Chris Soler has been tinkering with small hydro-electric systems for three decades. He started by configuring homebrewed systems for himself and his neighbors, and is known for his ingenuity and creative ability to wring a few kilowatt-hours out of a seasonal stream on a low budget. Chris has been living with a custom hydro-electric system at his home in the foothills of Washington State’s Cascade Mountains since 1986.
Over the years, Chris’ knowledge and experience have grown, and at the same time, his clients’ electrical energy needs and budgets have increased. Folks who may have been considered “backwoods” when Chris first worked with them are now in the midst of professional careers, or even starting retirement. Their originally simple homes have become more modern and complex, and require more energy. Chris has been modernizing several of his simple homebrew systems into more productive hydro-electric producers.
This history and evolution is full of lessons for potential hydro electricity users, and my chat with Chris allows Home Power to share some of those lessons, and the stories that go along with them.
As a kid, I pretended to make electricity by damming a ditch on my family’s farm. So, when as an adult on my own place in 1986, I needed to supplement my one 30-watt solar-electric module for lights in the cloudy winter, I naturally thought to try to harness water power.
I had installed a 1-inch pipe to bring water from a pond to my gardens, and it dropped 35 feet from the intake to the garden. I fitted the top end of the pipe with a fine mesh screen wrapped around the end in a cone shape, and the pipe was dug through the bank of a pond, which eliminated the need for a syphon. The pond was fed by a roadside ditch that ran heavily after a rain, but the flow quickly slowed after a few days of no rain. I fashioned buckets that slipped over the shaft of a bicycle generator, and aimed a jet of water to spin it.
Having 3 W to charge a battery for a reading light instead of relying on kerosene lamps hooked me on continuing to improve my hydro system. I upgraded to 4-inch pipes and added another 2,000 feet of pipe to gain 110 feet of drop from a second source. The higher source was runoff from a hilly pasture with flows between 10 and 200 gpm from November to June.
I upgraded to car alternators mounted on square plastic buckets, with the runner inside to direct splashing away from the alternator. Four nozzles accommodated varying stream flows. I started using a low-speed permanent magnet motor to produce 2 A at 12 V, jumping up to a 24 W output. Later, after talking with microhydro expert Don Harris, I started using 70-amp Motorcraft car alternators. After that, I bought “real” bronze Pelton wheels from him. Each change brought higher efficiencies and more power to do more on the homestead.
The first hydro systems I put together for some local friends used a car alternator on a plastic bucket, with four nozzles and a Harris Pelton runner. I was nicknamed “the human backhoe,” as I hand-trenched thousands of feet of pipeline for my clients. The first system included some old solar-electric modules to provide power during the dry summers. A Trace modified-square-wave inverter ran some AC lights, and a TV, washing machine, and water pump. Radios and chargers were run directly at 12 VDC. That allowed the inverter to go into sleep mode at night. Everything was done to make the most of the small amount of energy available.
I built a diversion controller from a circuit described by Chris Greacen in a very early issue of Home Power (“Homebrew Shunt Regulator” in HP18). Before the Internet, I would scour the articles and ads in the magazine to get ideas on how others were dealing with producing their own electricity. Innovations were being pioneered by those actually using the systems, who then told their stories in Home Power.
The microhydro business is still a small, niche market. Most products, with the exception of the turbines themselves, are adapted from the solar market. The North American turbines are from microhydro pioneers such as Don Harris of Harris Hydro; Paul Cunningham of Energy Systems & Design (ESD); and Jerry Ostermeier of Alternative Power & Machine (APM). It has been nice to be able to call up and talk directly with the people who designed and built the units. When Don Harris retired, I was worried about being able to get parts and new turbines. However, Denis Ledbetter has taken over the production of the turbines and repair parts.
In 2001, Don Harris started producing his adjustable permanent-magnet generators for his hydro turbines. I switched to those and got a 40% jump in power output. I then realized that further improvements were coming from specialized manufacturers.
Today’s typical systems are much larger, and the owners are more concerned with reliability and ease of use than back in my homebrew days. Using permanent magnets eliminates the changing of brushes in alternators. Using self-cleaning intake screens (like the Coanda-type) cuts down on the time required to clean intakes. High voltage/low current (which requires smaller, and therefore less expensive, wire) is now possible with maximum power point tracking (MPPT) adapted from solar-electric systems. Specialized breakers handle the higher voltages. Sine-wave inverters run all of the AC loads without the worry of damaging sensitive electronics, which sometimes occurred with older, modified-square-wave inverters.
Some of my older systems are still 12 V and producing modest amounts of power. Other systems have gradually added more solar-electric modules to the renewable energy mix. The hydro resource is usually limited, so higher efficiency is the only way to get more power. I look at what the owner wants to accomplish and see what improvements are possible.
Many of my hydro systems I upgraded as new products became available, and as more power or better reliability was needed. All the systems are now using permanent-magnet alternators. By continuing to use the original Pelton wheels, Don Harris was able to keep the upgrade costs low.
Some of my clients switch to higher voltage with MPPT controllers to minimize the line losses associated with increased output current. Some systems extend the pipeline to increase the head, if available. The switch to self-cleaning screens cut losses caused by plugged intakes. Upgrading to a larger-diameter penstock to cut friction loss can allow more water flow.
The introduction of reasonably priced MPPT controllers for solar has opened up new design possibilities for small DC hydro systems. Before MPPT controllers were available, the hydro generator had to run at the battery voltage. That meant large wires, or accepting large voltage loss in the long-distance wires.
