Poul Sorensen

• MSc
• Professor (Full) at Technical University of Denmark

The operational profitability of co-located hybrid power plants (HPPs) consisting of wind and storage has emerged as a subject of great interest in both academia and industry. Addressing the uncertainties associated with wind power and market prices during the operation process has become a critical focus. While existing studies have explored optim...

In recent years, there has been a growing interest in reducing greenhouse gas emissions by integrating new technologies into energy delivery systems. Hybrid power plants (HPPs) have become popular for their potential to add market value benefits. The harmonization of diverse dynamic technologies and intricate interactions within an HPP to meet mand...

p>In recent years, utility-scale hybrid power plants (HPPs) have emerged as promising electricity generation resources by combining multiple generation technologies and storage capabilities. This paper presents a novel framework for optimizing the offering and operation of HPPs in the voluntary balancing market, specifically for providing regulatin...

p>In recent years, utility-scale hybrid power plants (HPPs) have emerged as promising electricity generation resources by combining multiple generation technologies and storage capabilities. This paper presents a novel framework for optimizing the offering and operation of HPPs in the voluntary balancing market, specifically for providing regulatin...

Since hybrid power plants (HPPs) play an intensive role in the energy supply balance of future energy systems, there is today increased attention on co-located wind–battery HPPs both in industry and academia. This paper proposes an energy management system (EMS) methodology for wind–battery plants participating in two sequential electricity markets...

Hybrid power parks (HPPs) that combined renewable power sources and storage can improve generation flexibility compared to single-resource parks, making HPPs able to participate in different electricity markets, e.g., regulating markets. Despite the foreseen advantages with HPPs, a challenging aspect relate to coordination of the included assets du...

p>Since hybrid power plants (HPPs) play an intensive role in the energy supply balance of future energy systems, there is today an increased attention on co-located wind-battery HPPs both in industry and academia. However, the profitability of HPPs in sequential electricity markets to overcome initial investment costs has not been yet well examined...

p>Since hybrid power plants (HPPs) play an intensive role in the energy supply balance of future energy systems, there is today an increased attention on co-located wind-battery HPPs both in industry and academia. However, the profitability of HPPs in sequential electricity markets to overcome initial investment costs has not been yet well examined...

Utility-scale co-located hybrid power plants (HPPs) have received global attention due to enhanced controllability and efficient utilization of electrical infrastructure. While control of mono-technology plants has been extensively studied over the past decades, the control of co-located HPP including sub-plants of multiple technologies is yet to b...

Uncertainty is one of the core challenges posed by renewable energy integration in power systems, especially for solar photovoltaic (PV), given its dependence on meteorological phenomena. This has motivated the development of numerous forecasting tools, recently focused on physics informed machine learning (ML). Virtually, every paper claims to pro...

Increasingly advanced stochastic energy management systems are employed to facilitate the integration of wind and solar PV in worldwide power grids. In this context, forecasting is a key tool limiting the success of said control actions. This paper explores the suitability of stacked machine learning based models to predict wind and solar power ava...

The ongoing energy transition and incoming water scarcity crisis demand coordinated research to ensure a fossil-free future for humankind. Aiming to increase energy efficiency, reduce curtailment and decarbonize water production, this paper proposes a novel energy management system (EMS) for a hybrid plant compound by a small modular nuclear reacto...

The utility-scale co-located hybrid power plants (HPPs) have been receiving attention globally due to enhanced controllability and efficient utilization of electrical infrastructure. While power plant control has been extensively studied for single-technology power plants in the past decades, how to control a co-located HPP that includes sub-plants...

Frequency control (FC) enables utility-scale grid-connected hybrid power plants (HPPs) to operate in compliance with grid code requirements while to capture value streams from provision of frequency control services (FCSs). In this paper, a novel hierarchical FC approach is proposed to allow HPPs to provide three types of FCSs, namely fast frequenc...

