Environmental Engineering Reference
In-Depth Information
Figure 2.21
Artist's impression of Pelamis array. (Reproduced with permission of Pelamis Wave
Power)
cylinders is resisted by hydraulic rams that pump oil into high pressure tanks which then is
used to drive an electrical generator.
While the UK is fortunate in having a good wave climate, the political climate has not
always favoured the technology. Attitudes, however, are changing, prompted by the need to
address global climate change, by the long term resource security of fossil fuels and by the
increasingly competitive economics of wave energy. UK R&D teams conducted much of the
early work, but many other countries are now active in wave energy development. Commer-
cial involvement is now signifi cant and schemes or concepts from the Netherlands, Norway,
Australia, Sweden, Denmark, the USA as well as the UK are now being developed.
2.7.3 Variability
The power output from a single wave power device will follow an exaggerated variation of
the wave height trains because of the square relationship between power and wave height.
Not unlike offshore wind farms, a substantial wave power installation will consist of an array
of such devices, the outputs from which when added together, because of spatial effects, will
be relatively smoother than that from one device. If this were extended to hundreds of such
devices in geographically dispersed arrays, the overall output will be smoother still. The short
term variability of the output from wave power converters is unlikely to present integration
problems, assuming that the outputs from arrays are connected to a grid voltage level capable
of absorbing variable generated power without adverse network effects.
