Optimal Operation of the Multi-reservoir Rainwater Harvesting System for Hydropower Generation

Abstract

Reservoir operations for single and multi-reservoirs of rainwater harvesting systems has been tested to address the deficit in supplying water and electric power for remote rural communities of semi-arid region of AL-Khoser watershed, Iraq. The main basin was divided into four sub-basins 1B, 2B, 3B and 4B. The Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) was applied to estimate water volumes of the above proposed reservoirs. To optimize reservoir operations for the objective function of maximized total annual hydropower generation, a technique was used to convert non-linear to linear problems. In which a linear approximation of the non-linear power production term can be expressed linearly by summing the vectors, the release and storage, where the relationship between the head and the storage is directly proportional. Total annual hydropower generation is maximized by optimized sustainable operation policies for single and multi-reservoirs. Dry, average, and wet rainfall seasons were selected for 1985–2020. The annual harvested water in the reservoirs of Main Basin, 1B, 2B, 3B and 4B ranged between: 0.7790–4.1788, 2.1256–11.4010, and 5.10158–28.1985 MCM for the three seasons. The capacity of hydropower generation was 82.59, 436.75 and 1034.70 Kw for the three seasons. The increase in hydropower generation is achieved with multi-reservoirs operations by 110%, 66% and 41% respectively. The importance of hydropower generation increase is demonstrated by providing hydropower to additional families in the rural community as their primary source of power in addition to an increase in the irrigated areas.