Offshore grids can play key roles in the transition of energy systems toward sustainability. Although they require extensive infrastructure investments, they allow for the exploitation of additional resources and may be important in providing for part of the increasing electricity demands driven by sector coupling. This paper quantifies the socioec...

Machine Learning (ML)-based methods have been identified as capable of providing up to one day ahead Photovoltaic (PV) power forecasts. In this research, we introduce a generic physical model of a PV system into ML predictors to forecast from one to three days ahead. The only requirement is a basic dataset including power, wind speed and air temper...

The aim of this paper is to demonstrate the usefulness, practical applicability, accuracy and reliability of Standard IEC 61400-27-1. The objective of this standard is to specify generic simulation models for the four main types of wind turbines, as well as procedures to validate them. Given that most of the works published and related to the valid...

This paper presents a validation of atmospheric reanalysis data sets for simulating onshore wind generation time series for large-scale energy system studies. The three reanalyses are the ERA5, the New European Wind Atlas (NEWA) and DTU’s previous generation European-level atmospheric reanalysis (EIWR). An optional scaling is applied to match the m...

With frequency stability being challenged in modern power systems, transmission system operators have been designing new mitigation measures, such as fast frequency response (FFR), to maintain operation security of power systems. To accommodate technical requirements of new frequency control services (FCSs), the corresponding control should be impl...

Offshore grids can have a key role in the transition of the energy system to sustainability. Although they require extensive infrastructure investments, they open up for the exploitation of additional resources and may be important to provide for part of the increasing electricity demand driven by sector coupling. This paper quantifies the socio-ec...

The utility-scale co-located hybrid power plants (HPPs) have been receiving attention globally due to enhanced controllability and efficient utilization of electrical infrastructure. While power plant control has been extensively studied for single-technology power plants in the past decades, how to control a co-located HPP that includes sub-plants...

The utility-scale co-located hybrid power plants (HPPs) have been receiving attention globally due to enhanced controllability and efficient utilization of electrical infrastructure. While power plant control has been extensively studied for single-technology power plants in the past decades, how to control a co-located HPP that includes sub-plants...

The aim of this paper is to review and compare present European and Indian grid code requirements imposed to hybrid power plants (HPPs) combining wind, solar and storage technologies. Since there are no grid codes specifically for HPPs, the paper will review grid codes for the power plant based on individual renewable technology in the HPP. Europea...

Providing trustworthy and accurate multi-frequency (or harmonic) models for renewable energy generators (REG) is an ongoing challenge for harmonic studies. There have been effective attempts to propose and design a test device to validate the harmonic models, mainly based on shunt current perturbations. However, using additional devices for perturb...

The concept of hybrid wind power plants (HWPPs) that consist of wind, solar and batteries has received a lot of attention, since HWPPs provide a number of advantages thanks to the complementary nature of wind and solar energy and the flexibility of batteries. Nevertheless, converter-based technologies, as interfaces of HWPPs to the utility grid, co...

Fully renewable, isolated power systems have gained relevance given the global agenda related to the energy transition. Thus raising the amount and diversity of the performed grid-related research. However, the existing generic reference systems are usually aimed to a particular type of study and don’t capture the influence of technologies and meth...

Detailed simulation of wind generation as driven by weather patterns is required to quantify the impact on the electrical grid of the power fluctuations in offshore wind power fleets. This paper focuses on studying the power fluctuations of high-installation-density offshore fleets since they present a growing challenge to the operation and plannin...

div>Offshore grids can have an important role in the transition of the energy system to sustainability. Although they require extensive infrastructure investments, they open up for the exploitation of a vast amount of additional resources and may be important to provide for part of the increasing electricity demand driven by sector coupling between...

div>Offshore grids can have an important role in the transition of the energy system to sustainability. Although they require extensive infrastructure investments, they open up for the exploitation of a vast amount of additional resources and may be important to provide for part of the increasing electricity demand driven by sector coupling between...

With increasing wind installations, there is a need to analyse wind generation variability in detail. This paper applies the reanalysis approach for modelling the variability; however, with two important additions. Firstly, high-resolution microscale data is combined with mesoscale reanalysis time series to model local variability in wind. Secondly...

