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Journal articleSpyrou E, Zhang Q, Hytowitz R, et al., 2025,
Flexibility options: a proposed product for managing imbalance risk
, IEEE Transactions on Energy Markets, Policy and Regulation, ISSN: 2771-9626The presence of variable renewable energy resources with uncertain outputs in day-ahead electricity markets results in additional balancing needs in real-time. Addressing those needs cost-effectively and reliably within a competitive market with unbundled products is challenging as both the demand for and the availability of flexibility depends on day-ahead energy schedules. Existing approaches for reserve procurement usually rely either on oversimplified demand curves that do not consider how system conditions that particular day affect the value of flexibility, or on bilateral trading of hedging instruments that are not co-optimized with day-ahead schedules. This article proposes a new product, ‘Flexibility Options’, to address these two limitations. The demand for this product is endogenously determined in the day-ahead market and it is met cost-effectively by considering real-time supply curves for product providers, which are co-optimized with the energy supply. As we illustrate with numerical examples and mathematical analysis, the product addresses the hedging needs of participants with imbalances cost-effectively, provides a less intermittent revenue stream for participants with flexible outputs, promotes value-driven pricing of flexibility, and ensures that the system operator is revenue-neutral. This article provides a comprehensive design that can be further tested and applied in large-scale systems.
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Journal articleSpyrou E, Hobbs B, Chattopadhyay D, et al., 2024,
How to assess uncertainty-aware frameworks for power system planning?
, IEEE Transactions on Energy Markets, Policy and Regulation, Vol: 2, Pages: 436-448, ISSN: 2771-9626Computational advances along with the profound impact of uncertainty on power system investments have motivated the creation of power system planning frameworks that handle long-run uncertainty, large number of alternative plans, and multiple objectives. Planning agencies seek guidance to assess such frameworks. This article addresses this need in two ways. First, we augment previously proposed criteria for assessing planning frameworks by including new criteria such as stakeholder acceptance to make the assessments more comprehensive, while enhancing the practical applicability of assessment criteria by offering criterion-specific themes and questions. Second, using the proposed criteria, we compare two widely used but fundamentally distinct frameworks: an ‘agree-on-plans’ framework, Robust Decision Making (RDM), and an ‘agree-on-assumptions’ framework, centered around Stochastic Programming (SP). By comparing for the first time head-to-head the two distinct frameworks for an electricity supply planning problem under uncertainties in Bangladesh, we conclude that RDM relies on a large number of simulations to provide ample information to decision makers and stakeholders, and to facilitate updating of subjective inputs. In contrast, SP is a highly dimensional optimization problem that identifies plans with relatively good probability-weighted performance in a single step, but even with computational advances remains subject to the curse of dimensionality.
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Journal articleO'Malley M, Holttinen H, Cutululis N, et al., 2024,
Grand challenges of wind energy science - meeting the needs and services of the power system
, Wind Energy Science, Vol: 9, Pages: 2087-2112, ISSN: 2366-7443The share of wind power in power systems is increasing dramatically, and this is happening in parallel with increased penetration of solar photovoltaics, storage, other inverter-based technologies, and electrification of other sectors. Recognising the fundamental objective of power systems, maintaining supply–demand balance reliably at the lowest cost, and integrating all these technologies are significant research challenges that are driving radical changes to planning and operations of power systems globally. In this changing environment, wind power can maximise its long-term value to the power system by balancing the needs it imposes on the power system with its contribution to addressing these needs with services. A needs and services paradigm is adopted here to highlight these research challenges, which should also be guided by a balanced approach, concentrating on its advantages over competitors. The research challenges within the wind technology itself are many and varied, with control and coordination internally being a focal point in parallel with a strong recommendation for a holistic approach targeted at where wind has an advantage over its competitors and in coordination with research into other technologies such as storage, power electronics, and power systems.
