Conception, modelling and dimensioning of an energy storage system for wind energy with hydro accumulators
Kleiber, Nils (2020)
2020
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202004044472
https://urn.fi/URN:NBN:fi:amk-202004044472
Tiivistelmä
Humankind currently faces an unstoppably increasing energy demand and scarcity of resources. The associated problems of climate change and global warming have intensified the role of renewable energies, especially of wind energy, in today’s energy supply. However, a critical disadvantage of renewables is their intermittent availability, which complicates the reliability of supply. As a result, energy storage technologies have become more and more important in recent times to overcome periods, when renewables do not provide power to the electrical grid.
Among the various storage methods, a research team at the University of Applied Sciences of Saarland focuses on a particularly sustainable and environmentally friendly storage solution: The decentralised storage of excess wind energy with pressurised air. Here, purely pneumatic (i.e. compressed air energy storage, CAES) and hydraulic-pneumatic storage systems are considered simultaneously. Both systems are designed, dimensioned and modelled in separate scientific studies for the research project by ensuring comparability. This work deals with the hydraulic-pneumatic approach whereby hydro accumulators are utilised to store the surplus energy.
Within the research scope, important theoretical and physical basics are illustrated for the storage concept. A first approach is provided for the dimensioning of the hydro accumulator system, which can serve as a starting point for the design of a prototype. For the dimensioned storage system, several basic models are created and simulated for evaluation and comparison purposes with the software tool AMESim. The simulation results are consistent with the outcome of the dimensioning and allow first statements about the system’s efficiency and performance. The comparison with the purely pneumatic system shows that achievable energy densities of hydraulic accumulators are much lower. However, CAES systems have to challenge comparably high thermal losses during the storage process. Hydraulic accumulators are therefore most likely to achieve better efficiencies, which CAES systems could only achieve by laboriously reusing the waste heat. At the current research stage, more precise statements cannot be made, since idealised conditions have been assumed for initial simulations. For this reason, the scientific paper is structured in a way that the research team can use the provided models and collected data as a foundation for further investigations and optimisations.
Among the various storage methods, a research team at the University of Applied Sciences of Saarland focuses on a particularly sustainable and environmentally friendly storage solution: The decentralised storage of excess wind energy with pressurised air. Here, purely pneumatic (i.e. compressed air energy storage, CAES) and hydraulic-pneumatic storage systems are considered simultaneously. Both systems are designed, dimensioned and modelled in separate scientific studies for the research project by ensuring comparability. This work deals with the hydraulic-pneumatic approach whereby hydro accumulators are utilised to store the surplus energy.
Within the research scope, important theoretical and physical basics are illustrated for the storage concept. A first approach is provided for the dimensioning of the hydro accumulator system, which can serve as a starting point for the design of a prototype. For the dimensioned storage system, several basic models are created and simulated for evaluation and comparison purposes with the software tool AMESim. The simulation results are consistent with the outcome of the dimensioning and allow first statements about the system’s efficiency and performance. The comparison with the purely pneumatic system shows that achievable energy densities of hydraulic accumulators are much lower. However, CAES systems have to challenge comparably high thermal losses during the storage process. Hydraulic accumulators are therefore most likely to achieve better efficiencies, which CAES systems could only achieve by laboriously reusing the waste heat. At the current research stage, more precise statements cannot be made, since idealised conditions have been assumed for initial simulations. For this reason, the scientific paper is structured in a way that the research team can use the provided models and collected data as a foundation for further investigations and optimisations.