Now with the DC-to-DC conversions in the MPPT controllers, it is possible to operate the hydro at high voltage to keep the amperage low, minimizing line losses on long-distance wires. The MPPT units also allow the hydro turbine to run at the speed and voltage that produces the most power. Some small hydros allow varying the strength of the magnets to better match the varied flow of a stream, but the MPPT will unload the unit to let it speed up, and do the adjusting automatically.
The problem with using these units is they are designed for solar-electric arrays that put out a defined high-voltage limit that isn’t too much higher than the system’s running voltage. However, in a DC hydro turbine, the open-circuit voltage is twice the running voltage. So using an MPPT controller directly with a hydro turbine is limited to low-voltage systems.
One “bleeding edge” method is to connect the hydro in parallel with a solar-electric array at about the desired voltage, and the array will “clip” the peak voltage at about 10% above its rated open-circuit voltage. The modules act like giant zener diodes protecting the MPPT controller in high-voltage conditions. Many small hydro systems are on seasonal creeks that dry up in the summer, so a PV array is already a part of the off-grid hybrid system. The MPPT controller gets the maximum output from both components of the renewable energy system.
I would love to see some real numbers comparing the efficiency between the different manufacturers’ turbines. If independent testing showed their efficiency under specific conditions, it would aid in deciding which turbine to install. There are newer products available, but I hesitate to invest in lower-cost turbines if the savings is negated by lower output.
All I have is my own tests of Harris units that back up the claims of up to 70% efficiency. I always use these turbines except for low-head sites where the Turgo wheel on the ESD turbines can handle higher flow and faster rpm. With their simpler, nonadjustable magnets, the APM turbines might be a lower-cost alternative if the efficiency is still high. PowerSpout turbines have some interesting features, including a built-in voltage clamp that works with MPPT without other electronic tricks, or with higher voltage grid-tied systems.
Educate yourself as much as possible before getting expert help. The more you know, the better questions you can ask. Read older articles in Home Power and online. I find the best level of expertise is on the fieldlines.com forum. I try to answer questions about hydro posted on that site.
There are a limited number of people with experience with multiple hydro systems, so you will have to choose someone who can see all the possibilities of your site and create a system that does what you need. Any RE dealer can provide the batteries and inverters, but you may have to search harder for someone local to design and install the hydro system.
My personal off-grid system includes two Harris hydro turbines. One is producing about 200 W at 24 VDC from 35 feet of head. The other is currently putting out about 1,000 W at 70 VDC from 110 feet of head into an OutBack Power Systems FLEXmax 80 MPPT charge controller.
During times of higher flows, the larger magnets in the second Harris turbine boost the energy output. The old configuration topped out at 920 W, and it’s now more than 1,000 W. I haven’t completed testing this arrangement to find its maximum output.
To keep the unit cooler at high output, I carved a fan blade from a piece of 2-inch PVC pipe and slid it on the upper shaft inside the alternator. A digital pressure switch turns on several Belimo 24 V electric valves to automatically adjust the number of jets sending water to the Pelton. The stream flow varies daily and this allows maximum use of available water. I am also experimenting with a small needle-valve nozzle (an adjustable nozzle) to vary the effective size of one jet, but need a way to get it closer to the Pelton wheel for higher efficiency. My intake screens are 15-gallon barrels with dozens of slots cut all around the barrel, located in a hole off the primary stream flow.
I have 1,500 W of PV modules charging through a Xantrex XW-MPPT60 charge controller, and more than 1,000 W of modules wired directly to the battery with diversion loads using surplus power to control the voltage. My house still has many lights and a refrigerator running at the original 12 V. A Vanner 24-to-12 V battery equalizer powers that part of the system. The battery bank is eight 360 Ah Surrette batteries in series–parallel for 24 V. The inverter is an OutBack Power Systems FX2824T with a thermostat-controlled exterior fan to increase capacity.
Dump loads include DC heating elements in a 50-gallon hot water tank controlled by a TriStar 45, DC air heaters in the kitchen run by a Xantrex C40 and a 24 V, 1-gallon countertop water heater set at 190°F turned on by the auxiliary output of the FLEXmax 80.
I have the auxiliary output of the OutBack inverter programmed to turn on a relay sending electricity to two heat pumps. The automatic controls can turn one or both heat pumps on. On sunny winter days with the hydro running at full output, the two heat pumps can draw up to 2,000 W. On low-output days, the smaller of the two heat pumps can draw as little as 300 W. If enough electricity is available, I can heat our earth-bermed house to above 70°F and heat our domestic water to more than 150°F. We cook all our meals with insulated electric pressure cookers, an electric frying pan or a 120 V convection/microwave oven. We use a converted 12 V refrigerator and a chest freezer with added foam insulation to cut our electricity consumption. The computer and TV are on plug strips to eliminate “standby” electricity usage when they are not in use. When hydro and PV input is lower, we use wood from thinning the trees around our orchard and garden to heat the house and water.
I continue to tinker with my system, and improve the efficiency of how the energy is used. All of our cooking and water heating is done with renewable energy—our propane tank has been shut off for 10 years. And I keep decreasing the amount of firewood needed to keep our house comfortable.
Even the chainsaw and lawn mower are powered with electricity from the system. My goal when I moved here in 1984 was to demonstrate that it was possible to live comfortably without fossil fuel, which is getting more expensive as the easy-to-obtain supplies are used up. Now I am helping others make the same transition.
Chris Soler helps his neighbors with small hydro systems as Soler Hydro-Electric, from his home in Bow, Washington, where he has lived off-grid since the 1980s.
Home Power senior editor Ian Woofenden teaches and consults on hydro and other renewable energy systems in North and Central America, while enjoying site visits to those blessed with hydro resources.