Search Results (80)

As states within the United States respond to future grid development goals, there is a growing demand for reliable and resilient nighttime generation that can be addressed by low-cost, long-duration energy storage solutions. This report studies the potential of including concentrating solar power (CSP) in the technology mix to support California’s goals as defined in Senate Bill 100. A joint agency report study that determined potential pathways to achieve the renewable portfolio standard set by the bill did not include CSP, and our work provides information that could be used as a follow-up. This study uses a capacity expansion model configured to have nodal spatial fidelity in California and balancing-area fidelity in the Western Interconnection outside of California. The authors discovered that by applying current technology cost projections CSP fulfills nearly 15% of the annual load while representing just 6% of total installed capacity in 2045, replacing approximately 30 GWe of wind, solar PV, and standalone batteries compared to a scenario without CSP included. The deployment of CSP in the results is sensitive to the technology’s cost, which highlights the importance of meeting cost targets in 2030 and beyond to enable the technology’s potential contribution to California’s carbon reduction goals. Full article

Insular regions face unique energy management challenges due to physical isolation. Graciosa (Azores) has high renewable energy sources (RES) potential, theoretically enabling a 100% green system. However, RES intermittency combined with the lack of energy storage solutions reduces renewable penetration and raises curtailment. This article studies the technical and economic feasibility of producing green hydrogen from curtailment energy in Graciosa through two distinct case studies. Case Study 1 targets maximum renewable penetration with green hydrogen serving as chemical storage, converted back to electricity via fuel cells during RES shortages. Case Study 2 focuses on maximum profitability, where produced gases are sold to monetize curtailment, without additional electricity production. Levelized Cost of Hydrogen (LCOH) values of €3.06/kgH₂ and €2.68/kgH₂, respectively, and Internal Rate of Return (IRR) values of 3.7% and 17.1% were obtained for Case Studies 1 and 2, with payback periods of 15.2 and 6.1 years. Hence, only Case Study 2 is economically viable, but it does not allow increasing the renewable share in the energy mix. Sensitivity analysis for Case Study 1 shows that overall efficiency and CAPEX are the main factors affecting viability, highlighting the need for technological advances and economies of scale, as well as the importance of public funding to promote projects like this. Full article

Electric arc furnace technology is a key factor in the sustainable transformation of the iron and steel industry. This study compares two discrete-time multi-objective optimization models—integer and mixed-integer linear programming—that integrate unit commitment with economic and environmental dispatch. After evaluating both approaches, the integer linear programming model is used, due to its reasonable calculation time, to assess demand-side management potentials under real-world processes and day-ahead market conditions. The model is applied to various scenarios with differing energy price dynamics, CO₂ pricing, EAF utilization levels, and weighting of the objective functions. Results indicate cost savings of up to 6.95% and CO₂ emission reductions of up to 10.86%, though these are subject to a non-linear trade-off between economic and environmental goals. Due to process constraints and market structures, EAFs’ flexibility in energy carrier use (switch between electricity and natural gas) is limited to 3.07%. Additionally, lower furnace utilization does not necessarily increase flexibility, as downstream process requirements restrict scheduling options. The study underscores the importance of green electrification, with up to 36% CO₂ savings when using 100% renewable electricity. Overall, unlocking industrial flexibility requires technical solutions, supportive market incentives, and regulatory frameworks for effective industrial decarbonization. Full article

To enhance spatial resource complementarity and cross-entity coordination among multi-regional integrated energy systems (MRIESs), an optimized operation strategy is developed based on a bilevel Stackelberg game framework. In this framework, the integrated energy system operator (IESO) and MRIES act as the leader and followers, respectively. Guided by an integrated demand response (IDR) mechanism and a collaborative green certificate and carbon emission trading (GC–CET) scheme, energy prices and consumption strategies are optimized through iterative game interactions. Inter-regional electricity transaction prices and volumes are modeled as coupling variables. The solution is obtained using a hybrid algorithm combining particle swarm optimization (PSO) with mixed-integer programming (MIP). Simulation results indicate that the proposed strategy effectively enhances energy complementarity and optimizes consumption structures across regions. It also balances the interests of the IESO and MRIES, reducing operating costs by 9.97%, 27.7%, and 4.87% in the respective regions. Moreover, in the case study, renewable energy utilization rates in different regions—including an urban residential zone, a renewable-rich suburban area, and an industrial zone—are improved significantly, with Region 2 increasing from 95.06% and Region 3 from 77.47% to full consumption (100%), contributing to notable reductions in carbon emissions. Full article

