Optimal Utilization of the Hydropower System

1.        Introduction

Today power system has import in normal inflow years, and without the reduction in consumption seen in 2002-2003 the energy deficit in the 2003 would have been hard to neglect. The expected future growth of the consumption together with reluctance to usage the remaining hydropower resources shifts the balance even further. The criterion for the thesis is to contribute to an efficient usage of the hydropower system in compliance with other natural energy resources in Norway. The overall picture is illustrated in fig. 1, this is the framework for utilizing hydro power in Norway.

Fig 1. Optimal usage of hydropower

2.      Outer ring

Most elements in the outer ring impact on the conditions for optimal utilization of the hydropower resources. In the research the resource inflow will be considered exogenous given but impact from a changing climate is briefly covered in [1]. So far the climate change goes in favor of hydro power. Not only will the inflow in important hydro power areas increase, the inflow will also a change in distribution over the year that reduces spillage. Energy policy is considered an externality except when it comes to environment. Environment for hydropower usage is dependent on both national and international trends. Global emission is debated and the value of hydropower can be expected to increase [6]. Local impact from hydropower may be discussed in terms of how to minimize these impacts this could somehow be included in the research. Combined action with neighboring systems will be important for security of the energy supply in the hydropower system and may lead to synergy effects on money flow and environment as well.

3.      Market & Rules

Then the market ring is a task by itself. In this project “Market&Rules” is provider of premises for the planning processes that decides whether hydropower can be optimally utilized or not. At least at this point the market, the set rules and other constraints are considered externally given. The modeling of market and market imperfections is important to understand and model in order to investigate the current market situation. An exam work for a course in market power at NHH showed that even a small imperfection may lead to a large shift in benefit between supply and demand. A publication describing market models and market modeling is under construction together with Post. Doc. Geir Warland. How to implement the short-term decisions in the market is described in [2] and [3].

4.      Planning process

From an operation research perspective the planning processes are complex and for practical purposes it also needs to be decomposed. The main focus of the research in the PhD-project will be to improve this process in means of models and especially the connection between them.

Fig. 2. Decomposing the planning process

Describing the overall process is important and a publication focusing on methods on different levels and how to connect them is under writing. Establishing a better model for connecting the long- and medium-term strategic planning with short-term scheduling is the main focus on the practical work carried out at the moment. This could also be called refitting the strategy. The main challenge is that the number of details, it is possible to include in stochastic models on the long-term or medium-term level, is lower, that the number of details that must be included in operational models. This may result in errors when implementing the long-term strategy. Such errors are not only bad for the companies but may also impact on the overall success of maintaining the energy balance in the system.

How to implement the short-term decisions in the market is described in [2] and [3]. Various techniques have been developed over the years for modelling short-term scheduling in thermal as well as hydropower dominated systems. An overview of these methods and their implications regarding application for hydropower is described in [5]. The area of short-term scheduling for hydro power is becoming more focused in the power companies. This increases the need for decision support for special topologies as described in [4].

References

[1] M.M. Belsnes, A. Haakestad and L. Tøfte, ”Impact from climate change on regulated watercourses”,

Hydropower’05, Stavanger, May 2005.

[2] O.B. Fosso and M.M. Belsnes, “Short-term Hydro Scheduling in a Liberalized Power System”, PowerCon 2004, Singapore, Nov. 2004

[3] M. M. Belsnes, I. Honve, SINTEF Energy Research Prof. O. B. Fosso, Norwegian University of Science and Technology “Bidding in the secondary reserve market from a hydropower perspective”, PSCC 2005, Liege, Aug.2005.

[4] M.M. Belsnes, J. Røynstrand and O.B. Fosso, “Handling State Dependent Nonlinear Tunnel Flows in Short-term Hydropower Scheduling”, POWERCON 2004, Singapore.

[5] M.M. Belsnes, T. Gjengedal and O.B. Fosso, “Methods for Short-term Generation Scheduling in Hydro Power Dominated Power Systems”, Hydropower’05, Stavanger, May 2005.

[6] Michael M. Belsnes, Arne Haugstad, Birger Mo and Peter Markussen ”Quota Modelling in Hydrothermal

Systems” PowerTech 2003, Bologna, June 2003.