01.04.12
Wave energy from community to utility scale
Source: Public Sector Executive Mar/Apr 12
Michele Grassi, chairman and CEO of 40south Energy Ltd, analyses issues and solutions related to this new renewable source.
Wave energy seems the perfect choice for distributed generation of electricity on a community scale. After all, a large majority of the world’s population lives near reasonably energetic seas.
The distributed generation of renewable wave energy has many advantages over centralised generation. Not only do you save on the cost of grid infrastructure but also each community becomes responsible for the operations and maintenance of their wave energy resource and for its conversion.
Moreover, distributed wave energy generation makes cheap and renewable energy immediately available to more isolated communities which are beyond the reach of the high voltage grid.
Wave Energy Converters can be located inside Wave Energy Parks, which consist of a consented sea area, an electrical cable reaching the user of the electricity and a light local support infrastructure. Wave Energy Parks are the service hubs for the Wave Energy ecosystem. The consented area for the Wave Energy Park itself is very similar to the one necessary for offshore aquaculture, although in the Wave Energy case the environmental impact of the installation is much lower. Contrary to aquaculture, the Wave Energy installation does not emit any chemicals or pollutants in the sea, and also the acoustic and electromagnetic emissions are extremely limited and within tolerance levels also of marine mammals.
The similarity with offshore wind energy parks is also very close, both in terms of economic impact and value estimate and in terms of grid or user connection and the concession of incentives (if at all available). Also in this case however the environmental impact of the Wave Energy Park is much lower than that of an offshore wind park, both in terms of impact on sea life and in terms of visual impact. A very interesting possibility is the coexistence of wave energy converters and wind energy converters within the same (Round 3) consented sea area. This hybrid configuration optimises utilisation of the resource, as wind and waves are not immediately correlated, and optimises the utilisation of the sea area and of the transport cable (the two parks can share the same intermediate station).
Of course wave energy has a higher capacity factor and a lower ‘levelised cost of energy’ with respect to wind, but it is a newer technology with a higher perceived risk, so it is likely that offshore wind turbines will coexist with wave machines in hybrid parks, at least in the near future. The presence of a Wave Energy Park will provide advantages to the local fishing community because the Wave Energy Park will share its goals: a healthy local economy, good employment level for people going at sea, secure and regulated access to the sea resources, effective and useful monitoring of the sea. The presence of a Wave Energy Park can help the local fishing community perform a generation jump in terms of productivity and security of its activity. The Wave Energy Park is actually a monitoring hub of the sea conditions, of the fish population and of the actual fishing activity performed near it; the local fishermen can use the sensors of the Wave Energy Park to know the wave climate, temperature, and general sea conditions around the Wave Energy Converters.
At any scale, from centralised (utility scale) generation to distributed (community scale) generation, Wave Energy Parks collect several wave machines in a unified energy production site, and are sizable from 25kW to several megawatts.
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