Exploring wind curtailment effects and economic implications in the growing variable renewable energy penetration

Power system flexibility need induced by wind and solar power intermittency on time scales of 1–14 days

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 need to develop models and tools to analyze the variability and uncertainty in VRE generation. To address the varied needs, the tools should be versatile and applicable to different geographical and temporal scales. Time series simulation tools can be used to model both today and future scenarios with varying VRE installations. Correlations in Renewable Energy Sources (CorRES) is a simulation tool developed at Technical University of Denmark, Department of Wind Energy capable of simulating both wind and solar generation. It uses a unique combination of meteorological time series and stochastic simulations to provide consistent VRE generation and forecast error time series with temporal resolution in the minute scale. Such simulated VRE time series can be used in addressing the challenges posed by the increasing share of VRE generation. These capabilities will be demonstrated through three case studies: one about the use of large‐scale VRE generation simulations in energy system analysis, and two about the use of the simulations in power system operation, planning, and analysis.This article is categorized under: Wind Power > Systems and Infrastructure Energy Infrastructure > Systems and Infrastructure Energy Systems Economics > Systems and Infrastructure

India’s power system is facing growing challenges of ramping due to the increasing share of variable renewable energy (VRE) sources such as solar and wind. As net load profiles become steeper and more volatile, particularly during solar generation drops due to cloud cover and evening peaks, the ability to manage ramping, defined as the rate of change in generation output, has become critical in maintaining grid stability. A comprehensive analysis of state-wise ramping behaviour using hourly data for the year 2023 reveals that opposing ramp directions between states occurred in 30%-50% of time blocks, challenging the net national ramp and complicating system-level balancing. Despite these challenges, India possesses sufficient ramping capability, particularly from thermal generators, but lacks a mechanism to harmonize ramping efforts of generators across state as well as regions. The paper proposes a layered Security-Constrained Economic Dispatch (SCED) framework, which combines intrastate optimization with a national-level coupling layer to align state-level ramp vectors without disrupting existing contractual structures. The paper also includes the recommendations e.g. regulatory recognition of ramping, improved data transparency, and incentivization of flexible generation to support integration of renewables reliably in a cost-effective manner.

As variable renewable energy (VRE) sources like wind and solar increasingly enter the electricity spot market, they face challenges due to their unpredictable, fluctuating output, which weakens their market competitiveness. Additionally, the volatility of day-ahead electricity prices adds complexity to VRE market participation. Hydropower, with its flexibility, is often utilized to balance VRE output. In order to address the problems posed by the uncertainty of VRE’s output and day-ahead clearing tariffs for VRE’s participation in the electricity spot market, this study proposes an optimal scheduling model for a joint Hydro-Wind-Solar spot market. The model generates scenario sets for VRE output and tariffs using the Monte Carlo method, which are then reduced via K-means clustering. An optimal dispatch model is developed based on the reduced scenarios, aiming to maximize expected market returns. The model is solved using the Gurobi optimization solver, and its effectiveness is demonstrated using data from a hydropower plant, wind farm, and solar farm in southwest China.

The attainment of carbon neutrality requires a research agenda that addresses the technical and economic challenges that will be encountered as we progress toward 100% renewable electricity generation. Increasing proportions of variable renewable energy (VRE) sources (such as wind turbines and photovoltaic systems) render the supply-and-demand balance of VRE-dominated power grids difficult. The operational characteristics and effects of VRE inverters also require attention. Here, we examine the implications of the paradigm shift to carbon neutrality and summarize the associated research challenges in terms of system planning, operation, and stability, and the need for energy storage integration, demand-side participation, distributed control and estimation, and energy sector coupling. We also highlight the existing literature gaps, and our recent studies that can fill in the gaps, thereby facilitating the improvement of grid operation and estimation. The numerical results of comparative case studies are also provided on the operational stability and economics of power grids with a high level of VRE sources, assisting stakeholders in establishing specific roadmaps and making relevant decisions.

