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Papers by Christos Simoglou

Research paper thumbnail of ANN-based scenario generation methodology for stochastic variables of electric power systems

Electric Power Systems Research, May 1, 2016

Research paper thumbnail of Comparison of SARIMAX, SARIMA, modified SARIMA and ANN-based models for short-term PV generation forecasting

This paper compares four practical methods for electricity generation forecasting of grid-connect... more This paper compares four practical methods for electricity generation forecasting of grid-connected Photovoltaic (PV) plants, namely Seasonal Autoregressive Integrated Moving Average (SARIMA) modeling, SARIMAX modeling (SARIMA modeling with exogenous factor), modified SARIMA modeling, as a result of an a posteriori modification of the SARIMA model, and ANN-based modeling. Interesting results regarding the necessity and the advantages of using exogenous factors in a time series model are concluded from this comparison. Finally, intra-day forecasts updates are implemented to evaluate the forecasting errors of the SARIMA and the SARIMAX models. Their comparison highlights differences in accuracy between the two models. All models are compared in terms of the Normalized (with respect to the PV installed capacity) Root Mean Square Error (NRMSE) criterion. Simulation results from the application of the forecasting models in a PV plant in Greece using real-world data are presented.

Research paper thumbnail of Hydrothermal Producer Self-Scheduling

Research paper thumbnail of Storage management by rolling stochastic unit commitment for high renewable energy penetration

Electric Power Systems Research, 2018

Research paper thumbnail of Probabilistic evaluation of the long-term power system resource adequacy: The Greek case

Research paper thumbnail of Artificial neural network-based methodology for short-term electric load scenario generation

2015 18th International Conference on Intelligent System Application to Power Systems (ISAP), 2015

In this paper a novel scenario generation methodology based on artificial neural networks (ANNs) ... more In this paper a novel scenario generation methodology based on artificial neural networks (ANNs) is proposed. The methodology is able to create scenarios for various power system-related stochastic variables. Scenario reduction methodologies can then be applied to effectively reduce the number of scenarios. An application of the methodology for the creation of short-term electric load scenarios for one day up to seven days ahead is presented. Test results on the real-world insular power system of Crete present the effectiveness of the proposed methodology.

Research paper thumbnail of Large-scale res integration in electricity markets: Challenges and potential solutions

2015 50th International Universities Power Engineering Conference (UPEC), 2015

Research paper thumbnail of Optimal operation of insular electricity grids under high RES penetration

Renewable Energy, 2016

This paper presents a scenario-based simulation analysis of the operation of the insular power sy... more This paper presents a scenario-based simulation analysis of the operation of the insular power system of Crete, Greece, on an hour-by-hour basis aiming at the evaluation of the impact of high Renewable Energy Sources (RES) penetration on the short-term power system scheduling. The possibility of introducing a pumped-storage plant as a storage facility to alleviate the negative effects of increased RES generation on the short-term operation is also investigated. The renewable generation impact is evaluated in terms of specific system indicators. An integrated software tool that performs annual simulation of the insular power system with hourly granularity aiming at the minimization of the total production cost while respecting the system and various generating unit operating constraints is used. Simulation results for the year 2015 provide quantitative assessment of the insular power system performance regarding its short-term operation under large-scale RES penetration and valuable conclusions are drawn.

Research paper thumbnail of Bidding strategy for risk-averse producers in transmission-constrained electricity markets

2015 12th International Conference on the European Energy Market (EEM), 2015

ABSTRACT

Research paper thumbnail of Benefits of demand response on a wind power producer bidding strategy

2015 IEEE Eindhoven PowerTech, 2015

ABSTRACT This paper proposes an optimal bidding strategy for a wind producer who participates as ... more ABSTRACT This paper proposes an optimal bidding strategy for a wind producer who participates as price-maker in the day-ahead electricity market. In order to empower the wind producer against the challenges introduced by the intermittent nature of wind power and improve his position into the market, demand response schemes are considered to be incorporated into his portfolio. The producer objective is the maximization of the day-ahead profit in conjunction with the minimization of the anticipated real-time production imbalance charges. A two-stage stochastic bi-level optimization model has been formulated, where the uncertainty lies in the day-ahead wind production and load consumption. Simulations on the Greek power system prove the effectiveness of the proposed synergy.

