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Possible Tidal Sites:
Central America has several relatively small bays and gulfs where tidal power conversion technology may be installed. The list would include:
- Gulf of Nicoya and Golfo Dulce on the coast of Costa Rica;
- Gulf of Fonseca on the coast of Honduras;
- Lake Maracaibo on the coast of Venezuela;
- Lago de Chiriqui and Bahia de San Miguel on the coast of Panama.
At first glance, the Central American tidal power sites appear to be too small to be worthwhile to for any future development. However, new and evolving technological developments that are occurring in fields that are related to engineering may offer the opportunity to develop a powerful tidal power conversion installation in Central America.
Building a Tidal Tunnel:
During the 19th century, a British engineer named Isambard Kingdom Brunel pioneered a method to construct a tunnel under the Thames River that flows through London. Over the decades since, tunnel boring has evolved from being dependent on manual physical labor to becoming more highly mechanized and progressively more automated. The advances in modern tunnel building technology can also be used to develop tidal power conversion on the Gulf of Panama that is renowned for extended high tides that occasionally exceed 20-feet and last for up to 20-hours. On the eastern side of this gulf is the tiny Bahia de San Miguel where a north-south geological fault line is suspected to passing beneath its entrance.
Bahia de Caledonia is located on Panama's East Coast and the tidal record shows this bay to in a virtual perpetual state of low tide with tidal peaks reaching a height of 9-inches. The extended high tide in Bahia de San Miguel rises to an average 8.7-feet height and reaches a daily maximum of over 14-feet. It occasionally reaches a peak height of 20-feet. An overland distance of 33-miles separates the innermost points of Bahia de Caledonia and Bahia de San Miguel. Channels may be excavated inland for up to 4-miles from each bay and toward the other so as to reduce the innermost overland distance between them to 25-miles.
At a future time, a tunnel of 50-feet in width and 75-feet in height (arched roof) could be built under the land between the proposed inlet channels of Bahia Caledonia and Bahia de San Miguel. The arched tunnel roof would be below (low-tide) sea level. The average height difference between the tides in the 2-bays is 8-feet. According the Bernoulli relationship (velocity = square root of (2 x gravity x height)), this difference in height would yield a water flow velocity in the tunnel of 22.698-feet/second in the tunnel with a cross section of 3480-square feet.
The power potential calculated from the flow speed, water density and tunnel area (0.5 x density x area x velocity*3) would yield a maximum potential of 1740-megawatts. If the power conversion could be achieved at an efficiency of 81%, the tidal power output would be 1400-Mw. Surface friction losses were neglected due to a low friction factor. The hydraulic radius for the tunnel is 228.5-ft and its wall roughness factor of 0.01 yields a low friction factor in the tunnel of f = 0.01/228.5 = 0.0000437.
Economic viability over the long term will determine if and when a tunnel-based tidal power generation station is built in Panama. Tunnel building technology is likely to evolve and improve to make tunnel building more cost competitive in the future. The tunnel approach offers an alternative to tidal power generation at a few locations around the world where the tidal bays may be small, where entrances to bays may be very deep or very wide. The entrance to the Gulf of Panama has a depth of over 600-ft and is some 120-miles in width. Bahia de San Miguel is a shallow and tiny bay that has an extended high tide and a very brief low tide.
A tunnel built between Bahia de Caledonia and Bahia de San Miguel could bypass that region's geological fault line. The environmental impact of the tunnel would be little different to that of the Suez Canal when it was first opened. The canal enabled some species of oceanic life to swim between the Red Sea and Mediterranean Sea and over the years that followed, the marine ecology remained unchanged. A tidal tunnel built across Panama that connects the Caribbean Sea to the Pacific Ocean would be unlikely to affect marine ecology in the Caribbean Sea.
Energy Storage and the Panama Canal:
The future development of tidal power in Panama would require technology could store large amounts of energy. One option to store energy in Panama would be to use the Panama Canal. There is scope to pump water in the canal to higher elevations if the energy to do so became available. A tidal power station in Panama would provide the power needed to pump water to higher elevations. During low tide in Bahia de San Miguel, water that would be in storage at higher elevations in the canal system may be allowed to pass through hydroelectric installations and generate electric power for the Panamanian market.
The tidal power station in Panama may be built with several tunnels enough water may be available in Bahia de San Miguel during high tide to support the operation of up to 5-tunnels generating up to 7000-Mw of electric power. Some of the power may be exported into neighboring countries like Costa Rica, Colombia, Nicaragua, San Salvador, Honduras and Guatamala. These countries have high elevations where water storage tanks may be built and into which water to be pumped from lower elevations when the tide is high at Bahia de San Miguel. A tidal power station built in Panama would be able to support much future economic development in Central America.
Conclusion:
The technology that can generate electric power from the differences in tidal heights that occur across an isthmus is presently being developed on a small scale at small islands. This technology has potential for future development and will be able to contribute to serving the future energy needs of many nations. An ocean tidal power conversion system using a tunnel in Panama could become a cost-effective method of generating electricity from renewable sources in the future.
