Power/energy: Low-head hydro power: Small may be beautiful but, so far the economics for small-scale hydroelectric sites cloud a bright potential

Large-scale hydroelectric generation remains one of the cheapest forms of electricity in the United States, but the best sites with high heads (the height of the water drop available) have been used. The remaining low-head sites have seemed far less economical. With the rise in oil prices, however, many of these low-head sites are being reexamined.