Wind farms
Farming the wind
With the offshore wind sector experiencing impressive growth, Sam Fenwick hears from
Semco Maritime about the use of TETRA to ensure workers’ safety and co-ordination
While critical communications deployments
in the public safety sector are often driven
by a combination of technology change
and existing infrastructure reaching
obsolescence or end of life, in many other
sectors the main driver is growth in the form of new projects,
be they airports, metro lines or oshore wind farms.
e global oshore wind industry had nearly 4GW
of grid-connected capacity added in 2017, driven by
record investment of more than $15bn, according to the
International Energy Agency (IEA). It notes that in the
EU, auction results have indicated that 30-50 per cent cost
reductions are thought to be possible over the medium term,
as larger turbines cut construction costs and larger products
boost economies of scale (turbines at sea can dwarf those
on land – the Vestas V164 has a rated capacity of 8MW,
upgraded to 9.5MW, with an overall height of 220metres).
However, the personnel involved in the construction,
running and maintenance of oshore wind farms have to
cope with a variety of hazards – simply moving from a boat
onto a turbine in rough conditions can be daunting, and
while there are means of making this easier, it presents more
of a risk than just landing in a helicopter on a purpose-built
platform (far more commonplace in the oil and gas industry).
Martin Søndergaard, product specialist, radiocom at
Semco Maritime, a company that among its other activities
provides integrated turnkey communication systems for the
onshore and oshore energy industry, adds that as personnel
on oshore wind farms are eectively lone workers, good
communications together with fallback procedures are vital.
In addition to the need to ensure workers’ safety, reliable
communications are required due to the way in which
operations are highly weather dependent – according to
Søndergaard’s colleague, Russell Gallant, sales manager
(telecom), this means they have to maximise their uptime.
“It’s critical that they make the most of their coordination
of moveable activities across a very large area
– there’s a lot of co-ordination that’s needed,” Gallant says.
“We’ve done some calculations – renting a transfer vessel can
cost €18-25,000 a day, so if you’ve got a cancelled trip, that’s
going to hit you very quickly.”
Søndergaard says for a typical wind farm, Semco Maritime
deploys a redundant TETRA base station, on a substation
that consists of two transceivers from DAMM and two
controllers. It decides, depending on the capacity required,
whether to have two carriers or one with a hot standby,
though it is typically the former. is TETRA system is
integrated with “a lot of additional equipment such as VHF
(AM and FM) implemented via a gateway”, with a PABX
system (if required). e use of VHF (AM and FM) gateways,
according to Gallant, means “they don’t have to have lots of
dierent terminal types in the eld and can just use a TETRA
terminal for all voice communication applications”.
While VHF FM (SOLAS) and AM (Helicopter) are
mandatory, the use of gateways is not; however, he adds that
the TETRA system oers a great deal of redundancy because
if the backhaul to the land cuts out then “we can still work in
trunked mode in the eld, and if one transceiver goes down,
The Northwind
offshore wind farm
in the North Sea
near Belgium
20 www.criticalcomms.com January 2019
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