Abstract

There has been an increasing need to address the lack of food cold chain in order to save wasted food in Sub-Saharan Africa. TRNSYS has been considered as a powerful tool to simulate transient energy systems. In this study, TRNSYS has been utilised to model a standalone year-round adsorption cooling system driven by solar thermal energy to preserve fruits and vegetables after the harvest in Rwanda. The required solar collector area and heat storage size were optimised to run the adsorption refrigeration system 24/7, meet the cooling demand of the cold room and maintain its conditions. A combination of evacuated tube solar collector area of 45 m2 with a hot storage size of 10 m3 and 50 m2 with 8 m3 were found optimal to drive the cooling system 24/7 and maintain a cold room of 38 m3 at the desired operating temperature of 10 oC to preserve a selected range of fruits and vegetables.

Abstract

This paper investigates the consequences of divergence in policy assumptions in energy planning for preparing national low-carbon pathways and enhancement of Nationally Determined Contributions (NDCs) in Indonesia, Thailand and Vietnam. We present an assessment of the resulting forecasts based on a multimethod exploratory study. Our analysis contributes to an ongoing debate on the policy coherence and integration in the energy sector and climate action strategies. Our results indicate how data availability, ownership and transparency, as well as institutional factors inbuilt in national energy planning impact policy implementation and climate action. This analysis can provide valuable insights for policy-makers working with enhancing NDCs to ensure the updated NDC is actionable.

Abstract

A new electricity progressive tariff (PT) was introduced to South Korea in 2017 to alleviate financial burden of households from air conditioning use in hot summers. Although people were concerned that this policy may lead to additional household energy use across the year, very limited evaluations have been conducted partially due to the lack of extensive and targeted datasets. This study examines how the new PT influences residential electricity use in different apartments in Seoul. A combined dataset was collected from both multisource big data and urban geospatial data. The significance of household electricity use changes of 402 apartments was estimated based on the dataset with interrupted time series analysis. Relationships between the significance of change and energy use, household socioeconomic status, and built environment of apartments and neighborhoods were further examined using logistic regression. Results showed that significant changes are likely to occur with reduced previous electricity use, high adult male ratio, and high apartment density. The findings of this study can help policymakers further evaluate the new policy for sustainability goals, including social welfare, urban energy, and economic development.

Abstract

With the target of carbon neutrality in 2060, China’s energy system must undergo a huge transformation. Based on the bottom-up energy system model China-TIMES, this paper generates energy consumption, CO2 emissions and technology options for the future deep decarbonization scenario. The model result shows that the peak time of CO2 will significantly affect the emission level in 2050 and will have a crucial impact on the achievement of carbon neutrality. Quantitative analysis indicates electric vehicles and renewable energy will be essential if we hope to accomplish carbon neutrality target. With the rapid development of electric vehicles, the demand for energy storage technology is growing, and the operating mode of energy storage technology will change from charging at night to charging during the day. The coordinated development of electric vehicles, renewable energy and energy storage technology will become a highlight of China’s low carbon transition.

Abstract

The stability of maximum power point tracking (MPPT) of wind turbine(WT) system will be affected by the disturbance of external environment. The response speed, accuracy, and stability of the controller directly affect the efficiency and power generation of WT. In this paper, a novel robust adaptive controller with prescribed performance is designed to achieve MPPT. Robustness of the controller is used to overcome the effects of instantaneous variation characteristics of wind and disturbances on the stability of the WT system. Considering the uncertainty of the precise parameters of the WT system in the actual operation process, the adaptive algorithm is used to estimate the system parameters. In additional, the prescribed performance function is applied to MPPT to ensure the tracking speed and accuracy. The simulation results show the effectiveness of the controller in natural continuous turbulent wind speed.

Abstract

The wind power industry has boomed in the decades and offshore wind energy has been growing rapidly in the recent year. However, the significant O

Abstract

The pretreatment is the most important step for biomass conversion which alters the structure of lignocellulosic biomass to make the substrate accessible enzymatic saccharification and fractionates biomass into the major components for complete utilization of biomass. The fractionation of major biomass components after traditional organosolv pretreatment is tedious and energy-intensive especially when solvent recovery is crucial. In this study, pentanol/water biphasic pretreatment of acacia wood was carried out to investigate energy benefits of the process, pretreatment efficiency, and lignin potential to produce value-added chemicals. The two completely immiscible phases facilitated the separation of biomass fractions which reduced about 46.5% of the total energy consumption for pretreatment and fractionation process. Besides, the lower distribution co-efficient of acid in the organic phase preserved approximately 26.4% of β-aryl ether (β-O-4) linkage in lignin which further increased the energy benefits of the pretreatment process by increasing lignin valorization potential.

Abstract

For a wind turbine (WT), the maximum power point tracking (MPPT) is always required to ensure its operational reliability and increase its annual production capacity. However, it is difficult to quickly and accurately track the maximum power point since the parameter uncertainty and external disturbances, which ultimately leads to a decrease in annual power generation. In this paper, a new type of practical prescribed time controller with fault-tolerant performance is proposed to ensure the reliable operation of WT and quickly capture the maximum wind energy. First, we construct a time varying bounded performance function embedded with convergence speed and tracking accuracy that can be preset by designer, and then use this function to perform error conversion. Based on this, the problem is transformed into a new one with the bounds of the conversion error variable aiming to improve the systems fault tolerance and robustness. Finally, through FAST and simulink joint simulation, the effectiveness of the control scheme is verified.

Abstract

Combining renewable energy, waste-to-energy (WtE), and negative emission technologies could provide efficient solutions to mitigate emission or even achieve negative emissions. However, there is a lack of understanding of the global potential of such systems considering countries or regions with varying resource portfolios. In this article, we quantify the potential role of such combination in climate change mitigation around the world and recommend the top places for technology implementation. A mixed-integer linear programming (MILP) optimization was used to select the specific technologies for 20 countries. The result showed that 17 countries were decided to be profitable locations for the proposed system when net present value was maximized. Negative emission was possible to be achieved in 16 countries if greenhouse gas emission was minimized, but it may result in a dramatic increase in cost compared to the optimal NPV scenario.

Abstract

The introduction of advanced metering infrastructure (AMI) is imminent in Korea as it is expected to demonstrate the next generation AMI in 2021. In addition, several countries around the world such as Italy, Germany have already deployed and operating AMIs or are planning. They also show a trend to utilize various functions of AMI to use new energy services for reasons of energy efficiency. In order to reflect this trend in recent years, specific use cases and related procedures should be defined. Thus, in this paper, we classify and structure the business cases of AMI that are required to support new energy services. Furthermore, we will summarize the lower business use cases and present the information exchange sequences of the business use cases in class and sequence unified modeling language diagrams. 5 use cases are found, we carefully selected which new energy service to support beyond the structural and functional limitations of the existing infrastructure in Korea. We hope that through such work, the foundation for implementing and operating various functions of AMI can be laid.