Combining construction and renovation works to increase techno-economic feasibility of very low head run of river hydro power

In the Lower Rhine river two hydro-power plants have been built at weirs. The third, most upstream weir at Driel was considered as well, but at the time (1988) could not be made feasible due to the low head difference at Driel. Developments in low-head hydro-power have given new possibilities and reason for reassessment. Locations such as Driel, where a discharge and a small head-difference are available, are common, but many are not utilised for power production. Additionally, a large number of existing weir complexes are nearing the end of their design life-time or are in need of renovation. Combining the construction and/or renovation works with the implementation of hydro power can significantly lower the costs, increasing the economic feasibility for low head locations. The research shows that it is indeed possible with current state of the art technology to extract sufficient amounts of power. Turbines that start at low head-differences or enhancements to increase the pressure difference over the turbine can be used to make sure the turbines reach comparable capacity factors (percentage of full-load-hours in a year) to existing run-of-river-plants with larger head-differences. In terms of economic performance it is necessary to use every opportunity to keep investment costs as low as possible, like using planned maintenance work to also implement the power-house.