Search Results (305)

Rising electricity prices, grid instability, and climate concerns are increasing the need for sustainable residential energy solutions in developing countries. This study evaluates four residential photovoltaic (PV) configurations for a household in Karachi, Pakistan, to identify a suitable option for sustainable urban energy transition and climate mitigation. The assessed systems include daytime PV with grid supply, daytime PV with 6 h battery backup and grid supply, daytime PV with full battery backup, and daytime PV with net metering. Energy requirements, installed capacity, area demand, and battery storage were calculated using household load data, while economic performance was assessed through payback period, net present value (NPV), and levelized cost of electricity (LCOE). Environmental benefits were evaluated using avoided CO₂, CH₄, and N₂O emissions, and the best-performing system was further simulated in PVsyst. Case C, comprising daytime PV with full battery backup, achieved the highest NPV of USD 25,104.3 and a payback period of approximately 4 years. Case B achieved the second-highest NPV of USD 19,183.58 while providing a more practical balance between battery backup and grid support. Case D achieved the lowest LCOE of USD 0.0307/kWh. Fully solar-dependent configurations provided the greatest emission reductions. The findings support residential PV deployment as a practical pathway for improving urban energy security and reducing climate impacts. Full article

The aim of this study is to identify, through layout-coverage testing, the upper fixed-wall ratio at which the reconfigurable layout set can still fully satisfy mainstream spatial demand, and to quantify, under consistent structural, temporal, and accounting conditions, how 90-year cumulative embodied carbon emissions change across δ scenarios and how crossing this threshold alters the residential update pathway. A design-sample database of 954 residential floor plans was used to develop a common “basic unit,” and a wall-based index, δ, was defined as the ratio of fixed-wall length to total interior-wall length. A multiple-response survey of 168 households was then used to establish a mainstream layout set; layouts were ranked by selection frequency, and the smallest ranked set whose cumulative share exceeded 50% of all selections was retained. Eleven δ scenarios were assessed over a potential 90-year service-life scenario that incorporated interior reconfiguration, I-wall renewal, and possible demolition–reconstruction. The results identify δ ≈ 0.72 as the upper fixed-wall-ratio threshold compatible with full coverage of the mainstream layout set. When δ ≤ 0.72, internal reconfiguration maintains mainstream-layout coverage, and cumulative embodied carbon ranges from 224.88 to 313.46 tCO₂e, equivalent to 1772.10–2470.13 kgCO₂e/m². When δ > 0.72, at least one mainstream layout becomes infeasible and the modeled update pathway shifts to demolition–reconstruction, increasing emissions to 402.62–503.95 tCO₂e, or 3172.73–3971.24 kgCO₂e/m². Dynamic trajectories for the representative δ = 0.72 and δ = 0.81 scenarios show that the former accumulates emissions gradually, with limited increases associated with I-wall renewal at Years 30 and 60, whereas the latter undergoes sharp jumps at the same nodes because insufficient layout coverage triggers demolition–reconstruction. These findings provide an operational basis for using the fixed-wall ratio as an early-stage carbon-screening variable while retaining the need for project-specific multi-performance verification. Full article

The building sector accounts for nearly 30% of global energy use and 28% of CO₂ emissions, with residential buildings in Canada contributing about 17% of national energy demand. In cold regions such as Labrador, approximately 82% of this consumption is associated with space heating and domestic hot water, making heating the dominant residential load, while fossil-fuel furnaces and electric baseboard heaters remain common. These conditions highlight the need for efficient and sustainable heating alternatives for cold-climate residential buildings. This study examines the design and performance of a hybrid solar photovoltaic (PV) and geothermal heat pump (GTHP) system for a typical detached home in L’Anse-au-Loup, Labrador, Newfoundland and Labrador, Canada (51.52° N, 56.84° W), with the goal of improving energy efficiency and reducing dependence on the electrical grid. Heating and cooling loads were developed using the Hourly Analysis Program (HAP 6.1), while system operation and economic performance were assessed through the Hybrid Optimization Model for Electric Renewables (HOMER Pro 3.18.3). The proposed design combines a rooftop PV array, a ground-source heat pump, and second-life lithium-ion batteries repurposed from retired electric vehicles to lower costs and support short-term energy storage. The system is modelled under grid-connected conditions to reflect realistic operation for northern households. Results show that the hybrid system can meet annual electrical and thermal needs while reducing grid consumption by more than half. Annual carbon emissions decrease by roughly 4–5 tonnes, and repurposed batteries offer a cost-effective alternative to new storage. Overall, the study demonstrates that PV–GTHP systems can provide reliable, efficient, and practical energy solutions for cold-climate homes. Full article