Research paper thumbnail of Coordination of day-ahead scheduling with a stochastic weekly unit commitment for the efficient scheduling of slow-start thermal units

2010 IREP Symposium Bulk Power System Dynamics and Control - VIII (IREP), 2010

This paper addresses the problem of the coordination of the day-ahead scheduling with a stochasti... more This paper addresses the problem of the coordination of the day-ahead scheduling with a stochastic weekly unit commitment for the efficient scheduling of slow-start thermal units. The solution of the 24-hour unit commitment may lead to cases, in which slow-start thermal units that are initially offline cannot be scheduled efficiently, due to their long start-up and minimum-up times as well

Research paper thumbnail of Scheduling Models and Methods for Efficient and Reliable Operations

Operations, Planning, and Economics of Insular Electricity Grids, 2015

Research paper thumbnail of Evaluation of the impact of RES integration on the Greek electricity market by mid-term simulation

2011 IEEE Trondheim PowerTech, 2011

ABSTRACT This paper presents a yearly simulation model for the analysis of the impact of the larg... more ABSTRACT This paper presents a yearly simulation model for the analysis of the impact of the large RES penetration in the energy production mix of Greece on the operation of the Greek electricity market. This impact is analyzed in terms of the electricity market clearing prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge, imposed by the government for the payment of the feed-in tariff to the RES producers. A mid-term scheduling model based on the day-ahead market clearing algorithm of the Greek wholesale electricity market is used for the yearly simulation under ten different scenarios regarding the RES installed capacity (multiple RES technologies are considered). Valuable conclusions are drawn from the application of the proposed model for the year 2011.

Research paper thumbnail of Evaluation of the Impact of IPPs on the Greek Wholesale and Retail Electricity Markets

Power and Energy Systems, 2012

Research paper thumbnail of Optimal Offering Strategies in Day-Ahead Electricity Markets under Uncertainty

8th Mediterranean Conference on Power Generation, Transmission, Distribution and Energy Conversion (MEDPOWER 2012), 2012

ABSTRACT This paper addresses the self-scheduling problem of a hydrothermal producer, which is fo... more ABSTRACT This paper addresses the self-scheduling problem of a hydrothermal producer, which is formulated and solved as a two-stage stochastic programming problem with recourse in order to account for market uncertainty. The producer is considered to own thermal and hydro generating units and participate as a price-maker in the day-ahead energy market. Forward bilateral contracts with end-consumers are considered and their effect on the producer self-schedule and profits is examined. The CVaR metric accounting for risk management is also incorporated. Post-processing techniques are applied for the construction of the generating units optimal offer curves to be submitted to the day-ahead energy market.

Research paper thumbnail of Optimal self-scheduling of a dominant power company in electricity markets

International Journal of Electrical Power & Energy Systems, 2012

Research paper thumbnail of Effect of increased RES penetration on the system marginal price of the Greek electricity market

2010 7th International Conference on the European Energy Market, 2010

This paper analyzes the effect that increased RES penetration in the energy production mix of Gre... more This paper analyzes the effect that increased RES penetration in the energy production mix of Greece has on the system marginal prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge. The market clearing algorithm of the Greek day-ahead electricity market is used for the simulation of the Greek energy

Research paper thumbnail of Impact of increased RES penetration on the operation of the Greek electricity market

7th Mediterranean Conference and Exhibition on Power Generation, Transmission, Distribution and Energy Conversion (MedPower 2010), 2010

ABSTRACT This paper analyzes the impact that the increased RES penetration in the energy producti... more ABSTRACT This paper analyzes the impact that the increased RES penetration in the energy production mix of Greece has on the operation of the Greek electricity market, in terms of the electricity market prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge, imposed by the government for the payment of the feed-in tariff to the RES producers. The market clearing algorithm of the Greek day-ahead electricity market is used for the simulation of the Greek energy market under ten different scenarios regarding the RES installed capacity. The units' emissions cost is appropriately incorporated in their total production cost function. Test results from the application of the scenarios on four typical weeks of year 2009 are also discussed.

