The Electric Power Research Institute estimates tat wave and tidal energy could supply 7 percent of the electricity for the United States – and in the United Kingdom, that contribution could be double. Engineers are designing all sorts of devices to tap this clean, renewable energy: “snakes” that jiggle over the water’s surface, buoys that bob with the swell, and turbines that spin in the current. (Items illustrated here show the diversity of wave power devices but wouldn’t be implemented together.)
Since populations are often concentrated near coasts, energy from moving water can be produced close to where it’s needed. And unlike wind energy, dependent on inconsistent gusts, this technology is as predictable as the tides. Technical and financial hurdles still exist, but projects are in the works for waters off Maine, New York, Oregon, Canada, and Scotland. Ocean power farms might be just over the horizon. 

Hop to it

One young lady hopped for half an hour,” recalls the animal physiologist, who, like his subjects, was visiting from Australia at the time. “She’d come out of the pen and stand on the treadmill, waiting for us to turn it on.” Dawson spent the next four decades back in Oz studying what is mostly a curiosity to others: how a kangaroo moves. Observing red kangaroos, he and colleagues found that longer strides, not more frequent ones, increase speed. Hopping strides range from 2.5 to 17 feet. Walking changes to hopping at around 4 miles an hour. And top speeds reach about 35 miles an hour. Specialized body features give kangaroos superb power and mechanical efficiency, says Dawson. Hopping marsupials may have evolved from tree ancestors some 40 million years ago – plenty of time to patent a signature gait. “It’s an incredibly graceful way of moving,” he notes. “They appear to be just gliding along.”

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