• Energy Research
• 11. Sustainability close
• CN close
• JP close
• Renewable Energy close

This paper presents a multi-objective optimization model for a long-term generation mix in Indonesia. The objective of this work is to assess the economic, environment, and adequacy of local energy sources. The model includes two competing objective functions to seek the lowest cost of generation and the lowest CO2 emissions while considering technology diffusion. The scenarios include the use of fossil reserves with or without the constraints of the reserve to production ratio and exports. The results indicate that Indonesia should develop all renewable energy and requires imported coal and natural gas. If all fossil resources were upgraded to reserves, electricity demand in 2050 could be met by domestic energy sources. The maximum share of renewable energy that can be achieved in 2050 is 33% with and 80% without technology diffusion. The least cost optimization produces lower generation costs than the least CO2 emissions, as well as the combined scenario. Total CO2 emissions in 2050 are five to six times as large as current emissions. The least CO2 emissions scenario can reduce almost half of the CO2 emissions of the least cost scenario by 2050. The proposed multi-objective optimization model leads some optimal solutions for a more sustainable electricity system.

Abstract To ensure techno-economically suitable installation of ground source heat pump (GSHP) systems, thermal and hydrogeological properties of the subsoil need to be investigated. In this paper, the geothermal potential for three types of GSHP installations in the urban area of Wuhan city is assessed based on preliminary geological investigations. The potential for shallow geothermal energy is evaluated for surface water heat pump systems (SWHP), groundwater heat pump systems (GWHP) and ground coupled heat exchanger heat pump systems (GCHP). The mapped shallow geothermal potentials provide essential information for the installation of GSHPs and for the management of geothermal resources of Wuhan city. Furthermore, the heat transfer rates for some typical configured borehole heat exchanger (BHE) are tested by field Thermal Response Tests (TRT). In order to understand the techno-economic feasibility of the GSHPs, different types of the installed systems are measured and analyzed.

While previous studies focused on managing charging demand for private electric vehicles (EVs), we investigate ways of supporting the upgrade of an entire public urban electric taxi (ET) system. Concerning the coexistence of plugin charging stations (CSs) and battery swap stations (BSSs) in practice, it thus requires further efforts to design a holistic charging management especially for ETs. By jointly considering the combination of plug-in charging and battery swapping, a hybrid charging management framework is proposed in this paper. The proposed scheme is capable of guiding ETs to appropriate stations with time-varying requirements depending on how emergent the demand will be. Through the selection of battery charging/swap, the optimization goal is to reduce the trip delay of ET. Results under a Helsinki city scenario with realistic ETs and charging stations show the effectiveness of our enabling technology, in terms of minimized drivers’ trip duration, as well as charging performance gains at the ET and station sides.

Abstract Standardization of biogas technology is immensely important for the promotion of the biogas industry worldwide. China has built a complete biogas standard system, which is divided into common, household biogas, biogas engineering, biogas digester for domestic sewage treatment, output utilization, and service system standards. The problems and potential barriers for biogas standardization in China are analyzed and come down to sluggish standard, overlapped standard, government-dominated standard, and lagging international standard. Accordingly, all potential biogas standards should be evaluated and placed under the same department. China Biogas Society and China Association of Rural Energy Industry play leading roles in developing enterprise or group/association biogas standards and ISO biogas standards. The bio-natural gas standard system and experimental standardization should be developed as well to replenish biogas standard system. A paradigm shift in biogas standardization should be from government-dominated to market-oriented model. The lessons learned for other developing countries includes expanding standardization to multi-aspects to realize full lifecycle control and management, building rapid responding mechanism of standardization to adopt industry transformation, integrating outdated standards into new versions, and establishing market-based standard system.

Abstract Various technologies as can be seen in vernacular architecture especially in Japanese traditional buildings are reviewed and the ways and means to have those technologies applied to the design of modern architecture are discussed with some examples. It is stressed that the vernacular technologies have been devised uniquely to the region where people lived to cope with the severe climate by inventing various devices without resorting to fossil fuels, thus the form of vernacular architecture representing regionalism of their own. For example earth sheltered buildings corresponds to thatched roof houses where evaporation from the wet surface gives rise to cooling effects in hot and humid climate. The optimum shape of sun shades is devised to a given orientation so that it allows the air to flow through for making ventilative cooling effective. Direct solar heat gain as representing a passive solar system is no less than fundamental for both vernacular and modern architecture with most appropriate design of geometry associated with wall orientation. Various suggestions are given for architects to consider how to apply vernacular technologies to the design of modern architecture.

