* Island planned for North Sea, 3 km off Belgian coast
* Would be doughnut-shaped with a reservoir in the middle
* Will take five years or more to build
BRUSSELS, Jan 17 Belgium is planning to build a
doughnut-shaped island in the North Sea that will store wind
energy by pumping water out of a hollow in the middle, as it
looks for ways to lessen its reliance on nuclear power.
One of the biggest problems with electricity is that it is
difficult to store and the issue is exaggerated in the case of
renewable energy from wind or sun because it is intermittent
depending on the weather.
"We have a lot of energy from the wind mills and sometimes
it just gets lost because there isn't enough demand for the
electricity," said a spokeswoman for Belgium's North Sea
minister Johan Vande Lanotte.
"This is a great solution," she said, adding she thought it
could be the first of its kind.
Excess energy would be used to pump water out of the centre
of the island, and then the water would be let back in through
turbines when demand outpaces supply.
Vande Lanotte revealed the plans during a presentation at
the Belgian port of Zeebrugge late on Wednesday.
Belgium plans a complete exit from nuclear power as soon as
enough energy from alternative sources becomes available, but
last year it postponed the closure of its oldest reactor for a
decade over energy supply worries.
In 2011, around 57 percent of Belgium's energy came from
Belgium hopes eventually to generate 2,300 MW from its
network of North Sea wind farms, which could replace a
significant part of either of its two nuclear sites, Doel and
Tihange, which each generate about 3,000 MW.
The island is still in the planning stages, but will be
built out of sand 3 km off the Belgian coast near the town of
Wenduine if it gets the final go-ahead.
The island, which would also work as an offshore substation
to transform the voltage of the electricity generated by wind
turbines, could take five or more years to plan and build.
It won't be until Elia, Belgium's power grid
operator, strengthens the power lines leading out to the coast.
"One of the driving elements is the reinforcement of the
grid onshore towards the coast," a spokeswoman for Elia said.
Belgium's nuclear power operator Electrabel, a division of
France's GDF Suez, shut down two of its reactors last
year while it investigates cracks found in the reactor casing.
(Reporting By Ben Deighton; editing by James Jukwey)