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Hybrid renewable energy systems (HRES) have emerged as a promising solution for delivering sustainable energy to off-grid communities. However, the vulnerability of specific regions to extreme weather events has raised concerns about the resilience of these systems. This study undertakes a techno-economic analysis to assess the impact and significance of incorporating storm hardening measures and insurance into an HRES designed for the Busuanga island cluster. Central to our study is introducing a novel cost metric, the probability-averaged levelized cost of electricity (LCOE), which adeptly captures the inherently probabilistic nature of climate-induced damages to HRES energy assets. This metric serves as the linchpin for comparing the economic viability of HRES configurations, considering both scenarios with and without storm hardening or insurance. Our findings unveil a clear trend: for a solar photovoltaic (PV) panel with an annual probability of damage at 1%, insurance emerges as a financially prudent choice, while storm hardening gains merit at a probability of 4%. The weighted average cost of capital (WACC) is pivotal in shaping investment decisions. HRES setups featuring non-hardened solar PV panels become more economically appealing than their insured or hardened counterparts under higher WACC conditions, under the condition that the solar PV panels can maintain functionality for 15 years without impairment. Our study demonstrates the importance of accounting for often overlooked factors such as storm hardening and insurance premiums for solar PV panels in climate-vulnerable areas, which are commonly disregarded in many techno-economic studies. Moreover, our findings and conclusions on the optimal balance between capital costs, insurance premiums, and storm-hardening markups can readily extend to other climate-vulnerable areas.

In line with one of the objectives of Sustainable Development Goal 7 to close energy poverty, the techno-economic feasibility of deploying hybrid renewable energy systems (HRES) in Philippine off-grid islands has been extensively studied to address reliance on diesel generators in these areas. Several works have analyzed HRES deployment at a nationwide level in terms of levelized costs, but the financial sustainability in terms of profits and subsidies of such schemes is largely unexplored. In this work, we analyzed the potential profits and subsidy requirements of HRES in 634 Philippine off-grid islands. First, we developed a database of inhabited off-grid islands containing their load profiles and solar and wind resources. A techno-economic analysis was then performed by sizing HRES with solar photovoltaics, wind turbines, lithium-ion batteries, and diesel generators in each island to minimize net present costs. A profitability analysis was then carried out by calculating profitability metrics, such as the net present value, internal rate of return, and payback period at various tariff rates. The techno-economic analysis revealed that larger islands had a higher proportion of RE technologies, which decreased long-term costs but increased capital costs. Meanwhile, the profitability analysis showed that HRES projects in larger islands become profitable at lower electricity rates but require larger subsidies to maintain when they are unprofitable. In this regard, we argue that government subsidies should be targeted towards smaller islands, while the private sector should be enticed to invest in larger islands. This work demonstrates that quantifying subsidies and profits, and not just the costs, of HRES can yield better insights on the economics of HRES deployment. Moreover, this work highlights the importance of government subsidies and private sector participation for achieving 100% energy access in the Philippines.

Density functional theory was used to investigate the effects of doping alkaline earth metal atoms (beryllium, magnesium, calcium and strontium) on graphene. Electron transfer from the dopant atom to the graphene substrate was observed and was further probed by a combined electron localization function/non-covalent interaction (ELF/NCI) approach. This approach demonstrates that predominantly ionic bonding occurs between the alkaline earth dopants and the substrate, with beryllium doping having a variant characteristic as a consequence of electronegativity equalization attributed to its lower atomic number relative to carbon. The ionic bonding induces spin-polarized electronic structures and lower workfunctions for Mg-, Ca-, and Sr-doped graphene systems as compared to the pristine graphene. However, due to its variant bonding characteristic, Be-doped graphene exhibits non-spin-polarized p-type semiconductor behavior, which is consistent with previous works, and an increase in workfunction relative to pristine graphene. Dirac half-metal-like behavior was predicted for magnesium doped graphene while calcium doped and strontium doped graphene were predicted to have bipolar magnetic semiconductor behavior. These changes in the electronic and magnetic properties of alkaline earth doped graphene may be of importance for spintronic and other electronic device applications.

Density functional theory was used to investigate the effects of doping alkaline earth metal atoms (beryllium, magnesium, calcium and strontium) on graphene. Electron transfer from the dopant atom to the graphene substrate was observed and was further probed by a combined electron localization function/non-covalent interaction (ELF/NCI) approach. This approach demonstrates that predominantly ionic bonding occurs between the alkaline earth dopants and the substrate, with beryllium doping having a variant characteristic as a consequence of electronegativity equalization attributed to its lower atomic number relative to carbon. The ionic bonding induces spin-polarized electronic structures and lower workfunctions for Mg-, Ca-, and Sr-doped graphene systems as compared to the pristine graphene. However, due to its variant bonding characteristic, Be-doped graphene exhibits non-spin-polarized p-type semiconductor behavior, which is consistent with previous works, and an increase in workfunction relative to pristine graphene. Dirac half-metal-like behavior was predicted for magnesium doped graphene while calcium doped and strontium doped graphene were predicted to have bipolar magnetic semiconductor behavior. These changes in the electronic and magnetic properties of alkaline earth doped graphene may be of importance for spintronic and other electronic device applications.