Abstract Renewable energy resources and technologies, especially solar thermal and photovoltaic systems, can provide advantageous and clean options for meeting electrical demands. The location and sizing of photovoltaic systems affect the system losses significantly. Here, a new hybrid framework for the optimal location and size for an off-grid solar/hydrogen energy system is proposed using an improved heuristic approach: improved harmony search and geographic information system (GIS). To determine the appropriate capacity and location for a grid-independent photovoltaic scheme in rural areas, a GIS module is used subject to several criteria: social, economic, technical, and environmental. The life cycle cost, the main objective function, is minimized and employed to assess the viability of the stand-alone photovoltaic scheme with hydrogen storage accounting for the reliability of the scheme. The system reliability is measured with the parameter loss of power supply probability. The proposed framework is useful, and is applied here to an actual case study in Iran for illustrative purposes. To validate the effectiveness of the proposed algorithm, the results obtained by proposed algorithm are compared with those of harmony search algorithm-based geographic information systems. The results of the simulation show the advantages of utilizing the proposed framework, based on improved harmony search and geographic information systems, for a grid-independent photovoltaic scheme considering both power quality and cost in remote and island areas.

Abstract Renewable energy plays an important role in the modern economic growth paradigm. As a perpetual source, solar-based renewable energy has the ability to reduce CO2 emissions, which has been neglected in prior empirical studies. We have analyzed the asymmetric association between solar energy consumption and CO2 emissions in the top ten solar energy-consuming countries (Australia, Germany, Japan, Spain, Italy, USA, South Korea, UK, France, and China). Using data from 1991 to 2018, a novel methodology, ‘Quantile-on-Quantile (QQ)’, is applied. The results explore the mode of how quantiles of solar energy consumption asymmetrically affect the quantiles of CO2 emissions by providing an adequate framework to comprehend the overall dependence structure. The empirical findings demonstrate that solar energy consumption reduces CO2 emissions at different quantiles for all selected countries except France. The overall relationship is stronger at higher quantiles of CO2 emissions for various countries. The outcomes suggest that the intensity of asymmetric relationship in solar energy-CO2 emissions nexus differs with countries that need individual caution and attention for governments in formulating the policies connected to solar energy and the environment. Our empirical evidence also emphasizes that solar energy should be integrated for sustainable growth and environmental quality.

Polyurethane (PU) possesses excellent thermal properties, making it an ideal material for thermal insulation. Incorporating Phase Change Materials (PCMs) capsules into Polyurethane (PU) has proven to be an effective strategy for enhancing building envelopes. This innovative design substantially enhances indoor thermal stability and minimizes fluctuations in indoor air temperature. To investigate the thermal conductivity of the PU-PCM foam composite, we propose a hierarchical multi-scale model utilizing Physics-Informed Neural Networks (PINNs). This model allows accurate prediction and analysis of the material's thermal conductivity at both the meso-scale and macro-scale. By leveraging the integration of physics-based knowledge and data-driven learning offered by PINNs, we effectively tackle inverse problems and address complex multi-scale phenomena. Furthermore, the obtained thermal conductivity data facilitates the optimization of material design. To fully consider the occupants' thermal comfort within a building envelope, we conduct a case study evaluating the performance of this optimized material in a single room. Simultaneously, we predict the energy consumption associated with this scenario. All outcomes demonstrate the promising nature of this design, enabling passive building energy design and significantly improving occupants' comfort. The successful development of this PINNs-based multi-scale model holds immense potential for advancing our understanding of PU-PCM's thermal properties. It can contribute to the design and optimization of materials for various practical applications, including thermal energy storage systems and insulation design in advanced building envelopes. 25 pages, 25 figures

Abstract Energy-efficient urban design is an important prerequisite to sustainable urban development and reduction of greenhouse gas emissions. This study proposes an automatic framework to optimize urban design through the use of an urban building energy model. Three optimization goals were defined: maximum solar energy utilization, solar lighting of the first floor, and minimum building energy demand. Urban morphology was integrated into the optimization process as the bridge between the urban design scenario and the actual urban block. To validate the model, this study abstracted basic urban forms from actual urban contexts to generate urban blocks with the Rhino tool and run optimization in the Wallacei X, for multi-objective optimization in Rhino. The long short-term memory (LSTM) network was applied to infer energy performance of 41 actual urban blocks in Jianhu, China. In the results, the proposed framework can be validated feasibly with optimization of 100 iterations. A set of optimal results will be achieved for three goals and five clusters defined for different concerns of urban design strategies. The LSTM can achieve the best accuracy of 1.21% and 1.37% for energy generation of photovoltaic and total building energy use intensity respectively.