Energy Independence: Part III

A River Runs Through It!!!

One of the most desirable characteristics of a chunk of land that any determined homesteader looks for when purchasing is water. Wells are expensive to drill and getting more expensive, so a good many people in appropriate areas of the country will be seeking either an already developed spring-fed system or a piece of property that boasts springs that can be tapped. But for energy purposes it’s more important to have a creek or two running through the property, as these can be developed to produce power for either the household water system or for the entire homestead.

Our homestead is lucky to have two creeks, one on each side of the north-south ridgeline that divides the property, both of which drain the National Forest on this south-facing slope of mighty Mount Mitchell, and both of which run all year long without freezing over. These are small creeks unless it’s raining hard in the high country, and the one on the house side of the ridge boasts more springs and greater downhill grade than the one on the nearly inaccessible ‘other’ side.

Our water system originates from a spring bubbling up among the roots of a gigantic tulip poplar tree near the creek. A depression collects more water than silt, and this water is transferred through 2 quarter-inch copper pipes slightly downhill to a small, capped cistern made out of a 4′ tall section of 2′ wide concrete pipe with a concrete lid that can be removed to de-silt when necessary. The bottom of the pipe is buried about a foot in the ground and is not sealed because it doesn’t have to be. This allows it to be mostly self-cleaning, as the silt slowly percolates out and back into the creek. 1″ pipe from the top of this first de-silting stopover takes water to a large, 750-gallon concrete cistern (that is sealed at the bottom and lined), around which we built a spring house enclosure to protect the pump wiring and cistern itself.

To pump the water more than 200 feet up to the house requires a hefty energy hog of a 220 sump pump which represents a goodly chunk of our electricity usage (and bill) every month. This will be the first energy independence project we will tackle, hopefully this spring. The goal is to use the energy of water in the creek to get the spring water to a new cistern we’ll put on top of the ridge behind the house, which means it will have to be pumped another 65 feet uphill farther than the hefty pump pumps it now. Still, once that cistern is in operation, we’ll get gravity feed to the house that will cure all our water pressure problems as well as allow us to have running water whenever the electricity goes out. Which, in this neck of the woods, is fairly often.

The first thing a homesteader needs to establish per the usability of their creek for power is how much of a ‘drop’ it represents between its incoming source (your property line) and either its use-point or its exit boundary. Water power works on the principle of falling water turning a waterwheel, turbine or ram jet, and the amount of drop (plus flow) you can manage will determine how much water power will be available to you.

Now, we could dam the creek and use the overflow to power a turbine generator, since we have a hefty amount of fall. This would generate electricity (allowing us to keep using the 220 sump pump), but I’d much rather use the water power directly to get the water where we want it to go and ditch that energy-sucking pump altogether. So it looks like a small dam at the high incoming source could give us enough water to divert through pipes to where we want it while at the same time not causing much of any significant alterations to the creek itself along its course or diverting too much of its flow. There are a number of springs between the property lines that feed the creek further, so my power plan won’t affect concurrent plans to establish a three-tier step-dam system for trout farming. Someday…

The alternative is that we could use a no-head water motor, since we do have an average flow velocity of 4 feet per second. It couldn’t be very large, though, because the creek itself is only a few feet wide. No-heads don’t require a dam. They’re ‘undershot’ wheels that are installed above the water, with their bottom paddles sitting in the flow. After some research, however, we’re fairly convinced that an overshot wheel is the best answer for our needs.

Overshots are those ’standard’ water wheels you see at old mills, where the diverted water pours out over the top of the wheel to turn it. It’s much more efficient than the undershot variety of water wheel in that it uses both the weight of the water and the force of gravity to turn the wheel. More power is available for use, more efficiently (up to 93%).

Now that we know what kind of wheel and diversion flow we can best use on our creek, we have to decide whether to install a power generator - and suffer the usual indignities of power storage or do the backwards meter thing by hooking up this 24-hour supply straight to the grid - or just use the water power to get the water uphill and eliminate half our electricity usage immediately. This choice is then between the power generator (expensive!) or the ram jet (cheap). Hmm, let me think… yep. Hydroram. We can offset the rest with solar on the house, shed and barn roofs.

All this requires some very detailed engineering, some tricky calculations, some skill in the woodshop, and some backbreaking work. Then there are the gears and exchangers to consider, the most efficient ways of getting the power out of that turning wheel. There is some great information out there about all the possibilities, all the engineering specifications, all the ratio calculations and all the nifty ways to put your water to work. Do check out some of the links below so you too can start planning for the water-harvest on your property!

Small Creek Provides Plenty of Power for Off-Grid Home

Waterpower for personal use

Design calculations for overshot waterwheels

Design calculations for no-head, low-head waterwheels

FAO: Water lifting devices

The Water Wheel Man: Plans

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