A smaller model (right) and a working system (left) of a small-scale hydropower in the central Oregon Cascade Range. (Courtesy of Oregon State University)
SAN FRANCISCO, July 2 (Xinhua) -- Researchers at Oregon State University (OSU) have developed a software program to help people around the world assess the potential of a stream for small-scale "run of river" hydropower.
The program, a computer modeling package, does not require data that is often unavailable in some developing countries or remote locations, and is expected to be useful for now and in the future, as projected changes in climate and stream runoff occur.
"These types of run-of-river hydropower developments have a special value in some remote, mountainous regions where electricity is often scarce or unavailable," said Kendra Sharp, the Richard and Gretchen Evans Professor in Humanitarian Engineering in the OSU College of Engineering.
The technology was field-tested at a 5-megawatt small-scale hydropower facility built in the early 1980s on Falls Creek in the central Oregon Cascade Range, according to a news release from OSU. At that site, it projected that future climate changes will shift its optimal electricity production from spring to winter and that annual hydropower potential will slightly decrease from the conditions that prevailed from 1980-2010.
Most probably by diverting part of a stream into a holding basin, which contains a self-cleaning screen that prevents larger debris, insects, fish and objects from entering the system, and then channel and feed the diverted water through a turbine at a lower elevation before returning the water to the stream, small-scale hydropower can be developed with fairly basic and cost-competitive technology, and does not require large dams or reservoirs to function, the researchers said.
Although all forms of power have some environmental effects, this approach is believed to have less impact on fisheries or stream ecosystems than major hydroelectric dams.
And as it is influenced by the seasonal variability of stream flow, the "head height," or distance the water is able to drop, and other factors, proper regulations to maintain minimum needed stream flow can help mitigate environmental impacts.
"There are parts of northern Pakistan, for instance, where about half of rural homes don't have access to electricity, and systems such as this are one of the few affordable ways to produce it," said Sharp, one of the three authors of a study published in the recent issue of journal Renewable Energy. "The strength of this system is that it will be simple for people to use, and it' s pretty accurate even though it can work with limited data on the ground."
Most previous tools used to assess specific sites for their small-scale hydropower potential have not been able to consider the impacts of future changes in weather and climate, said the authors, and are far too dependent on data that is often unavailable.
Known as the Hydropower Potential Assessment Tool (HPAT), the open source software program developed at OSU is available to anyone on request, and the researchers hope it will allow engineers and policy makers to make better decisions about hydropower development and investment.
