Journal article 1059 views 126 downloads
Power variability of tidal-stream energy and implications for electricity supply
,
Ian Masters ,
Matthew Allmark,
Tim Stallard,
Simon Neill,
Alice Goward-Brown,
Peter Robins
Energy, Volume: 138, Pages: 1061 - 1074
Swansea University Authors:
Grazia Todeschini, Michael Togneri , Ian Masters
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DOI (Published version): 10.1016/j.energy.2019.06.181
Abstract
Temporal variability in renewable energy presents a major challenge for electrical grid systems. Tides are considered predictable due to their regular periodicity; however, the persistence and quality of tidal-stream generated electricity is unknown. This paper is the first study that attempts to ad...
| Published in: | Energy |
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| ISSN: | 0360-5442 |
| Published: |
2019
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa51005 |
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| Abstract: |
Temporal variability in renewable energy presents a major challenge for electrical grid systems. Tides are considered predictable due to their regular periodicity; however, the persistence and quality of tidal-stream generated electricity is unknown. This paper is the first study that attempts to address this knowledge gap through direct measurements of rotor-shaft power and shore-side voltage from a 1 MW, rated at grid-connection, tidal turbine (Orkney Islands, UK). Tidal asymmetry in turbulence parameters, flow speed and power variability were observed. Variability in the power at 0.5 Hz, associated with the 10-min running mean, was low (standard deviation 10–12% of rated power), with lower variability associated with higher flow speed and reduced turbulence intensity. Variability of shore-side measured voltage was well within acceptable levels (∼0.3% at 0.5 Hz). Variability in turbine power had <1% difference in energy yield calculation, even with a skewed power variability distribution. Finally, using a “t-location” distribution of observed fine-scale power variability, in combination with an idealised power curve, a synthetic power variability model reliably downscaled 30 min tidal velocity simulations to power at 0.5 Hz (R2 = 85% and ∼14% error). Therefore, the predictability and quality of tidal-stream energy may be undervalued in a future, high-penetration renewable energy, electricity grid. |
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| Keywords: |
Tidal energy, Prediction, Turbulence, Power quality, Orkney, Resource characterisation |
| Start Page: |
1061 |
| End Page: |
1074 |