Pico hydro is a term used for hydroelectric power generation of under 5 kW. It is useful in small, remote communities that require only a small amount of electricity - for example, to power one or two fluorescent light bulbs and a TV or radio in 50 or so homes. Even smaller turbines of 200-300W may power a single home in a developing country with a drop of only 1 meter. Pico-hydro setups typically are run-of-stream, meaning that dams are not used, but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before being exhausted back to the stream.
Like other hydroelectric and renewable source power generation, pollution and consumption of fossil fuels is reduced, though there is still typically an environmental cost to the manufacture of the generator and distribution methods.
Two examples of pico hydro power can be found in the towns of Kithamba and Thimba in the Central Province of Kenya. These produce 1.1 kW and 2.2 kW, respectively. Local residents were trained to maintain the hydro schemes. The pico hydro sites in Kenya won Ashden Awards for Sustainable Energy.
In Vietnam, several Chinese manufacturers have sold pico-powerplants at prices as low as $20–$70 for a powerplant of 300-500W. However, the devices sold are said to be low in quality and may damage connected equipment if connected improperly.
Sam Redfield of the Appropriate Infrastructure Development Group (AIDG) has developed a pico-hydro generator made from common PVC pipe and a modified Toyota alternator housed in a five gallon bucket. The generator was developed to provide power to communities without access to the electricity grid in developing countries. Envisioned as an energy source to charge cell phones, provide lighting and charge batteries, the generator is designed to be made by artisans with basic skills and can be built for less than $150.00. The Toyota alternator used in the generator is converted to a permanent magnet alternator allowing it to generate power at low RPMs. The Five Gallon Bucket Hydroelectric Generator was the subject of a work group at the 2008 International Development Design Summit (IDDS) at the Massachusetts Institute of Technology. During the Summer of 2013 an energy project in Abra Malaga, Peru was completed using the bucket generator.
A website has been put together as a forum for ideas and further iterations of the generator that includes a build manual.
If the power will be used more than 100' feet from the generator, then the transmission distance may be an important consideration. Many small systems use alternators producing 12VDC, and possibly charging a battery. For example, a 12V system that produces 1Kw of power has a flow of 80Amps and the wire size is 4 gauge. The cost to run two strands of wire 1000' is $2400(US). To avoid such a high wire cost a higher voltage is required. If a 240VAC alternator is used instead the flow is only 4Amps over 1000' of 18 gauge wire costing $180(US). The cost of wire resulted in North America using 120/240VAC after DC voltage lost the War of Currents in the late 1800's.
- Small hydro up to 10,000 Kw
- Micro hydro up to 100 Kw
- Hydro power
- Renewable Energy
- Sustainable energy
- "What is Pico Hydro?". Pico hydro publications. University of Nottingham, UK. Retrieved 6 September 2010.
- Mattijs Smits. "Technography of pico-hydropower in the Lao PDR" (PDF). The Lao Institute for Renewable Energy (LIRE). Retrieved 6 September 2010.
- "Pico-Hydropower Franchising: A Test Bed in Rural Honduras". National Collegiate Inventors and Innovators Alliance. Retrieved 24 January 2013.
- "Micro Hydro Project". Technologies for Conservation & Development project. Retrieved 6 September 2010.
- "Ashden Award for Pico hydro power in Kenya". Ashden Awards. Retrieved 6 September 2010.
- Shahidur R. Khandker, Douglas F. Barnes, Hussain Samad, Nguyen Huu Minh (September 2008). "Welfare Impacts of Rural Electrification: Evidence from Vietnam" (PDF). World Bank. Retrieved 6 September 2010.
- "Five Gallon Bucket". Retrieved 2012-06-20.
- Sam Redfield. "Five Gallon Bucket Hydroelectric Generator Build Manual" (PDF). Appropriate Infrastructure Development Group. Engineering for Change. Retrieved 2012-06-20.