This paper analyses several energy system scenarios towards 2050 for the North Sea region. With a focus on offshore wind power, the impacts of meshed offshore grid and sector coupling are studied. First, a project-based scenario, where each offshore wind power plant is connected individually to the onshore power system, is compared to a meshed grid...

This paper investigates how current-limited converters influence system stability. An improved approach for assessing voltage stability is introduced, which determines the maximum deliverable power to a load by accounting for changes in the Thévenin voltages. The new approach is able to detect voltage instability well before the traditional approac...

In order to participate in energy market, variable renewable energy sources need to reduce the uncertainty of forecast errors. Inclusion of storage can be a viable option not only to minimize the penalties due to forecast uncertainties but also to maximize the revenue generation. This paper presents a decision framework for respecting the market co...

The multi-frequency (harmonic) interaction among converters is an increasing challenge in converter-dominated power grids. To study steady-state harmonics and transient harmonic stability, it is crucial to develop accurate multi-frequency models for converters. However, the frequency and sequence couplings have not been addressed in the state-of-th...

The quantification of reactive power reserves can be essential for transmission system operators for the secure operation of large power systems with high share of renewables. Reactive power support from renewable energy sources needs to be included in reactive power reserve estimation. The reactive power capability of variable renewable energy sou...

Detailed simulation of wind generation as driven by weather patterns is required to quantify the impact on the electrical grid of the power fluctuations in offshore wind power fleets. This article focuses on studying the power fluctuations of high installation density offshore fleets since they present a growing challenge to the operation and plann...

With increasing wind installations, there is a need to analyze wind generation variability in detail. This paper applies the reanalysis approach for modelling the variability; however, with two important additions. Firstly, high-resolution microscale data is combined with mesoscale reanalysis time series to model local variability in wind. Secondly...

Diode-rectifier-based high voltage dc (DR-HVdc) systems can be a promising low-cost solution for exporting wind power from remote offshore wind farms to onshore power systems. Industrializing the offshore DR-HVdc requires technical maturation, achievable through in-depth studies and pilot experiments. Deployment of offshore DR-HVdc systems may enta...

Increasing renewable energy sources in power system has brought forth many challenges in terms of power system stability, one of which is voltage stability. Preventive and corrective actions to alleviate voltage instability are mainly developed for traditional power systems without high share of renewables. This article aims to assess the reactive...

The North Sea region offers large amounts of investable offshore wind generation and several interconnection lines are located in the area, with more planned. Optimal transmission and generation investments are modelled in the region towards 2050. A project‐based scenario, where each offshore wind power plant is connected individually, is first ana...

As installed wind generation capacities increase, there is a need to model variability in wind generation in detail to analyse its impacts on power systems. Utilization of meteorological reanalysis data and stochastic simulation are possible approaches for modelling this variability. In this paper, a combination of these two approaches is used to m...

The electrical test and assessment of wind turbines go hand in hand with standards and network connection requirements. In this paper, the generic structure of advanced electrical test benches, including grid emulator or controllable grid interface, wind torque emulator, and device under test, is proposed to harmonize state-of-the-art test sites. O...

Abstract. This paper analyses several energy system scenarios towards 2050 for the North Sea region. With focus on offshore wind power, the impacts of meshed offshore grid and sector coupling are studied. First, a project-based scenario, where each offshore wind power plant is connected individually to onshore, is compared to a meshed grid scenario...

Offshore high-voltage dc (HVDC) grids are emerging as a technical reliable and economical solution to transfer more offshore wind energy to inland power grids. It is also envisaged that the offshore HVDC grids pave the way for both offshore wind participation and sharing inland frequency reserves for efficient power systems' frequency control. The...

Traditional voltage stability assessment methods do not include temporal variation of renewable power generations like wind. This paper proposes a novel methodology for probabilistic voltage stability assessment methodology which can be used in conjunction with any of the existing traditional voltage stability indices. Historical wind power data ar...