Achieving net zero relies on siting large-scale solar and wind where they are cheapest and most socially acceptable. We present a transferable, evidence-based siting framework and apply it to Australia. The landscape is divided into millions of 250 m pixels, each assigned an indicative cost based on resource quality, distance-weighted connection costs, and land use exclusions. Two bounding generation mix scenarios (high solar vs. high wind) stack the cheapest pixels until a fully electrified demand of 20 MWh per capita per year is met. Results are aggregated to all 547 Local Government Areas (LGAs) and 150 federal electorates and expressed as capital inflow, construction job-years, long-term jobs, and land-lease income. We find Class A solar (<50 AUD/MWh) is abundant nationwide except in Tasmania, while high-quality wind is concentrated in Victoria, Tasmania, and coastal Western Australia. Just 15% of LGAs, mainly within 100 km of the existing 275–500 kV transmission backbone, can host over half of least-cost capacity. A single top-ranked LGA such as Toowoomba (Queensland) could attract around AUD 33 billion in investment and sustain over 50,000 construction job-years. Mapping ten candidate high-voltage transmission corridors shows how new lines shift opportunities to under-served councils. The results bridge the gap between state-level renewable energy zones and fine-scale site suitability maps, with policy recommendations proposed. Because the workflow relies mainly on globally available datasets, it can be replicated in other countries to raise public awareness, align policy with community support, and accelerate clean-energy buildouts while maximising regional benefit. Full article

Most types of packaging that are in contact with food are made of polypropylene (PP), and the environmental impacts of their production and use are still high. Currently, incorporating recycled PP in the food industry is not a viable solution for reducing environmental impacts due to its complexity and high costs. For this reason, understanding how to reduce the environmental impacts derived from the production process of plastic food packaging is essential. This study aims to analyze the environmental performance of the production of single-use PP food-contact packaging using the Life Cycle Assessment approach in order to estimate the effectiveness of proposed solutions to mitigate its impacts. Furthermore, the economic savings from the avoided CO₂ emissions were estimated. To achieve these goals, three diverse scenarios with different energy source mixes were studied. The analysis was carried out using SimaPro v9.5 software, the Ecoinvent v3.8 database, and a ReCiPe 2016 impact assessment. The findings show that upstream processes are the main contributors to the environmental profile, with 67% of the total impact, followed by core processes, with 32% of the total impacts. An increase in the use of renewable energy can lead to environmental benefits, with an impact reduction ranging from 13% to 61% depending on the energy source mix. Furthermore, up to EUR 12,458 per 100 tons of units produced was saved due to the lack of CO₂ emissions. The results of this research will be useful to encourage the use of renewable energy in the processes of PP packaging production as an alternative when polymer replacement is difficult. Full article

Biodiesel is a renewable and environmentally friendly alternative energy source to conventional diesel. The use of biodiesel blends with diesel to meet energy needs can significantly reduce greenhouse gas emissions, as biodiesel produces smaller amounts of carbon dioxide (CO₂) when burned. In addition, diesel/biodiesel blends can be used as fuel in existing diesel engines without the need to modify them, and their exploitation reduces dependence on oil imports and the impact of oil prices on the economy. Since increasing the percentage of biodiesel in diesel/biodiesel blends aims to increase the environmental and economic benefits, it is necessary to know the physicochemical properties of these blends, such as density, specific gravity, etc. The aim of the present work was to use appropriate mathematical equations that can predict the physicochemical properties of mixtures under different conditions of temperature and mixing ratios. Kay’s mathematical mixing expression, the Tammann–Tait equation, and empirical equations were used to describe the dependence of the density ($\rho$, kg/m³) of the mixtures on the volume percentage (v%) of biodiesel mixed with diesel and the temperature variance (T, K). In addition, mathematical equations were used to predict the specific gravity (Sg) of the mixtures. Mathematical estimations were based on experimental data obtained by blending diesel and animal or vegetable biodiesel volume percentages. These data showed the effect of different mixing volume percentages of biodiesel and diesel (from 0% to 100% biodiesel) on their physicochemical characteristics under different temperatures (278 to 298 K). The accuracy of the mathematical estimations was evaluated using factors such as the Nash and Sutcliffe coefficient (E) and relative root mean squared error (MSE%). The results showed that the selected mathematical equations were able to accurately estimate (E up to 0.9988 and MSE up to 0.4%) the increased density and specific gravity as the volume percentage of biodiesel increased and temperature decreased. The present study uses mathematical tools for choosing the right blending ratios and conditions, depending on the desired features of the finished product. Full article

