned a lot of things both good and bad in just the last few months that I've even considered renewables. As they say, the day you quit learning is the day you start dieing....

[Sunking]

Another design factor I have been weighing is the aspect of building the solar system for 3 phase with the conext XW+ or similar equipment.

Steve trust me on this one but last thing you want to do is use 3-phase, especially on as small of a house as you have. I would not even advise that on large homes.

The only benefit going 3-phase is if you have an extremely large demand for electricity. Completely counter productive to efficient. Secondly a 208/120 service means very expensive Water Heaters, Clothes Dryer, Cooktops, Ovens, and most importantly Air Conditioning and Heat. Not a lot of selection out there and what is available is expensive because it is for lack of a better word Queer in the USA.

One example where you see 3-phase used is in some Apartments where service is delivered at 480/277. However requires expensive transformer to convert to Single Phase 250/125 for the units. They do it that way so the building owner does not get stuck with 208/120 and having to buy expensive appliances.

[Mike90250]

When building your "utility shed" use separate compartments with Fire Rated walls, so if the generator goes, the inverter is still safe. Or the batteries leak, everything else is safe. Generator and fuel storage will now (or soon) need "moats" to isolate oil leaks. Cast that into the slab when you pour it.
And look at Fiber Reinforced concrete along with standard rebar, cheap addition of chopped fiber greatly increases strength.

[PNPmacnab]

It is interesting how conservation, environmental concerns, energy security, social stability, weather damage, quickly turns into 400A service. Hard to get family to accept the minimalist life.

You seem like a curious guy and not intimidated by soldering a couple wires. Should you want to dabble in the world of solar, I have a couple ideas. In an emergency people would rather freeze than be without their cell phones, laptops and internet. Most modern wall warts will operate if supplied with more than 60V DC (A 36V PV string). I have a camp off grid and runs off a single car battery. The main array is only 900W and I can run a refrigerator and have hot water with less than $100 for all the electronics. That is possible by scheduling and using every possible electron from the panels. This is all possible by a $3 Arduino NANO, development software is FREE. Just simple IF statements, copy and paste available software. The lower element of a water heater can easily be powered with three 250W grid tie panels and supply some of your hot water needs. The electronics cost is next to nothing. With only panel costs, the payback is higher than any other use. 100% of possible production is used. You don;t get that with anything else. Got a boat battery you store? Keep that on charge and run the refrigerator twice for 15 minutes every hour in an emergency. No need to buy a charge controller, my NANO drives several by adding just a FET and a few other parts. It is just amazing the control capability. Just think of yourself in a room with a lot of meters and switches. What you would do under different conditions is your program. Great feeling to take a hot shower and know it is free. $3 isn't a lot to spend to learn something and change your world. Others here wouldn't have a chance with this. Just thinking you would. I have the software.