Homes on the Arctic tip of Norway are getting power from the moon via a unique underwater power station driven by the rise and fall of the tide. Caused by the gravitational tug of the moon on the earth, a tidal current near the town of Hammerfest is turning the 30-foot blades of a turbine bolted to the seabed to generate electricity for the local grid.
The prototype looks like an underwater windmill and is expected to generate about 700,000 kilowatt hours of non-polluting energy a year, or enough to light and heat about 30 homes.
“This is the first time in the world that electricity from a tidal current has been fed into a power grid,” Harald Johansen, managing director of Hammerfest Stroem, told Reuters.
$11 million project
The plant in the Kvalsund channel, which had cost about $11 million by Saturday’s launch, is a tiny contributor to help cut dependence on fossil fuels like oil and gas that many scientists blame for global warming.
The water flows at about 8 feet per second for about 12 hours when the tide is rising through the Kvalsund channel, pauses at high tide and then reverses direction. The blades on the turbine automatically turn to face the current.
If successful, the project could herald far wider use of predictable tides in green energy and generate millions of dollars in orders. Aboveground windmills, by contrast, are useless in calm weather and have to be built to withstand hurricane-force winds.
Tides have previously been tapped for power plants in France, Canada and Russia in barrages that trap water in artificial lagoons at high tide. When the tide goes out, gravity sucks the water through turbines to generate electricity.
But such barrages can disrupt the habitats of animals and plants in river estuaries and along the coasts.
Proponents of turbines turned by tidal currents say that they cause less impact — they are silent and invisible from the surface and fish, whales and seals can probably swim round them without the risk of being sliced up.
Initially more costly
Drawbacks are that costs are high. Hammerfest Stroem has estimated that electricity will cost about three times that of typical hydro-generated electricity in Norway.
And maintenance — with divers having to go down to the seabed — could be tricky.
Still, partners like Norwegian oil group Statoil are excited about the prospects. “We want to get experience from this and see that we can also be a producer of green electricity,” said Hanne Lekva at Statoil.