This study assesses the environmental impacts of producing 1000 tinplate aerosol cans at a Portuguese packaging company using the life cycle assessment (LCA) methodology. The inventory analysis is based on real industrial data collected from the company for foreground processes, complemented with the literature data for background processes. Two energy scenarios are compared: the current production setup, which relies on electricity from the Portuguese grid and 100% natural gas, and an optimized renewable energy scenario powered entirely by photovoltaic electricity, with thermal energy supplied by a mix of 20% green hydrogen and 80% natural gas. The ReCiPe 2016 Midpoint (E) method was applied to assess 18 environmental impact categories. For the production of 1000 cans, the associated impacts are as follows: 287.11 kg CO₂ eq for GWP, 1.01 × 10⁻⁴ kg CFC-11 eq for ODP, 16.52 kBq Co-60 eq for IRP, 51.59 kg 1,4-DCB for FETP, 0.69 kg PM_2.5 eq for PMFP, 77.20 kg oil eq for FFP, and 2.57 m³ for WCP. Tinplate exhibits the highest environmental burden across most impact categories, particularly in HTPc (96%) and SOP (98%). Offset aluminum printing plates have the greatest impact on FETP (33%), while wood pallets significantly contribute to LOP (81%). The renewable energy scenario resulted in significant reductions in IRP (60.9%), LOP (50.3%), ODP (39.8%), FFP (26.1%), and GWP (24.4%). However, it also led to notable increases in other impact categories, including FETP (135.3%), METP (130.8%), FEP (128.8%), MEP (114.3%), HTPnc (112.0%), SOP (107.8%), TETP (103.4%), and WCP (75.2%), primarily due to green hydrogen production and photovoltaic systems. Among the renewable options, wind electricity stands out as the most environmentally favorable choice for hydrogen production, outperforming both photovoltaic and hydroelectricity. Full article

Air pollution remains a critical environmental and public health issue, requiring diverse research perspectives, including those related to energy production and consumption. This study examines the relationship between Poland’s energy mix and air pollution trends by integrating national statistical data on primary energy consumption and renewable energy sources over the past 15 years with air pollution measurements from the last eight years. The air pollution data, obtained from reference-grade monitoring stations, focus on particulate matter (PM). To address discrepancies in temporal resolution between daily PM measurements and annual energy sector reports, a bootstrapping method was applied within a regression framework to assess the overall impact of individual energy components on national air pollution levels. Seasonal decomposition techniques were employed to analyze the temporal dynamics of specific energy sources and their contributions to pollution variability. A key aspect of this research is the role of renewable energy sources in air quality trends. This study also investigates regional variations in pollution levels by analyzing correlations between geographic location, industrialization intensity, and the proportion of green areas across Poland’s administrative regions (Voivodeships). This spatially explicit approach provides deeper insights into the linkages between energy production and pollution distribution at a national scale. Poland presents a unique case due to its distinct energy mix, which differs significantly from the EU average, its persistently high air pollution levels, and recent regulatory changes. These factors create an ideal setting to assess the impact of energy sector transitions on environmental quality. By employing high-resolution spatiotemporal big data analysis, this study leverages measurements from over 100 monitoring stations and applies advanced statistical methodologies to integrate multi-scale energy and pollution datasets. From a PM perspective, the regression analysis showed that High-Methane Gas had a neutral impact on PM concentrations, making it a suitable transition energy source, while renewables exhibited negative regression coefficients and coal-based sources showed positive coefficients. The findings offer new perspectives on the long-term environmental effects of shifts in national energy policies. Full article

Bioethanol is a renewable, environmentally-friendly biofuel conventionally produced through the alcoholic fermentation of sugary or starch-rich substrates by microorganisms, commonly Yeast Saccharomyces cerevisiae. Intermediates of industrial wheat flour wet milling processing to starch, such as A-starch and B-starch milk, are cost-effective, abundant, and non-seasonal feedstocks for bioethanol production. This study evaluates the bioethanol production from wheat A-starch and B-starch milk and mixtures of these two substrates in different ratios (1:3, 1:1, and 3:1) using two cold hydrolysis procedures at 65 °C: (i) simultaneous liquefaction and saccharification (SLS) followed by fermentation, and (ii) liquefaction by alpha-amylase followed by simultaneous saccharification and fermentation (SSF). The results demonstrated that SSF and SLS are equally efficient procedures for reaching a high ethanol yield of 53 g per 100 g of starch and 93% of starch conversion to ethanol for all investigated substrates. Lower levels of non-starch components in A-starch milk, which typically contribute to volatile by-product formation, allowed clear distillate profiles in terms of and lower content of aldehydes, methanol, and volatile acidity, enhancing ethanol distillate purity compared to B-starch milk. Mixing high-quality A-starch milk with low-cost B-starch milk enables higher ethanol yield, improved distillate quality, and energy savings for efficient industrial-scale applications. Full article

Utilizing new and renewable energy sources, particularly coconut shell charcoal briquettes, represents a crucial solution in addressing the limitations of fossil energy sources and combating climate change. The objective of this study is to design, fabricate, and test a mixing machine tailored to the requirements of micro-, small-, and medium-sized enterprises (MSMEs) in the briquette industry. The target is a minimum output of 100 kg per hour, meeting the quality standards outlined in SNI NO. 01/6235/2000. The composition used consisted of 100% charcoal, 4% adhesive flour, and 25% water. Various testing durations—4 min, 8 min, and 12 min—were employed. Optimal mixing of these components was achieved using a machine measuring 1130 × 750 × 700 mm, rotating at 44.4 rpm, and powered by a 2HP motor. The most effective mixing duration was found to be 12 min, resulting in a total mixed mass of 25.8 kg. Full article

