New and Overwhelmed!

**gj.gibson** · April 20th, 2010, 14:05 PDT

I thought that I was really ignorant when it came to wind/solar power. After scanning this forum, I have realized that it is much worse than I expected!
WOW! You folks are very knowledgeable about everything solar.
I am wanting to build my retirement home in the next 3 years. I have a spot very suitable. It is a Tennessee hilltop with great sun exposure and almost always a breeze. The problem I ran into was with the power company. I was nowhere near a power line and it was going to cost me a fortune to get power to the top of my hill, only to have the power company send me a bill every month.
So, I have the spot and and rough floorplan(subject to change). but nothing else.
I am looking for some direction. I plan on keeping the house under 2000 sq ft and want to incorporate wind, solar and geo-thermal to be completely energy independent.
My biggest question(s) is , Are there complete systems available for new construction houses? Can anyone give me some direction or point me to a reputable company that can help me?
I am just setting sail on this journey and I appreciate any and all advice, knowledge and direction this forum has to offer.
Thank you all for your time!
Regards,
Jeff G.

**icarus** · April 20th, 2010, 14:21 PDT

First question,,, how far away is grid power and how much is it going to cost to bring it to your door?

Nearly all other answers hinge on that number.

Next, spend as much time as you can so you can avoid the single biggest pit fall (s) of RE, Ready, fire, aim. (And overcoming preconceived notions!)

If you are really going to be 100% off grid, realize that it is going to come at some considerable cost, (the power definitely won't be free!) and that everything you can do now, in the design stage to reduce total net energy use will pay very big dividends in terms of reducing RE costs going forward. Pay particular attention to HVAC options, energy recapturing or geothermal if you have to use A/C. Proper solar exposure for maximum solar gain during the heating season, and minimum during the cooling season. Roof overhang details that shade in summer, allow direct sunlight in winter, and so on. (Plantings/awnings too!) As you design, an eye for electrical loads are important, but other energy loads are also important, including water heat, water pumping, space heat etc.

I would spend every available minute reading everything you can, (here and elsewhere) so that you know as best you can going in what it is going to cost, and most importantly, what the limitations are likely to be.

That said, grid power is far and away your cheapest alternative. Grid tie solar is a great investment (in certain areas, depending on a number of factors) and battery based solar is far and away the most expensive option (on a per KWH basis) I like to say that battery based systems cost ~ twice as much as a similar grid tie system, and operate about 1/2 as efficiently, resulting in net/net four times as expensive power than grid tie.

I would go to here first to see your solar potential :

http://rredc.nrel.gov/solar/calculat...ATTS/version2/

Then here : http://www.windsun.com/Batteries/Bat...of%20Batteries

http://www.batteryfaq.org/

And here: http://www.freesunpower.com/system_sizing.php#startGrn

That is enough homework for now,,,

Good luck, welcome to the forum, and feel free to ask any question(s) you wish. the are some very sharp, very helpful people here, many who have forgotten more about PV than most of us will know,

tony

Ps I think you will find that most of the folks here are not real high on small scale wind. It comes with some pretty tough problems. The long and short of it, is in most cases if you have enough wind to make it viable, you then have too much to keep the hardware from self destrutcing quickly.

Flowing water on the other hand,,,,

PPS. I don't get it, but home power magazine is often considered the "bible" for off gridders. Worth reading some back issues.

PPPS,, Some idea of your location would help answer some general questions better. Arizona has different solar dynamics than Maine for example.

**Cariboocoot** · April 20th, 2010, 14:34 PDT

Just to address the "off-the-shelf" question; solar/wind/hydro are highly site specific. There really can't be a "one size fits all" solution by any standard, not even per Watt hour. That does not, however, stop companies from selling them.

You have the advantage of being able to design for solar to begin with, getting orientation, insulation, and passive solar factors right from the start rather having to try and retrofit everything.

Always remember the most important aspect of off-grid energy use: conservation!
That should be the most important aspect of on-grid as well, but alas ...

**gj.gibson** · April 20th, 2010, 15:26 PDT

Here's what I have in mind so far.
"First question,,, how far away is grid power and how much is it going to cost to bring it to your door?"
Tony,
I am looking at 1/4 to 1/3 mile at $1k per power pole. That is the first reason but not the most important. I just don't want to be dependent on the power company. I guess on the other hand if I can't do repairs myself I will be dependent on the repair man LOL!
The house will be or can be designed around the system within reason. I don't like the way earth houses look so it will have a more traditional look from the outside at least.
It will sit in the middle of a bald hill roughly 1200 ft in elevation and about 3-5 acres in size in south-central Tennessee with great exposure southward. I will have plenty of room for panels, etc.
Thank to you all for your introduction and your thoughts. They are welcome anytime!

