diameter of 5 m could be managed by cranes from relatively small vessels. This
way the algae on the ring construction could be examined at most dates and at
harvest while in the worst case it was at least possible to tow the ring into the
harbour, where a larger crane could lift it onshore. The described characteristics and
the modular nature of the ring construction promise to make it a sensible and
effective choice to be used in aquaculture situations where offshore wind farms are
located (Buck 2002; Krause et al. 2003; Buck et al. 2003, 2004; Buck and Buchholz
2004a). Moreover, one could transfer the technique to less developed countries
using suitable materials, e.g. bamboo or rattan, and the craftsmanship of local
people. However, lifetime and stability of these systems using materials in these
countries will have to be tested before large-scale employment.
Concerning the most favourable location for aquaculture of macroalgae, our
experiments suggest that fairly exposed sites with rough conditions are suitable,
however, only if the carrying support structure is sufficiently rigid to withstand the
rough to extreme conditions encountered in most of the trials. Aquaculture in
sheltered waters must avoid shallow areas, like in the Sylt backwaters, because of
possible contact with the seabed and the high siltation and suspended solid load
which creates low light conditions. Any location selected for seaweed culture
should have a minimum depth of 5–8 m. Offshore areas, such as “Roter Sand” and
Helgoland Roads, seem to be well-suited for future commercial-scale seaweed
culture.
11.4.3 Fish Cages in Multi-use with Offshore Wind Turbine
Foundations
11.4.3.1 Integrating a Fish Cage into a Tripod Foundation
So far, no findings exist on the question how fish cages interact with offshore wind
energy converters and how large additional forces could grow in the presence of
waves (Goseberg et al. 2012). To investigate the potential multi-use of offshore
wind turbine foundations with offshore submersible fish cages the offshore wind
farm “Veja Mate” was taken as a case study site. Next to different foundation types,
a tripile foundation of “Bard Engineering” was used to erect the 5 MW turbines and
towers (Fig. 11.34a–g). The advantage of the triple foundation in direct comparison
to other foundation types is that due to its three-monopile character with a rigid
platform on top it creates an open space under the platform above the water surface
down to the seabed marked-off by the three foundation piles (Fig. 11.34d–g). The
initial idea was to design different cages types to be installed exactly in this open
space allowing submerging it towards the seafloor while also enabling it to be in a
floating mode during maintenance and harvest procedures (Figs. 11.35a–d and
11.38a, b, e, f).
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311
way the algae on the ring construction could be examined at most dates and at
harvest while in the worst case it was at least possible to tow the ring into the
harbour, where a larger crane could lift it onshore. The described characteristics and
the modular nature of the ring construction promise to make it a sensible and
effective choice to be used in aquaculture situations where offshore wind farms are
located (Buck 2002; Krause et al. 2003; Buck et al. 2003, 2004; Buck and Buchholz
2004a). Moreover, one could transfer the technique to less developed countries
using suitable materials, e.g. bamboo or rattan, and the craftsmanship of local
people. However, lifetime and stability of these systems using materials in these
countries will have to be tested before large-scale employment.
Concerning the most favourable location for aquaculture of macroalgae, our
experiments suggest that fairly exposed sites with rough conditions are suitable,
however, only if the carrying support structure is sufficiently rigid to withstand the
rough to extreme conditions encountered in most of the trials. Aquaculture in
sheltered waters must avoid shallow areas, like in the Sylt backwaters, because of
possible contact with the seabed and the high siltation and suspended solid load
which creates low light conditions. Any location selected for seaweed culture
should have a minimum depth of 5–8 m. Offshore areas, such as “Roter Sand” and
Helgoland Roads, seem to be well-suited for future commercial-scale seaweed
culture.
11.4.3 Fish Cages in Multi-use with Offshore Wind Turbine
Foundations
11.4.3.1 Integrating a Fish Cage into a Tripod Foundation
So far, no findings exist on the question how fish cages interact with offshore wind
energy converters and how large additional forces could grow in the presence of
waves (Goseberg et al. 2012). To investigate the potential multi-use of offshore
wind turbine foundations with offshore submersible fish cages the offshore wind
farm “Veja Mate” was taken as a case study site. Next to different foundation types,
a tripile foundation of “Bard Engineering” was used to erect the 5 MW turbines and
towers (Fig. 11.34a–g). The advantage of the triple foundation in direct comparison
to other foundation types is that due to its three-monopile character with a rigid
platform on top it creates an open space under the platform above the water surface
down to the seabed marked-off by the three foundation piles (Fig. 11.34d–g). The
initial idea was to design different cages types to be installed exactly in this open
space allowing submerging it towards the seafloor while also enabling it to be in a
floating mode during maintenance and harvest procedures (Figs. 11.35a–d and
11.38a, b, e, f).
11 The German Case Study: Pioneer Projects of Aquaculture …
311