You might remember I bought this wind turbine
a few weeks ago for one of my previous videos. It's been upon the bookcase since then, but
I thought it might come in handy again today. You see while onshore wind power is something
we've all become quite used to seeing in most parts of the world, offshore wind actually
represents the biggest opportunity for generating massive quantities of power for our electricity
grids. That's because winds are stronger and steadier at sea than they are on land, so offshore
wind delivers a higher power per unit area than onshore wind. Winds out in the open sea often
blow during the afternoon too which means the offshore turbines can provide very useful power at
a peak time of the day. We've already got loads of offshore wind farms here in the UK and around
the coast of some other European countries, but they're all located in relatively shallow
waters, only about 25 to 30 metres deep where everything can be nicely bolted down to the
seabed. Now though the race is on to develop wind turbines that can be towed out into the deep
ocean where the winds are even stronger and more consistent. The only snag is that those open ocean
waters are far too deep for a tower to be extended down and bolted to the bottom. So apparently
these turbines are just going to float... So how they're going to do that then Hello and welcome to Just Have a Think. The
first ever offshore wind farm was opened at Vinderby in Denmark in 1991. It had a
power generating capacity of 5 megawatts providing for the annual electricity consumption
of just over 2 000 Danish households. In 2013 a comprehensive review of offshore
wind concluded that the benefits to cost ratio was not as good as the industry had suggested,
and that the offshore wind market "doesn't look as if it's going to be big". The review pointed to
what it saw as critical disadvantages of offshore installations, including difficulty of access
and harsher conditions like higher humidity and saltwater corrosion and oxidation which tend
to increase maintenance and repair costs and in general make every aspect of installation
and operation more difficult and dangerous, and therefore more time consuming and expensive
than sites on land. Despite that pessimism, the offshore wind market has grown strongly. There
are now 162 offshore wind farms around the world, with a combined generating capacity of nearly 33
gigawatts. That's more than 6 000 times the size of that very first Danish installation. Just last
year another 15 new offshore wind farms went into operation with a combined capacity of 5.2
gigawatts. The majority of those installations are located in Europe and China, but the United
States is now starting to get into the market too. President Biden has pledged to deploy 30 gigawatts
of offshore wind power within the next decade, and the first major project, called Vineyard
Wind 1 - an 800 megawatt farm off the coast of Massachusetts, was announced in May 2021. All
these installations stay close to the shoreline where waters are shallow and the distances to
large urban connections are relatively small. The technology is now fairly mature and
there's 40 years of industry knowledge and experience in the field bringing efficiencies
and economies of scale that just weren't foreseen in that 2013 review paper. So why rock the boat,
quite literally, and push out into deep waters where the whole operation takes on far greater
risk and expense? Well, here in Europe wind farm developers are rapidly consuming the low-hanging
fruit of easily accessible near-shore shallow water locations that can be exploited without
too much objection from local fishing fleets, conservation groups and coastal residents who
complain about having their views spoiled. So going further out to sea is becoming
an increasingly urgent consideration. Installing turbines in the open sea also presents
fewer risks for other species that we share the planet with too. Krag Peterson, a wildlife
ecologist at Aarhus University in Denmark, says birds like eagles, ducks, griffins, stalks
and gannets can collide with the mammoth blades of offshore rigs, but the density of turbines in
deep sea wind arrays is far lower and bird flights are more thinly distributed, so the potential
impact on their population is greatly reduced. Up off the windswept northern coast of Scotland, five
towering turbines -each standing 174 meters tall - make up a renewable energy project called Highwind
Scotland, a floating deep water demonstration wind farm that's been generating enough electricity
for more than 20 000 homes since 2017. The giant masts and turbines float in waters more
than 90 metres deep, sitting in buoyant concrete and steel keels that enable them to stand upright
on the water a bit like a (UK) buoy or (US) buoy. The cylindrical bases of the turbines weigh
10,000 tons and are held in place with three taught mooring cables attached to anchors
which lie on the sea floor. Each cable has a 60 ton weight hanging from its midpoint to
provide additional tension. Control software on board constantly monitors the operation of the
wind turbine and alters the pitch of the blades to effectively dampen the motion of the tower
and maximize production. So far the high wind demo has functioned well in all the wind and wave
conditions the North Sea has been able to throw at it over the past four years, including hurricane
Ophelia in 2017, and other harsh winter storms bringing hundred mile an hour winds and eight
meter high waves. Just a few miles away, off the coast of Aberdeen, the world's largest floating
wind farm received its fifth and final turbine in July 2021 and it will be fully operational at the
start of 2022. The six turbines at the Kincardine installation are the largest machines ever to have
been installed onto floating platforms and they'll have a generating capacity of 50 megawatts -
enough power to run almost 60,000 Scottish homes. The area beyond reach of conventional offshore
turbines makes up 80% of the world's maritime waters and the mind-boggling amount of energy
available out in the wilds of the open ocean is proving to be just a bit too tempting for
turbine makers to ignore. Over in the United States, according to the National Renewable Energy
Laboratory or NREL, the total potential production capacity of offshore wind farms there is nearly
double the entire US annual power consumption of four thousand terawatt hours per year.
