Level of Intervention:
Voies Navigables de France operates the French inland waterways network. It is responsible for modernizing the network and the civil works. Regarding climate change adaptation needs of the hydraulic network, VNF is engaged in an ambition modernization program including the modernisation of hydraulic equipment. The modernisation of Lock34bis at Crissey was launched in 2020. Built in the early 1970s, Lock 34bis at Crissey is located at the eastern end of the Center Canal, at the junction with the Saône River.
At each lock use, the volume of water passing through the lock is large (2200 m3) and quickly brings down the level of the reach. This is why a pumping station was installed to raise the water from the Saône immediately in the reach. The pumping station consisted of two non-submerged pumps, which have become obsolete and ineffective.
Aim of the Experience:
As to improve water and energy consumption efficiency of the pumping station, Voies navigables de France chose to install a new pump, with a complete automation of pumps control. The works took place from February to November 2020.
Description of the experience:
The works consisted of, beyond the modernization of the electrical system and the securing of the evacuation of floods,
- the automation of the control of the pumps for the control of the level of the upstream reach
- and the installation of a new pump.
Particular attention was paid to the correct sizing and technical performances of the pumps for optimal hydraulic and energy efficiency.
Summary of measures:
The installed pump is a Xylem Flygt CT 3400/735 3-830 (nominal power 125 kW). Downstream, the height of the Saône varies. The manometric head (HMT) is between 6.26 and 12.53 m, for a flow rate between 630 l/s and 860 l/s.
The pumping system can operate in manual or automatic mode. Automatic mode is preferred.
The automaton calculates at a regular time step, the time necessary to raise the reach to expected level. Based on this calculation, the pump starts at the calculated time so that the reach is level early in the morning. This is done for three main reasons:
- With the aim of limiting pumping volumes, the pumping delay makes it possible to take into account the quantities of water that could arrive from upstream (water from the upstream reaches, rainfall, part of the rainwater from the town of Chalon that arrives in this reach);
- Pumping during the cooler hours and therefore when evaporation is lower;
- Pumping during off-peak hours and thus limit the demand for power on the French energy network. In addition, in certain French contracts, energy consumption per hour is reduced at a reduced rate.
The electrical installation of the pump is also provided with a reactive energy compensator. Capacitors absorb the additional power demand when starting the pump.
The pump flow rates are controlled with a Krhone brand flowmeter. It consists of an optiflux 2000 electromagnetic measurement sensor and an IFC 100 measurement converter.
Pumping system data is collected into the controller and sent to VNF water supervision system.
Estimate of CO2 reductions and other outcomes:
The two old pumps could not operate simultaneously. For an equivalent water level (Saone river level is variable), pump on the left river side was consuming 0.052 Kwh/m3 of electricity. The second pump, on the right river side was consuming 0.081 Kwh/m3. Based on local measurements after the new pump installation, the new pump electricity consumption is now around 0.042 Kwh/m3.
The electricity consumption decreased by about 19.3% compared to previous left side pump, and by 48.1% to the right side pump.
The global energy consumption reduction is estimated at 36.8%. Considering the pumping a water volume of 3 000 000m3/year, on a year basis, the energy economy is around 73 000 Kwh and 4400 kg CO2, based on the french electricity CO2 emissions average.
VNF operates 85 pumping stations on the french hydraulic network.
The experience is aiming at being extended to other pumping stations within VNF hydraulic modernisation program. VNF aims at saving 20% on energy consumption of pumping operations on VNF network.