Economical conversion of low-head hydropower

Publisher Summary The chapter describes a method of harnessing energy from low heads, without using water turbines. The system is simple and robust. All the major parts are mounted out of the water, and in particular the turbine and alternator can be placed in a convenient dry location. The relatively low cost of this system could make significant amounts of new hydropower economically available in many parts of the world. Proposals for exchanging pressure between water and air have been put forward based on alternating displacement mechanisms but these suffer from the disadvantages of large size and cyclic operation. The hydropower system based on pressure-exchanging siphons offers the prospect of harnessing power economically from the large number of low-head hydro sites that are not viable using water turbines. Efficiencies of 70% or better should be achievable. Although such values of efficiency are lower than usually found in hydro plant, siphon installations should be economic owing to the relatively low capital cost of the system.