FLUXUS^® measures flow in 13 ft diameter pipelines

In order to modernize the measurement and control technology at their pumped-storage hydroelectric power plant Leitzachwerke, the Stadtwerke München (Munich City Utilities) chose FLEXIM, the best solution for retrofitting their 13 ft headrace pipelines:

Non-invasive flow measurement using clamp-on ultrasonic technology with FLUXUS^®.

The Stadtwerke München (SWM, Munich City Utilities), one of Germany's largest energy and infrastructure companies, is pursuing an extremely ambitious objective: To create enough green electricity in its own plants to supply approximately 800,000 private households in Munich by 2015. This corresponds to about 2 billion kiloWatt hours per year. By 2025, SWM aims to fulfill Munich's entire 7.5 billion kWh power requirements. To accomplish these ambitious goals, SWM has started the Renewable Energies Expansion Offensive.

Efficient storage of energy

The basic difficulty in supplying electrical energy is generating the right amount of power required at a given time. With the growing number of renewable energies available, the difficulty of buffering between supply and demand becomes more significant. The amount of energy generated from wind and sun fluctuates considerably depending on weather conditions. Using pumped-storage power plants, electrical energy can be stored effectively with a high degree of efficiency.

If the amount of electricity generated exceeds demand, the surplus can be used to pump water from a reservoir to a high-lying water storage basin. On the other hand, the potential energy of the stored water can then be quickly converted into power as required, using the turbines of the power station.

The Leitzach plants, located about 25 miles south of Munich, include 120 acres of lower lying basins. These basins are capable of approximately 2.6 million cubic yards and are connected to the Seehamer See via two pressure pipes, each measuring 13 feet in diameter. Since the lake is 420 feet higher, the basins can be used as pendular water.

In order to modernize the measurement and control technology, the headrace pipelines were equipped with flow measuring devices for safety monitoring.

Comfortable and cost-saving retroffiting

Given the huge nominal widths, the ideal solution proved to be non-invasive, ultrasonic clamp-on flow measurement. Initially, the non-invasive technology was demonstrated in a test measurement using the FLUXUS^®F 601. The efficiency of the installation proved to be one of the most important factors and the two measuring points were fitted with stationary FLUXUS^®ADM 7407 transmitters. The transmitter is paired with the Variofix mounting system to ensure optimal transmission of the measuring signal into the pipe at all times and provide permanent protection. Due to non-invasive measurement technology, FLEXIM and SWM were able to permanently increase the operational safety of the system at a relatively low cost, without a great deal of construction work.