An optimal sizing model of the battery energy storage system (BESS) for large-scale wind farm adapting to the scheduling plan is proposed in this paper. Based on the analysis of the variability and uncertainty of wind output, the cost of auxiliary services of systems that are eased by BESS is quantized and the constraints of BESS accounting for the effect of wind power on system dispatching are proposed. Aiming to maximum the benefits of wind-storage union system, an optimal capacity model considering BESS investment costs, wind curtailment saving, and auxiliary services compensation is established. What’s more, the effect of irregular charge/discharge process on the life cycle of BESS is considered into the optimal model by introducing an equivalent loss of the cycle life. Finally, based on the typical data of a systems, results show that auxiliary services compensation can encourage wind farm configuration BESS effectively. Various sensitivity analyses are performed to assess the effect of the auxiliary services compensation, on-grid price of wind power, investment cost of BESS, cycle life of BESS, and wind uncertainty reserve level of BESS on this optimal capacity.

Due to the rapidity required for primary frequency control (PFC), the decentralized responses of distributed energy resources (DERs) are often uncoordinated and cannot be aggregated into a desired outcome. This paper proposes a novel approach to consolidate the decentralized responses of ON/OFF DERs as an organized droop control. For a DER population, a dynamic response threshold can be calculated based on its statistical distribution, enabling DERs to autonomously respond to PFC according to local states. The aggregation of their responses can align with any preset droop curve (linear or nonlinear). The approach is demonstrated by a novel DER, 5G base stations (gNBs) and their backup energy storage systems (BESSs), marking the first attempt of gNBs for PFC support, to the authors’ knowledge. In this regard, gNB dormancy model, based on user equipment (UE) access, and dynamic BESS response model, derived from experimental data, are developed. An adaptive droop control scheme is designed to enable gNBs within multiple radio access networks (RANs) to provide differentiated responses based on disturbances degree and RANs busyness level. Simulations based on real device data show that the proposed approach enables decentralized gNBs to perform accurate response, providing PFC support without affecting communication network operation.

Governments around the world have been developing intermittent renewable energy generation (IREG) technologies such as wind power and solar power aiming at securing energy supply and carbon emission reduction. However, the uncertainty of intermittent renewable energy-based generation brings challenges to a power system with a high penetration of IREG. Given this background, through joint energy and frequency regulation service (FRS) clearing, a new two-sided spot electricity market mechanism is proposed in this paper, which can quantitatively determine the FRS demand of the system to cope with the high IREG penetration rate. The proposed mechanism also incorporates the consumer side to manage uncertainties of both IREG outputs and flexible loads, via providing economic incentives to market participants. Besides, in the proposed market mechanism, carbon emission is included in the market clearing function, which can not only contribute to the decarbonization of electricity resources, but also promote the coupling relationship between electricity and carbon emission markets. Subsequently, the correlation analysis between electricity and carbon prices confirms the positive effect of the proposed mechanism on deepening the electricity-carbon synergy. Finally, case studies demonstrate the feasibility and effectiveness of the proposed market mechanism.

We herein report the development and testing of a novel material, namely activated carbon-supported nano titanium dioxide (ACTD) for the immobilization of arsenic in soil. This material, which was prepared using a sol-gel method, effectively reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiologically based extraction test (PBET) bioaccessibility of As(III) in soil samples. Upon processing the soils for 56 d at an ACTD dosage of 0.25 mmol g⁻¹, the TCLP leachability of As(III) was reduced by 82.7–97.7%, while the bioaccessibility was lowered by 58.6–81.2%. In addition, sequential extraction resulted in an 11.5–96.0% decrease in the mobile-As(III) and the mobilizable-As(III) fractions, but an increase in the residual-As(III) fraction upon treatment with ACTD. These observations indicate that the application of ACTD could result in an 80% reduction in As(III) environmental leaching, thereby confirming that ACTD appears suitable for the treatment of arsenic-contaminated soil.

Conventional DC-DC converters for renewable energy systems work in large duty cycle conditions, which will lead to the inductor saturations and decrease the system efficiencies and stabilities. In this paper, a new fifth-order boost converter, which can work in dual operating modes when different control technologies are adopted, is proposed. To obtain a wider conversion ratio, the required duty cycle for the proposed converter with synchronous controller is smaller than 0.333 while with interleaved controller is smaller than 0.5. Also, dual modes of this converter both have lower switches voltage stress. Then, the inductor saturation issues can be avoided and the system efficiencies and stabilities can be improved. Besides, the lower topological order and simple grounded structure of this converter are benefit to reduce the modeling complexity, topology volume and system noises. Detailed analyses, comparisons and prototype are implemented to study the improved conversion ratio, efficiency and power density of the proposed converter in-depth, and to validate its feasibilities for renewable energy applications.

The current electricity market trading mechanism mainly includes the bilateral negotiation transaction and centralized transaction, with defects such as information asymmetry, insufficient competition, and weak price discovery. Thus, a new double‐market parallel trading mechanism is proposed to improve the efficiency of the competitive electricity market in this paper. Regard the electricity market as a price‐searching market and divide into two sub‐markets composed of a price‐searching market for buyers and a price‐searching market for sellers. Market entities can trade synchronously in two sub‐markets as price searchers or bidders. Searchers are responsible for organizing transactions in line with the market clearing rule library, and bidders participate in transactions initiated by searchers. Under the parallel mechanism, the traditional trading mechanism is also applicable. the framework of the proposed mechanism is presented from four aspects, including the description, clearing process, operation mode, and linkage between two sub‐markets. Then, a market clearing model of the proposed mechanism is built with several traditional transaction modes as special cases of the presented double‐market parallel transactions. Finally, taking the centralized transaction as an example, results show that the proposed mechanism can effectively provide market entities more chances to win contracts, and enhance the market liquidity.