The deployment of rural electrification actions through off-grid mini-grid solutions is one of the most effective approaches to achieving universal access to electricity in an affordable, reliable, and sustainable way. To assess the sustainability of three mini-grid projects (Sembezea, Mawayela, and Dongane), this study applied a framework that integrates different methods (HOMER, LCA based on SimaPro, and Input–Output) and indicators under the economic, environmental, and social dimensions. Data for the analysis were obtained through site visits in the case study areas, a literature review, and the HOMER and ecoinvent databases. Sembezea and Mawayela were assessed based on their operational experience, whereas the Dongane biogas system is analyzed based on a projected household biodigester experience. The results of this study revealed the considerable benefits of biogas in generating local employment (506 employees) compared to wind/solar PV (98 employees) and hydro/solar PV (91 employees), as it is expected to require a considerable number of employees for feedstock collection for the digester, under the assumed scale and conditions. Additionally, in the long term, biogas would present the lowest cost of electricity at $0.22/kWh compared to wind/solar PV ($0.28/kWh) and hydro/solar PV ($0.60/kWh), thereby improving the ability of the local community to pay for electricity. In contrast, this study concluded that, in terms of environmental impact—particularly CO₂ emissions—biogas has relatively poor environmental performance (4.58 × 10⁻² kg CO₂ eq) compared to wind/solar PV (8.50 × 10⁻⁴ kg CO₂ eq) and hydro/solar PV (3.94 × 10⁻⁴ kg CO₂ eq) in the long term. Nevertheless, biogas presents carbon neutrality as an advantage, in the sense that the CO₂ released during its combustion is assumed to be carbon-neutral. By applying the framework to the aforementioned case studies, the extent to which it is possible to provide an integrated overview of the economic, environmental, and social aspects, as well as the impacts of different HRES options in line with the SDGs, is demonstrated. Full article

Higher education institutions (HEIs), engaged in education, research and community services, play an important role in promoting sustainable development. This study investigated the relationships between carbon emission-related variables—Knowledge, Attitude, and Practice (KAP)—and the amount of carbon emissions in HEIs. A cross-sectional design was adopted, and data were collected via an online questionnaire from September to December 2024. The participants were students from eight colleges and universities in central Taiwan, yielding 293 valid responses. The average daily per capita carbon emissions were calculated based on activity categories and emission coefficients. Carbon emissions from daily life contributed 87.7%, followed by transportation and academic activities (9.7% and 2.6%). The average carbon emission was 11.82 kg CO₂e/day/person. Statistical analysis showed that living arrangements and household size exhibited significant differences (p < 0.05). Regarding the KAP analysis, attitude and practice showed a significant positive correlation (r = 0.59, p < 0.01), while practice and individual-level Scope 3 emissions were negatively correlated (r = −0.12, p < 0.01), indicating that carbon reduction behaviors can effectively decrease individual carbon emissions. This study quantified the carbon emission in HEIs and addressed a research gap by linking individual-level energy behaviors with carbon emission estimates in Taiwan. The findings provide a basis for policy-making and promoting low-carbon behaviors. Future campus initiatives should focus on equipment upgrades, environmental education, and low-carbon actions to achieve sustainability and net-zero carbon goals. Full article

