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Pelc and Fujita (2002) raised concerns about the
potential for floating devices to reduce water
mixing causing detrimental effects on food supply
for benthic organism. However, WTC devices
will usually be subjected to fouling where sessile
mussels(Wilhelmsson & Malm 2008, Langhamer
2009a, Langhamer et al. 2009b). WTC devices may,
thus, rather enhance benthic productivity within
the areas, through the deposition of organic mate-
rial, such as faecal matter, and live and dead organisms
originating from the WTC device (Wilhelmsson
et al. 2006, Langhamer & Wilhelmsson 2009,
Maar et al. 2009). WTC parks may also increase
inorganic sedimentation rates in the area by altering
the hydrodynamics (See Annexe 1, section 1.3.).
However, even slight currents in the area are likely
to minimise these impacts (see e.g. Cruz 2008 for
references).
Figure 7: Deployment of a wave energy foundation that has been perforated with holes
to investigate how it may enhance abundance of fish and crustaceans (Langhamer &
Wilhelmsson 2009, Photo: O. Langhamer.
In particular wave power devices, which float on
the surface and are only anchored to the seabed
(Figures 3 and 4), or have comparably small foundations
(Figure 5), will have less impact on the seabed
than wind turbines. A study by Langhamer (in press)
suggests that the impacts of wave power on the
seabed in the area as a whole are minimal. Shoreline
devices, such as OWC (Figure 5), may have
greater short-term impacts than those deployed
offshore, as the former may require excavation of
the coastline (Cruz 2008).
Damping of waves by large arrays of wave energy
converters may reduce erosion on the shoreline.
However, most devices will be placed more than
1-2 kilometres from the shoreline, and the sheltering
effect of wave energy devices is probably negligible
in most cases (Pelc & Fujita 2002, Cruz 2008,
and Ångström Laboratory, personal communication
2009).
It should be emphasised again that primary data is
to date only available from studies in conjunction
with small scale pilotwave energy projects using e.g.
point absorbers (Figure 5). Future wave parks may
claim sizable areas (tens of square kilometres), and
cumulative effects of large numbers of wave energy
converters need to be thoroughly considered.
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