by Gregory L. Morris
Although wind and photovoltaics are today’s poster children for renewable energy, hydropower has been around for a much longer time and now boasts plants that have been operating reliably for over 100 years, some of them with original equipment. Run-of-river hydropower plants on streams with good hydrologic characteristics can achieve a plant capacity factor on the order of 70 percent, as opposed to values in the vicinity of 20 percent for solar. Thus, a 10 megawatt (MW) hydro plant can produce more energy than a 30 MW solar installation. Hydropower facilities are capital intensive with investment typically in the vicinity of $2 million/megawatt, but annual operating costs only run around 2 percent to 3 percent of capital cost. Despite hydro’s high initial cost, when evaluated based on capacity factor and annual energy production it falls at the low end of the energy cost spectrum. Hydropower is perhaps the closest thing there is to a perpetual cash cow; it is a highly attractiv