Research paper thumbnail of A unified unit commitment — Economic dispatch model for short-term power system scheduling under high wind energy penetration

11th International Conference on the European Energy Market (EEM14), 2014

ABSTRACT This paper presents a unified unit commitment and economic dispatch tool for the short-t... more ABSTRACT This paper presents a unified unit commitment and economic dispatch tool for the short-term scheduling of a power system under high renewable penetration. The proposed model uses variable time resolution and scheduling horizon extended up to 36 hours ahead and produces robust real-time decisions making the short-term operation of the power system almost insensitive to RES forecast errors. The proposed model is tested for a monthly period on the Greek interconnected power system using real load and wind power data for two different wind penetration levels. Simulation results show that the proposed methodology allows for the accommodation of large amounts of wind energy into the short-term scheduling of the power system at minimum cost.

Research paper thumbnail of A MILP approach to the short term hydrothermal self-scheduling problem

2009 IEEE Bucharest PowerTech, 2009

This paper addresses the hydrothermal electricity producer self-scheduling problem in day-ahead e... more This paper addresses the hydrothermal electricity producer self-scheduling problem in day-ahead energy and reserves markets. A 0/1 mixed integer linear formulation of the producer self-scheduling problem is presented, which allows a realistic modeling of the unit's operating phases (synchronization, soak, dispatchable, desynchronization). Prohibited operating zones and daily hydro energy production constraints are also modeled. Test results address the effect of

Research paper thumbnail of ANN-based scenario generation methodology for stochastic variables of electric power systems

Electric Power Systems Research, May 1, 2016

Research paper thumbnail of Comparison of SARIMAX, SARIMA, modified SARIMA and ANN-based models for short-term PV generation forecasting

This paper compares four practical methods for electricity generation forecasting of grid-connect... more This paper compares four practical methods for electricity generation forecasting of grid-connected Photovoltaic (PV) plants, namely Seasonal Autoregressive Integrated Moving Average (SARIMA) modeling, SARIMAX modeling (SARIMA modeling with exogenous factor), modified SARIMA modeling, as a result of an a posteriori modification of the SARIMA model, and ANN-based modeling. Interesting results regarding the necessity and the advantages of using exogenous factors in a time series model are concluded from this comparison. Finally, intra-day forecasts updates are implemented to evaluate the forecasting errors of the SARIMA and the SARIMAX models. Their comparison highlights differences in accuracy between the two models. All models are compared in terms of the Normalized (with respect to the PV installed capacity) Root Mean Square Error (NRMSE) criterion. Simulation results from the application of the forecasting models in a PV plant in Greece using real-world data are presented.

Research paper thumbnail of Hydrothermal Producer Self-Scheduling

Research paper thumbnail of Storage management by rolling stochastic unit commitment for high renewable energy penetration

Electric Power Systems Research, 2018

Research paper thumbnail of Probabilistic evaluation of the long-term power system resource adequacy: The Greek case

Research paper thumbnail of Artificial neural network-based methodology for short-term electric load scenario generation

2015 18th International Conference on Intelligent System Application to Power Systems (ISAP), 2015

In this paper a novel scenario generation methodology based on artificial neural networks (ANNs) ... more In this paper a novel scenario generation methodology based on artificial neural networks (ANNs) is proposed. The methodology is able to create scenarios for various power system-related stochastic variables. Scenario reduction methodologies can then be applied to effectively reduce the number of scenarios. An application of the methodology for the creation of short-term electric load scenarios for one day up to seven days ahead is presented. Test results on the real-world insular power system of Crete present the effectiveness of the proposed methodology.

