The Someday Energy Barons

The Alaska Natural Energy Institute's newsletter crossed my desk the other day, and set me thinking. ANEI apparently believes that civilized life will be possible after oil is gone, and that intelligent life exists right now---that is, people are smart enough to develop alternative energy technologies while they still have oil to burn.

I hope both are true, but my musings ran instead toward post-petroleum geopolitics: What corners of the world will replace the Middle East as global powers controlling the new energy resources?

Answering that question requires predicting what the new resources are likely to be. If coal or natural gas replaces oil as fuel and chemical feedstock of choice, the United States (especially Alaska) will be well off. We have abundant supplies of both coal and natural gas. But if worldwide concerns---and regulations---clamp down on greenhouse gas emissions and air pollutants, those faithful old combustibles won't look so good. Then, replacing names like Qatar or Bahrain in discussions of global energy leaders, talk may turn to Raratonga or Pukapuka. In the United States, Texas and Alaska may take a back seat to Hawaii.

Thanks to their location, these Pacific islands are bathed in warm waters, with sea- surface temperatures near 24°C (75°F). But they are also surprisingly close to cold water. Chilly salt water, consistently near temperatures of 4°C (39°F), flows nearby at the bottom of the deep ocean.

With essentially unlimited supplies of seawater at two different temperatures, many fortunate islands are perfectly situated to take advantage of ocean thermal energy conversion. Taylor A. Pryor, a government planner from Cook Islands, explained this OTEC technology informally in the March/April issue of Pacific Magazine. Big pipes are sunk so their deep ends lie in the cold water, another pipe taps surface waters "so both warm and cold seawater can be pumped ashore. On shore is a structure housing two heat exchangers---one a condenser, the other an evaporator---plus a turbo-generator. Inside the exchangers is ammonia, a volatile substance that will vaporize at 24 degrees and liquefy at 4 degrees. When it vaporizes, there is a modest pressure increase, which is what can be induced to drive the turbine. Once that work is done, the ammonia is chilled, returned to its liquid form and the cycle begins again."

Pryor wasn't selling a science-fiction scheme. An experimental OTEC plant is working right now on the island of Hawaii. It's discussed in some detail in the March/April issue of another magazine, Sea Frontiers. That article indicates the experiment isn't a perfect success; the cost of electricity generated in the process depends on the life cycle of the equipment, and no one yet knows how long the plant components will last. But even optimistic estimates come out with kilowatt-hour costs higher than those for standard oil-burning generators consuming $20 a barrel oil.

However, the Hawaiian OTEC plant generates more than plain electricity, and its byproducts are valuable. Most of them are luxury foods in high demand--even salmon thrive in the cold, clean, but nutrient-rich water from the deep sea. Ocean Farms of Hawaii, a neighboring commercial venture using OTEC's cold sea water, estimates eventual salmon production of 4 million pounds a year.

Such pricey products improve OTEC economics, but don't turn OTEC sites into international energy exporters. However, as Taylor Pryor noted, OTEC-generated electricity can be used to split seawater into hydrogen and oxygen. Hydrogen is top candidate for ultimate fuel, what we'll use when everything else is gone, and the subject of extensive efforts to make it useful sooner. (The Alaska Natural Energy Institute, for example, is presently organizing the world's first hydrogen-powered vehicles competition.) Someday, supertankers loaded with transportable forms of hydrogen may sail from the South Pacific, the new energy capital of the world.

See Alaska Science Forum #1327 Harnessing the Energy of Arctic Air and Water  for a closely related article on this theme.