Traditional voltage stability assessment methods do not include temporal variation of renewable power generations like wind. This paper proposes a novel methodology for probabilistic voltage stability assessment methodology which can be used in conjunction with any of the existing traditional voltage stability indices. Historical wind power data ar...

div>In order to participate in energy market, variable renewable energy sources need to reduce the uncertainty of forecast errors. Inclusion of storage can be a viable option not only to minimize the penalties due to forecast uncertainties but also to maximize the revenue generation. This paper presents a decision framework for respecting the mark...

div>In order to participate in energy market, variable renewable energy sources need to reduce the uncertainty of forecast errors. Inclusion of storage can be a viable option not only to minimize the penalties due to forecast uncertainties but also to maximize the revenue generation. This paper presents a decision framework for respecting the mark...

Abstract. The electrical test and assessment of wind turbines (WT) are going hand in hand with standards and network connection requirements. In this paper, the latest developments in the testing of the electrical characteristics of WTs, including IEC standards, compliance test methods, and industrial test benches, are studied. In this paper, the g...

Our electrical world is changing. The journey we are on today parallels the era of Edison, Tesla, and Westinghouse in the early race for electrification. Change abounds: energy from nature, inverter-based technology, smart and smarter grids; decentralized power, and intercontinental interconnection. This new age of energy offers new choices and cha...

Developing an integrated pan-European energy system based on renewable energy sources (RES) has technical and economic benefits. In this way, harmonized rules for grid connection of RES are required at the international level. Wind energy is one of the most promising renewable energy worldwide. The integration of wind energy into the power system i...

This paper analyses impact of different load types on voltage stability of a power system with wind power. To analyse voltage stability, dynamic as well as static voltage stability assessment are performed. Dynamic model of wind turbine based on Type 4A IEC 61400-27-1 is used to develop an aggregated wind power plant model including the wind power...

Offshore high-voltage DC (HVDC) grids are developing as a technically reliable and economical solution to transfer more offshore wind power to onshore power systems. It is also foreseen that the offshore HVDC grids pave the way for offshore wind participation in power systems’ balancing process through frequency support. The primary frequency contr...

The rapid development of renewable energy sources drives the European power systems toward a green transition. Growing shares of wind power create the need to model the variability in wind generation. For modelling using the reanalysis approach, meteorological data along with the technical parameters of wind power plants (WPPs) are needed. This pap...

The development of efficient and reliable offshore electrical transmission infrastructure is a key factor in the proliferation of offshore wind farms (OWFs). Traditionally, high-voltage AC (HVAC) transmission has been used for OWFs. Recently, voltage-source-converter-based (VSC-based) high-voltage DC (VSC-HVDC) transmission technologies have also b...

The participation of wind power in the energy mix of current power systems is progressively increasing, with variable-speed wind turbines being the leading technology in recent years. In this line, dynamic models of wind turbines able to emulate their response against grid disturbances, such as voltage dips, are required. To address this issue, the...

Due to characteristics of wind which is inherently variable, active power production from wind power plants fluctuates over time. Reactive power capability of wind power plant is dependent on active power production. This paper investigates the impact of active power fluctuations on reactive power capability of wind power plants and quantifies the...

The objective of this paper is to review and elaborate qualitatively and quantitatively the benefits of wind-based hybrid power plant (HPP) as compared to individual wind/PV power plant. A set of analyses are performed to assess annual energy production/capacity factor, power fluctuations and ramp rates of HPP production and to identify different o...

Presently, there is a large need for a better understanding and extensive quantification of grid stability for different grid conditions and controller settings. This article therefore proposes and develops a novel mathematical model to study and perform sensitivity studies for the capabilities of different technologies to provide Frequency Contain...

This article presents the development of a reactive power capability model for a wind power plant (WPP) based on an aggregated wind power collection system. The voltage and active power dependent reactive power capability are thus calculated by using aggregated WPP collection system parameters and considering losses in the WPP collection system. Th...

