ABP Marine Environmental Research Ltd (ABPmer) has published a further freely available tidal layer as part of its ongoing development of the Atlas of UK Marine Renewable Resources. The most recent addition illustrates tidal excursion ellipses around the UK continental shelf.
Tidal ellipses are a representation of two key properties of the tide, namely the magnitude of tidal flows and the nature of tidal rotation. The ellipses are based on tidal M2 harmonic originally developed in conjunction with Proudman Oceanographic Laboratory.
Conventionally, maximum potential power generation from tidal stream devices is achieved at locations which have a tidal ellipse that is linear in form, so that flows are delivered directly in line with the device for both the flood and ebb phases of the tide. Knowledge of the level of linearity of the tide, as well as the magnitude of the tidal excursion, is therefore key in making judgements about the suitability of a device and the commercial viability of sites.
Bill Cooper, Managing Director ABPmer said “ We maintain our commitment to share new information as it becomes available via The Renewables Channel where we host the Renewables Atlas. We are excited to give this latest visual to the industry; tidal excursion data can provide a significant advantage in resource planning, when compared to other non-dimensional measures of tidal excursion.
We have also recently released data representing the percentage of time for which a current speed of 1m/s is exceeded over the course of a typical year. We developed this layer as it had been shown that an indicator of flows greater than 2m/s on the peak of a mean spring tide offered little insight to how often the tide would provide strong flows. The 1m/s threshold was chosen as tidal energy converters often have a minimum cut-in speed for power generation around this value, but other threshold values can also be considered .”
ABPmer announced a new phase in the dissemination of marine renewable resource mapping tools for wind, wave and tidal developers with the switching on of the Renewables Channel in WEBvision, their online spatial information sharing platform in June this year.
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Source: abpmer, October 10, 2011