This study evaluates the scalability and sustainability impacts of integrating Napier grass cultivation with biofertilizer production and dairy systems in rural West Bengal. Field-level evidence indicates that biofertilizer application and irrigation optimization significantly enhance soil organic carbon (SOC), improving nutrient availability and enabling Napier yields of up to 500 tons/acre on fallow land. A technoeconomic model shows strong economies of scale, with production costs decreasing by 40% when area under cultivation is simulated from 1 acre to 100 acres. Statewide scaling scenarios demonstrate significant development potential. Under 10% adoption of fallow land by 2040, approximately 75 million tons of biomass can be grown annually, benefiting 3.75 million households, doubling under a 20% adoption scenario by 2050. The system enables a 2.5–4× increase in household income while delivering substantial climate co-benefits. Avoided emissions from manure management are estimated at ~40 Mt CO₂ annually by 2040, increasing to ~80 Mt CO₂ by 2050, alongside additional gains from soil carbon sequestration and reduced high-emission urea-use. Overall, the proposed circular model offers a scalable pathway for achieving multiple Sustainable Development Goals through integrated agricultural transformation. Full article

Solid waste management (SWM) is a major global challenge for environmental sustainability and public health. This study analyzed SWM perceptions and practices before and during the COVID-19 pandemic in Playa Boca Chica, Tecpan de Galeana, Guerrero, Mexico, using a descriptive and quantitative approach. Data was collected from 60 households between September and October 2022 and analyzed using SPSS statistical software version 26; reliability was confirmed with Cronbach’s Alpha; and the generation-associated greenhouse gas (GHG) emissions were estimated using the SWM-GHG climate calculator. This study explored socio-environmental dynamics in informal coastal settlements through a case study in the Global South. The results showed that waste generation remained stable during the pandemic (3.25 kg/day; p = 0.116), suggesting a pattern of behavioral rigidity in which entrenched waste management practices persisted despite the global health crisis, likely due to the absence of structural environmental interventions and policy-driven behavioral incentives. The climate calculator estimated GHG emissions of 92 and 99 tons of CO₂-eq/year before and during the pandemic, respectively. Residents highlighted the need for improved infrastructure, recycling, and composting, while 97% emphasized environmental education and waste separation. The absence of a local waste management policy contributes to persistent emissions, underscoring the need for integrated and sustainable SWM strategies. Full article

Automated demand response in residential sectors is critical for grid stability, but centralized control strategies fail to address the unique energy profiles of individual households. This limitation becomes more pronounced in districts where buildings differ in load demand, photovoltaic (PV) production and battery energy storage system (BESS) behavior, while electricity prices and grid carbon intensity vary hourly. Conventional rule-based controllers can exploit patterns, but they require tuning and do not generalize across heterogeneous buildings. Existing centralized reinforcement learning methods improve adaptivity, yet they often learn compromise policies and scale poorly as the number of buildings increases. To address these issues, this paper proposes an AttentionKAN-based multi-agent reinforcement learning controller for district-level BESS scheduling. The method uses centralized training with decentralized execution, where each building is controlled by its own actor and a centralized critic models cross-building interactions through a multi-head query-key-value attention mechanism. To improve approximation accuracy under nonlinear and constrained battery dynamics, multilayer perceptron (MLP) blocks in the actor and critic are replaced with Kolmogorov-Arnold Networks (KANs), whose spline-parameterized univariate functions capture saturation effects, tariff discontinuities and couplings among state of charge, PV availability and carbon intensity. Implemented in CityLearn and evaluated on a residential net-zero community dataset, the proposed controller is assessed using building-level and district-level indicators for cost, ${\mathrm{CO}}_2$ emissions, peak demand, ramping and load shape. The learned policy charges during solar-rich hours and discharges during evening peaks, achieving the strongest performance among benchmark controllers, including an approximately 50% cost reduction versus the reference case and emissions reduction. From a sustainability perspective, the results indicate that coordinated multi-building BESS control can support low-carbon residential electrification through emission reduction, lowering electricity expenditure and improving renewable-energy utilization and providing grid-supportive flexibility through reduced peaks and ramping. Full article