With increasing penetrations of wind generation, based on power‐electronic converters, power systems are transitioning away from well‐understood synchronous generator‐based systems, with growing implications for their stability. As wind penetration levels rise, conventional generation will gradually be displaced, with implications for the frequency...

In future, large volume of offshore wind power developments can be envisaged in North Sea. Large share of renewables infers large fluctuations. Also, large share of renewables infers large forecast error. These forecast errors and fluctuations create balancing challenges in the power system. A model tool chain encompassing market modelling, forecas...

This paper proposes a method for real‐time estimation of the possible power of an offshore wind power plant when it is down‐regulated. The main purpose of the method is to provide an industrially applicable estimate of the possible (or reserve) power. The method also yields a real‐time power curve, which can be used for operation monitoring and win...

The increasing share of variable renewable energy (VRE) generation poses challenges to power systems. Possible challenges include adequacy of reserves, planning and operation of power systems, and interconnection expansion studies in future power systems with very different generation patterns compared to today. To meet these challenges, there is a...

Weather-driven renewable generation is characterized by being uncertain and geographically dependent. In this regard, the recent deployment of wind and solar power has had a significant impact on the operation and planning of modern electricity grids; justifying the need to model high dimensional dependence. It is a relevant topic which is starting...

Modelling and understanding variability in wind generation will be increasingly important in the future with growing shares of wind power in energy systems. Crucially, the modelling needs to be extended to future scenarios, also considering the expected technological development of installations. Reanalysis data is often used in large-scale simulat...

The growing share of variable renewable energy (VRE) sources, which are driven by weather patterns, can cause challenges to the operation and planning of power systems. This paper studies the variability in wind and solar photovoltaic generation in Nordic and Baltic countries. Combined with load time series, the resulting residual load is analysed...

The uncertainty arising from high levels of solar photovoltaic (PV) penetration can have a substantial impact on power system operation. Therefore, there is a need to develop models capable of representing PV generation in a rigorous manner. This paper introduces a novel transformation-based methodology to generate stochastic solar area power forec...

Variable renewable generation, primarily from wind and solar, introduces new uncertainties in the operation of power systems. This paper describes and applies a method to quantify how wind power development will affect the use of short-term automatic reserves in the future South African power system. The study uses a scenario for wind power develop...

Variable renewable generation, primarily from wind and solar, introduces new uncertainties in the operation of power systems. This paper describes and applies a method to quantify how wind power development will affect the use of short-term automatic reserves in the future South African power system. The study uses a scenario for wind power develop...

The deployment of Renewable Energy Sources (RES) is driving modern power systems towards a fundamental green transition. In this regard, there is a need to develop models to accurately capture the variability of wind and solar photovoltaic (PV) power, at different geographical and temporal scales. This paper presents a general methodology based on...

The low impedance characteristics of DC transmission lines cause the voltage source converter (VSC) in HVDC networks to become electrically closer together and increase the risk of severe interactions between the converters. Such interactions, in turn, intensify the implementation of the grid control schemes and may lead the entire system to instab...

This article concentrates on designing of frequency control and protection strategies for wind turbines during overfrequency emergencies. Critical overfrequency event on NorthEastern part of the UCTE network on 4 th November 2006 is considered as a base case for investigation. A single bus power system model is developed to analyse the protection s...

Increasing levels of penetration of renewables may pose challenges to power system security. When security is compromised due to some disturbances, defence plans must be in place to prevent system blackout. Traditional defence plans have been developed without considering large penetration of renewable generations. Therefore, opportunities and thre...

High penetration of renewable energy sources poses numerous challenges on stability and security of power systems. Wind power plants (WPPs) of considerable size when connected to a weak grid by long transmission line results in low short circuit ratio at the point of connection. This may result in both transient voltage fluctuations and poor steady...

In recent years, international working groups, mainly from the International Electrotechnical Commission (IEC) and the Western Electricity Coordinating Council (WECC), have made a major effort to develop generic —also known as simplified or standard— dynamic wind turbine models to be used for power system stability analysis. These models are requir...