Numerical assessment of tidal potential energy in the Brazilian Equatorial Shelf

The Brazilian Equatorial Shelf (BES) is one among the macrotidal regions worldwide. This study used a highresolution numerical configuration of the ocean model ROMS (Regional Ocean Modeling System) forced with realistic surface and lateral forcing, as well as with tides and river discharges. Tidal heights of more than 2 m were found in three regions in BES due to the large tidal amplification across the estuarine channels inside each region: Amazon, Para, and Maranhao, and for a considerable time fraction. Heights between 4 and 5 m occurred with a frequency greater than 20%-30% in some regions. All hypothetical barrages proposed in this study were capable of an annual power production, in two-way mode, higher than La Rance (533 GWh year-1, two-way operation, France) and Sihwa (553 GWh year-1, flood-only operation, South Korea), except one with the same production as Sihwa barrage. The installation effort was evaluated using the Gibrat ratio, the ratio between the length of the barrage and its annual energy production. Among the proposed barrages, the most efficient ones have an annual power generation greater than 1500 GWh year-1 and a Gibrat ratios between 1.17 and 3.26, much lower than the Gibrat ratio of Sihwa tidal barrage.

Automated summary

This study analyzed the Brazilian Equatorial Shelf using a high-resolution ocean model and found significant tidal variations in the area. Several hypothetical barrages were proposed with higher annual power generation than existing barrages. The study also evaluated the installation effort of these barrages.