Research paper thumbnail of Large-scale res integration in electricity markets: Challenges and potential solutions

2015 50th International Universities Power Engineering Conference (UPEC), 2015

Research paper thumbnail of Optimal operation of insular electricity grids under high RES penetration

Renewable Energy, 2016

This paper presents a scenario-based simulation analysis of the operation of the insular power sy... more This paper presents a scenario-based simulation analysis of the operation of the insular power system of Crete, Greece, on an hour-by-hour basis aiming at the evaluation of the impact of high Renewable Energy Sources (RES) penetration on the short-term power system scheduling. The possibility of introducing a pumped-storage plant as a storage facility to alleviate the negative effects of increased RES generation on the short-term operation is also investigated. The renewable generation impact is evaluated in terms of specific system indicators. An integrated software tool that performs annual simulation of the insular power system with hourly granularity aiming at the minimization of the total production cost while respecting the system and various generating unit operating constraints is used. Simulation results for the year 2015 provide quantitative assessment of the insular power system performance regarding its short-term operation under large-scale RES penetration and valuable conclusions are drawn.

Research paper thumbnail of Bidding strategy for risk-averse producers in transmission-constrained electricity markets

2015 12th International Conference on the European Energy Market (EEM), 2015

ABSTRACT

Research paper thumbnail of Benefits of demand response on a wind power producer bidding strategy

2015 IEEE Eindhoven PowerTech, 2015

ABSTRACT This paper proposes an optimal bidding strategy for a wind producer who participates as ... more ABSTRACT This paper proposes an optimal bidding strategy for a wind producer who participates as price-maker in the day-ahead electricity market. In order to empower the wind producer against the challenges introduced by the intermittent nature of wind power and improve his position into the market, demand response schemes are considered to be incorporated into his portfolio. The producer objective is the maximization of the day-ahead profit in conjunction with the minimization of the anticipated real-time production imbalance charges. A two-stage stochastic bi-level optimization model has been formulated, where the uncertainty lies in the day-ahead wind production and load consumption. Simulations on the Greek power system prove the effectiveness of the proposed synergy.

Research paper thumbnail of Coordination of day-ahead scheduling with a stochastic weekly unit commitment for the efficient scheduling of slow-start thermal units

2010 IREP Symposium Bulk Power System Dynamics and Control - VIII (IREP), 2010

This paper addresses the problem of the coordination of the day-ahead scheduling with a stochasti... more This paper addresses the problem of the coordination of the day-ahead scheduling with a stochastic weekly unit commitment for the efficient scheduling of slow-start thermal units. The solution of the 24-hour unit commitment may lead to cases, in which slow-start thermal units that are initially offline cannot be scheduled efficiently, due to their long start-up and minimum-up times as well

Research paper thumbnail of Scheduling Models and Methods for Efficient and Reliable Operations

Operations, Planning, and Economics of Insular Electricity Grids, 2015

Research paper thumbnail of Evaluation of the impact of RES integration on the Greek electricity market by mid-term simulation

2011 IEEE Trondheim PowerTech, 2011

ABSTRACT This paper presents a yearly simulation model for the analysis of the impact of the larg... more ABSTRACT This paper presents a yearly simulation model for the analysis of the impact of the large RES penetration in the energy production mix of Greece on the operation of the Greek electricity market. This impact is analyzed in terms of the electricity market clearing prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge, imposed by the government for the payment of the feed-in tariff to the RES producers. A mid-term scheduling model based on the day-ahead market clearing algorithm of the Greek wholesale electricity market is used for the yearly simulation under ten different scenarios regarding the RES installed capacity (multiple RES technologies are considered). Valuable conclusions are drawn from the application of the proposed model for the year 2011.

