2023-12-26 08:00:00
Cold water here, warm water there. Engineers associate this with the idea of using the temperature gradient to generate electricity. This actually works, for example with thermoelectric elements. Tropical seas offer the best conditions. Even at a depth of 200 meters, the water can be five degrees Celsius cold; on the surface it is 25 degrees or more, and the trend is rising due to climate change. However, power plants that have been built so far have been anything but efficient. A 120-kilowatt power plant on Nauru, operated by the Tokyo Electric Power Company, requires 90 kilowatts to operate the system, primarily for pumping up water.
The London company Global OTEC believes that it can get this disparity under control with the barge Dominique. It is scheduled to be anchored off the coast of the African island state of São Tomé and Príncipe in 2025. Its cargo consists of a special power plant, a pump for extracting cold seawater from the depths and electrical systems that bring the generated electricity to land. The 1.5 megawatt system is expected to cover 17 percent of the island’s needs.
Georg Küffner Published/Updated: Recommendations: 32
Instead of a thermoelectric element, the engineers in London opted for a marine thermal power plant. It works in practically the same way as a steam power plant, with the steam driving a turbine generator unit. Instead of water, which would not boil at 25 degrees, ammonia or other organic liquids with a low boiling point are used.
The cold water from the deep sea has the task of converting the relaxed steam back into liquid, which is used again, i.e. circulated. The only slightly warmed cooling water is led into the sea.
4000 times as much
On an average day, tropical oceans absorb 4,000 times as much heat energy as would be needed to power the entire world. Global OTEC believes that progress now allows the technology to be revived with the prospect of good efficiency. The production costs should be the equivalent of 140 to 280 euros per megawatt hour.
#Electricity #tropical #ocean #heat