Water is the cleanest, safest, and often the cheapest ''fuel'' for producing electricity. And Americans are developing small-scale water-power installations at a rate unprecendented since early New England industrialists harnessed swift-running streams to power their mills.
Most states have at least some potential for useful development of small-scale hydro units. But New England and northern California - both subject to high electricity rates and occasional power shortages in recent years - have seen the most rapid development of such generating plants, which the Federal Energy Regulatory Commission defines as facilities producing no more than 30 megawatts of electricity.
Idaho, Washington, and Oregon have many potential sites for small-scale power facilities, but the presence of relatively cheap electricity from large federal and state hydro plants has kept the pace slow in those states until recently, according to an Oregon energy official.
A more serious obstacle to development of all types of small-scale electric generation, including wind power, is the nullification by the US Supreme Court of two sections of the Federal Public Utilities Regulatory Policy Act (PURPA). These required that major electricity suppliers provide tie-ins for small producers and pay them the equivalent of the utilities' own cost of production.
Legislation now before Congress, and expected to be passed, would remedy the technical flaws in the law found by the high court after Consolidated Edison of New York challenged PURPA. With enactment of the corrective legislation, the surge in development of small-scale hydroelectric sites is expected to continue.
In California, streams once diverted by gold miners into canals, ditches, and flumes for washing gold from gravel now are being dammed to produce electricity.
Karen Miller of the State Energy Commission says that more than 1,000 small-scale hydro generators now are providing some 740 megawatts of power in California. Most individual sites have the capacity to generate from 5 to 10 megawatts, enough to power 5,000 to 10,000 homes at any one time. By comparison, southern California's Rancho Seco nuclear plant has a 900 megawatt capacity.
Don Buell of the Oregon Water Resources Department says that in both 1978 and 1979 only four applications for development of small hydro sites were filed. There were 50 applications in 1980 and 119 in 1981. Apparently because of the Supreme Court ruling, only 33 have been filed so far in 1982, but Mr. Buell says he expects an increase if the corrective legislation becomes law.
Nationwide figures also indicate this rapidly developing interest in hydropower. In fiscal 1980 there were only 100 applications to the Federal Energy Regulatory Commission for hydro permits; in fiscal 1981 there were 1,800 - and about half that number were for small-scale projects. According to the commission, some 12.5 percent of US electricity is produced by hydro generation - 283 billion kilowatt hours a year. Much of this power is produced by small installations. The savings in fossil fuel is calculated at 480 million barrels of oil or 130 million tons of coal.
The commission figures that there are sufficent usable sites available, most of them small-scale, to boost hydroelectric power production by another 40 percent - the equivalent of 682 million barrels of oil or 187 million tons of coal.
Karen Miller of the California commission points out that development of all feasible small-scale hydropower sites will not make the US free of dependence on fossil fuels for electricity generation. But the combined impact of windpower, cogeneration (using industry byproducts to produce electricity), conservation, and other measures can be impressive, she explains.
Recently, a dedication of a small hydro plant in Shasta County, Calif., was presided over by a top US energy official and attended, interestingly enough, by the San Francisco-based consul general of the People's Republic of China. He was there because the builder-owner of the Bailey Creek hydoelectric plant, Consolidated Hydroelectric Inc., of Redding, Calif., purchased its generating equipment from China.
Terrence O'Rourke, Consolidated vice-president, cites simplicity, reliability , low price (in comparison to American and Japanese equipment), and speed of delivery as reasons for using the Chinese generator, manufactured in Hangzhou. European firms supply generation equipment for small hydro sites as well.
Consolidated is one of a number of US firms that develop small hydro facilities of their own as well as build them for others. The firm is developing another site it owns in Shasta County and is looking into 22 more northern California sites. The total potential of all these sites is 100 megawatts - capacity enough to provide electricity for 100,000 homes at the same time.
Some 20 years ago, at the dawn of what many thought would be the nuclear power age, US experts were pointing out that almost all suitable hydroelectric sites in the lower 48 states had been developed. Now the country is finding that , where electric power is concerned, small ism beautiful.