This study proposes an integrated analytical framework (IAF) as a tool to simultaneously assess vulnerable social groups within their administrative context. This study hypothesizes that analyzing vulnerable groups through socio-spatial delineation reveals subnational disparities and sub-regional heterogeneity in energy poverty (EP) indicators, associated with additional context-sensitive environmental consequences of energy use. Using Hungarian deprived rural settlements (DRSs) (n = 300) as an example, mixed methods were applied to examine national–regional disparities, intra-regional variations, and the environmental implications of extreme household energy use practices. Results show that both socio-economic indicators and building energy efficiency, and energy-use profiles, fall short of national indicator performance. The sample outlined by the IAF performed homogeneously regarding socio-economic circumstances and showed mild differences in housing quality and energy access. These results indicate not structural differences but variation in underlying regional drivers, highlighting the region-specific manifestation of EP. The energy-use-related environmental assessment was performed using a parametrized building-stock model and the two most extreme energy-use scenarios for households relying on solid fuels. The results suggest that the use of substitute fuels substantially increases the combined emissions of CO₂, CO, PM, NOx, and SOx by up to 32 percentage points. Although limitations constrain the reporting of empirically representative results, findings underscore the potential policy relevance of DRSs in national climate objectives. Full article

The building sector is responsible for 40% of CO₂ emissions in Portugal, making the integration of renewable energy systems increasingly relevant. Photovoltaic (PV) technologies have become more accessible due to declining levelized costs of energy, and when coupled with battery energy storage systems (BESSs), they can enhance grid independence, reduce household energy expenses, and mitigate peak load stress. However, high upfront costs still limit adoption, particularly among vulnerable communities. This study evaluates the technical, economic, and environmental performance of PV systems, with and without BESSs, compared with an existing solar thermal configuration in a social-housing neighbourhood in Porto, Portugal. Numerical simulations were conducted for three scenarios, optimising system sizing and ensuring hourly energy flow balance between generation, storage, and grid supply. Results indicate that all configurations are technically feasible within Porto’s climate conditions, though with distinct investment needs, payback periods, and CO₂ reduction outcomes. The findings offer practical guidance for designing renewable energy solutions tailored to social housing, supporting both decarbonization goals and long-term mitigation of energy poverty. Full article

Excessive fertilizer use not only harms agricultural sustainability but also leads to massive energy waste and carbon emissions. Under China’s carbon peaking and carbon neutrality goals, using social networks to spread better fertilization practices and reduce excessive application can deliver real wins for both energy savings and emission cuts. This paper examines whether farmers’ social network positions affect their fertilizer use. We analyze 14 years of data from 206 farm households in Gansu, China, using fixed effects models that incorporate degree, betweenness, and closeness centrality. Our results reveal that centrally positioned farmers substantially reduce fertilizer application: each 0.1 unit rise in standardized degree, betweenness, and closeness centrality corresponds to reductions of 1.26%, 0.84%, and 0.78%, which translate to actual reductions and carbon emission reduction of 1.06, 0.71, and 0.66 kg/mu; 9.52, 6.38, and 5.93 kg CO₂e/mu. The effects are stronger for farmers with more education, higher off-farm income, and tighter network connections. The effect of degree centrality on fertilizer reduction increased by 7.2 percentage points after 2018. Extension services should build on existing social networks and use key node farmers to drive other farmers in the village to reduce fertilizer use. It helps reduce carbon emissions from fertilizer production and promote sustainable agricultural development. Full article

Hydrogen-enriched compressed natural gas (HCNG) is a promising transitional fuel for residential-scale distributed power, yet its impacts on direct-combustion thermoelectric generator (TEG) systems remain insufficiently quantified. In this study, a micro-scale TEG integrated with a commercially available self-aspirating household burner was experimentally investigated under thermal inputs of 700–2500 W and hydrogen blending ratios of 0–20 vol%, using open-loop water cooling to maximize heat rejection. The hot- and cold-side temperatures exhibited negligible variation with a hydrogen addition, and the maximum electrical output was essentially preserved across all blending ratios; at 2500 W the system delivered 75.8 W with a system efficiency of 3.03%. In contrast, hydrogen blending substantially reduced pollutant emissions: at 2500 W, CO decreased from 52.7 to 1 mg/m³ and CO₂ from 6.73% to 5.36% as the hydrogen fraction increased from 0 to 20 vol%. Meanwhile, combustion stability improved, indicated by a reduced coefficient of variation (0.77% → 0.49%). These results demonstrate that up to 20 vol% hydrogen blending can achieve significant emissions mitigation without compromising TEG power performance, supporting HCNG-fueled TEGs as a practical option for residential backup power. Full article

