• Energy Research
• 2021-2025close
• Closed Access close
• Embargo close
• Energy close

Abstract Energy storage systems (ESS) are widely used in active distribution networks (ADN) to smoothen the drastic fluctuation of renewable energy sources (RES). In order to enhance the scalability and flexibility of ESS, a virtual energy storage system (VESS), which is composed of battery energy storage system (BESS), RES as well as flexible loads (FL), is developed in this paper to realize the functionalities of ESS in more cost-effective way in ADN. Aiming at achieving voltage regulation, dynamic pricing strategies based on system voltage condition are designed for VESS. A distributed real-time power management model containing dynamic pricing strategies is proposed to accomplish the voltage regulation and economic power sharing in VESS. Moreover, a set of distributed algorithms, over time-varying unbalanced directed networks, are designed for dynamic pricing strategies and optimal power management model. Furthermore, the convergence property, optimality and system voltage stability are explained by detailed mathematical analysis. Three various case studies which were ran on a real time digital simulator (OPAL-RT OP5600) were designed to validate the effectiveness of the strategy. Finally, simulation results show that the economic power dispatch and voltage regulation are achieved among VESS simultaneously, even in the presence of time-varying directed and unbalanced communication networks.

Abstract This study investigates the macroeconomic effects of adverse oil price shocks on a small oil-exporting economy — the Azerbaijan economy. We estimate a recursive (near) VAR model by using monthly macroeconomic data from 2006 to 2018. The results indicate the Azerbaijan economy is adversely influenced by an oil price decline. Specifically, we find that a negative oil price shock deteriorates trade balance, causes a currency depreciation, increases inflation and falls economic activity. Furthermore, our findings imply that the oil price-led devaluation shapes the inflationary and recessionary consequences of this shock.

Abstract Variable electricity generation from wind and solar influences the design of a cost-efficient and reliable energy system. This paper presents a method that uses stochastic programming to represent variable renewable electricity generation in long-term energy system models, and demonstrates this on a Norwegian TIMES model. First, we derive hourly PV- and wind-generation data by modifying satellite-based data, based on a comparison with historical generation data. Second, the satellite-based dataset is transformed into a manageable set of scenarios that is used as an input to the stochastic energy-system model. This is done using six different scenario generation methods. Third, we solve the energy-system model with three of the scenario-generation methods and evaluate the quality of the corresponding model value by stability tests. We demonstrate that scenarios generated from the six methods have significantly different moment-based and Wasserstein distance error relative to the dataset. Further, the energy system model results show that the number of scenarios needed to achieve stability differs between the three used scenario generation methods.

Abstract Cold is an important cause of the death of people who fall into the water. The use of a gas generating agent to inflate an inflatable lifejacket is a kind of self-heating inflatable lifejacket, which maintains the inflation effect and portability of the original lifejacket and can also play an auxiliary heating effect. In this paper, a nitrogen-rich substance, 5-aminotetrazole 3-nitro-1,2,4-triazole (5ATNTZ) was synthesized, together with the selected oxidant and binder to complete the preparation of the gas generating agent. Commercial life jackets were selected for inflation test to explore the actual dosage and inflation effect of gas generating agent. The experimental results show that when the amount of gas generating agent is 19 g, the amount of physical coolant is 20 g, and the amount of chemical coolant is 7 g, the lifejacket is inflated and its surface temperature reaches at least 40.3 °C. The energy utilization efficiency reaches 75.17% when the chemical energy of the gas generating agent is converted into the heat of the bag and inflation work in the whole inflation process. Therefore, the gas-filled lifejacket using a gas generating agent has a good auxiliary heat effect, and is a type of self-heating inflatable lifejacket with excellent performance, which has great application value.