For four decades, the 800-pound gorilla for electrical and automobile energy that no one is paying attention to is Ocean Thermal Energy Conversion (OTEC). A system whose proof of concept was first established by the U.S. government in a research project in Hawaii in 1979, the execution of that idea has simply languished because thinking big doesn’t come easy.
Any time a nonlinear jump in technology comes along that demands massive investments, the best explanation is that everybody’s knees shake and hands tremble, even if it would give us electrical energy for 10-12 cents for the kilowatt hour and remove the need for automobile fuels.
OTEC sounds truly unbelievable: it’s a system that generates electricity 24/7, needs no fuel of its own, produces no toxic emissions, is inexhaustible, and doesn’t take up any land at all. For all practical purposes, it’s the ideal dream we’ve always dreamt. But in America, dreams are fading fast. Large corporations, vested interests and big government appear to have stolen your dreams and your right to advance as a society. As a result, our competitive edge in technology is being stolen by other nations because what goes around comes around.
First, the OTEC plant is installed offshore — perhaps about 5 miles out — so no land is required. Next, the engineers use the properties of ammonia to perpetuate a closed-cycle engine. Since ammonia vaporizes at surface sea temperature because of its low boiling point, liquid ammonia is passed through pipes that come in contact with surface water intakes. The ammonia evaporates, passes through the blades of a turbine to produce electricity, and is then returned to come in contact with a cold-water intake brought up from depths of around half-mile, thus liquefying the ammonia, which is vaporized once again in a perpetual closed cycle.
Because of the ocean temperatures involved, the tropical regions have roughly the best locations for positioning OTEC. Thus, Hawaii has very favorable conditions for this.
The wonder of OTEC is that it doesn’t need to be on a fixed platform. It can be on a floating ship or even a submarine if people don’t want the plant to be visible.
Our initial studies show that OTEC may cost about a billion dollars for the first 200 megawatts (MW); and successively cost $100 million for the last 100 MW out of 1,600 MW needed for Hawaii.
Among the greatest byproducts of OTEC is hydrogen that could be used in hydrogen cars. We all realize that automobile fuels are a challenge, not to mention we’re giving ourselves terrible diseases by burning gasoline. Consequently, you kill two birds with OTEC. And the growing success of hydrogen cars is that they perform well in tropical climates and have a higher efficiency than gasoline engines — so once again Hawaii’s natural location comes to its rescue.
With OTEC, you wouldn’t have to pay for automobile fuel with anything more than a token amount, and you could bring down electricity costs by three to four times in Hawaii. What a great windfall.
In these turbulent times of oil unreliability, economic volatility, political uncertainty and bioterrorism, there is a pressing need for Hawaii to have its own sources of electricity and automobile fuel. The government must understand it has an essential duty to the public that comes foremost.
Amarjit Singh is a professor of civil and environmental engineering at University of Hawaii-Manoa.