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This document is a summary of a report prepared by the IEEE PES Task Force (TF) on Microgrid (MG) Dynamic Modeling, IEEE Power and Energy Society, Tech. Rep. PES-TR106, 2023. In this paper, the major issues and challenges in microgrid modeling for stability analysis are discussed, and a review of state-of-the-art modeling approaches and trends is presented. In the context of the IEEE 1547 standard, the document covers issues associated with component models for MG dynamic studies and simulations, including generator and grid modeling, full and average converter models, unbalanced and balanced system conditions, dynamic and static loads, protection requirements, and detailed and simplified controls considering communications delays, packet losses, and security issues. Considering the future integration of grids and MGs to form broad integrated networks, a discussion is presented of the use of phasor vis-à-vis electromagnetic transient simulation tools for MG dynamic stability studies, as well as modeling scale-up issues and MG equivalent models. Specifically white-, grey-, and black-box models, are presented. This TF paper and companion report constitute a modeling guide for R&D groups working on developments and standards of MGs with a focus on stability issues.

The Energy Center has developed a co-construction methodology to address the challenges of technology transfer-based on distributed generation projects- in the context of energy transitions in isolated locations. Based on the experiences developed between 2010 and 2017, this paper analyses the process of preparing the Co-construction methodology. New tools were identified under the light of a theoretical-methodological reflection and a new version of co-construction methodology is proposed from this discussion. This learning process combines academic research and applied projects. It has provided Energy Center with an improved set of tools for current projects, and also contributed to a theoretical-methodological discussion based on new research activities. The main problems of method faced are presented during interdisciplinary work, such as: common understanding of fundamental concepts (sustainability, participation, community); the domination of one discipline over the others; the different visions of the priorities within the same project. And those problems given by the participation process under the paradox of “framing-overflowing”, where the constraints of actual projects (deadlines, budget, and specific KPIs) could limit the possibility of performing in depth diagnostics and building trust. One of the main challenges identified is that an actual impact on the overall experience is only feasible if lessons can be translated into concrete products (best practices, guidelines, tools), so can be adopted by future project developers.

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Hydrologic alteration due to hydropeaking reservoir operations is a main concern worldwide. Subdaily environmental flow constraints (ECs) on operations can be promising alternatives for mitigating negative impacts. However, those constraints reduce the flexibility of hydropower plants, potentially with higher costs for the power system. To study the economic and environmental efficiency of ECs, this work proposes a novel framework comprising four steps: (i) assessment of the current subdaily hydrologic alteration; (ii) formulation and implementation of a short‐term, grid‐wide hydrothermal coordination model; (iii) design of ECs in the form of maximum ramping rates (MRRs) and minimum flows (MIFs) for selected hydropower reservoirs; and (iv) identification of Pareto‐efficient solutions in terms of grid‐wide costs and the Richard‐Baker flashiness index for subdaily hydrologic alteration (SDHA). The framework was applied to Chile's main power grid, assessing 25 EC cases, involving five MIFs and five MRRs. Each case was run for a dry, normal, and wet water year type. Three Pareto‐efficient ECs are found, with remarkably small cost increase below 2% and a SDHA improvement between 28% and 90%. While the case involving the highest MIF worsens the flashiness of another basin, the other two have no negative effect on other basins and can be recommended for implementation. Framework for Pareto‐efficient environmental flow constraints on hydropeakingCompromise between grid‐wide cost and subdaily hydrologic alterationPareto‐efficient constraints are found with cost increase below 2%

Integrating thermal energy storage (TES) for solar systems is crucial for better performance. To ensure the completion of solar cooking activity under fluctuating solar irradiance and reduce the subsequent loss, the integration of thermal storage to a solar cooker can play a vital role. Thus, this paper reveals the thermal performance of a solar cooker with a tracking type bottom parabolic reflector (TBPR) retrofitted with a new design of absorber plate integrated with thermal storage. Paraffin wax, a phase change material, acts as thermal storage. The TES integrated cooker is tested in two configurations, i.e., without TBPR (SC1) and with TBPR (SC2), to assess the impact of a design change on the thermal performance parameter (TPP) under field conditions. The cooker opto-thermal ratio (COR) and the first figure of merit (F1) acts as TPPs. The Levelized cost of the cooking a meal (LCCM) enables the economic analysis of the cooker. The average values of COR for cooker SC1 and SC2 are 0.118 and 0.140 (m2·K)/W, respectively. The cookers SC1 and SC2 attain the reference cooking temperature in ~75–82 min and ~61–66 min, respectively, and retain the heat at temperatures ~70–72 °C until 18:00 h in the evening. The LCCM for the cookers SC1 and SC2 are approximately the same ~0.024 ± 0.0005 USD/Ml. Nevertheless, SC2 exhibits additional advantages like increasing the cooked meals in the year and extending cooking periods (early morning and late afternoon cooking). Thus, the present work provides useful insights on TPP based rating/grading of the proposed solar cooker with thermal storage and its connection with the solar cooker economics in terms of LCCM.

Letter to the Editor