Thanks to the excellent passivation, high conductivity, low parasitic absorption and simple process, the wide-bandgap doping-free carrier selective contacts have been attracting much attention. In this work, the wide-bandgap high work function of Al O /MoO stacks were prepared using the low-temperature atomic layer deposition and thermal evaporation technique, respectively, and the interfacial evolution and the elements distribution were examined using high-resolution transmission electron microscopy coupled with energy-dispersive spectroscopy. The passivation and conductivity of the Al O /MoO stacks were systematical investigated by varying their thicknesses. The high effective minority carriers lifetime of 513 μs and the low series resistance of 0.24 mΩ are realized on the 7nm-Al O /5nm-MoO and 7nm-Al O /3nm-MoO stacks, respectively. Benefiting from the excellent surface passivation and conductivity, the industrial size (182×185.3 mm ) n-TOPCon solar cell with a total area front 7nm-Al O /3nm-MoO stacks demonstrates a champion power conversion efficiency (PCE) of 24.48%, as well as a short-circuit current density of 41.06 mA cm , an open-circuit voltage of 721 mV, and a fill factor of 82.66%. This work provides an effective way to enable the PCE over 26.0% and lower the process temperature for TOPCon solar cells with doping-free carrier selective contacts.

Agrivoltaics is a relatively new concept of agriculture and photovoltaic power generation on the same area. While an increased land use efficiency and potential synergies between agriculture and power generation speak in favor of agrivoltaics, higher investment cost compared to ground-mounted photovoltaics represents a challenge for a broader market launch in most countries.This work analyses the economic performance of agrivoltaics in apple farming focusing on potential synergies and adverse effects regarding investment requirements and operational cost of the farming system. The analysis is based on literature, expert interviews, and data of three pilot projects in Germany. The results show that average investment cost from the farming system could be reduced by 26% mainly due to partially replacing the hail protection structure. Annual operating costs of the farming system reduce by up to 9% through lower cost for land and maintenance works. However, annual revenues also decrease by about 9% due to an expected reduction in high quality apple yield. Overall, the cost of apple production decreases by about 5%. Regarding the total cost of agrivoltaics, though, the potential contribution from cost savings in the farming sector to reduce the cost of electricity only amounts to <1%. The expected Land Equivalent Ratio of the analyzed agrivoltaic system amounts to 1.54.The results indicate that agrivoltaics in orcharding is only economically feasible if the regulatory framework provides sufficiently high feed-in tariffs or comparable support payments. The work also shows that the theoretical potential of agrivoltaics in apple farming in Germany amounts to 23.8 GWp which could contribute to 13% of the PV development required to meet Germany's climate goals by 2030 [1].

The extraction of rare metals like lithium (Li) from geothermal fluids is a promising alternative to conventional mining. Membrane distillation (MD) could support energy-efficient fluid treatment enabling further freshwater production. For the operation of geothermal plants and MD uncontrolled precipitation of silica (Si) represents a major hurdle. Herein, we demonstrate the transfer of a Si treatment from lab to field demonstrator scale, tested under conditions of an operating geothermal power plant.For the treatment, lime precipitation was chosen showing good Si reduction rates using artificial fluids. The high alkaline conditions of this process (pH > 10) in combination with the high salinities of the geothermal brines (TDS > 100 g/L) are transferred into real geothermal environment with a newly developed numerical design calculation. The resulting demonstrator consists of three major process steps - 1) Si-reduction, 2) liquid/solid separation, and 3) post-concentration using MD. The Si treatment efficiently reduced 98 % of Si in <5 min reaction time, without influencing the lithium concentration negatively. The MD resulted in Li concentrations of ∼500 mg/L while producing fresh water. Beyond the approval of the concept, neuralgic points for improvement were identified expanding fundamental knowledge about the material use of geothermal fluids.

