Author(s): Francois Nuc; Patrick Hendrick

Linked Author(s): Francois Nuc, Patrick Hendrick

Keywords: "hydropower" "water grid" "electrical flexibility"

Abstract: Water adduction Network: can it bring electricity flexibility for the TSO or the DSO? Investigating the flexibility that a water adduction network can bring to TSO & DSO require to look at: - Load shifting of heavy consumers during electricity peak hours - Turbining the remaining pressure found on flow control valves In the case of the water supply network in Belgium, the study showed that: - The main pumping and treatment plant of this network consumed about 30 GWh/year. - Many stations are equipped with flow control valves where energy is constantly dissipated through water pressure loss. - In the largest dispatching station of the hydraulic network, two expansion valves are installed. The power dissipated in pressure loss at these valves amounts to approximately: - 1000Mwh/year for the 1st valve - 1500Mwh/year for the 2nd valve we reach a cumulative power of 2.5 GWh. This represents only 1% of the total energy consumed annually by the largest treatment/pumping station. We saw that every day of the week there is a variation in the power dissipated at the expansion valves. This evolution of the power has the form of a "square signal". This is essential information for understanding how the water adduction network operates. In an attempt to answer the relevance of the study, clear questions must first be asked: - How can a water grid be a flexibility factor for the TSO of an industrial country? o If we consider an electrical load consuming 30 GWh/year. o If we consider 8760h per year o We can deduce that the connected load is 3.4 MW of installed power o This corresponds to a wind turbine. Has this load a flexibility potential for a TSO? a DSO? - Is it relevant to compare: o the power that could be "load shifted" from a treatment station o the power that could be recovered from the expansion valves? -What is the benefit/risk factor of replacing the expansion valves with turbines? - Is the operating inertia of a water system compatible with the operating immediacy of a power system? - Which turbines or other technologies could: o adapt to (large) changes in power on a daily basis? o while maintaining a high enough efficiency? o with a low maintenance o and low risk of water pollution (oil, ...). - Do all water grids operate with a "square signal"? - The energy that would be produced at the level of these valves would be legally considered as a form of an energy production optimisation, a bit like cogeneration in an engine cycle? To answer those questions, a test bench is currently being design.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221383

Year: 2022