Greenhouse gas emissions from sanitation systems remain underquantified, particularly when considering the entire service chain. Previous studies have largely focused on emissions from containment, with limited attention to later stages such as collection, transport, treatment and disposal. To address this gap, this research comprehensively estimates greenhouse gas (GHG) emissions from sanitation systems in Lahan municipality, Nepal. We used an extended version of the IPCC-based Tier-1 approach. Data collection included a household survey and key informant interviews. In scenario A, the baseline total annual emissions are 8.7 Gg CO₂e, mostly from the digestion of faecal sludge in the containment (7.3 Gg CO₂e). In scenario B, when a projected faecal sludge treatment plant (FSTP) is built and in operation, annual emissions reach 10.0 Gg CO₂e, driven by methane emitted by the anaerobic digester in the plant. Scenario C considers climate mitigation strategies: increasing the share of households emptying their containments, increased emptying frequency and adding of methane capture in the FSTP. This can reduce annual emissions to 7.9 Gg CO₂e per year, which is 21% less than in scenario B. Our results suggest that methane capture in the FSTP is the most critical mitigation strategy. Full article

South Korea has decided to increase the mandatory biodiesel (BD) blending ratio from 5.0% to 8.0% in 2030 to mitigate CO₂ emissions. This study provides a nationally representative empirical estimate of public willingness to pay (WTP) specifically for increasing the mandatory BD blending ratio, and addresses a critical gap in the literature on biofuel policy acceptance. Although a one-and-one-half-bound format was employed, the single-bound spike model is adopted as the main specification due to evidence of response effects. This paper seeks to delve into public acceptance of the increase by gathering and analyzing the data on the public’s WTP through the application of contingent valuation (CV). Based on a national CV survey administered over a five-week period from mid-April to mid-May 2025, 1000 valid observations were obtained and analyzed. Since 60.5% of all respondents stated a WTP of 0, a spike model that could account for this was adopted. The key coefficients and the model achieved statistical significance. The average household WTP figure obtained was KRW 5052.3 (USD 3.50) per annum. Expanding this value to the entire population gives us KRW 111.69 billion (USD 77.46 million) annually, based on December 2024 constant prices. The additional costs in 2030 resulting from the increase will reach KRW 456.24 billion (USD 316.41 million). Since the WTP figure is smaller than these additional costs, it seems that public acceptance is not sufficiently high. Therefore, it is necessary to implement policy measures such as government subsidies and research and development support to reduce the price of BD. Full article

With the rapid adoption of dishwashers in China’s households, the consequent growth in energy and water consumption presents new challenges for energy conservation, emission reduction, and water resource management in China. To address this, this study adopts the concept of the energy–water nexus to analyze the factors influencing dishwasher usage behaviors and quantifies the co-benefits of energy and water conservation through questionnaire surveys, establishing a household dishwasher energy and water accounting model. The findings reveal that dishwasher usage behaviors are influenced by dietary habits—greater oil usage in cooking leads to higher frequency of use and a greater tendency to select intensive wash modes, thereby increasing energy and water consumption. It is projected that by 2030, promoting energy-efficient dishwashers could achieve annual savings of approximately 390 million kWh of electricity and 4 million m³ of water. Furthermore, shifts in dietary habits offer significant potential for achieving co-benefits in energy and water conservation. Encouraging households to adopt low-oil cooking practices could yield additional annual savings of 5.14 billion kWh of electricity and 9.57 million m³ of water. Based on these results, this paper puts forward policy recommendations to facilitate the coordinated management of household energy and water conservation. Full article