**icarus** · April 20th, 2010, 15:45 PDT

So let's just assume for the moment that it will cost ~$25k to bring a meter to the house.

The same $25k will by a PV system that might be 3 kw say.

Using my off grid rule of thumb, that 3 kw system might produce 3000/2*4=6kwh net/net out of the inverter of usable power. (Battery based systems run ~55% efficient (or less,, more on that later) and certainly on a year round basis one can't count on much more than 4 hours of good sun every day.

Now, keep in mind, that a very efficient, well managed house might use anywhere from say 10-30 kwh/day. So you can easily see that battery based solar is hobbled by it's expense, and it's limited capacity.

Add to that, ~1/2 the cost of a battery based system is the batteries, which have a finite life span,, seldom more than 10 years of full time use, so you have to calculate in the replacement cost of the batteries in this case. So let's say you have $10,000 worth of batteries in the above system, and they last 10 years,, that is $1000/year, or $83 per month, just to amortize the batteries.

So while being free of the power company is a great idea, one has to seriously consider the cost, and the limitation. That said, I am not meaning to discourage you, but rather keep your eyes open.

In addition to your PV system you will need a significant generator system to power the house during construction, and to keep the batteries up when the sun isn't sufficient. (Adding to the net cost, plus fuel/maintenance etc.)

All this said, all the conservation choices you might make for an off grid house, you might rightly make for a grid tie house as well, as the benefits are just as important, even though they may "pay off" slower.

All things being equal, I would bite the bullet, get the power, but design for (and hopefully) install grid tie, get the tax credits and the utility credits while they are still available. That way, you can turn the tables on the utility by making your meter run backwards all the time you live in the house. By being able to start with a clean slate, should make any install somewhat cheaper, and certainly more efficient.

PS That same $25,000 that I was talking about earlier, might buy ~5kw of Pv, yielding ~ 5000*.90*4=18kwh/day, 6 times as much power for the same money. Add to that tax credits and utility rebates, state and local incentives that may or may not be able to off grid systems, and the net cost might ~1/2 of that, making a grid tie system ~12 times more financially efficient. (I don't know in the US if tax credits (state and local) are available to off grid,, I'm sure others will add)

Tony

PS My per watt cost of battery based vs grid tie may not be quite on as the prices have change a bit in the last while, others can chime in, but the relationship between the two is still about the same.

**Cariboocoot** · April 20th, 2010, 16:59 PDT

You really have to get a firm price on running utility power in, right to the box.
Then work up an estimate on what size off-grid system you'd need and its cost.
Compare the two, and if the capital expenditure is roughly the same, then the O-G is good.

But it won't be the 48 kW that houses are normally wired for.

**BB.** · April 20th, 2010, 17:17 PDT

Running utility lines to your home will probably increase the value of your property too...

Really rough numbers, off-grid solar power will net out costing you are around $1 to $2+ per kWhr... Ideally, off-grid system are not too bad (cost and size wise) for 100 kWhrs per month (or less).

But, a 2,000 sqft home with A/C is going to chew up; a lot of power.

See if you can get a good idea of how much electricity you will need by season (if A/C is used in your area) (assuming you use propane for all cooking, heating, hot water, drier, etc.). If you keep your usage down (lots of insulation, make usage of natural cooling/ventilation, etc.) and use mini-split A/C systems for just a couple rooms--you may be OK with off grid power.

-Bill

**gj.gibson** · April 22nd, 2010, 18:57 PDT

Gentlemen,
Thanks for your advice and knowledge. I may have been expecting too much from the technology itself. It is a shame in this day and age that you cannot run an entire house on wind and solar. Hopefully someday that may come to fruition. Hopefully it will by the time I decide to build. The first thing I will do is pin down a firm cost to run power to the hill and go from there. I do plan on designing a system that will use as little electricity as possible with generator power backup and gas appliances etc.
I will continue to lurk here and learn as much as I can.
Thanks again,
Jeff

**Cariboocoot** · April 22nd, 2010, 19:10 PDT

You can run a whole house on solar & wind. Several of us do so. You just have to make certain adjustments, and spend a lot of money. A LOT of money.

You could even build a 48kW system. But then we'd need a new adjective for "LOT" of money!

**icarus** · April 22nd, 2010, 19:35 PDT

I would quibble with Marc just a bit. You don't have to spend "a lot of money" if you are prepared to make considerable compromises. (No electric heat devices, using the generator for the shop/laundry etc). If you expect to live just like one might in a grid connected house then yea, it gets expensive.

Tony