The UK's first wind farm
in the Irish Sea which will supply 50,000
homes with power.
13/04/2005 - Even without an advanced degree,
you can admire the technology behind offshore
wind farms - the underwater construction,
the towers, the turbines, the elegant physics
of the whole thing. That these spinning blades
can power homes, factories and whole cities
is, well, pretty cool. This is easy to see.
Obvious. What people rarely ever think about
is how all that electricity gets back to shore.
Enter the humble power grid.
Thought about or not, power grids take years
to build - especially across the ocean floor.
It’s not like you can make do with a few kilometers
of extension cord and duct tape. There are,
first off, the technical challenges. Salt
water is not the best for electrical components,
so it will have to be kept out despite hundreds
of kilos of water pressure. Then there are
the distances involved, and the various environmental
considerations - the effects of electro-magnetic
fields, noise and construction on marine wildlife.
Fortunately, most of these challenges already
have solutions gained from experience with
existing wind farm instillations. No doubt
a lot of hard work and cleverness will still
be needed, but the technologies involved are
proven enough that, from an engineering perspective,
there is every reason to expect success at
sea.
It’s on shore that the real troubles begin
- troubles that are more political, institutional
and bureaucratic than technical. On land the
power grid has often been built by existing
old guard companies that have their own power
plants (coal, nuclear, etc.), and aren’t keen
about competition from the emerging wind industry.
Of course, the existing grids are mostly optimized
for the benefit of these old guard power companies.
To put it simplistically: Starting at the
power plants, big electric cable trunks branch
out to smaller and smaller cables that carry
a smaller and smaller amount of power. Another
way to picture it is to look at how thick
the cable running into your home is. Compare
this to the much smaller wires going to individual
appliances (like a lamp or microwave). It’s
sort of like water pipes, big ones branch
out to little ones, and the one that goes
to your tap is a lot smaller then the one
going into your house from the street.
With this in mind, you can see how it doesn’t
work to take a big 1000-megawatt cable, supplying
electricity from a wind farm, and plug it
into a much smaller regular street cable.
But odds are that where the cable from a wind
farm comes to shore is at the edge of the
land grid - where there are only regular street
cables serving residential needs. Therefore,
new trunk cables, and other grid infrastructure,
needs to be added to accommodate the wind
farm. This is not a serious engineering problem,
and is done all the time when a power plant
is built someplace new. Of course, the old
guard power companies resist changes to “their”
power grid that will let the wind industry
compete.
But if these entrenched forces can be overcome,
offshore wind has huge potential. Although
it’s comparatively small now, the wind industry
is already growing despite these odds (by
20 percent last year), and future payoffs
are going to be huge. For example, with grid
modernization by 2020 offshore wind power
could be supplying enough energy to the European
Union for every single one of its 150 million
households. And, naturally, the EU doesn’t
have a monopoly on wind - vast potential exists
around the world - but without the humble
power grid it goes nowhere.
