June/July 1983 RAIN Page 27 Diagram ofPelton Wheel. Hydroelectric Honey Production The Mitchell family operated their honey business for four years without electricity, using solar and wood energy to heat a waterbath for bottling honey, and a solar-powered melter to refine their used beeswax. They found that manual extraction of honey from their 45 hives was time-consuming and kept them from meeting their income requirements. In order to mechanize some of their business and to expand the number of hives to 200, the Mitchells needed electricity. However, the remoteness of their home and business made tying into the local utility prohibitively expensive. In 1980, the Mitchells received a grant front the US- DOE to install a power plant to generate electricity on one of their farm's creeks. They built a small wooden dam on a year-round creek that flows through their property at an average rate of 418 gallons per minute. The dam was constructed to create a reservoir. Water runs from the reservoir through 900 feet of six-inch PVC pipe to a four-jet, impulse-type Pelton wheel 80 feet below. The Pelton wheel, using belts and pulleys, turns a three kilowatt generator. The electricity is transmitted 350 feet to their house and the honey extracting workshop. A wheel speed governor synchronizes the Pelton wheel with the requirements of the generator. During the winter, when the creek is high, the system is capable of producing up to 3,000 watts. It can power an extractor (350W), uncapping knives (300W), a refrigerator (400W), a washing machine, small appliances, and lights. Excess electricity is diverted by the load controller to a heat coil which will eventually heat water for a hot tub or greenhouse. During the rest of the year, there is enough power for lights, radio, and small appliances, but in order to run the extractor, they will have to invest in a smaller (1.5 kW) generator which can still produce power when the creek is low. The system is running well now, although according to Cynthia Mitchell, "Everything that could go wrong— did! It's been a lot more work than we thought." When they installed the system, they found that almost every electronic part didn't work and needed to be sent back to the manufacturer for repair. Because micro-hydro is a relatively new technology, Mitchell believes that "a lot of the information on micro-hydro isn't accurate, and it doesn't tell you all the things you need to know. For example, we found out the hard way how important soil stability is; we've had a lot of problems with silt just because of the geography of this area. ... Perhaps what's needed is a do-it-yourself book by people who've actually installed systems themselves." The Mitchells are developing their honey business as a model project, demonstrahng both the nature of an apiary and the use of renewable energy resources. Along with a live, three story observation hive (three bee stories are about 6 feet high), the Mitchells are constructing a schematic diagram of how the honey extracting power is generated and how wood, hydro, and solar energy are used in the honey production. (Cynthia and Jeff Mitchell, Rt. 1, Box 405-A, Nashville Rd., Eddyville, OR 97343). Recycled Induction Motor System Near Corbett, Oregon, Roger Mackaness and his neighbor and colleague, Clifton Graff, are using a grant from the USDOE to experiment with a micro-hydro system on Trapper Creek. Graff has used the creek for several years as a water supply. An existing diversion dam backs up water just enough so that approximately 150 gallons of water per minute flow into an 800-foot long ditch. It follows contours along the hillside above the stream and then enters a three inch pipe which directs the water straight down the canyon wall into a hydraulic ram. This device pumps water to the Graff homestead, where it is used for irrigation and domestic water. Mackaness and Graff used the USDOE grant to upgrade and modify the existing headworks and hydraulic ram water pump. Their aim is to produce electricity throughout the year and pump water during the summer months when it is needed for irrigation. In order to produce electricity, the water is diverted through a screened intake and down 1,300 feet of pipe, delivering 1 to 2 cubic feet of water per second to a small, shop-built, cross-flow turbine. The turbine powers a five horse-power, three-phase induction motor which can generate 2,000-3,000 watts of single-phase power. The maximum output is 3.7kW. The power feeds directly into the Portland General Electric's power lines. Mackaness and Graff decided to use a three-phase induction motor as a single-phase generator because it has several advantages over other generators. It can provide synchronous 60 cycle AC constantly in phase with the power company's grid. The motor is phased- referenced by them, and since it is overspeeded slightly by the turbine, it acts as a generator instead of a motor. The need for rectifiers, inverters, and synchronizers is avoided. An induction motor is also much less expensive than a synchronous generator of comparable size.
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