December 25, 2024
Column

Harness ocean waves

Without a doubt, the pounding waves of the world’s oceans have the capacity to support our tireless demand for electricity. Scientific researchers have estimated that if we converted less than 1 percent of the ocean’s renewable energy into electricity, the world’s demand for energy would be satisfied more than 50 times over. And just recently, the World Energy Council concluded that about two terawatts (1 billion kilowatts) of electricity could be harvested from the oceans quite easily. That is an amazing sum considering that the entire world currently requires only about one terawatt.

But do we have the technology to take advantage of this ocean energy reserve? Twenty years of research and development in Scotland lead scientists to say, “absolutely.” Before ringing in the new year, engineers at WAVEGEN, a wave power development corporation, and scientists from Queen’s University Belfast took a huge step in electricity production. On the Scottish Island of Islay, the group flipped the switch on its wave energy converter known as LIMPET (Land Installed Marine Powered Energy Transformer), sending 500 kilowatts of electricity to the island’s grid.

At first sight, the LIMPET system on Islay looks like nothing more than a small concrete retaining wall roughly 50 feet in width keeping the rocky shore from collapsing into the ocean. As in most cases, appearances are quite deceiving. The concrete face of the system (the part that appears as a retaining wall) is the most visible piece of a partially submerged concrete shell. Waves break below this face, sending water into the bottom section of the structure. As this water enters, it forces air trapped at the top of the shell through a small blow hole. Here, the air blasts across turbines, producing electricity.

Then, as the water in the bottom part of the structure recedes, the air heads back through the blow hole. And the turbines go spinning wildly once more. This closed circuit makes the LIMPET system highly efficient.

As mentioned earlier, the LIMPET system produces 500 kilowatts of electricity, which can meet the energy demands of over 400 homes. All that energy from a little bit of concrete stuck to the shore.

The most appealing aspect of the system, aside from its extremely small size, centers on its lifetime. Because the generator and all other mechanical parts remain above the water, the LIMPET, engineers believe, can function for over 60 years with few needed repairs.

But the LIMPET, like most pieces of innovative technology, has its downfalls. The Scottish scientists and engineers chose Islay as the home of the first ocean energy converter because riotous waves constantly pound the island’s rocky shores. It’s a place where the ocean has amazing amounts of energy to give. Thankfully (yet unfortunately when it comes to electricity production), not all coasts around the world take such beatings by Mother Nature. A lot of tropical areas are massaged rather than battered by waves. In these places, LIMPET systems wouldn’t have the needed resource to operate to their full potentials.

But many other coastlines around the world have the capacity to serve as ideal locations for WAVEGEN’s converters. The rocky shores of New England and many Canadian provinces, the areas around seaports in Iceland and Greenland, and even the volcanic cliffs surrounding the islands of Hawaii are invaluable sites for future development.

In a world threatened by global warming, we need sources of energy that do not require fossil fuels, that do not emit greenhouse gases. In a world already plagued by electricity shortages, we need to find new ways for producing energy. Scotland has revealed a new source and given us a new way. It’s our responsibility to take the next step and begin harnessing the renewable energy of our oceans.

Scott Dionne of Caribou is a senior at Dartmouth College where he studies English literature and environmental science.


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