Destructive weather extremes – the key impacts of the climate emergency – acutely signal the need to increase the resiliency, especially of climate-vulnerable islands and its peoples. “Islands” are detached communities that are either geographically bounded by water or are metaphors for inland off-grid villages. The extant literature on resilient infrastructures is rich, but this corpus is mostly concentrated on food and water systems, security, and transport. Making energy systems resilient in islands, this paper argues, is equally important. In these island energy systems, resilience can be achieved by regarding them as sociotechnical assemblages where engineering innovation is co-produced alongside social and institutional shifts. This article suggests that resilient energy systems in islands can be checked against their explicit characteristics as a system condition, as a set of processes, and as a set of outcomes. Understanding power relations and ethical concerns are also important. To illustrate these characteristics, case studies from Romblon in the Philippines (a geographic island) and Petchaburi in Thailand (a metaphorical island) are provided. There is no perfect resilient island energy systems, but these illustrations show that they can be pursued.

Destructive weather extremes – the key impacts of the climate emergency – acutely signal the need to increase the resiliency, especially of climate-vulnerable islands and its peoples. “Islands” are detached communities that are either geographically bounded by water or are metaphors for inland off-grid villages. The extant literature on resilient infrastructures is rich, but this corpus is mostly concentrated on food and water systems, security, and transport. Making energy systems resilient in islands, this paper argues, is equally important. In these island energy systems, resilience can be achieved by regarding them as sociotechnical assemblages where engineering innovation is co-produced alongside social and institutional shifts. This article suggests that resilient energy systems in islands can be checked against their explicit characteristics as a system condition, as a set of processes, and as a set of outcomes. Understanding power relations and ethical concerns are also important. To illustrate these characteristics, case studies from Romblon in the Philippines (a geographic island) and Petchaburi in Thailand (a metaphorical island) are provided. There is no perfect resilient island energy systems, but these illustrations show that they can be pursued.

Destructive weather extremes – the key impacts of the climate emergency – acutely signal the need to increase the resiliency, especially of climate-vulnerable islands and its peoples. “Islands” are detached communities that are either geographically bounded by water or are metaphors for inland off-grid villages. The extant literature on resilient infrastructures is rich, but this corpus is mostly concentrated on food and water systems, security, and transport. Making energy systems resilient in islands, this paper argues, is equally important. In these island energy systems, resilience can be achieved by regarding them as sociotechnical assemblages where engineering innovation is co-produced alongside social and institutional shifts. This article suggests that resilient energy systems in islands can be checked against their explicit characteristics as a system condition, as a set of processes, and as a set of outcomes. Understanding power relations and ethical concerns are also important. To illustrate these characteristics, case studies from Romblon in the Philippines (a geographic island) and Petchaburi in Thailand (a metaphorical island) are provided. There is no perfect resilient island energy systems, but these illustrations show that they can be pursued.

Traditional understanding of electrocatalytic reactions generally focuses on either covalent interactions between adsorbates and the reaction interface (i.e., electrical double layer, EDL) or electrostatic interactions between electrolyte ions. Here, our work provides valuable insights into interfacial structure and ionic interactions during alkaline oxygen evolution reaction (OER). The importance of inner-sphere OH- adsorption is demonstrated as the IrOx activity in 4.0 M KOH is 6.5 times higher than that in 0.1 M KOH. Adding NaNO3 as a supporting electrolyte, which is found to be inert for long-term stability, complicates the electrocatalytic reaction in a half cell. The nonspecially adsorbed Na+ in the outer compact interfacial layer is suggested to form a stronger noncovalent interaction with OH- through hydrogen bond than adsorbed K+, leading to the decrease of interfacial OH- mobility. This hypothesis highlights the importance of outer-sphere adsorption for the OER, which is generally recognized as a pure inner-sphere process. Meanwhile, based on our experimental observations, the pseudocapacitive behavior of solid-state redox might be more reliable in quantifying active sites for OER than that measured from the conventional EDL charging capacitive process. The interfacial oxygen transport is observed to improve with increasing electrolyte conductivity, ascribing to the increased accessible active sites. The durability results in a liquid alkaline electrolyzer which shows that adding NaNO3 into KOH solution leads to additional degradation of OER activity and long-term stability. These findings provide an improved understanding of the mechanistic details and structural motifs required for efficient and robust electrocatalysis.

Traditional understanding of electrocatalytic reactions generally focuses on either covalent interactions between adsorbates and the reaction interface (i.e., electrical double layer, EDL) or electrostatic interactions between electrolyte ions. Here, our work provides valuable insights into interfacial structure and ionic interactions during alkaline oxygen evolution reaction (OER). The importance of inner-sphere OH- adsorption is demonstrated as the IrOx activity in 4.0 M KOH is 6.5 times higher than that in 0.1 M KOH. Adding NaNO3 as a supporting electrolyte, which is found to be inert for long-term stability, complicates the electrocatalytic reaction in a half cell. The nonspecially adsorbed Na+ in the outer compact interfacial layer is suggested to form a stronger noncovalent interaction with OH- through hydrogen bond than adsorbed K+, leading to the decrease of interfacial OH- mobility. This hypothesis highlights the importance of outer-sphere adsorption for the OER, which is generally recognized as a pure inner-sphere process. Meanwhile, based on our experimental observations, the pseudocapacitive behavior of solid-state redox might be more reliable in quantifying active sites for OER than that measured from the conventional EDL charging capacitive process. The interfacial oxygen transport is observed to improve with increasing electrolyte conductivity, ascribing to the increased accessible active sites. The durability results in a liquid alkaline electrolyzer which shows that adding NaNO3 into KOH solution leads to additional degradation of OER activity and long-term stability. These findings provide an improved understanding of the mechanistic details and structural motifs required for efficient and robust electrocatalysis.