4 research outputs found

    Sizing and control of a Hybrid hydro-battery-flywheel storage system for frequency regulation services

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    Energy security and environmental challenges are some of the drivers for increasing the electricity generation from non-programmable Renewable Energy Source (RES), adding pressure to the grid, especially if located in weakly connected (or isolated) islands, like Sardinia. Variable-speed Pumped Storage Hydro Power (PSHP) can offer a high degree of flex ibility in providing ancillary services (namely primary and secondary regulations), but due to the hydromechanical nature of the equipment, sudden variations in the power output cause wear and tear. Other energy storage devices can not compete with PSHP in terms of energy and power availability. This work aims to assess the potential benefits derived from the hybridization of a PSHP with Battery Energy Storage System (BESS) and Flywheel Energy Storage System (FESS) in providing frequency regulation services to the grid of the Sardinia Island (Italy). The focus of the study tries to cross both the plant owner point of view, whose aim is to have a smooth PSHP operation and the economic incentive to hybridize the plant, and the Transmission System Operator’s, whose aim is to have a fast reacting plant that better stabilizes the grid frequency. This is done by simulations of a detailed dynamic model of the PSHP, whose hydraulic machine has been characterized from real experimental data, the BESS and the FESS. Moreover, two power management strategies are presented, based on different criteria, to effectively coordinate the devices making up the Hybrid Energy Storage System (HESS). First the simulations are performed open-loop, to assess the impact of various combinations of installed BESS and FESS powers over the wear and tear of the equipment. Later the model is used in an optimization procedure to find the combination of installed BESS and FESS powers and the respective controlparameters that would guarantee the maximum economic return at the end of the investment life. Last, the model is included into a Sardinian power system model and simulated in a future scenario with high RES penetration, assessing the plant capabilities to effectively contain and restore the frequency. Results show that there is not a catch-all solution in terms of hybridization and that a trade-off must be made between the plant owner’s urge to smoothly operate the plant in order to reduce the equipment degradation, and the TSO’s objective to have fast responsive plants providing high quality frequency regulation services. If on one hand open-loop simulations show that the hybridization reduce the main wear and tear indicators, on the other the optimal hybrid system limits the plant ability to contain the frequency excursions in closed-loop simulations, as the optimization problem was formulated over the plant owner’s interests. The results show that there much potential for frequency stabilization and wear and tear reduction, but more techno-economic data is required to fully investigate the benefits of this configuration.Energy security and environmental challenges are some of the drivers for increasing the electricity generation from non-programmable Renewable Energy Source (RES), adding pressure to the grid, especially if located in weakly connected (or isolated) islands, like Sardinia. Variable-speed Pumped Storage Hydro Power (PSHP) can offer a high degree of flex ibility in providing ancillary services (namely primary and secondary regulations), but due to the hydromechanical nature of the equipment, sudden variations in the power output cause wear and tear. Other energy storage devices can not compete with PSHP in terms of energy and power availability. This work aims to assess the potential benefits derived from the hybridization of a PSHP with Battery Energy Storage System (BESS) and Flywheel Energy Storage System (FESS) in providing frequency regulation services to the grid of the Sardinia Island (Italy). The focus of the study tries to cross both the plant owner point of view, whose aim is to have a smooth PSHP operation and the economic incentive to hybridize the plant, and the Transmission System Operator’s, whose aim is to have a fast reacting plant that better stabilizes the grid frequency. This is done by simulations of a detailed dynamic model of the PSHP, whose hydraulic machine has been characterized from real experimental data, the BESS and the FESS. Moreover, two power management strategies are presented, based on different criteria, to effectively coordinate the devices making up the Hybrid Energy Storage System (HESS). First the simulations are performed open-loop, to assess the impact of various combinations of installed BESS and FESS powers over the wear and tear of the equipment. Later the model is used in an optimization procedure to find the combination of installed BESS and FESS powers and the respective controlparameters that would guarantee the maximum economic return at the end of the investment life. Last, the model is included into a Sardinian power system model and simulated in a future scenario with high RES penetration, assessing the plant capabilities to effectively contain and restore the frequency. Results show that there is not a catch-all solution in terms of hybridization and that a trade-off must be made between the plant owner’s urge to smoothly operate the plant in order to reduce the equipment degradation, and the TSO’s objective to have fast responsive plants providing high quality frequency regulation services. If on one hand open-loop simulations show that the hybridization reduce the main wear and tear indicators, on the other the optimal hybrid system limits the plant ability to contain the frequency excursions in closed-loop simulations, as the optimization problem was formulated over the plant owner’s interests. The results show that there much potential for frequency stabilization and wear and tear reduction, but more techno-economic data is required to fully investigate the benefits of this configuration

    A framework for whole lifecycle cost of long-term digital preservation

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    Digital preservation, also known as digital curation, is the active management of digital information, over time, to ensure its accessibility and usability. Digital preservation is nowadays an active area of research, for many reasons: the rapid evolution of technology, which also results in the rapid obsolescence of old technologies; degradation of physical records; constantly increasing volumes of digital information and, importantly, the fact that it has started to become a legal obligation in many countries. This research project aims to develop an innovative framework estimate costs of long term digital preservation. The framework can lead to generating a cost model that quantifies costs within different business sectors, while capturing the impact of obsolescence and uncertainties on predicted cost. Case studies from financial, healthcare and clinical trials sectors are used to prove the framework concept. Those sectors were chosen because between them they share all file types that are required to be preserved and all are either obliged by European or local laws, e.g. EU Data Retention Directive (2006/24/EC) and/or UK Data Retention Regulations 2014 No. 2042, or interested in preserving their digital assets. The framework comprises of three phases: assessing digital preservation activities, cost analysis and expansion and cost estimation. The framework has integrated two processes that will enable the user to reach a more accurate cost estimate; a process for identifying uncertainties with digital preservation activities and a cost modelling process. In the framework cloud computing was used as an example for storage and compute technologies. Combining different research methodology techniques was used in this research project. Starting with conducting a thorough literature review covering digital preservation and cost modelling. Following the literature review; is a combination qualitative and quantitative approaches, using semi-structured interview technique to collect data from industry experts. Industry experts were chosen from companies, firms and government bodies working with or researching digital preservation. Finalising with validating results by real-life case studies from businesses in selected sectors and experts’ verdict. Comparing the output of the framework to real-life case studies, demonstrated how companies/firms, who target to preserve their digital assets, can utilise it to predict accurately future costs for undertaking such investment. By applying industrially-based cost modelling approaches the framework generates a cost model that predicts single-point and three-points cost estimates, an obsolescence taxonomy, uncertainties identification process and quantifying uncertainties and obsolescence impact on cost prediction. Providing decision makers with all the framework outputs, will provide them with quantifiable information about their future investment, while remaining clear to understand and easy to amend. This makes the framework provide long-term total cost prediction solution for digital preservation to firms; helping, guiding and adding insight into digital preservation added value
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