Introducing a new wind speed complementarity model

As the share of variable renewable energy (VRE) such as wind and solar power continues to grow across Europe, understanding how climate change may affect their short-term variability and extreme events is critical for energy planning, system stability, and resilience. This study investigates projected changes in sub-daily variability and the frequency of extreme conditions in wind and solar energy resources using regional climate model simulations over Europe.We employ a suite of features to characterize the short-term dynamics of VRE resources, including ramp rates, lag-1 autocorrelation, and event-based metrics such as the duration and persistence of power drops (e.g., time below the P10 threshold). These features are computed from 3-hourly wind speed and surface solar radiation data, covering both historical and future periods from the Euro-CORDEX ensemble under the RCP8.5 scenario. To support the robustness of the analysis, model outputs are compared against long-term observations from tall towers and surface radiation stations at selected European sites.The results suggest that future climate conditions could lead to both beneficial and adverse changes in VRE variability: increased persistence may enhance predictability in some regions, while intensified ramp events and prolonged low-production periods may pose challenges for grid management and storage needs elsewhere. The spatially diverse impacts highlight the need for regional-scale assessments.These findings demonstrate the importance of integrating short-term variability and extremes into long-term energy system modeling and risk assessments, and they provide actionable insights for improving the resilience of future low-carbon energy systems.

The power system inertia is gradually decreasing with the growing share of variable renewable energy (VRE). This may jeopardize the frequency dynamics and challenges the secure operation of power systems. In this paper, the concept of frequency security margin is proposed to quantify the system frequency regulation ability under contingency. It is defined as the maximum power imbalance that the system can tolerate while keeping frequency within the tolerable frequency range. A frequency constrained unit commitment (FCUC) model considering frequency securitymargin is proposed. Firstly, the analytical formulation of system frequency nadir is derived while considering both the frequency regulation characteristics of the thermal generators and the frequency support from VRE plants. Then, the frequency security margin is analytically formulated and piecewise linearized. A novel FCUC model is proposed by incorporating linear frequency security constraints into the traditional unit commitment model. Case studies on a modified IEEE RTS-79 system and HRP-38 system are provided to verify the effectiveness of the proposed FCUC model. The impacts of VRE penetration on system frequency security are analyzed using frequency security margin.

Optimal sizing and placement of battery energy storage system for maximum variable renewable energy penetration considering demand response flexibility: A case in Lombok power system, Indonesia

Assessment of curtailed wind energy potential for off-grid applications through mobile battery storage

ABSTRACTLong‐term power system expansion planning aligned with current sustainable development policies plays a pivotal role in achieving global targets for energy transition, particularly in developing countries. This paper presents a comprehensive long‐term expansion planning model for Brazil, taking into account decarbonisation pathways using OSeMOSYS integrated with Flextool. Four scenarios explore the potential benefits of increasing the share of variable renewable energy (VRE), specifically photovoltaic (PV) and offshore wind, to 40% of the total energy produced, both with and without a storage system. Results indicate that policies better aligned with net‐zero strategies do not impose a significant cost burden.

This study investigates the effects of the construction and operation of a large Danish offshore wind farm on harbor and gray seal haul-out behavior within a nearby (4 km) seal sanctuary. Time-lapse photography, visual monitoring, and aerial surveys were used to monitor the number of seals on land in daylight hours. Seals were monitored during two preconstruction periods (19 June–31 August 2001 and April–August 2002), a construction period of the wind farm (August 2002–December 2003), and a period of operation of the wind farm (December 2003–December 2004). Monthly aerial surveys were conducted to estimate the proportion of seals in the sanctuary relative to neighboring haul-out sites. From preconstruction to construction and through the first year of operation the number of harbor seals in the sanctuary increased at the same rate as the number of seals at the neighboring haul-out sites. No long-term effects on haul-out behavior were found due to construction and operation of the wind farm. However, a significant short-term decrease was seen in the number of seals present on land during sheet pile driving in or near the wind farm. Acoustic deterrents were utilized simultaneously to avoid hearing damage.

Wind energy is a rapidly expanding source of renewable energy, but is highly intermittent. The performance of a wind farm, composed of a collection of wind turbines, depends not only on the placement of wind turbines in a farm, but also control actions taken by individual turbines. The wind turbine placement (layout) design problem involves adjusting turbine locations within a given area to improve a performance objective (such as maximizing annualized energy production). This layout problem has been addressed previously considering the effect of constraints such land configuration, installed capacity, and wake model choice on the performance of wind farms. All the studies, however, ignore the effects of the control system, which can have significant impact on performance. A well designed wind farm — without an optimal controller — will not achieve the full system level optimal performance, and vice-versa. In this article, we propose a novel layout co-design approach that includes optimal control considerations to exploit this synergy between farm layout and control. Layout case studies involving 8 and 12 turbines are presented. An annual energy production improvement of up to 17% is observed when accounting for coupling between control and layout design, when compared to layout-only optimization.

A multiscale numerical framework coupled with control strategies for simulating a wind farm in complex terrain

A spatial cost-benefit-externality modelling framework for siting of variable renewable energy farms: A case in Bohol, Philippines