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Conference paperThakar S, Ramasubramanian D, Matevosyan J, et al., 2024,
System services from inverter based resources for reliable operation
, 2024 IEEE Power & Energy Society General Meeting (PESGM), Publisher: IEEE, Pages: 1-5With the increasing penetration of inverter based resources (IBRs) in present and future power systems, it is important to consider the different grid services needed from/provided by IBRs. To ensure network stability after a contingency such as trip of a synchronous generator or a fault, a grid may require services (for example, fast voltage control) from various IBRs. New IBRs to be installed with future capabilities (inherent blackstart capability) are often seen as a potential source for such services. However, the capability of many existing IBRs today are underutilized and if the capability from existing IBRs is utilized efficiently, it could greatly improve the network performance and reduce services needed from the future IBRs. This paper provides few illustrative examples detailing some of the services that may be needed by an IBR-dominated grid and the impact of asking these services from future IBRs and/or supplementing with services from existing IBRs.
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Journal articleHawker G, Bell K, Bialek J, et al., 2024,
Management of extreme weather impacts on electricity grids: an international review
, PROGRESS IN ENERGY, Vol: 6 -
Journal articleChaudhuri B, Ramasubramanian D, Matevosyan J, et al., 2024,
Rebalancing needs and services for future grids: system needs and service provisions with increasing shares of inverter-based resources
, IEEE Power and Energy Magazine, Vol: 22, Pages: 30-41, ISSN: 1540-7977The primary objective of electricity grids is to reliably meet the electricity demand at a minimum cost. This objective can be broken down into a set of needs that are met through services. These services are procured by mandating them either in grid codes or via market mechanisms. While grids in different countries/regions share common features in terms of needs and services, there are variations arising in physical, regulatory, and policy contexts. With the increased use of inverter-based resources (IBRs), such as wind and solar photovoltaic (PV) power and battery energy storage systems (BESSs), grids are undergoing changes that are altering the balance between needs and services. This balance is crucial in managing changes that will ensure that grids will continue to be able to meet demands. As increasingly more synchronous machines (SMs) are replaced by IBRs, the services inherently provided by the remaining SMs are dwindling, thus requiring the IBRs to contribute where they can.
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Journal articleXu L, Feng K, Lin N, et al., 2024,
Resilience of renewable power systems under climate risks
, Nature Reviews Electrical Engineering, Vol: 1, Pages: 53-66, ISSN: 2948-1201Climate change is expected to intensify the effects of extreme weather events on power systems and increase the frequency of severe power outages. The large-scale integration of environment-dependent renewables during energy decarbonization could induce increased uncertainty in the supply–demand balance and climate vulnerability of power grids. This Perspective discusses the superimposed risks of climate change, extreme weather events and renewable energy integration, which collectively affect power system resilience. Insights drawn from large-scale spatiotemporal data on historical US power outages induced by tropical cyclones illustrate the vital role of grid inertia and system flexibility in maintaining the balance between supply and demand, thereby preventing catastrophic cascading failures. Alarmingly, the future projections under diverse emission pathways signal that climate hazards — especially tropical cyclones and heatwaves — are intensifying and can cause even greater impacts on the power grids. High-penetration renewable power systems under climate change may face escalating challenges, including more severe infrastructure damage, lower grid inertia and flexibility, and longer post-event recovery. Towards a net-zero future, this Perspective then explores approaches for harnessing the inherent potential of distributed renewables for climate resilience through forming microgrids, aligned with holistic technical solutions such as grid-forming inverters, distributed energy storage, cross-sector interoperability, distributed optimization and climate–energy integrated modelling.
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Journal articleVeers P, Dykes K, Basu S, et al., 2022,
Grand Challenges: wind energy research needs for a global energy transition
, Wind Energy Science, Vol: 7, Pages: 2491-2496, ISSN: 2366-7443Wind energy is anticipated to play a central role in enabling a rapid transition from fossil fuels to a system based largely on renewable power. For wind power to fulfill its expected role as the backbone – providing nearly half of the electrical energy – of a renewable-based, carbon-neutral energy system, critical challenges around design, manufacture, and deployment of land and offshore technologies must be addressed. During the past 3 years, the wind research community has invested significant effort toward understanding the nature and implications of these challenges and identifying associated gaps. The outcomes of these efforts are summarized in a series of 10 articles, some under review by Wind Energy Science (WES) and others planned for submission during the coming months. This letter explains the genesis, significance, and impacts of these efforts.
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