Research paper thumbnail of Evaluation of the Impact of IPPs on the Greek Wholesale and Retail Electricity Markets

Power and Energy Systems, 2012

Research paper thumbnail of Optimal Offering Strategies in Day-Ahead Electricity Markets under Uncertainty

8th Mediterranean Conference on Power Generation, Transmission, Distribution and Energy Conversion (MEDPOWER 2012), 2012

ABSTRACT This paper addresses the self-scheduling problem of a hydrothermal producer, which is fo... more ABSTRACT This paper addresses the self-scheduling problem of a hydrothermal producer, which is formulated and solved as a two-stage stochastic programming problem with recourse in order to account for market uncertainty. The producer is considered to own thermal and hydro generating units and participate as a price-maker in the day-ahead energy market. Forward bilateral contracts with end-consumers are considered and their effect on the producer self-schedule and profits is examined. The CVaR metric accounting for risk management is also incorporated. Post-processing techniques are applied for the construction of the generating units optimal offer curves to be submitted to the day-ahead energy market.

Research paper thumbnail of Optimal self-scheduling of a dominant power company in electricity markets

International Journal of Electrical Power & Energy Systems, 2012

Research paper thumbnail of Effect of increased RES penetration on the system marginal price of the Greek electricity market

2010 7th International Conference on the European Energy Market, 2010

This paper analyzes the effect that increased RES penetration in the energy production mix of Gre... more This paper analyzes the effect that increased RES penetration in the energy production mix of Greece has on the system marginal prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge. The market clearing algorithm of the Greek day-ahead electricity market is used for the simulation of the Greek energy

Research paper thumbnail of Impact of increased RES penetration on the operation of the Greek electricity market

7th Mediterranean Conference and Exhibition on Power Generation, Transmission, Distribution and Energy Conversion (MedPower 2010), 2010

ABSTRACT This paper analyzes the impact that the increased RES penetration in the energy producti... more ABSTRACT This paper analyzes the impact that the increased RES penetration in the energy production mix of Greece has on the operation of the Greek electricity market, in terms of the electricity market prices, the total CO2 emissions, the total payment of the consumers for the energy withdrawal and the RES uplift charge, imposed by the government for the payment of the feed-in tariff to the RES producers. The market clearing algorithm of the Greek day-ahead electricity market is used for the simulation of the Greek energy market under ten different scenarios regarding the RES installed capacity. The units' emissions cost is appropriately incorporated in their total production cost function. Test results from the application of the scenarios on four typical weeks of year 2009 are also discussed.

Research paper thumbnail of A unified unit commitment — Economic dispatch model for short-term power system scheduling under high wind energy penetration

11th International Conference on the European Energy Market (EEM14), 2014

ABSTRACT This paper presents a unified unit commitment and economic dispatch tool for the short-t... more ABSTRACT This paper presents a unified unit commitment and economic dispatch tool for the short-term scheduling of a power system under high renewable penetration. The proposed model uses variable time resolution and scheduling horizon extended up to 36 hours ahead and produces robust real-time decisions making the short-term operation of the power system almost insensitive to RES forecast errors. The proposed model is tested for a monthly period on the Greek interconnected power system using real load and wind power data for two different wind penetration levels. Simulation results show that the proposed methodology allows for the accommodation of large amounts of wind energy into the short-term scheduling of the power system at minimum cost.

Research paper thumbnail of A MILP approach to the short term hydrothermal self-scheduling problem

2009 IEEE Bucharest PowerTech, 2009

This paper addresses the hydrothermal electricity producer self-scheduling problem in day-ahead e... more This paper addresses the hydrothermal electricity producer self-scheduling problem in day-ahead energy and reserves markets. A 0/1 mixed integer linear formulation of the producer self-scheduling problem is presented, which allows a realistic modeling of the unit's operating phases (synchronization, soak, dispatchable, desynchronization). Prohibited operating zones and daily hydro energy production constraints are also modeled. Test results address the effect of