A case for true specialists

Photo | Bosch Rexroth
Marginal Column

Above: (from left) Alberto Hidálgo, Héctor Vázquez, Martín Gómez, Héctor De Reza and Abraham Huerta of the Rexroth team in Mexico – hard at work.

When building the La Yesca hydroelectric plant in Mexico, not only were the technical challenges in the limelight for Bosch Rexroth. Differences in languages and time zones made it necessary to install clever organizational structures from the very outset.

 

At a height of 208.5 meters, this gigantic rockfill dam for the La Yesca hydroelectric facility in Mexico is currently the second tallest of its kind in the world. It is exceeded only by the Shuibuya Reservoir Dam in China, measuring 233 meters. The huge dam rises on the Rio Santiago, about 100 kilometers to the northwest of the city of Guadalajara and in the Mexican federal state of Nayarit. This project is emblematic of the country’s aspiring economy. Mexico registered continuous economic growth in recent years.

This growth is, of course, accompanied by rising energy demands. Since the country is committed to stemming climate change, one large government initiative is intended to ensure a climate-friendly power supply over the long term. Hydroelectric plants are central to this effort. Mexico sees their enormous energy potentials as the key to mastering the balancing act between economic and social advance on the one hand and reducing emissions on the other hand – while at the same time powering the national growth engine.

Photo | CFE

The La Yesca rockfill dam is the world’s second tallest of its kind.
Photo: CFE

 

La Yesca is just one element in a water power project that involves several dams with total energy potentials of 4,300 mega-watts. Following five years of construction work, this plant began producing power on November 6, 2012. Two generators with rated output of 750 megawatts will, on average, produce 1,210 gigawatt hours of power each year. This amount could supply electricity for eighteen months to the approximately one million residents of Nayarit.

This project, with a price tag of 1.3 billion U.S. dollars, not only presented technical challenges to Bosch Rexroth. An unforeseen delay in construction, the seven-hour time difference between Mexico and Europe, and the different languages spoken by those involved in the project required flexibility and resourcefulness.

Persuasion was of the essence

The consortium responsible for construction comprised the large ICA company in Mexico and Power Machines, a Russian specialist in energy systems and mechanical engineering. At mid-2008 the consortium signed a cooperation agreement with Bosch Rexroth in Mexico. That had been preceded by intensive consultations between local project heads and the experts in steel structures for hydraulic engineering, at Lohr in Germany, and those at the regional subsidiary in Boxtel, Netherlands, which delivered the cylinders. The result was a sensible concept that included both many solutions that had been tested in practice and certain specially developed technologies attuned to customer requirements right down to the last detail.

Photo | CFE

Nighttime view of the overflow chutes.
Photo: CFE

 

The first basic measure aimed at good cooperation was to form a Spanish-speaking project group, assembled by Carlos Holzinger, project manager at Bosch Rexroth. “The customer’s staff spoke Spanish almost exclusively. Fundamental to cooperation for such a demanding project is that everyone speaks a common language,” he explains. The logic of this initiative was shown above all whenever technical questions required clarification. One example was the effort that Holzinger’s team, together with their colleagues, had to expend to spark customer interest in Rexroth’s Enduroq® surface finish.

“Customers normally prefer cylinders with a piston finished in chromium steel. This final layer guarantees a certain degree of hardness, greater than the softer substrate. It is also resistant to corrosion and rust. The Mexican customers were at first skeptical about our new product, however,” Carlos Holzinger recalls. Working together with the specialists, he was able to convince the customer of the advantages of the heat-injected, single-layer technology. “Enduroq® offers great resistance to wear, is highly impermeable, and exhibits extremely low porosity. Piston rods finished in this way are just as corrosion-resistant as the chromium version, but they also extend service lives and significantly reduce life cycle costs,” Holzinger points out.

Project on hold

Before construction started, geologists took exploratory cores at the site planned for the dam. They found irregularities in the earth’s crust. “If the dam had been erected there, then water might have undercut and damaged the dam,” explained Martin Gomez, project manager for the Bosch Rexroth regional subsidiary in Mexico. That would have been an unacceptable risk for a gravity dam that was to hold back an artificial lake with 33.4 square kilometers of surface area and about 1.329 billion cubic meters of water.

The site was relocated. “This delay forced us to apply metal preservatives to the parts, since in most cases they were delivered ready for immediate installation,” Gomez explains. His team of experts created the required storage space – locally and in short order. Sunlight and temperature fluctuations were just as troublesome as moisture. The effort certainly paid off, since a full two years elapsed before the components could be installed.

 
Illustration | Bosch Rexroth

Working the night shift

The project team’s working hours were no less unusual. The seven-hour time difference made it necessary for many key people to put in night shifts on cell phones and computers to ensure quality and perfect service. Among the items Rexroth delivered were the hydraulic cylinders, power units, measurement systems, and control and power supply consoles. These are critical components that guarantee both proper functioning and the safety of the La Yesca facility. Other assignments went smoothly, too, including support work when installing piping at the construction site, laying all the wiring, commissioning procedures, and on-site acceptance. This was the product of excellent cooperation between Lohr, Boxtel and the Bosch Rexroth regional subsidiary in Mexico.

La Yesca will guarantee the region a clean and reliable energy supply for years to come. The reservoir will also be a boon to fish farming and the tourist industry. The project rewarded Bosch Rexroth with valuable new experience and, once again, the realization that if you apply expertise, ingenuity and flexibility, virtually every hurdle can be overcome.