• Energy Research
• 2025-2025close
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This paper presents a novel coordinated Conservation Voltage Reduction (CVR) and Electric Vehicle Demand Control (EVDC) method for energy-efficient power system operation. The goal of coordinated CVR-EVDC is to minimise the total energy consumed by the distribution network through coordination of the scheduling of EV charging, the OLTC transformer tap position, and the switching of the capacitors on the network. Using publicly available statistics of journey length and travel time of car drivers in the UK, a stochastic model is developed for EV battery State-of-Charge (SOC) and its availability for home charging to generate EV charging demand profiles for different levels of EV penetration. These are then used in conjunction with Particle Swarm Optimisation (PSO) and a relaxation equality constraint to explore the potential for optimally coordinating CVR operation and the scheduling of charging of EVs on LV distribution networks. Results for five different LV network scenarios show that a coordinated CVR-EVDC approach enables more significant energy savings than with independent operation of CVR and EVDC – 4% greater with dumb charging and 3% greater with valley-filling smart charging. This study shows that distribution network operators can manage the networks by coordinating CVR and EVDC to manage consumer charging requirements for better energy savings.

© 2024Vehicle-to-grid (V2G) charging, where vehicles can send power to the grid, can provide valuable services to energy systems and network operators. However, social acceptance is an essential and overlooked barrier which must be addressed if V2G is to be successfully deployed. This study investigates the factors that govern attitudes towards V2G, and how electric vehicle (EV) ownership and participation in V2G changes them. For the first time, this includes survey data from users who had experience using a V2G charger, comparing the response of V2G users (n=49) with EV owners (n=520) and non-EV owners (n=1091). We show that time and EV ownership have lowered concerns around range anxiety, and that EV ownership and V2G trial participation leads to a 15%–35% increase in stated willingness to participate in V2G or Smart Charging as compared to a 2013 baseline. Additionally, it is demonstrated that the strongest single predictor for V2G willingness is whether the consumer believes that V2G can contributes to a stable electricity system. These results suggest that education around V2G benefits and allowing consumers to test V2G before committing could be key factors in increasing adoption. We also highlight the importance of data privacy, which for some consumers contributes towards a negative attitude towards V2G. We release the raw survey data and code with this manuscript.

This paper presents the first comparative study evaluating towing and onsite replacement strategies for heavy maintenance of floating offshore wind (FOW) turbines. The towing maintenance strategy is characterised by a Markov chain and implemented within a computationally-efficient operation and maintenance (O&M) model. This model includes all key phases of the towing strategy: transit-to-site, turbine disconnection, towing-to-port, component replacement, towing-to-site, turbine connection, and transit-to-port. Additionally, the paper provides the first spatial assessment of heavy maintenance for FOW turbines in the North Sea. Evaluation across the ScotWind area shows that onsite replacement can reduce turbine downtime, especially for quick heavy maintenance operations like blade and gearbox replacements. However, for longer operations, such as generator and pitch and hydraulic system replacements, onsite solutions are more effective than towing only when O&M vessels can operate in wave heights over 1.5 metres. Otherwise, a mixed heavy maintenance strategy is recommended, combining onsite replacements for blades and gearboxes with towing for generators and pitch and hydraulic systems. The average turbine availability reduction with the mixed strategy is 0.39%, followed by the fully towing strategy at 0.43%, and the fully onsite replacement strategy at 0.46%.

Urban roof development serve as a form of urban tinkering that could provide favorable conditions to meet wicked food, water, and energy challenges. In this research, three urban roof systems are designed featuring food production, rainwater collection, building energy saving, and photovoltaic power generation, which are named the bare roof system, green roof system, and open-air farming roof system. Here we establish a generalizable framework to reveal the multifaceted tradeoffs of urban roof schemes integrating geographic information system, life cycle assessment, and multi-objective optimization and decision-making. Testing the framework in a typical compact city Shenzhen, China, results show that the rooftop suitability for food-water-energy function development within the city ranges from 26.21 % to 42.83 %. When implementing a city-wide roof system upscaling, the harvested rainwater on rooftops would contribute to 82.5 % of urban recycled water utilization target in 2035 and exhibit the fewest economic costs, but comes at the cost of life cycle carbon emissions and land occupation with 1850 kt and 140 km2. City-wide roof farming scenario shows potential to achieve the local self-sufficiency of vegetables, and stands out as the avoided transboundary energy footprints which are 4.5 times greater than life cycle energy consumption. Our research can foster the multiple tradeoff understanding between upscaling roof systems and urban food-water-energy nexus. The findings will assist in multi-objective decision-making for roof planning and sustainable transition in cities.