Micro-Hydro for Homestead/Retreat Power Generation

A majority of survivalist websites spend a large portion of their time expounding on the benefits of generating one's own electricity through the use of solar panels. Who can blame them? Solar panels are an out-of-the-box solution (other than having to mount them), they produce clean, reliable electricity and they require almost no upkeep on the part of the user. Heck, even if you choose to make them yourself instead of buying commercially-built panels, all but the 'out-of-the-box solution' part is still true. Basically, the only thing bad about outfitting your homestead or retreat with solar panels is the expense, which, depending on how much power you need, can be phenomenally high.

Another very popular approach is to install one or more wind turbines in order to harness that resource to generate clean electricity. In the classic sense of a windmill, the wind catches the blades and turns the wheel, which in turn spins a permanent magnet alternator that generates power. This type of system is often used in concert with solar panels as the two smartly complement one another: the wind typically blows stronger at night when the solar is obviously not going to be working, thus picking up the slack; this is also true in the winter months when overcast conditions greatly reduce solar panel efficiency, but the wind typically blows faster and stronger than at any other point in the whole year. Small wind turbines, capable of generating up to 400 watts in the proper windspeeds, can be purchased for home use, or you can build your own. You can even make yours larger and capable of producing more power, if you possess the ingenuity and a suitable location for a large tower.

But, depending on the location of your homestead or retreat and its proximity to a reliable source of running water, you may have another option for generating clean, reliable power: Micro-Hydroelectric. There is some debate over the terminology involved with some insisting that the 'Micro-' prefix be used only when describing systems that produce between 5-100 kW of power and those producing less (suitable for a single homestead or retreat) be referred to as Pico-Hydro instead, but we will not be concerning ourselves with such distinctions here. Many assumptions concerning Pico-Hydro setups, such as that it is "useful [only] in small, remote communities that require only a small amount of electricity - for example, to power one or two fluorescent light bulbs and a TV or radio in 50 or so homes," are likewise not germane to our conversation here, because the system I am describing would be used to charge a bank of deep-cycle batteries as opposed to running appliances, etc. directly from the amperage produced.

A well thought-out and informative treatise on Small Hydroelectric Plants can be found online in PDF format courtesy of the West Virginia extension site at http://www.wvu.edu/~exten/infores/pubs/ageng/epp13.pdf, but it mostly concerns itself with the standard practice of using a water source that has a lot of head and flow.

Another alternative site that showcases a design I really like is http://www.HomeBrewHydro.com. This setup utilizing an old olive barrel was initially producing "90 watts at 36PSI from a 1-1/2 inch pipe with roughly 100 feet of head" before upgrading his penstock and nozzles, which he estimates to have roughly doubled the output.

Another very promising concept is the one built by Sam Redfield of the Appropriate Infrastructure Development Group (AIDG) that is housed in a common five gallon bucket and fabricated using common PVC components and an old Toyota alternator that has been modified to make it capable of generating usable electricity at low RPMs.

The generator was envisioned as a means to provide electricity to remote communities in the developing world without access to the power grid. What you end up with is a generator producing about 60 watts that can be used to charge batteries and small appliances such as cellular telephones, or other small-scale purposes. It is simple and easy to build with readily-available and/or easily scroungeable parts and, at worst, you may have to invest a few hundred dollars maximum. (source)

Yeah, I know 60 watts doesn't sound like much, but remember what I said earlier about this being a system for charging a bank of deep-cycle batteries and not planning to run any appliances or anything like that directly off the power it is spitting out. Run your stuff directly from the batteries, while using this system to charge them. If you built it sturdy enough that you felt comfortable leaving it running over night, 60 watts would net you 1,440 watts. According to my math, this would allow you to comfortably drain your battery bank by 120 amp-hours per day, while remaining confident that your hydroelectric system would replenish what you had used. Still not impressed? Consider then that a slightly more powerful setup, say somewhere in the neighborhood of 150 amp-hours per day in a 12 volt arrangement, would allow me to run my big ol' two-door Energy Star refrigerator/freezer combo with ice in the door. Suddenly, 120 AH doesn't sound so puny, huh?

Of course, to be fair, this doesn't account for the power that would be used by other components such as the inverter and the charge controller, and you would need to spend some money on deep-cycle batteries because you never want to let them get discharged too deeply. It kills them. Being sure, however, to limit your average depth of discharge to around 25% will net you long battery life (10-15 years in some instances) before they have to be replaced. So, if you're using 150 AH per day to run a fridge, you need to have a battery bank capable of storing no less than 600 AH. For instance, one could purchase six (6) of these 12 Volt 105 Amp Hour Sealed Solar Deep Cycle Batteries at just shy of $1,500.00 total and it would do the trick pretty well. Add to that a few hundred dollars to put together the bucket hydro system described above and you have the beginnings of a self-sufficient, off-grid electrical system for under $2,000.00 that you can continue to add to as you go.

And, oh yeah, to do the same thing with solar would require panels that add up to about 750 watts (750 watts x about 2.5 dependable average solar hours at my latitude = 1,875 watts / 12 volts = 156.25 amps or amp-hours). A solar array equaling that kind of wattage would cost me just under $1,500.00 in today's prices and that's before I pay the $1,500.00 listed above to procure my batteries, bring the total cost to around $3,000.00, fully $1,000.00 more expensive than with the system described here in this article. And remember that's at today's solar prices where panels can be had for as little as $1.98/watt with a little shopping around; as recently as 6-9 months ago they were still hovering around $5.00/watt.

Also, one should keep in mind that building a 2nd bucket hydro generator would double the electrical output, while only bringing the total cost to around $2,300.00. This would provide another 90 AH of power (120 x 2 = 240 - 150 = 90) or 1080 watts (90 x 12 volts = 1080) to use for other smaller appliances, lighting, etc. The AH rating of the batteries listed above still leaves us with a 30 AH cushion above and beyond the 600 we said we needed also. Therefore, we only need to purchase battery capacity equaling 330 AH (90 x 4 = 360 - 30 = 330) to keep our system under the 25% discharge ceiling we set earlier. The only problem is the batteries are rated for 105 AH each, so it is impossible to hit the mark exactly; purchasing 4 more batteries would be best, especially if you intend to continue to expand, but you could probably get away with only 3 since the 25% discharge ceiling is meant to be an average estimate. So, after adding the batteries, that leaves you with a system that cost you under $3,050.00 and allows you to produce 2,880 watts or 240 AH of total electricity per 24 hour period. The same output using solar panels would cost around $4,530.96 (1,152 watts of panels x about 2.5 dependable average solar hours at my latitude = 2,880 watts / 12 volts = 240 amps or amp-hours and 1,152 watts of panels x $1.98/watt = $2,280.96 + slightly less than $2,250.00 for the battery bank = just shy of $4,530.96 total cost). So, as you can see, the savings over solar increase exponentially each time you expand the system.

All that from a homemade bucket generator that produces a measly 60 watts.

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