Search Results (8)

The increasing deployment of islanded microgrids in disaster-prone and infrastructure-constrained regions has elevated the importance of resilient energy storage systems capable of supporting autonomous operation. Grid-forming energy storage (GFES) units—designed to provide frequency reference, voltage regulation, and black-start capabilities—are emerging as critical assets for maintaining both energy adequacy and dynamic stability in isolated environments. However, conventional storage planning models fail to capture the interplay between uncertain renewable generation, time-coupled operational constraints, and control-oriented performance metrics such as virtual inertia and voltage ride-through. To address this gap, this paper proposes a novel distributionally robust optimization (DRO) framework that jointly optimizes the siting and sizing of GFES under renewable and load uncertainty. The model is grounded in Wasserstein-metric DRO, allowing worst-case expectation minimization over an ambiguity set constructed from empirical historical data. A multi-period convex formulation is developed that incorporates energy balance, degradation cost, state-of-charge dynamics, black-start reserve margins, and stability-aware constraints. Frequency sensitivity and voltage compliance metrics are explicitly embedded into the optimization, enabling control-aware dispatch and resilience-informed placement of storage assets. A tractable reformulation is achieved using strong duality and solved via a nested column-and-constraint generation algorithm. The framework is validated on a modified IEEE 33-bus distribution network with high PV penetration and heterogeneous demand profiles. Case study results demonstrate that the proposed model reduces worst-case blackout duration by 17.4%, improves voltage recovery speed by 12.9%, and achieves 22.3% higher SoC utilization efficiency compared to deterministic and stochastic baselines. Furthermore, sensitivity analyses reveal that GFES deployment naturally concentrates at nodes with high dynamic control leverage, confirming the effectiveness of the control-informed robust design. This work provides a scalable, data-driven planning tool for resilient microgrid development in the face of deep temporal and structural uncertainty. Full article

In response to the severe occurrence of mining pressure in the fully mechanized top coal caving face of the extra-thick coal seam and the problem of strong rock pressure caused by the remaining coal pillars in the mining area on the isolated island fully mechanized top coal caving face, taking the 8102 isolated island working face of Tongxin Coal Mine as the background and by using methods such as on-site measurement and numerical simulation experiments, the characteristics of roof mining in the island longwall panel of extra-thick coal seams were analyzed. Establishing a mechanical model for the mining stress and overlying rock stress arch of an isolated working face, the mechanical characteristics of the isolated working face under special conditions were obtained. The results show that the longwall panel no. 8102 has an asymmetric long-arm T-shaped covering layer structure before mining and a C-shaped covering rock structure during mining, which will exacerbate the degree of mining pressure manifestation in the working face. Directional high-pressure hydraulic fracturing was implemented in the gob of longwall panel no. 8102, and the pressure reduction effect of the advance support section of the gob was obvious, ensuring the safety of the working face. Full article

Large-energy microseismic events, coal bursts, and other abnormal mine stress are often observed in spatial isolated island areas in the roof water-rich gob-side working face during mining operations. In view of this problem, numerical simulation and on-site microseismic monitoring are employed to study the advance abutment stress and strata fracture structure in the spatial island area formed by ‘roof drainage + goaf’ during mining and the method of eliminating the spatial island area. The results show that the lateral stress is distributed in a step-like pattern, and the drainage area and goaf are superimposed to form a high-stress space island area before the mining of the working face along the goaf. The distribution pattern of the advance abutment stress in the spatial island area changes from ‘C’ type to ‘S’ type during the mining process. The strata structure of the roof water-rich gob-side working face is either a single-peak arch or double-peak arch, and the arch peak corresponds to the boundary of the drainage area. The method of local hydraulic fracturing can eliminate the influence of spatial island areas and improve the safety of roof water-rich gob-side working face mining. Full article

Environmental protection is an important key to achieving sustainable development. Since humans depend on the environment in countless ways, preserving them contributes directly to the sustaining of people and human societies and hence, to social sustainability. The central question in this dissertation asks why the environmental protection policies enacted in Madagascar are not efficient and how they impact the SDG’s achievement at the national level. This paper discusses Madagascar’s achievements of the sustainable development target with special emphasis on environmental issues, which is currently a major concern in the country. This review aimed at suggesting improvements in line with the challenges the country is facing by reviewing the indicators provided by the UN SDGs. It also reaffirmed the nexus of poverty and the environment, which is important for setting the development target. In order to conduct this study, journal articles, review papers, working papers, research reports, and books related to environmental management and sustainable development in Madagascar were reviewed. Madagascar has made a little improvement in accomplishing SDGs 12 and 13 in 2021, but achieving all SDGs goals in 2030 remains a big challenge. The country is a party to numerous international environmental conventions, treaties, and agreements. Many policy changes have been implemented to address both conservation and development issues, but these efforts have had little impact. Forest fires and slash-and-burn were on the rise in Madagascar on October 2022, which poses a major concern for the economic and social development of the island. In order to achieve sustainable development, environmental protection shall constitute an integral part of the development process and cannot be considered in isolation from it. The strategies proposed in this paper might be helpful for the Malagasy government and private sector in decision-making. This paper is also useful for researchers in developing countries. As Madagascar did not reach the Millennium Development Goals 2015 and will not achieve the SDGs in 2030, should we not start learning from our mistakes and thinking about the post-SDGs? Full article

