Techno-economic feasibility of retired electric-vehicle batteries repurpose/reuse in second-life applications: A systematic review

In line with the global target in decarbonising the transportation sector and the noticeable increase of new electric vehicles (EV) owners, concerns are raised regarding the expected quantity of Retired EV Batteries (REVB) exposed to the environment when they reach 70–80% of their original capacity. However, there is significant potential for REVB, after deinstallation, to deliver energy for alternative applications such as storing surplus. This systematic review evaluates state-of-art modelling/experimental studies focused on repurposing REVB in second-life applications. Technical and economic viability of REVB repurposing has been confirmed to solve the unreliability of cleaner energy technologies and mitigate the high investment of new storage systems. 40% of included studies considered hybrid systems with PV being a dominant technology where REVB was evaluated to be small-scaled and large storage systems. Additionally, successful attempts were conducted to evaluate REVB performance in providing grid services. It has however, been discovered intensive grid services applications like frequency regulation, was technically challenging due to demanding working requirements. Reviewed studies considered different prices for REVB due to lack of market regulation on REVB resale; similarly, technical parameters, including initial State of Health (SoH) and State of Charge (SoC) constraints were inconsistent due to lack of standardisation

From Wind to Hybrid: A Contribution to the Optimal Design of Utility-Scale Hybrid Power Plants

ABSTRACT: When a substantial number of wind parks are approaching the end of their lifespan, and developers of renewables are facing decisions about what to do with their assets, concepts such as hybrid power plants are emerging as a promising solution to enable renewable integration in a cost-effective and robust manner. This work proposes a decision-aid algorithm to perform a comprehensive analysis of hybrid power plants, focusing on the energetic contribution and economic feasibility of converting existing wind power plants into hybrid power plants (i.e., installing photovoltaic panels and a storage system). The analysis was performed by comparing the option of converting existing wind plants into hybrid plants with a pure repowering exercise or overplanting using wind technology only. The obtained results unequivocally demonstrate the added value of hybrid power plants as they promote: (i) a higher installed capacity and yearly capacity factor (up to 50%); (ii) an increased efficiency of existing electric infrastructures; and (iii) a positive contribution to a sustainable energy system with the ability to generate economic value.info:eu-repo/semantics/publishedVersio

Seasonal hydrogen storage decisions under constrained electricity distribution capacity

We consider a profit-maximizing renewable energy producer operating in a rural area with limited electricity distribution capacity to the grid. While maximizing profits, the energy producer is responsible for the electricity supply of a local community that aims to be self-sufficient. Energy storage is required to deal with the energy productions' uncertain and intermittent character. A promising, new solution is to use strategic hydrogen reserves. This provides a long-term storage option to deal with seasonal mismatches in energy production and the local community's demand. Using a Markov decision process, we provide a model that determines optimal daily decisions on how much energy to store as hydrogen and buy or sell from the power grid. We explicitly consider the seasonality and uncertainty of production, demand, and electricity prices. We show that ignoring seasonal demand and production patterns is suboptimal and that introducing hydrogen storage transforms loss-making operations into profitable ones. Extensive numerical experiments show that the distribution capacity should not be too small to prevent local grid congestion. A higher storage capacity increases the number of buying actions from the grid, thereby causing more congestion, which is problematic for the grid operator. We conclude that a profit-maximizing hydrogen storage operation alone is not an alternative to grid expansion to solve congestion, which is essential knowledge for policy-makers and grid operators

Seasonal hydrogen storage decisions under constrained electricity distribution capacity

The transition to renewable energy systems causes increased decentralization of the energy supply. Solar parks are built to increase renewable energy penetration and to supply local communities that become increasingly self-sufficient. These parks are generally installed in rural areas where electricity grid distribution capacity is limited. This causes the produced energy to create grid congestion. Temporary storage can be a solution. In addition to batteries, which are most suitable for intraday storage, hydrogen provides a long-term storage option and can be used to overcome seasonal mismatches in supply and demand. In this paper, we examine the operational decisions related to storing energy using hydrogen, and buying from or selling to the grid considering grid capacity limitations. We model the problem as a Markov decision process taking into account seasonal production and demand patterns, uncertain solar energy generation, and local electricity prices. We show that ignoring seasonal demand and production patterns is suboptimal. In addition, we show that the introduction of a hydrogen storage facility for a solar farm in rural areas may lead to positive profits, whereas this is loss-making without storage facilities. In a sensitivity analysis, we show that only if distribution capacity is too small, hydrogen storage does not lead to profits and reduced congestion at the cable connection. When the distribution capacity is constrained, a higher storage capacity leads to more buying-related actions from the electricity grid to prevent future shortages and to exploit price differences. This leads to more congestion at the connected cable and is an important insight for policy-makers and net-operators

Business Models for SEEV4-City Operational Pilots: From a generic SEEV4-City business model towards improved specific OP business models

This report, led by Northumbria University, provides a final analysis by project partners regarding Business Models for SEEV4-City Operational pilots. It is part of a collection of reports published by the project covering a variation of specific and cross-cutting analysis and evaluation perspectives and spans 6 operational pilots

Underwater Energy Storage - Emphasis on Buoyancy Technique

The present document is a manuscript-based dissertation covering Kyle Bassett’s PhD research from January, 2015 to January 2017. The research was particularly focused on studying and developing an emerging energy storage technique known as Buoyancy Battery Energy Storage (BBES). The buoyancy energy storage technique is presented and primary components are described and discussed. An idealized system was analyzed to determine governing equations of operation as well as ideal energy storage density. Experimental analysis was conducted to confirm properties of constant discharge force with respect to both float position and storage duration. Discharge testing was conducted with a developed scale system installed in the offshore testing tank and the University of Windsor. To evaluate the scalability of the technique, a utility scale BBES system was designed with power output capacity of 1 MW and energy storage capacity of 1MWh. Several commercially available marine lift bags were considered and evaluated for volume requirements and drag effects at various float speeds. Theoretical roundtrip efficiency for this designed system was found to be 83% based on results from drag calculations, pulley losses and electrical efficiency losses. Numerical simulations of system performance were completed to determine the revenue generation of the designed system based on 2015 Ontario market energy prices. To validate system operation in a marine environment, open water testing was conducted in Lake Huron. Testing validated surface deploy ability and steady state float motion was achieved. To further investigate the market opportunities and challenges facing the grid scale integration of energy storage, an analysis of market conditions was performed using Ontario, Canada as a case study. Ten years of Hourly Ontario Energy Price was analyzed using Fourier transform to reveal periodic trends within the data. It was found that the introduction of Time-of-use billing for electricity was effective in changing energy consumption behavior, improving balance for the electricity grid. Revenue generation simulations were completed for utility scale energy storage systems of various technologies (and thus various roundtrip efficiencies) using historic 2015 energy price data. Simulations included single and multi-cycle storage programs. It was determined that energy storage facilities are not currently financially viable, due to the minimal revenue produced through energy arbitrage transactions. The development of energy storage in Ontario will depend greatly on governmental subsidies and additional revenue-generating ancillary services such as regulation and black start capability. Additional experimental analysis was performed using a modified BBES system designed to convert input energy into mechanical work such that each quantity could be controlled and measured. Three float shapes of interest were tested including a horizontally configured cylinder, a vertically configured cylinder as well as a sphere. Discharge efficiencies greater than 90% were achieved. Roundtrip efficiencies of 78% were recorded. Results suggest that with improved conversion pulleys and component scaling, experimental roundtrip efficiencies should approach the theoretical efficiency used in the 1 MW BBES system designed