Assessing the energy potential of modernizing the European hydropower fleet

About 50% of all hydropower plants (HPPs) worldwide were originally commissioned more than 40 years ago, so that the advanced age of the fleet is a major concern across all continents, and especially in Europe. The retrofitting of HPPs can generate several benefits for production, flexibility, safety, management and environment. In this work, the benefits related to energy and flexibility were considered and quantified by conducting a large-scale assessment for the European Union and Europe, taking into account several retrofitting strategies: dam heightening, head loss reduction in waterways, increase of installed power in run-of-the-river and storage power plants, increase of annual inflow, increase of maximum efficiency and weighted efficiency of electro-mechanical equipment, start and stop improvement, digitalization and inflow forecast, floating photovoltaic and reservoir interconnection. For most of these strategies, an indicator of the additional capacity and/or annual production that could be obtained compared to the current conditions was calculated. Excluding site-specific strategies (e.g. installation of new parallel waterways, increase of withdrawals from existing intakes) the resulting compound value of the indicator is 10.2% for European Union and 12.2% for the whole Europe, plus 4-28.6 TWh achievable by interconnecting reservoirs. This suggests that the retrofitting of HPPs can generate significant benefits in terms of energy and flexibility, minimizing environmental impacts, and should be considered as an important element of both energy transition and water management policies

Vector Diagram: How to Get More Useful Information from Hydraulic Unit Monitoring

The development of an effective hydraulic unit (HU) diagnostic system, which recognizes critical fault at an early stage of their development, is a relevant and practically important objective for many hydroelectric power plants (HPP). The main trends in recent years in this area are the expansion of the hardware base and the introduction of digital technologies to handle the increasing flow of data monitoring. At the same time, much less attention is paid to the improvement of algorithms for potential defect recognition and the creation of new diagnostic rules; much of the monitoring data are used only for the trend construction, and do not participate in the diagnosis. The method of vector diagrams is proposed for estimating actual forces applied towards the support joints of an HU: each mode of operation is represented on a phase plane in the form of a vector proportional to the vibration displacement. The vector difference determines the actual forces of mechanical, electromagnetic and hydraulic origin in each operating mode, taking into account the individual characteristics of the HU. The example of vector diagram analysis shows how to obtain more useful information about the technical status of the unit from the same amount of basic vibration monitoring data, to predict possible deterioration in the operation of the equipment well before the generation of a warning or an alarm signal by the diagnostic system

Limitations of Modern Diagnostic and Prognostic Systems for a Hydraulic Unit’s Health

Modern diagnostic systems for the hydraulic unit’s health play an important role in ensuring the reliability and safety of the hydroelectric power plant (HPP). However, they cannot provide timely detection of such dangerous operational defects as fatigue cracks. This article reflects two main reasons for this problem. The first one is a high level of the individuality of hydraulic units, which does not allow the effective use of statistical methods of information processing, including BIG DATA and MACHINE LEARNING technologies. The second is the fundamental impossibility to identify cracks in some key components of hydraulic units only on the basis of data analysis from a standard diagnostic system usually used at the HPP. Developed computational studies on the example of Francis turbines confirmed this. It is proposed to supplement the functionality of standard diagnostic systems with a prognostic block for an individual analytical forecast of the unit’s residual lifetime based on the calculated assessment of fatigue strength. This article presents the developed conceptual diagram and the demonstration version of the proposed analytical predictive system. The comparison of the standard vibration diagnostic system and the proposed solution as a tool for the early detection of cracks in a Francis turbine runner shows some advantages of the proposed approach

Destruction of the hydraulic unit shaft: Why it is possible?

Hydraulic units produce around 20% from the total world energy and almost 75% from total renewable energy as well as play a vital role in providing energy system stability. The shaft is one of the key lifetime-determining elements for hydraulic units. Its durability, lifetime, fatigue and fracture resistance define reliability and safety of a hydraulic unit in general. Despite the presence of functioning continuous and periodic hydraulic unit technical condition control systems, there are several known cases of shaft destruction leading to their replacement, long downtimes and significant financial losses for energy industries.The goal of this research is determining main reasons for shaft destruction in hydraulic power plant operating conditions. Using computational modeling for a large vertical high-head hydraulic unit as an example shows that a growing crack doesn't significantly influence shaft dynamic properties. As a result, even a long through crack may escape detection by present vibration diagnostics systems. At the same time, non-destructive metal state control methods are also not always effective due to structural design features and large size of hydraulic unit shafts.To prevent serious incidents in the future there is a suggestion to improve vibration diagnostics data-processing algorithms, introducing an additional diagnostic sign – a ratio of registered double rotation frequency runout values to runouts at rotation frequency, which allows to identify a hydraulic unit with a growing shaft circumferential crack even with vibration state meeting compliance norms and requirements. Additionally, it is necessary to estimate residual HU shaft lifetime through calculation taking into account possible initial cracks not revealed previously by non-destructive control

Assessing the energy potential of modernizing the European hydropower fleet

Abstract About 50% of all hydropower plants (HPPs) worldwide were originally commissioned more than 40 years ago, so that the advanced age of the fleet is a major concern across all continents, and especially in Europe. The modernization of HPPs can generate several benefits in terms of generation, flexibility, safety, operation, and may have neutral or even positive implications for the environment. In this work, we appraise several options for the modernization of existing plants, with the exclusion of measures expected to increase the hydro-morphological pressure on water bodies (e.g. increase of withdrawals or new parallel waterways): dam heightening, head loss reduction in waterways, increase of weighted efficiency of electro-mechanical equipment, digitalization and inflow forecast, and floating photovoltaic (evaporation reduction). We provide an indicative estimation of the additional power and annual generation that could be obtained compared to the current condition. We estimate that the overall energy generation could be increased by 8.4% for European Union and 9.4% for the whole Europe by implementing the above-mentioned strategies. The additional energy gain achievable by increasing the inflow was discussed but not included in the above mentioned overall indicator, because it is very site-specific. The additional energy storage achievable by reservoir interconnection and coordinated operation has been estimated in literature as 169 TWh. This suggests that the modernization of HPPs can generate significant benefits in terms of energy, and should be considered as an important element of energy policy, also considering the additional benefits in terms of reliability and flexibility of the energy system that it may deliver. The modernization options considered here, insofar as not entailing a worsening of the hydro-morphological alterations, are also expected to cause limited or no conflict with the environmental objectives of water policies in Europe