Futurists have been pointing for decades to the colossal amount of sunlight absorbed by the Earth’s oceans. Indeed, the U.S. Department of Energy (DOE) estimates the planet’s tropical seas soak up the heat energy equivalent of 250 billion barrels of petroleum every day.
Ocean thermal energy converters (OTECs) were devised to access that heat reservoir, and they are truly cleverly designed mechanisms. They’re steam engines, basically, that spin electric turbines to generate power. There are a few important differences, however, that set these dynamos apart from the workhorses that created and sustained the Industrial Revolution in the19th century.
The steam pushing the pistons inside an OTEC is only around 70 degrees Fahrenheit — no hotter than the ambient temperature of the torrid waters in which OTECs operate.
Water can be flashed into steam at any temperature though; it’s the pressure at which this transition occurs that has as much to do with the process as temperature. So the internal chambers of an OTEC function in a partial vacuum, with the lower pressures allowing for far cooler steam.
The second difference is even more unique. An OTEC need not be fed fuel; it is immersed in its own fuel, warm seawaters. The final ingenuity is that the coolant required for each cycle of the engine is also provided free of charge by Nature — the frigid waters deep below are pumped up while the surface layer heat is converted to electricity.
These ingenious apparatuses can be installed in any deep tropical sea along the planet’s equator, so by now it might be supposed there should be hundreds or thousands of them in operation. That’s hardly the case though; there are only two fully operational OTEC power plants in the entire world — along with three other testing, research and demonstration facilities either planned or operational.
Unfortunately, the failure of OTECs to live up to expectations might be yet another historical example showing that the future doesn’t always unfold simply by the public checking a preference box on a communal multiple choice query. Oftentimes those options are selected in the end by much more subtle, but still quite powerful forces.
The Edsel might well have been a great automotive success rather than a dismal failure and Betamax may have been the video format of choice rather than VHS but for the all-important "invisible hand" of the consumer market, which determines in large part the progress of technology.
Likewise, investors have weighed the potential for producing and selling electricity via OTECs, and the balance sheet turned their time, effort and capital away from it. Tried and tested methods of conventional power plants — even factoring in the drawback of having to pay for fuel — far out-pace the meager profits garnered with OTECs.
So while it’s technically feasible to harvest solar thermal energy in tropical seas, the inadequate monetary results and feeble power output simply haven’t been deemed worth the trouble.
And that’s far less the judgment of any panel of authorities; it’s the opinion of the single voice that matters the most — the free market.
OTECs prove something else as well: that grandiose expectations based on accessing even an infinitely small portion of an immeasurable whole don’t always translate to astounding wealth, fantastic benefits, or inexhaustible energy.
Focusing on astronomical numbers in theory rather than what actually can be achieved in practical reality can lead to crushing errors. Certainly, the world’s oceans are one of the greatest collectors of solar energy in the solar system.
Yet, along with this enormous bounty of potential energy, the National Oceanic and Atmospheric Association (NOAA) have calculated that our seas also contain 20 million pounds of gold. That ostensible bounty might seem great news for treasure hunters, except for the requisite investment of trillions of dollars to harvest the precious metal.
Sometimes purported bonanzas aren’t all they are advertised.
Collective common sense and the workings of unimpeded economic systems are usually far better guides than armies of lobbyists, activists, and experts whose counsel engenders disasters as often as successes. No international committee of specialists was convened to advise humanity to discard its age-old reliance on manpower and horsepower and adopt steam power, and later to move from steam to the internal combustion engine.
It’s what works best, pure and simple, that steers peoples, nations and economies, and not what is in vogue in the salons of the intelligentsia.
Every great step forward, every age — copper, bronze, iron, steam, oil — required little in the way of boosters to change the world, seeming instead to have a force of its own.
Whatever energy innovation comes next will give its name to the successive epoch, and government, media, influence peddlers and all the rest may have far less to do with it than we might suspect.
David Nabhan is a science writer, the author of "Earthquake Prediction: Dawn of the New Seismology" (2017) and three previous books on earthquakes. Nabhan is also a science fiction writer ("Pilots of Borealis," 2015) and the author of many scores of newspaper and magazine op-eds. Nabhan has been featured on television and talk radio all over the world. His website is www.earthquakepredictors.com. To read more of his reports — Click Here Now.