Generating Power From Ocean Buoys and Kites

cheezitmike writes "Researchers at Oregon State University are testing a new type of wave-energy converter to generate electricity from ocean waves: 'Even when the ocean seems calm, swells are moving water up and down sufficiently to generate electricity. ... For decades the challenge has been to build a device that can withstand monster waves and gale-force winds, not to mention corrosive saltwater, seaweed, floating debris and curious marine mammals. ... In the most recent prototypes, a thick coil of copper wire is inside the first component, which is anchored to the seafloor. The second component is a magnet attached to a float that moves up and down freely with the waves. As the magnet is heaved by the waves, its magnetic field moves along the stationary coil of copper wire. This motion induces a current in the wire — electricity.'" Meanwhile, researchers at Stanford are working to design "turbine kites" that operate at 30,000 feet, where air currents flow much faster than they do close to the ground. Ken Caldeira, a Stanford associate professor, said, "If you tapped into 1% of the power in high-altitude winds, that would be enough to continuously power all civilization."

Comments

Re:1% is such a small number

[houstonbofh]

Just don't think about transmission losses... Those pesky realities mess up perfectly good theories.

Re:1% is such a small number

[TheRaven64]

Exactly my thought. 1% is a tiny number, until you multiply it by the surface area of the Earth. Let's talk some real numbers instead. Current world power consumption is around 500 Exajoules per year, or about 15 TW on average. About 89 PW of solar energy hits the Earth's surface. This means that you'd need 0.017% of the Earth's surface to be converted to solar power to generate enough power for the entire world[1]. Now let's turn these into real numbers, rather than percentages. The surface area of the world is 510,072,000km^2. For solar, you'd need 85,967.191km^2, or a square around 300km on each side. For wind energy, you'd need 5,100,720km^2, or a square around 2250km on each side. Which of these sounds more feasible?

The figures for solar are using the average power, but it's worth noting that a number of the places with the highest solar energy are not particularly suited to human habitation. The Sahara desert is 9,000,000km^2. Enough solar energy hits less than 1% of the Sahara to power the entire world.

That's not to say wind power is a waste of time. The nice thing about this idea is that it works at night. Without some very efficient storage system or room-temperature superconductors, it's not feasible to power the whole world with solar energy. It's much easier to take things like this seriously, however, without the needless hyperbole.

[1] Note I'm assuming 100% efficiency here. The original article stated 1% of the energy in the wind, not 1% of the extractable energy, meaning that he was also assuming 100% efficiency. Back in the real world, scale all of the areas up by another order of magnitude or so.

Re:Why use all these wires ?

[Ancient_Hacker]

Uh, no. You can't get any energy out of the pressure difference in the atmosphere or ocean. The pressure difference is there because the medium has already adjusted to the lowest energy state. You cant milk any more energy out of a system that is already at lowest equilibrium.