Rog (egosumquisum) wrote in off_grid,

Energy Self-Sufficiency in Hot Climates 

I'm in the process of improving 25 acres of rural land in Central Texas I own to build a home on that is as self-sufficient as possible. I've been reading lots of books and articles recently about passive solar home design, rainwater collection systems, PV solar energy, wind energy, small scale subsistence farming/ranching, biodiesel/SVO/WVO production, etc. Ive been reading a lot of Ragnar Benson's books, Home Power Magazine, Backwoods Home Magazine, Mother Earth News, and various other simple living/back-to-basics type books.

Just about all the books and magazines I read seem to be heavily geared/biased towards energy issues in colder northern climates. They spend an inordinate amount of time on issues related to heating, and generally only give minor lip service to cooling/air conditioning issues, if at all. I live in Texas where the winters are generally very mild and issues relating to heating are really not that serious. However, these days Texas is pretty much uninhabitable from June through October without some kind of air conditioning or cooling. Yes, I realize people have been living here for a helluva long time before air conditioning was invented but anyone who has been here long enough (like me, all my life) will readily know that life can be pretty damn miserable in August with 100-degree temperature with near 100% humidity.

When I talk to people in the solar power industry and mention how to run an air conditioner off the grid, they just kinda get squirrelly and start talking about how going with a grid-tied system is a great trade-off. Its as if they don't even want to think about it. I have discovered there ARE people who care about this issue, but these super high efficiency air conditioners are very new, very expensive, and relatively underpowered: Lots of people advocate evaporative "swamp coolers", but these are worthless in a humid environment.

The price of photovoltaics is still pretty high these days at around $1000 for a 200-watt PV panel. Low-maintenance gel batteries are even more expensive. A system that will generate 800 kWh per month will cost you at least $25k, if not more, so what do you do to be as self-sufficient as possible? In just about all of the "wind maps" I see of Texas, central Texas is always in the "poor" category, with a <10mph average wind speed, meaning that even a $10,000 1kW wind turbine may only produce about 100kWh per month when the average wind speed is only 10mph.  Ive looked at microhydro power, but Im nowhere near rich enough to buy land with live running streams on it and besides, the state gets VERY irate when you dam or divert streams for your own purposes, even on your own land... something about all waterways (of a certain size) being public property.  

The main part of the solution is to build a home thats as energy efficient as possible in the first place, but there are some major trade offs here.  I'm considering an earth-sheltered/earth bermed home to cut down on energy costs but thats only one part of the equation.  The sort of appliances you use will very much dictate your energy requirements as well.  SunFrost refrigerators and freezers can be bought that are extremely efficient at keeping food cool/frozen, and there are ultra high efficiency washers as well. But what about appliances that generate heat like stove/ranges, clothes dryers, water heaters, and home heaters? Sure, the kneejerk reaction is to just "go gas", but is that really wise? Do I really want to be beholden to an energy source I cant create myself? What happens in a SHTF situation and I cant get the propane/butane tank refilled? I suppose I could dry clothes on a clothesline, heat the house with wood in a fireplace (for the very little amount of the year that Texas is cold enough to need it), and cook over a fire as well but that would expend my wood lot pretty damn fast. Heating water can be done via solar, but its also quite expensive as well. Electric clothes dryers and ovens/stoves require HUGE amounts of electricity, so much so that Energystar doesn't even both rating them. People who do solar power systems just laugh when I mention these and just assume people will use propane delivered by truck.  Yes, Ive heard of solar ovens but the few that I've seen are veeeeeery slow and not very hot. 

In general most solar power companies I've dealt with are more focused on grid-tied systems and haven't given much thought to those who want to live self-sufficiently, plan for the worst but hope for the best.  In addition, Ive noticed a great many many people in the so-called "green" movement seem to think living self-sufficiently is somehow selfish or makes you a tinfoil-hat paranoid "survivalist", and a great many are generally more focused on improving "the environment" as a whole for everyone rather than preparing themselves and their family to produce and consume in a more direct and localized way as self-sufficiently as possible... but thats another debate altogether that I would rather not get into right now.

Anyway, whats the best trade off here? Go grid-tied with solar and battery backup and just give up certain conveniences when the power shuts off or do it all the right (hard, expensive) way the first time? I could go with gas heating/cooking/clothes drying and just give that all up in a SHTF scenario, but it is absolutely critical to have air conditioning/cooling in Texas. It would be ideal to have everything run off energy that I myself can produce with as little external sourcing as possible, but that might be prohibitively difficult and expensive.  Theres the issue of running a generator, but that too makes me reliant on external energy sources for fuel. I am thinking of buying a 30-40hp small diesel tractor for my property anyway, and it would be easy to slap on a 10kW PTO generator for when I needed extra power, but thats likely not sustainable. I've looked into growing canola and running a canola press from a lister engine that burns canola oil as well as running the tractor used to sow and harvest the canola on canola oil.  Im still trying to work out whether I can get high enough yields to make the process sustainable, taking as many of the variables into account as I can come up with.

How have other people who live in hot/humid climates done self-sufficient off-grid living? What are the most sensible trade-offs to consider? How do I best maximize my off-grid sustainability potential without giving up too much comfort and without spending insane amounts of money?  I honestly do not believe its possible to live in Texas in ANY kind of structure with ANY kind of conceivable insulation without using SOME kind of air conditioning.  The issue is how to make the air conditioning system as efficient and self-sustainable as possible.  What are some other sources of self-sufficient (not necessarily efficient) energy generation I could consider?

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