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Curtailment of distributed photovoltaic (PV) and battery energy storage systems will have significant implications for power system transition around the world. Australia offers a unique case study as it has highest installation rate of distributed-PV and growing fleet of battery energy storage systems. Distributed-PV and battery inverters in Australia are required to exhibit voltage-responsive power-quality response modes to prevent excessive voltage rise caused by increasing day-time energy exports, but these modes can curtail power output and limit the value that can be gained from the renewable energy assets. For the first time in Australia, this paper studies all three inverter power-quality response modes and develops novel algorithms to assess curtailment. The algorithms are applied to a real-world dataset of 1-sec distributed-PV and battery power measurements from 1300 residential households; therefore, data resolution is higher and sample size is larger than previous related studies. Using these datasets, the study compares the experienced curtailment between distributed-PV only sites and distributed-PV coupled with battery sites for the first time. The study investigates and quantifies the energy loss due to curtailment within the South Australia region with over 40% distributed-PV penetration which has the highest uptake in the world. The results show that average curtailment loss was 1.5% for distributed-PV only sites and 0.2% for distributed-PV coupled with battery sites, however, some sites were heavily impacted losing up to 25% of generation. The reasons for the larger curtailment loss were identified as wiring and network connection faults and high voltage set-points at households' respective local substations. Other potential reason for the heavily impacted sites is being located towards the end of the low voltage feeder, however this couldn't be verified due to lack of spatial data. The large variation in curtailed generation across sites raises concerns for system owners and suggests further inquiry into the power-quality response mode design and regulations. The study also examines inverter conformance using real-world operational data for all three power quality response modes for the first time, and the results showed a low rate of conformance according to the Australian Standards and there were various discrepancies in the execution of these modes which raises concerns considering the increasing importance of distributed-PV and battery inverter fleet in supporting network operations and security. The results therefore warrant further investigation into the reasons behind these discrepancies and devising appropriate mechanisms to tighten inverter conformance checks. • Energy curtailment is calculated for D-PV only and D-PV coupled with BESS sites • Average loss due to curtailment is less than 2% of total D-PV generation • Curtailment is greater for D-PV only sites than D-PV coupled with BESS sites • Some sites lose up to 25% of generation due to curtailment • The large variation of curtailment losses across sites raises concerns • Inverters showed low conformance in power quality response mode standards [ABSTRACT FROM AUTHOR]

Understanding the complexities around managing the end-of-life (EoL) residential solar photovoltaic (PV) and battery energy storage systems (BESS) is a precursor to a better decision-making process that mitigates unintended product life-cycle impacts. In this paper, a participatory Systems Thinking approach was utilised to build a causal loop diagram (CLD) for this system based on the collective knowledge of stakeholders. The developed CLD was categorised into three sub-systems: (1) waste flows; (2) regulatory aspects; and (3) industry strategies and government incentives. Two main system archetypes were identified in a reflection to the CLD, namely fixes that fail and drifting goals. The identified feedback loops indicate the need to introduce a comprehensive national product stewardship scheme, complimentary landfill restrictions, and provide sufficient incentives to industries for promoting recovery activities within residential PV panels and BESS sectors. An effective waste management system for these renewable energy technologies is most effective if industries are required to participate through regulation which also specifies certain targets, such as product and material recovery rates and establishes a sustainable funding model to meet operational requirements and future needs. The increasingly prohibitive overseas waste export market will require local industries and governments to collaboratively improve domestic recycling capability and capacity. In this light, the failure to build an effective EoL management system for residential PV and BESS will result in valuable and hazardous materials in both technologies to be disposed of in the landfill, stockpiled or illegally dumped; consequently, reinforcing unintended and adverse environmental impacts. • Causal loop diagram mapped the complexity of EoL management system of PV and BESS. • Stakeholders were consulted to develop and validate the conceptual model. • Conceptual model is governed by three subsystems and 13 feedback loops. • Two system archetypes were identified, namely fixes that fail and drifting goals. [ABSTRACT FROM AUTHOR]

One way of setting up hybrid wind farms is through augmentation of turbines with battery energy storage systems (BESS). Due to variation in wind speed in such wind farms, the cost of BESS increases and reduction in battery life takes place. This paper proposes a wake management technique to reduce the operational cost of a hybrid wind farm equipped with BESS. The battery charging and discharging powers are ascertained considering error in the wind speed prediction. This investigation considers three different conditions for a wind farm, namely, (i) without wake (ii) without wake management and (iii) with wake management. An ageing model is utilized for the lead-acid battery while accounting for temperature and depth of discharge changes to assess the battery operational cost and lifecycle count. Simulation analysis for a two-turbine layout with the upstream turbine yawed from 0 ∘ to 5 ∘ , presents a 44.37% savings in operational cost and 79.74% increase in battery life evaluated for a dataset obtained from Challicum hills in Australia. Additionally, the battery operational cost is minimized at a yaw angle of 15°. Uncertainty analysis is done to study the effect of prediction technique on the lifecycle count. The proposed methodology is extended to a 5-turbine layout where along with lifecycle count and operational cost, the horizontal shear on the turbine blades is also analyzed. [ABSTRACT FROM AUTHOR]