SNMREC's test turbine.FAU / SNMREC
But environmentally, very little is known about life from the seafloor to the surface. SNMREC hopes that by deploying these single-device prototypes, it will be more able to predict how an array of permanent industrial equipment in the water column would put the ecosystems at risk.
One company that has already signed an agreement with FAU is Minesto, a Swedish firm that has produced electricity from its prototype, called Deep Green. The unit resembles an underwater kite and a turbine that is tethered to the ocean floor. While the current lifts the kite, a rudder is supposed to guide it in a trajectory shaped like a figure 8. A quarter-scale model is currently undergoing sea trials in Strangford Lough, Northern Ireland.
“Theirs is a tidal system, and they haven’t done it with ocean currents yet. So they will have to revise the design to make it applicable to this type of system,” said Skemp.
A distinctly different design would use a combination of small turbines encased in a large honeycomb-shaped device made of Kevlar and carbon fiber. Bruce Heafitz, CEO of Ocean Current Energy, said the lightweight turbines would have much lower maintenance costs than their competitors. “We’ll suspend this honeycomb structure from the ocean floor and bring it up to the top, where the current is equivalent to 200-mile-an-hour wind force,” said Heafitz.
But even as the focus is on designing the most efficient turbines — which undoubtedly produce “clean” renewable energy — the emphasis on environmental protection is also key. “Environmental groups really do support what we’re doing in terms of renewable energy, because it’s green and clean. But they are concerned about any ancillary affects to corals, marine species, and we’re trying to alleviate those fears in terms of development,” said Camille Coley, associate director of SNMREC.
Several years ago, when wave energy farm proposals were contemplated in California, the research and tracking of gray whales as they migrated past the San Francisco shoreline helped provide key information.
In Florida’s waters, all 16 populations of marine turtles are on the endangered species list, yet their lives remain mostly a mystery.
Jeanette Wyneken, an FAU marine biologist, is heading up a long-term, systematic study of marine sea turtles to answer basic questions about how these protected animals use the Gulf Stream.
“We need to know what is normal. And it’s complicated, to say the least. These species take 25 years to mature, and we have to look at variations in population over 10 years. Water temperature is a major factor in determining the sex ratio of the population — not only that, but climate and seasonal effects too,” said Wyneken.
Many believe the best approach to avoid negative environmental impacts will be some sort of adaptive management system as described by a 2009 U.S. Department of Energy report. As projects expand from small to commercial-scale developments, repeated evaluations of monitoring results will be crucial.
Skemp, who spent nearly three decades in the aerospace industry before heading SNMREC, said the state of ocean current technology is comparable to where space research was decades ago.
“We’ve got to be able to answer that question: What will be the interactions between the developer’s hardware and the marine ecosystem?" asked Skemp. "We don’t have the answers yet.’’