Micro Hydro Turbines: The Holy Grail of Off-Grid Power

What if I told you that you could power your home in a totally environmentally friendly way…with no drawbacks? Solar power is great, but the sun isn’t always shining. Wind is great, but the wind isn’t always blowing. Not to worry, there’s a solution that’s superior to both wind and solar.

The one caveat is that you must have moving water on your property. That’s a pretty big filter which prevents most people from utilizing micro hydro to power their homes. However, homesteaders looking for land to buy are in a unique position to choose land based on the suitability for hydro power and other factors relevant to off-grid living.

If you’re in that position, the value of having access to a river or creek passing through your property cannot be overstated. Unlike solar or wind, hydro power is not intermittent. Save for the possibility that the creek will dry up in the Summer, but then again if you have solar panels as well, that time of year is when solar performs the best anyway.

Providing also that the creek does not freeze in the winter, for all but the Summer months, you will have continuous, uninterrupted power. Lots of it too! Being that water is 700 times denser than air, a hydro turbine outputs considerably more power than a wind turbine.

Rather than start at the high end, this article will examine the options for small format hydro power from cheapest to most expensive. The output of each increases accordingly with price for the most part.

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EStream is a recently kickstarted project involving a fold-away backpacker’s turbine. It does not send power to shore over a cable as you might expect however. Rather the entire device is sealed with an O-ring, but can be unscrewed after you remove it from the water.

Inside is a modest battery pack which is charged by the spinning blades when submerged. This is not a really useful amount of power in my opinion, exacerbated by the inconvenience of having to remove the entire unit from the water to use it, or even just to check on the charge level.

Still, it could be useful as something to drag behind a sailboat. It would slow you very slightly but also give you a guaranteed source of emergency power for a cell phone/GPS if the sun and wind aren’t cooperating. For $250 it might be too pricey to buy as an experiment, but for certain use cases I can see the utility.

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Canadian company Idenergie now sells a DIY river/stream turbine suitable for any sufficiently deep, fast moving water. The entire unit submerges, after being secured with a restraint to a boulder or piling so the current does not carry it off. A cable carries the power back to shore.

It outputs either 24 or 48 volts DC (selectable) just like many small solar arrays common on cabins, and the rated output is between 100 and 500 watts depending on water speed. That may seem paltry, but don’t forget that it’s constant output, even at night.

While the ads say you can “power your house!” with it, in fact you would need either several of these (at $10,000 including installation) or you would need a very small home with 12v DC appliances and no heating or cooling. The ideal application I can see for this unit is as a supplement to a rooftop solar array.

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The range of fixed installation creek and stream turbines made by Powerspout, such as the Turgo (pictured above) represent the next step up. They are permanent installations and non-submersible. You drill the supports into a rock, and pipe the intake water from as high an elevation as possible, with the output hose leading to the lowest point of the creek or stream (within the boundaries of your property).

Maximizing elevation difference is the key to maximizing the power output of this type of turbine. They can output in excess of 1 kilowatt, putting them in a league above semipermanent turbines like the Idenergie unit discussed earlier. However that relies on optimizing the setup.

Besides the elevation difference, you also need to ensure the input trough is fully submerged and has a filter to keep out debris. If it’s not fully submerged, bubbles will get inside, causing cavitation on the ends of the turbine blades which reduce efficiency.

Of the turbines discussed so far however, this is by far the best option unless it’s a full blown river you live on, or there’s not a significant elevation change. If it’s just a creek or a stream, and there’s a significant elevation change in it, this is the type of turbine you want.

These units utilize essentially the same type of charge controller as a solar array, but of course the output is non-stop. This makes them incredibly valuable. Even while you’re sleeping soundly, it’s still out there by the creek, spinning madly, recharging your house batteries.

These also have fewer issues getting approved for installation than the submersible turbines because they represent less of a danger to fish. It’s less trouble, then, to install several of them in parallel on the same creek or stream. Conceivably, it’s possible to fully power your home with no need for batteries.

Realistically you would want batteries though, for a reliably stable output and to collect energy from rooftop solar panels or any other sources of power you might wish to add later on.

At $1,600 it’s not only more powerful than the Idenergie, but also suitable for DIY installation. Of course the two are intended for different situations, one for rivers and the other for creeks/streams with an elevation change, so really it’s apples/oranges.

If you’re able to get ahold of a parcel of land with a creek or stream on it, and there’s a significant elevation change between where it enters your property and where it leaves it though…you’re sitting pretty. You are ideally situated to generate a copious amount of renewable power with a reasonably priced turbine.

That’s the rub when it comes to hydro. It’s beautiful and amazing where it works. But of course, it won’t work just anywhere. It needs specific conditions, and you basically have to make your selection of land to purchase with hydro in mind if you’re ever going to be able to use it.

Armed with this information, anybody reading this with serious plans to buy land and homestead on it in the coming years now has an additional criteria to judge land by. I’ll wager you’re now rubbing your chin, re-evaluating the land you were considering and browsing for properties with access to moving water.

Of course, there’s always the possibility of building your own such turbine using a high output alternator…but that’s a topic for another article. :)

Citations:
https://www.kickstarter.com/projects/hyerinster/estream-a-portable-water-power-generator-fits-into
http://idenergie.ca/en/
http://www.powerspout.com/

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