Session 08: Power Generation Strategic Planning (1)
Short Term Power System Planning with Water Value and Energy Trade Optimization
1HEP Trgovina d.o.o.; 2University of Zagreb
This paper emphasises the importance of a well planned unit commitment model in coordination with water value evaluation to achieve optimal economic results. The familiar water value models are examined and customized for the simulated power system model. Linear programming methods are used for achieving best economic performance for hydro and thermal power plants production and their power exchange is calculated. Several scenarios of short term planning with emphasis on water value and power market exchanges are presented.
Short-term Value for the Water Stored in Headsensitivity Power System Reservoirs
Instituto Superior de Engenharia de Lisboa, Portugal
As it is well known, competitive electricity markets require new computing tools for generation companies to enhance the management of its resources. The economic value of the water stored in a power system reservoir is crucial information for enhancing the management of the reservoirs. This paper proposes a practical deterministic approach for computing the short-term economic value of the water stored in a power system reservoir, emphasizing the need to considerer water stored as a scarce resource with a short-term economic value. The paper addresses a problem concerning reservoirs with small storage capacities, i.e., the reservoirs considered as headsensitivity. More precisely, the respective hydro plant is headdependent and a pure linear approach is unable to capture such consideration. The paper presents a case study supported by the proposed practical deterministic approach and applied on a real multireservoir power system with three cascaded reservoirs, considering as input data forecasts for the electric energy price and for the natural inflow into the reservoirs over the schedule time horizon. The paper presents various water schedules due to different final stored water volume conditions on the reservoirs. Also, it presents the respective economic value of the water for the reservoirs at different stored water volume conditions.
Identification of the Best Power Plant Layout for Large Offshore Wind Farms Connected Via VSC-HVDC Links
University of Pavia, Italy
The overall purpose of this paper is to find out the best choice in terms of generator technology for large offshore wind farms connected to the EHV network by means of VSCHVDC transmission: besides the traditional benefits compared with HVAC and line commutated HVDC, this technology allows variable frequency operation, in order to increase the overall production of the wind farm. Two different types of generators – Squirrel Cage Induction Generator (SCIG) and Doubly-Fed Induction Generator (DFIG) – are compared in variable frequency operation: the related power plant layouts are analyzed, for different wind speed conditions, by means of a slightly modified version of an online optimization algorithm. The resulting programs are coded in MATLAB® environment and some tests are carried out.
Business Case Assessment of Balancing Large Scale PV with Flexible CHP
In a situation where the share of less predictable electricity production from renewable energy sources (like solar energy) in the overall electricity production-mix increases, the electricity system will be confronted with more imbalance. Balancing markets deal with these imbalances. In this context, a balancing responsible party (BRP) is responsible to maintain the balance in its portfolio on a quarter-hourly basis and is charged for any incurred imbalances. A BRP with less predictable electricity production in its portfolio, like PV production, has a higher imbalance risk and thus on average a higher imbalance cost. The case study under consideration aims at optimizing the portfolio of a BRP, which consists of a large scale PV installation and an industrial CHP unit. A software tool is used that is able to calculate to what extent the imbalance costs of the BRP can be decreased by actively controlling the available flexibility in its portfolio (in this case the CHP installation). The paper presents the results of the simulations and discusses the potential reduction in imbalance costs for the BRP if the flexibility of the CHP is used within different scenarios.
A Profit Maximization Model for a Power Producer in a Pool-Based Energy Market with Cost Recovery Mechanism
1Heron Thermoelectric S.A.; 2Aristotle University of Thessaloniki
The objective of this paper is to address the self-scheduling of a power producer in a pool-based energy market where a cost recovery mechanism is applicable. Under the cost recovery framework, generating units are guaranteed to receive payment at least equal to their actual operating cost, if committed. In the proposed model, the effect of cost recovery on the plant’s revenues is included in the objective of the profit maximization problem of the producer, who is assumed to be a price-taker. The proposed method is developed as a mixed-integer linear program using GAMS/CPLEX and tested for the simple case of a small thermal producer owning a single unit, under the general cost recovery provisions of the Greek electricity market. The model constitutes the first step towards a stochastic programming approach for a price-maker producer.
Representation of Electricity Generation Capacity Expansion by Means of Game Theory Models
Comillas Pontifical University, Spain
Electricity generation capacity expansion is still a complex and elusive problem. Nevertheless, the importance for generation companies and regulators of analyzing the decision of building new power plants, due to its economic impact, has led to a large number of studies that address this problem using different techniques. One of the most promising alternatives is the use of game theory.
This paper presents two game theory models that can be used in this context and compares them. The first model is an extension of a conjectured-price-response market equilibrium model that includes expansion decisions. In this case, each agent optimizes in a singleshot game the overall profit including investment and operation. The second model considers expansion and operation decisions separately to increase model realism. In this model expansion level considers overall profit, but market is considered as a constraint for the upper level game, in a bilevel game schema.
Some bilevel games can be reduced to a one-stage conjectured-price-response game. Thus, the objective of the paper is to assess if the one shot game, that is much easier to solve can be considered as a good approximation for the bilevel game formulation, without explicitly solving the bilevel game.
The Value of a Pumping-Hydro Generator in a System with Increasing Integration of Wind Power
1FCT/UNL, Portugal; 2ISEL/Cie3
Portugal established a strong commitment to increase the installed renewable capacity in order to decrease its external energy dependency. These goals are being achieved mainly due to increasing levels of wind power. One of the main characteristics of wind power is the inherent unpredictability and variability. By allowing the energy storage, pumped-hydro units are able to cope with this drawback, promoting the match between generation and consumption. This paper presents a model based on market prices to determine the optimal bidding strategies that enable the total profit maximization of a pumpedhydro unit. It is considered that this unit participates in the Iberian day-ahead electricity market and in the portuguese ancillary services market. The optimal bids of the unit were calculated for scenarios with different levels of wind energy in the day-ahead market. The results showed that most of the income of the pumped-hydro unit was obtained from the spinning reserve market.