Sharing Economy in Local Energy Markets

With an increase in the electrification of end-use sectors, various resources on the demand side provide great flexibility potential for system operation, which also leads to problems such as the strong randomness of power consumption behavior, the low utilization rate of flexible resources, and difficulties in cost recovery. With the core idea of 'access over ownership', the concept of the sharing economy has gained substantial popularity in the local energy market in recent years. Thus, we provide an overview of the potential market design for the sharing economy in local energy markets (LEMs) and conduct a detailed review of research related to local energy sharing, enabling technologies, and potential practices. This paper can provide a useful reference and insights for the activation of demand-side flexibility potential. Hopefully, this paper can also provide novel insights into the development and further integration of the sharing economy in LEMs.</p

Solid polymer electrolytes under nanoscale confinement: a molecular dynamics simulation

Solid polymer electrolytes (SPEs), though widely regarded as materials that can enable next-generation lithium metal battery with improved safety, extended stability, and high capacity, suffer from problems of low ionic conductivity. Myriads of strategies have been proposed to improve the performance of polymer electrolytes, but with little success, and the state-of-the-art polymer electrolytes are still based on LiTFSI dissolved in PEO, which have been proposed for more than 40 years. New design concepts are indispensable to improving the performance of SPEs. Using molecular dynamics simulation, we examine SPEs under nanoscale confinement, which has been demonstrated to accelerate the diffusion of neutral molecules such as water. While ion diffusion indeed shows an acceleration by more than two orders when the channel diameter decreases from 15~nm to 2~nm, the ionic conductivity does not show a paralleling increase. Instead, as the nanochannel diameter decreases, ionic conductivity shows a non-monotonic variation, with an optimal value above yet on the same order as its bulk counterparts. The reason for this trend is due to enhanced ion association with decreasing channel size, which leaves a smaller amount of effective charge carriers. This effect competes with accelerated ion diffusion, leading to the non-monotonicity in ion conductivity. We further show that this trend also appears in two-dimensional nanoslit pores. These findings not only manifest the intricacies of ionic transport behavior but also provide new concepts and necessary implications for designing composite SPEs

Estimating Safety Effects of Green-Man Countdown Devices at Signalized Pedestrian Crosswalk Based on Cellular Automata

Safety effects of Green-Man Countdown Device (GMCD) at signalized pedestrian crosswalks are evaluated. Pedestrian behavior at GMCD and non-GMCD crosswalks is observed and analyzed. A microsimulation model is developed based on field observations to estimate safety performance. Simulation outputs allow analysts to assess the impacts of GMCD at various conditions with different geometric layout, traffic and pedestrian volumes, and the green time. According to simulation results, it is found that the safety impact of GMCD is affected by traffic condition as well as different time duration within green-man signal phase. In general, GMCD increases average walking velocity, especially during the last few seconds. The installation of GMCD improves safety performance generally, especially at more crowded crossings. Conflict severity is increased during last 10 s after GMCD installation. Findings from this study suggest that the current practice, which is to install GMCD at more crowded crosswalks or near the school zone, is effective. Moreover, at crosswalks with GMCD, longer all red signal phase is suggested to improve pedestrian safety during intergreen period.MOE (Min. of Education, S’pore)Published versio

Aggregating Distributed Energy Resources for Grid Flexibility Services: A Distributed Game Theoretic Approach:(Extended abstract)

We propose a novel fully decentralized energy management scheme for aggregating distributed energy resources for grid flexibility services in wholesale electricity market. We model this problem as a multi-leader-multi-follower noncooperative game. Then a fully distributed algorithm in discrete-time is proposed to solve the problem and find the Nash Equilibrium(NE). In this algorithm, each aggregator only needs to exchange its estimate of the aggregate and an auxiliary variable with its neighbours. This scheme shows the scalability and efficiency in aggregating flexibility services from a large number of prosumers