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Average Tidal Hours & Flow per Year Assumptions
Tidal Turbines require, generally, a flow speed of 2.5 m/s (4.9 knots/hr or 5.6 miles/hr or 9.0 km/hr) or more.
Globally such locations are limited.
The peak power Tidal Flow used in the calculator example is 6,000 hours / year, or 250 24 hr days or 68% of the year.
This value is determined from 2 analysis:
1. The hourly data was determined by graphing data available at:
which resulted in peak power tidal flow hours of 5,050 hrs/yr
2. Another graphing analysis of power density data for Cumberland Sound Ga USA
which resulted in peak power tidal flow hours of 6,270 hrs/yr -- see diagram below.
Some groups report required flow speeds as low as 1.5 m/s, in this case the hours per year would not change as this is an average constant of the periods when the tidal flow is occuring at the force required by the specific turbine,
also, at 1.5 m/s the power density would be reduced from the 2.5 m/s flow rate
-- see note on Tidal Power Density in section 3 of cost comparison calculator.