Offshore wind (OSW) technology has recently been included in California’s plans to achieve 100% carbon-free electricity by 2045. As an emerging technology, many features of OSW are changing more rapidly than established renewable options and are shaped by local circumstances in unique ways that limit transferrable experiences globally. This paper fills a gap in the literature by providing an updated technological assessment of OSW in California to determine its viability and competitiveness in the state’s electricity generation mix to achieve its near-term energy and environmental goals. Through a critical synthesis and extrapolation of technical, social, and economic analyses, we identify several major improvements in its potential. First, we note that while estimates of OSW’s costs per MWh of installed capacity have generally documented and projected a long-term decline, recent technical, microeconomic, and macroeconomic factors have caused significant backsliding of this momentum. Second, we project that the potential dollar value benefits of OSW’s greenhouse gas reduction capabilities have increased by one to two orders of magnitude, primarily due to major upward revisions of the social cost of carbon. Several co-benefits, including enhanced reliability, economic growth, and environmental justice, look to be increasingly promising due to a combination of technological advances and policy initiatives. Despite these advancements, OSW continues to face several engineering and broader challenges. We assess the current status of these challenges, as well as current and future strategies to address them. We conclude that OSW is now overall an even more attractive electricity-generating option than at the beginning of this decade. Full article

Electro-fuels (E-fuels) represent a potential solution for decarbonizing the maritime sector, including pleasure vessels. Due to their large energy requirements, direct electrification is not currently feasible. E-fuels, such as synthetic diesel, methanol, ammonia, methane and hydrogen, can be used in existing internal combustion engines or fuel cells in hybrid configurations with lithium batteries to provide propulsion and onboard electricity. This study confirms that there is no clear winner in terms of efficiency (the power-to-power efficiency of all simulated cases ranges from 10% to 30%), and the choice will likely be driven by other factors such as fuel cost, onboard volume/mass requirements and distribution infrastructure. Pure hydrogen is not a practical option due to its large storage necessity, while methanol requires double the storage volume compared to current fossil fuel solutions. Synthetic diesel is the most straightforward option, as it can directly replace fossil diesel, and should be compared with biofuels. CO₂ emissions from E-fuels strongly depend on the electricity source used for their synthesis. With Italy’s current electricity mix, E-fuels would have higher impacts than fossil diesel, with potential increases between +30% and +100% in net total CO₂ emissions. However, as the penetration of renewable energy increases in electricity generation, associated E-fuel emissions will decrease: a turning point is around 150 gCO₂/kWhel. Full article

The worldwide promotion of carbon-neutral policies is leading to a continuously growing percentage of electricity being derived from renewable energy, which makes it feasible to design power systems composed of 100% renewable energy in the future. The question of how to realize stable transmission for 100% renewable energy-integrating grids under different operating conditions needs to receive more attention. Voltage source converter-based high-voltage direct current (VSC-HVDC) technology is one of the prospective solutions for large-scale renewable energy integration due to its unique dominance in areas such as independent reactivity and active control. In this study, we design a novel, 100% renewable energy system through grid integration via a VSC-HVDC system structure and a control strategy. Unlike in other research, a mixed control strategy based on grid-forming control (PSL) and grid-following control (GFL) is developed to realize smooth switching in order to ensure secure transmission and consistent operation when the operating conditions of the 100% renewable energy-integrating grid changes. The simulation results indicate that the proposed system structure and control could stabilize renewable energy transmission under normal operation conditions and provide necessary grid support under different system disturbances. Full article

Clean hydrogen (H₂) use (i.e., produced using either renewable or low-carbon energy sources) can help decarbonize energy-intensive industries, the transport sector, and the power sector. The European regulatory framework establishes that the production of green H₂ must be supported either by the electricity grid through a power purchase agreement (PPA) or by intermittent renewable energy source (RES) plants owned by the hydrogen producer. Although the issue of the optimization of hydrogen production costs has already been approached, constraints related to the current regulatory framework and the modeling of nonlinear electrolyzer efficiency still represent open problems. In this paper, a mixed-integer linear programming (MILP) problem, assuming as the objective function the overall cost minimization of the allowed energy mix for green H₂ production, is formulated. Two approaches are compared: in the first one, electrolyzers can only operate at 100% load, whereas the second one allows for more flexible electrolyzer scheduling, by enabling partial-load working operations. The simulation results of several scenarios considering different H₂ production targets, forecasted RES production, and cost for PPAs demonstrate the effectiveness of the proposed methodology. Full article