Grand Ethiopian Renaissance Dam production of less than 3 percent. The Grand Ethiopian Renaissance Dam could also lead to a permanent lowering of the water level in Lake Nasser, if floods are stored instead in Ethiopia. This would reduce the current evaporation of more than 10 billion cubic meter per year, but it would also reduce the ability of the Aswan High Dam to produce hydropower to the tune of a 100 MW loss of generating capacity for a 3 m reduction of the water level. However, the increased storage in Ethiopia can provide a greater buffer to shortages in Sudan and Egypt during
Hydropower policy in the United States of 90% efficiency. More importantly, Francis's mathematical and graphical calculation methods advanced turbine design and engineering and allowed confident design of high efficiency turbines to exactly match a site's flow conditions. In the 1870s and deriving from uses in the mining industry, the high efficiency Pelton wheel impulse turbine was developed to use hydropower under very different flow and pressure conditions. Advances in dam design also progressed, with the completion of Old Aswan Dam being considered a milestone of engineering over nature. At the time of its construction, nothing of such scale had ever been attempted: it also became one