Forty-two percent of that will most likely come from fixed-base offshore turbines in shallow
waters off the eastern seaboard like those being developed at Vineyard Wind 1, but it's a very
different story on the other side of the country where the continental shelf drops off
very rapidly and you're into deep water within only a few miles of the shore. The
remaining 58% of US offshore potential power is, according to NREL, therefore locked up in these
deep water ocean areas. And that's something that the American behemoth General Electric, or
GE, are fully engaged in trying to liberate. This guy is Rogier Blom. He's the Senior
Principal Engineer for Controls and Optimization at GE global research in Niskayuna, New York.
Rogier and his team have designed a 12 megawatt floating version of the Haliade X, the most
powerful offshore wind turbine in the world. These colossal feats of engineering will have 260
meter tall turbines with a rotor diameter of 220 meters. Each turbine will be capable of generating
67 gigawatt hours of electricity a year. That's enough power to run 16 000 households - just from
a single turbine! The system being developed by GE involves bolting the towers to floating platforms
which the development team refer to as floaters. Which is unfortunate! But those floaters are
essential to carry the turbine's tremendous weight and respond to the constant motion of the seas
and wind. As Blom explains in this GE article from May 2021 "building a floating wind turbine
is like putting a bus on a tall pole and keeping it upright floating and steady no matter what
conditions it faces". Blom's plan is for the floating platforms to be tethered to the ocean
floor by what he calls actuated tension legs. Active tendons will allow the turbines to
ride big waves and reduce the magnitude of the overall mechanical load. GE's concept
is based on what's called control co-design, in which the entire system - the turbine and
platform as well as the control algorithms - are all designed in tandem, and that avoids the
need to put additional mass into the system to withstand high winds and waves - something that
adds huge cost to the construction of floating oil rigs for example. That cost reduction results
in a lower levelized cost of energy or LCOE, which is the standard metric that the energy
industry uses to compare different technologies. Some renewable energy experts do still remain
skeptical though that the high cost of floating offshore wind turbines will come down far
enough to rival other clean energy technologies. Currently the electricity they generate is often
almost twice as expensive as near shore wind turbines and three times that of land-based wind
turbines. It is still maritime engineering after all, which makes it comparatively expensive
to build, deploy and maintain, with shorter operational life spans as a result of the
corrosive nature of the marine environment that they sit in. But advocates of floating wind point
out that the costs of onshore and near-shore wind energy have continuously dropped as efficiency
and economy of scales have improved over time, and those trends are likely to be the same for
floating wind turbines too. They argue that while some of the mechanical details are still being
tweaked, the basic technology of floating wind is sound. After all, they say, the oil and gas
industry has been using similar marine know-how for decades on their floating platforms in some
of the harshest marine environments on the planet. We are still some years away from a world with
hundreds of deep sea floating wind turbines providing huge quantities of renewable energy
to major populations all over the planet, and the rollout of these facilities at the sort of
scale required will certainly call for big backing from governments and corporate investors who will
of course need to be convinced of the long-term capital returns. As Frank Adam, an expert on
wind energy technology at Rostock University points out in this BBC interview, "it's easy to
produce one or half a dozen floating turbines, but 10 or 20 or 100? That's another story. This
requires supply chains, shipyards and ports that can handle such enormous structures, and
factories for serial fabrication". Nevertheless, despite these challenges, the potential of
this kind of renewable energy generation remains an attractive proposition and the amount
of energy that could be produced would be globally transformational. The International Energy
Agency projects that offshore wind power alone could eventually meet the entire electricity needs
of Europe, the US and Japan many times over. And if China does dive into offshore wind like they
have done with other renewable energy technologies then it may just provide yet another route
for them to slow down or even reverse their currently unsustainable schedule of opening
the equivalent of a new coal mine every week. If you've got news or views on this one, or if you
have direct experience in the industry that you'd like to share, then jump down to the comments
section below and leave your thoughts there. That's it for this week though.
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