Harnessing the Power of GNSS for Monitoring Hydro Energy Infrastructure

Author: Paolo Dallocchio, Steve Thurgood, Megan Hansen, Ruth Badley 

Hydropower is a cornerstone of the transition to safe and sustainable energy. The structural health of dams and other hydro infrastructure is monitored over time to track movements primarily caused by water load. Ensuring that any changes remain within a specified tolerance is crucial to maintaining safety. If left unchecked, the structures are at risk of damage and potentially catastrophic failure.

Enel Green Power, an Italian multinational corporation, and a global leader in the renewable energy sector, manages 1,200 plants worldwide with installations and assets from a mix of renewable resources including hydroelectric, wind, solar, and geothermal. In line with Enel’s vision for energy and digital transitions, the company embraces innovative, automated solutions that help engineers and data analysts mitigate risk, maintain safe operations, and improve efficiency.

Working closely with Leica Geosystems, Enel initiated a year-long project to evaluate the benefits of using Leica’s automated GNSS monitoring system to acquire real-time data 24/7. The monitoring team also wanted to correlate the GNSS data with bi-annual manual measurements taken with their existing Leica TS16 total stations, LS10 digital levels, tilt sensors and geotechnical equipment, to confirm deformation.

Complementary monitoring technologies for comprehensive data  

Alessio Ceccato, Geology & Remote Sensing Specialist for Enel Green Power’s Hydroelectric Technology Line, explains:

“Displacements observed via GNSS can be cross-correlated and validated with those of geotechnical sensors as part of the 24/7 system. Densifying the frequency of the GNSS measurements enables the extension of the structural analysis to have a more detailed and complete description of deformation. This ensures reliable and timely detection of possible anomalous behaviour.”

“We chose Leica Geosystems’ advanced, robust GNSS system because it provides stable, reliable, and continuous observations with high automation. Thanks to improvements over the years in GNSS analysis technologies and methodologies, high precision (2-5mm), continuous, and automatic positioning can be achieved with a latency of up to one hour.” 

For Enel, Leica Geosystems automated GNSS monitoring system provides continuous, independent measurements for understanding movement of their assets in 3D. When combined with geotechnical sensor data, the Enel team benefits by attaining data correlation from complementary monitoring technologies. As a result, more information on structural change is available to engineers and maintenance teams in near real time. Empowered by data, they can improve safety standards and manage risk strategies.

Displacement graph showing the monitoring points in Alanno, a part concrete, part earth dam in Abruzzo, Italy

Deployment at four sites

To evaluate the benefit of systems with additional data available for analysis, Enel installed enhanced monitoring real-time solutions at four locations. These were chosen to confirm where the biggest advantages would be seen. A total of 19 Leica AS10 antennas and GR30 receivers were installed during October and December 2020 at three hydropower plants in Italy, and a fourth in Spain. 

Installation locations included:

• Gusana, a concrete dam on the island of Sardinia, Italy
• Alanno, a part concrete, part earth dam in Abruzzo, Italy 
• Gandellino, a water channel in Lombardy, Italy 
• Pampaneira, a penstock in Grenada, Spain

Due to COVID-19 restrictions, installation and technical training for the project were conducted remotely; however, this was no barrier to learning. Due to the multinational project locations, Leica Geosystems in Italy and Spain assisted with support and training ahead of the installations. Duilio Guizzetti, Monitoring and Control Technical Specialist for Leica Geosystems Italy, led remote sessions for the Enel engineering management team to configure the GNSS network. This enabled easier system setup despite installation locations ranging across southern Europe.  

Alanno site, a part concrete, part earth dam in Abruzzo, Italy 

GNSS data and monitoring software

In addition to validating the results of manual survey methods and confirming 3D locations, the automated GNSS system acquired data continuously 24/7, serving as the primary alert system. To ensure the GNSS installation was resilient and reliable, the system used solar power with battery backup should the direct supply fail, and robust data communication via WiFi and/or GSM. The GNSS receiver, power, and communications were securely housed in a communication box installed at each location.

Data acquired by the sensors was automatically uploaded and processed using Leica GNSS Spider, a specialised software for computing GNSS baselines and positions. The results were then imported to Leica GeoMoS Monitor for displacement computation and alert notification, and then into GeoMoS Now! for analysis and visualisation via a user-customised web portal. This enabled engineering and remote teams around the world to securely share, view, and analyse the monitoring data using graphs, tables, and reports – accessing the project status at any time. 

GNSS measurement epochs were observed over 1- and 6-hour intervals, providing real-time, continuously computed, live data. Additionally, a post-processed position was computed every 24 hours for a definitive XYZ and to validate the real-time data. For those sites with GNSS baselines over 10kms, the web-based Leica CrossCheck monitoring service provided processing to achieve the required accuracy.

Gusana, a concrete dam on the island of Sardinia, Italy

An eye in the field

The results of the deployments demonstrated that significantly more information could be collected through continuous measurements with Leica Geosystems GNSS receivers than when solely relying on manual monitoring carried out bi-annually. The switch to 24/7 monitoring allowed the engineering team to know what happened, when and where, along with making movement trends clearly visible. The system enabled a greater understanding of the monitoring data and reinforced Enel’s analysis of external factors affecting structures.

Automation has another benefit: at some sites, access to the facilities and the availability of personnel to take manual measurements is limited, leading to a lack of continuity. The fully automated system delivers 24/7 live data, enhancing safety and efficiency by providing data about the infrastructure’s condition all the time, not just when survey crews are available. 

According to Alessio Ceccato, a big benefit of 24/7 monitoring is the availability of data to correlate movements between measurement systems:

“Displacements detected by GNSS systems can achieve competitive accuracies sufficient for monitoring the deformation of structures, overcoming some of the drawbacks associated with previous manual techniques.” 

With reliable, continuous data, time-consuming site visits only need to be carried out if the GNSS data indicates deformation, requiring a more detailed manual survey for investigations and validation. This now operates as an early warning system, adding huge value to Enel’s operations.

Ceccato adds, “with the large amount of data that can be collected and the easy installation of Leica’s real-time GNSS geodetic monitoring system, it is possible to obtain an accurate and widespread description of structure behaviour, leading to near real-time warnings.”

Using automated data collection and processing as the primary monitoring tool gives Enel a smarter way to manage their teams’ routines and resources. After successfully deploying Leica Geosystems’ GNSS sensors at four hydro plants and seeing the benefits to safety and efficiency from immediate, real-time deformation results, Enel is looking to expand automated monitoring workflows to other sites.

Interested in monitoring? Please feel free to read further case studies, showing how our customers use our solution to improve their monitoring workflow:

Monitoring Case Studies