Africa

Perspectives: Speeding toward the Future

Technology seems to be moving at the speed of light these days, with the newest, fanciest smartphone being launched before you’ve even had time to fully adapt to the capabilities – and limitations – of the previous iteration.
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Technology seems to be moving at the speed of light these days, with the newest, fanciest smartphone being launched before you’ve even had time to fully adapt to the capabilities – and limitations – of the previous iteration. Just a few years ago my daughter was “dying” for an iPad. She hasn’t looked at it in more than two years as her laptop and latest smartphone advanced past the allure of a now-obsolete technology. (Maybe I can see if her younger sister will still think it is worthwhile.)

Technology advancement in the hydropower and dams markets is NOT moving at the pace I just mentioned. But, some advancing tools and techniques from other markets can be applied to hydro and dams, and that’s an exciting option.

One example: Scientists at the GFZ German Research Centre for Geosciences in Potsdam have taken a pretty “sexy” technology – satellites – and applied it to the study of dam safety. They have shown that satellites can be used to monitor dam deformation, using as the technology the TerraSAR-X earth observation satellite and as the test subject the Masjed-Soleyman embankment dam in southwestern Iran, which impounds water for a 2,000-MW powerhouse.

Since the reservoir behind this dam was first filled in 2000, cracks began appearing on the dam crest. This satellite has crossed the dam every 11 days, taking measurements of the Earth’s surface with a resolution of 1 m. Compared with conventional measurements taken via a ground-based monitoring system, researchers determined the satellite data provide a much more detailed record of deformation. In fact, the high-resolution X-band synthetic aperture radar (SAR) data from the satellite revealed that the dam was subject to two different deformation regimes and was deforming at a rate of about 13 cm per year on the crest, along with about 7 cm per year of downstream movement.

The scientists say: “We believe that our results can be generally applied to dams with the same construction. The high-resolution satellite systems that deliver a new class of radar images with a resolution of up to 25 centimetres, compared to typically 10 to 20 metres available so far, have revolutionized the ability to assess infrastructure stability from space.”

A second example: Researchers at the University of Alcala in Spain have developed a new fiber-optic distributed sensor they say can be used “to continually monitor the structural health of large structures such as dams or bridges.” These sensors can be used in harsh environments and in areas that lack a nearby power supply and up to now have primarily been used to detect leaks in oil pipes and monitor for landslides along railroads, they say. A single fiber placed along the length of a structure, such as a dam, can be used to detect changes in the structure by changing the light traveling down the fiber.

This new sensor uses an approach known as Brillouin optical time domain analysis, which requires pulsed and continuous wave laser signals to interact. They changed the way the laser signal is generated, allowing an increase in power and improved sensing performance. They say this new sensor can sense strain and temperature changes from 1 million sensing points over a 10-km-long optical fiber in less than 20 minutes. This new sensor is reported to be about 4.5 times faster than previous sensor versions. In fact, the researchers demonstrated they could measure the temperaturee of a hot spot to within 3 degrees Celsius from the end of a 10-km-long fiber.

“With fiber-based sensors, it is possible to precisely detect erosion or cracking before a dam fails, for example,” said researcher Alejandro Domingo-Lopez. The scientists are now working to further reduce the acquisition time and to increase the density of sensing points to more than 1 per centimeter.

These are just a couple of examples of technology innovations that could make a significant difference for dams and hydropower. I know others exist. Email the details to [email protected] and we may feature them in the September issue of Hydro Review, when we plan to cover hydro innovations and new technology.