Dams with head increaser effect: Harnessing potential and kinetic power from rivers with large head and flow variation

Abstract

There is an enormous untapped potential for hydropower generation in rivers with large head and high flow variation, currently not feasible for conventional hydropower dams. Conventional dams make use of the potential energy, but waste kinetic energy from spillage during periods of high flows. This article studies the possibility of harnessing energy from potential and kinetic energy from hydropower dams with large head and flow variation, analyses its potential, and shows possible technologies. Focus is given to a Moveable HydroElectric Power Plant (HEPP) system in which the turbine module can be adjusted according to the flow and water level in the river. During floods the exceeding flows can pass above and below the Moveable HEPP results in a sub-pressure environment after the turbine module, thereby reducing the dam's downstream head, increasing the pressure difference between the turbine inlet and outlet and the flow through the turbine, which increases the electricity generation of the dam. Dams with head increaser arrangement have been implemented in several dams in the 1930-1950s and now are regaining attention in Middle Europe. The main intention for its implementation is harnessing hydropower generation at run-of-river plants, with low-head, with a 20% to 30% cost reduction, lower flooded area at the dam site, the resulting evaporation and the impact on the aquatic fauna. A case study was performed with the proposal of the Aripuanã Moveable HEPP in the Madeira River with a 26 meters height dam and a generation capacity of 1,400 MW. The increase in generation with the head increaser effect is as high as 21%. The estimated potential for this technology in the Amazon region is 20 GW. Other potential locations are discussed in the article. Dams with head increaser effect have been successfully implemented and have the potential to become a major alternative for base load renewable energy in the future.

Sedimentary Basin Water and Energy Storage: A Low Environmental Impact Option for the Bananal Basin

“…There is no spillway because the water flows above and below the plant during the wet period. This also increases the theoretical head of the plant due to the Venturi effect caused by the spilled water [19]. Another benefit of this technology is that the sediments from the Bananal basin can easily pass through the bottom of the dam with no restriction during the wet period.…”

“…However, the Indus river only has an average yearly water level variation of 3 m [18]. The Araguaia river varies on average 5 m annually in the Bananal sedimentary basin [19].…”

“…The flood results in the lack of biodiversity in the flooded region (Figure 2d). Every year, the level of the Araguaia river in the Bananal basin varies by 5 m in altitude [19]. The region suffers from climatic variability.…”

Lost Energy of Water Spilled over Hydropower Dams

“…The technical solutions proposed by Hunt et al [25] are possible solutions; the authors primarily focused on harnessing the kinetic energy of spilled water. The proposed idea is interesting but is feasible only during construction or with a reconstruction of the dam.…”

Electric Truck Hydropower, a Flexible Solution to Hydropower in Mountainous Regions

“…A lot of novel low head hydropower converters have been introduced. Also new approaches for the modernization of existing plants, such as dam heightening [3], new electrical equipment, digitalization [4] and floating PV [5].…”