Studies show that accurate division of spontaneous combustion (SC) zones in the goaf and the determination of the prediction system of the SC index are of great significance to prevent spontaneous and unwanted combustions in the goaf. Aiming at resolving the problem of coal SC in the goaf of an “isolated-island” fully mechanized caving face, a multiphysics model coupled with gas flow field and gas concentration field was established in the present study. Taking the 8824 working face of Nanzhuang coal mine as the research object and the oxygen concentration as the division index, coal SC was simulated in the goaf. The obtained results show that the ranges of heat dissipation zone, oxidation zone, and the asphyxia zone on the air inlet side are around 0–107 m, 107–239 m, and beyond 239 m, respectively. Moreover, the ranges of the three zones on the return air side are 0–13 m, 13–189 m, and beyond 189 m, respectively. The ranges of the three zones in the middle of goaf are 0–52 m, 52–213 m, and beyond 213 m, respectively. The performed analyses demonstrate that the obtained simulation results are consistent with the experimental data. Meanwhile, the coal programmed temperature rise experiment was carried out to improve the prediction index gas system of SC. It was found that CO and C₂H₄ can be used as early warning indices of SC in the goaf, while C₂H₆, C₃H₈, and C₂H₄/C₂H₆ are auxiliary indices to master the coal SC. Full article

The gob-side roadway in an isolated island working face is a typical representative of a strong mining roadway, which seriously restricts the efficient and safe production of underground coal mines. With the engineering background of the main transportation roadway 1513 (MTR 1513) of the Xinyi Coal Mine, this paper introduces the engineering case of gob-side roadway driving with small coal-pillar facing mining in an isolated island working face under the alternate mining of wide and narrow working faces. Through comprehensive research methods, we studied zoning disturbance deformation characteristics and stress evolution law of gob-side roadway driving under face mining. Based on the characteristics of zoning disturbance, MTR 1513 is divided into three zones, which are the heading face mining zone, the mining influenced zone, and the mining stability zone. A collaborative control technology using pressure relief and anchoring is proposed, and the differentiated control method is formed for the three zones. For the heading face mining zone, the control method of anchoring first and then pressure relief is adopted; for the mining influenced zone, the control idea of synchronous coordination of pressure relief and anchorage is adopted; for the mining stability zone, the control method of anchoring without pressure relief is adopted. Engineering practices show that the disturbance influence distance of working face 1511 on MTR 1513 changes from 110 m advanced to 175 m delay. At this time, the surrounding rock deformation is effectively controlled, which verified the rationality of the division and the feasibility of three zoning control technology. The research results can provide reference for gob-side roadway driving with small coal pillar facing mining in a special isolated island working face. Full article

Inspired by Felix Guattari’s Three Ecologies ([1989] 2000), this article explores recent Orkney literature with an environmental focus (Working the Map—ed. J & F Cumming and M. MacInnes; Ebban an’ Flowan—Finlay, A., Watts, L. and Peebles, A.; The Outrun—A. Liptrot; Swimming With Seals—V. Whitworth) in terms of Orkney ecologies—which are always personal, environmental and cultural. Informed by fieldwork carried out in Orkney, looking at discourse around the development of marine renewable energy in the islands, it argues for the use of ecological dialogism, an approach to language and communication which recognises meaning-making as embodied and emergent within a meshwork (Ingold 2011) of lived experience. It explores the texts as part of an ecology of meaning-making within the naturalcultural (Haraway 2007) world, in which environment, social relations and human subjectivity are inextricably entangled. In this view, literary texts can be approached, not as isolated examples of individual creative expression, but as moments of emergent meaning-making in the dialogue between individual, cultural and environmental ecologies, reaching beyond the page into a living meshwork, where we can think in terms of ‘Ecology as Text, Text as Ecology’ (Morton 2010). These Orkney ecologies entangle the natural, personal, cultural and technological, through and as, stories, emphasising interdependence and care for both human and more-than-human relationships. Such moments of connection offer hope of new narrative possibilities with which to face the uncertainty of an Anthropocene future. Full article

Many of the issues we face as a society are made more problematic by the rapidly changing context in which important decisions are made. For example buying a petrol powered car is most advantageous when there are many petrol pumps providing cheap petrol whereas buying an electric car is most advantageous when there are many electrical recharge points or high capacity batteries available. Such collective decision-making is often studied using economic game theory where the focus is on how individuals might reach an agreement regarding the supply and demand for the different energy types. But even if the two parties find a mutually agreeable strategy, as technology and costs change over time, for example through cheaper and more efficient batteries and a more accurate pricing of the total cost of oil consumption, so too do the incentives for the choices buyers and sellers make, the result of which can be the stranding of an industry or even a whole economy on an island of inefficient outcomes. In this article we consider the issue of how changes in the underlying incentives can move us from an optimal economy to a sub-optimal economy while at the same time making it impossible to collectively navigate our way to a better strategy without forcing us to pass through a socially undesirable “tipping point”. We show that different perturbations to underlying incentives results in the creation or destruction of “strategic islands” isolated by disruptive transitions between strategies. The significant result in this work is the illustration that an economy that remains strategically stationary can over time become stranded in a suboptimal outcome from which there is no easy way to put the economy on a path to better outcomes without going through an economic tipping point. Full article