Pumps as turbines for efficient energy recovery in water supply networks

• Published in: Renewable energy 2018-07, Vol.122, p.17-25
• Main Authors: Kramer, M., Terheiden, K., Wieprecht, S.
• Format: Article
• Language: English
• Subjects: Economic efficiency; Energy recovery; Micro-hydro; Pump as turbine; Water supply system
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2018.01.053

The present work aims to enhance the energy efficiency of water supply networks by investigating technical and economical feasibility of energy recovery plants at low installed capacities. A cost effective stainless steel machine is investigated in pump and turbine operation and established conversion methods are used for predicting the best efficiency point of the turbine. The obtained results show a reasonable agreement of the BEP, but experimental investigations are still indispensable for a determination of complete Q-H-characteristics. The hydraulic machine is implemented in field at the transfer shaft of a high-level tank and valuable data concerning investment costs and water hammer have been collected. A proposed cost classification scheme will facilitate the acquisition of investment costs for further applications. The economic profitability of the hydropower plant is evaluated by the net present value method and the obtained results give incentives to exploit unused energy recovery potential within water supply systems. •Technical and economical feasibility of energy recovery plants at low capacities.•Investigation of a reverse running stainless steel pump in laboratory and field.•Detailed discussion on conversion methods from pump to turbine mode.•New cost classification scheme facilitates the acquisition of investment costs.•Incentives for the exploitation of unused energy recovery potential.