Local reactive power control in distribution grids with a high penetration of distributed energy resources (DERs) will be essential in future power system operation. Appropriate control characteristic curves for DERs support stable and efficient distribution grid operation. However, the current practice is to configure local controllers collectively with constant characteristic curves that may not be efficient for volatile grid conditions or the desired targets of grid operators. To address this issue, this paper proposes a time series optimization-based method to calculate control parameters, which enables each DER to be independently controlled by an exclusive characteristic curve for optimizing its reactive power provision. To realize time series reactive power optimizations, the open-source tools pandapower and PowerModels are interconnected functionally. Based on the optimization results, Q(V)- and Q(P)-characteristic curves can be individually calculated using linear decision tree regression to support voltage stability, provide reactive power flexibility and potentially reduce grid losses and component loadings. In this paper, the newly calculated characteristic curves are applied in two representative case studies, and the results demonstrate that the proposed method outperforms the reference methods suggested by grid codes.

The demand for energy is increased by increasing global population and rapid developments in the current industry and modern lifestyle. It is a necessity to promote and modernize the control systems of the electrical network and move forward to the green and smart energy systems. The integration of the distributed generations (DGs) with the optimum capacity and position is one of the viable keys for reducing the active and reactive power losses, providing standard system power quality, and also injecting more renewable energy sources into the system in order to extend decarbonized and green systems. The Optimal DG (ODG) allocation and sizing have always been challenging for both suppliers and consumers/prosumers. The fundamental objectives of ODG are to enhance system overall efficiency with reduced power losses, maximize system security, voltage stability, and reliability. This paper proposes the implementation of the Grey Wolf (GWO) as state of the art for the nonlinear meta-heuristic optimization algorithm to solve ODG in the radial distribution system. The optimization aims are to reduce the percentage of daily power losses and voltage fluctuation of the radial systems. The GWO is applied to implement multiple DGs, by considering step-by-step injection strategy, to the IEEE 69 bus distribution test system. Two different scenarios are taking into account: the common DG with the fixed capacity to inject both active and reactive power to the system and time-series output for a photovoltaic generation which considered as a DC-battery.

This paper summarizes Electromagnetic Transient (EMT) simulation studies using PSCAD/EMTDC undertaken to evaluate the capability and suitability of commercially available large scale Grid Forming Inverters (GFMI) to dampen oscillations in a real bulk power transmission network. Faults and a range of grid voltage oscillation frequencies are tested on GFMI and synchronous condenser (SC) models using single source equivalent network model and comparisons of transient, post fault and oscillatory rejection tests are presented. A critical credible fault in the West Murray Zone (WMZ) was simulated on a wide-area EMT model of the Australian National Electricity Market (NEM) to show the effectiveness of GFMI in providing system strength services and improving damping of network sub-synchronous control interactions (SSCI). Two scenarios were examined: Direct replacement of existing centralized synchronous condensers in the WMZ of the NEM, and a decentralized distribution of GFMI in the transmission network (treated as expansion or repowering solution for existing grid following inverter equipped solar farms). Simulation results show that commercially available GFMI are a viable option for improving system strength in a practical transmission system with a high proportion of Inverter Based Resources (IBR).

While computer systems, software applications, and operational technology (OT)/Industrial Control System (ICS) devices are regularly updated through automated and manual processes, there are several unique challenges associated with distributed energy resource (DER) patching. Millions of DER devices from dozens of vendors have been deployed in home, corporate, and utility network environments that may or may not be internet-connected. These devices make up a growing portion of the electric power critical infrastructure system and are expected to operate for decades. During that operational period, it is anticipated that critical and noncritical firmware patches will be regularly created to improve DER functional capabilities or repair security deficiencies in the equipment. The SunSpec/Sandia DER Cybersecurity Workgroup created a Patching Subgroup to investigate appropriate recommendations for the DER patching, holding fortnightly meetings for more than nine months. The group focused on DER equipment, but the observations and recommendations contained in this report also apply to DERMS tools and other OT equipment used in the end-to-end DER communication environment. The group found there were many standards and guides that discuss firmware lifecycles, patch and asset management, and code-signing implementations, but did not singularly cover the needs of the DER industry. This report collates best practices from these standards organizations and establishes a set of best practices that may be used as a basis for future national or international patching guides or standards.