Cost Model for Pumps as Turbines in Run-of-River and In-Pipe Microhydropower Applications

Abstract

Pumps as Turbines (PATs) are standard water pumps utilized as hydraulic turbines by reversing the flow direction across them. The off-the-shelf availability of water pumps and their reduced purchase price with respect to conventional hydro turbines makes them an ideal technology for exploiting large portions of uncapped hydro potential that is technically viable but not financially convenient. Such low-cost technology could help to expand hydropower exploitation in water resources worldwide, helping to reduce climate change greenhouse gas emissions. However, in the literature, the few available cost figures relative to PAT purchase price are discordant and often outdated, and such a lack of information is likely a severe barrier to a more widespread PAT implementation. In order to overcome this limitation, data from 343 pumps and 286 generators were compiled to show graphically and analytically how the purchase price of PATs varies over different nominal powers and hydraulic conditions. Besides, a set of equations was developed to allow designers to predict the PAT and generator cost from the nominal flow rate and available hydraulic head.