For a given temporal scale the residual energy balance can
3.2. Power generation scenarios
Run-of-river (RoR) hydropower WYE-354 generated without upstream dam control, neither at the power plant nor along the upstream river section (by choice in our study). The power at a given time t is thus generated from natural water discharges only, following the Equation (3):equation(2)p(t)=ηHghρq(t),where p is the delivered power by the generator (kW), ηH the efficiency of the generator (no units), q the water flow through the turbines (m3s−1), g the acceleration of gravity (m3s−2), ρ the water density (kgm−3) and h the falling height (m). For a given plant, the power generation is bounded by minimum and maximum discharges qmin and qmax. These two thresholds correspond to the environmental low flow and to the maximum capacity of the generator, respectively.
We consider two different hydro-climatic regions from where RoR power is generated. They are located at the opposite bounds of a climatic gradient , mainly due to the range in elevation. We assume benthic zone the sum of the power generated at two different stations is a good indicator of the temporal organization of the production that could be obtained for an ensemble of similar RoR power plants distributed within the same hydro-climatic region, and thus fed with the same discharges series. In all four cases, continuous records of discharges at the gauging stations are obtained by applying the discharge rating for the stream to records of stage. Periodic measurements are carried out to either confirm the permanence of the rating or to follow changes (shifts) in the rating. Discharge data are available at hourly resolution.