Microhydro Electricity Unplugged
Microhydro, its simplicity is so attractive. So, you have always wanted to do it . . . go off grid and be self-sufficient. What does it actually take? From everyone I have spoken to who actually has done it, the answer seems to be, “Take your estimated cost for time, energy and money and triple it.”
Still reading this?
I recently visited some new friends who live at their homestead off the grid here in beautiful NW Montana. On grid or off, everyone needs to power something to move, heat, spin, or illuminate—so the question becomes, how best to do that in your situation? Well, if you are at a location well endowed with moving water (potential energy in nerd parlance) then alternative energy, like microhydro power may be for you.
Although I have not exhaustively quizzed wind generator users, the basic sentiment seems to be that it is not worth the investment due to the non-laminar conditions of wind—that is to say that the wind is not always blowing at a steady rate. Solar is promising as the technology gets more efficient every year (PRO Tip: shop by watt-per-dollar). However, if you are lucky enough to be set up where there is constantly flowing (laminar) water with a significant drop then microhydro electricity offers some very attractive benefits.
Energy has a cost, it always is, just ask Isaac Newton. The question is where are you going to get it? If you are plugged into the grid, then you are the benefactor of cheap, clean, stable electricity that is the envy of every developing nation the world over. However, some people are not tied into the grid due to personal choice or geographical location. So to generate electricity, something needs to be spinning a generator (except solar) by the force of wind, hydro, fossil fuel powered, coal fired, nuclear, etc. The amount of electricity that you require will dictate how large that generator needs to be. Back to Isaac Newton, to spin that generator takes energy of some kind which has to be of a greater strength than the minimum force required due to friction losses and other inefficiencies. With enough drop, a microhydro turbine offers great efficiency.
Anatomy of a micro-hydro generator:
For the force of water to spin a microhydro generator we rely on gravity. Any simple observation of a child playing with a paddle wheel toy and a cup of water is the simplest form of the principles in action namely distance (vertical drop or “hydraulic head”) and flow (volume or quantity of water falling). Where water is steadily falling, you have horsepower to work with.
The off-grid homestead that I visited had a 500 Watt “low head” (designed to work without a lot of drop) microhydro system manufactured by Energy Systems and Design out of Canada. This one unit powered the whole homestead!
Here in this picture is upstream side of the system; the canal coming from the creek is feeding the forebay or intake. I will not cite my disaffection for Eurasian Milfoil at this time, but you can see how that might definitely gum up the works over time with its prolific expansion.
Not pictured is the penstock or pipe that delivers the pressurized water to the business end of the system (power house). This homesteader deftly buried the pipe underground creating a sub-terrain conduit for the turbine on the other end.
A few hundred feet later you can just make out the white flange ring where the penstock or pipe comes into this trough. Unless you are hiring someone to do this for you, be prepared to come up with some do-it-yourself solutions. This homesteader is quite capable to shape metal and come up with creative solutions, so his total-cost-involved for the microhydro project was lower than if he paid someone else to do the whole project for him. (Note to self: buy a welder) This is only 6 feet of hydraulic head or drop from the intake to the power house—but it is plenty of water to spin the turbine.
Wilson: Would you have done anything different in your installation?
Homesteader: Yes, I would have made a variable height trough here in this setup. When the creek level rises and falls [on the uphill side] I lose or gain [hydraulic] head here and can lose efficiency.
This is the powerhouse or microhydro generator which is driven off of a water powered turbine.
This system is unique in that is has a vortex tube attached to the bottom of it to create suction.
If you picture water flowing into a megaphone with the small end up, the large end at the bottom creates a drop in pressure or suction (like an carburetor venturi) making the system more efficient for a low head set up like this one.
Barely noticeable above is the exit for the water back into the creek. The system is so simple it is brilliant!
Wilson: “What made you want to get into micro-hydro?”
Homesteader: “I wanted to get off the grid.”
Wilson: “There are a lot of good reasons for that.”
Homesteader: “The Lord just provided the place and the water. I looked at it and decided it was doable.”
Doable indeed! No utility bills is very nice, but you have to be patient for your return-on-investment (ROI).
Wilson: What was your total-cost-involved.
Homesteader: The permit from the state [of Montana] was $1500. And between the equipment, batteries, excavator, pipe, adding in my own labor I would guess about $18,000. I repurposed a lot of things that I had around the homestead here to accomplish this.
Wilson: Would you do it again?
This system is tied into a fully redundant back up generator.
Leaving nothing to waste, this whole house is heated with radiant heat!
Off-grid homes are very conscious of every watt they use, so when most people go off grid they will miserly look out for each power supply for a cell phone or LED on a power strip that is consuming power. This reduction in use and conservation mindset can net great savings if applied across the board by everyone.
Last thoughts on microhydro, I love this idea! To see it in action is quite impressive. Other than the fact that water is an indispensable requisite for life, seeing it utilized in a microhydro system for the creation of electricity was fascinating.
Pro Deo et Patria
Anatomy of a Microhydro from http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=11060
All other photos by Pantry Paratus
One last thought, if you are interested in learning more about micro-hydro systems, take a look at these two helpful websites that I found:
For more really cool information on eco-interesting uses for hydraulic head check out the “Salter’s Sink” concept:
Electricity is best left to professionals–please consult one if you intend to take on a project like this. Please do not take our results here for what you or someone else “ought” to do.