A giant offshore wind project has reignited debate over whether
the intermittent renewable energy technology could one day replace
Danish developer Ørsted said its Hornsea One plant, which
started delivering power to the grid this month, could help make up
for a lack of planned nuclear generation in the U.K. as plans for
new reactors have fallen by the wayside.
When complete, Hornsea One will cover more than 157 square
miles, making it bigger than the city of Denver, and have a peak
capacity of 1.2 gigawatts, thanks to 174 turbines of at least 7
It will be the biggest offshore wind plant on the planet,
dwarfing the current leader, Walney Extension, which Ørsted opened
last September with a capacity of 659 megawatts. Ørsted has plans
for an even bigger project, the 1.8-gigawatt Hornsea Two plant, in
In an interview with The Guardian after two Japanese firms
pulled out of building new British reactors, Henrik Poulsen,
Ørsted’s chief executive,
said that in future, “if nuclear should play less of a role
than expected, I believe offshore wind can step up.”
A battle of capacity factors
Can it, though? Depending on conditions, the U.K. already gets
more than a third of its energy from variable wind generation.
This month the country smashed a new record, with 15.32
gigawatts of power delivering 36 percent of the nation’s
said RenewableUK, an industry body.
It may seem risky to further increase the country’s reliance
on a generation source that depends on meteorological conditions.
However, advocates point out that offshore wind is a more reliable
energy source than the onshore variety, particularly as turbine
one analysis in 2017, the capacity factors of U.K. offshore
wind farms have risen from roughly 30 percent to 40 percent from
early to later projects, mainly as a result of installing larger
The analysis concluded Hornsea Two, if built, could potentially
have a capacity factor in excess of 60 percent. That’s still
below the capacity factors nuclear typically achieves. But perhaps
not as much as you might think.
While U.S. reactors have average capacity factors of around 90
percent, in the U.K. the level is significantly lower. World
figures show an average U.K. nuclear plant load factor of less
than 82 percent in 2017.
This was quite a high level for the U.K. fleet, according to
review of capacity factors by British anti-nuclear campaigner
He claims the U.K. fleet’s “consistently awful” capacity
factors are a result of the country installing reactor designs not
widely used elsewhere, which limits the potential to acquire
expertise in operating the technology.
Other data supports the idea that new nuclear technologies face
a learning curve before achieving high capacity factors.
U.S. Energy Information Administration
records, for example, show America’s nuclear fleet was still
struggling to achieve capacity factors above 60 percent a decade
after it began contributing double-digit percentage shares of
generation to the grid.
Not just a UK debate
Given that the U.K. is relying on a largely
un-tested reactor design for upcoming nuclear capacity, it is
perhaps legitimate to ask if the reliability of new reactors will
be significantly greater than those of gigawatt-scale offshore wind
farms built at the same time.
Tom Dixon, wholesale team leader at U.K. consultancy Cornwall
Insight, said: “New offshore wind farms being developed are now
much more reliable than older offshore sites or their onshore
As a result, he said, “it is credible to say that the shortfall
in new nuclear could be made up by offshore wind, with improving
operational performance and relatively low costs for the
technology, but additional flexibility would be required at times
when output is low.”
It is not just the U.K. where offshore wind could potentially
take over new nuclear’s mantle.
This month, in the wake of a tie-up between Ørsted and Tokyo
Electric Power Company, the analyst firm Wood Mackenzie Power &
Renewables questioned whether offshore wind could also be a cure
for rising energy demand as new nuclear languishes in Japan.
“Rising costs and a lack of public confidence in Tepco’s ability
as a nuclear operator has led the company to reconsider its future
strategy,” said senior Woodmac analyst Robert Liew. “Tepco’s
involvement in offshore wind is a crucial development.”
Source: FS – GreenTech Media
Orsted’s Hornsea Project Spawns Talk of Offshore Wind Replacing Nuclear