Ocean - Energy Policy Analysis: A Conceptual Framework - page 186

Figure 11.2 The Ocean Energy Fuel Cycle

Materials
acquisition

Manufacturing Installation

Waste disposal Decommissioning Operation

commercial fishing. A better understanding of the impacts of wave energy technology on the
shoreline is also needed (California Energy Commission 2011). Careful site selection is the key
to keeping the environmental effects of wave power systems to a minimum. Wave energy system
planners can choose sites that preserve scenic shorefronts and avoid areas where wave energy
systems can significantly alter flow patterns of sediment on the ocean floor (USDOI 2006b). Also
essential is a demonstration of the ability of the equipment to survive the salinity and pressure
environments of the ocean as well as weather effects over the life of the facility (California Energy
Commission 2011). With some technologies in some locations near shipping lanes, there is a risk
of collision due to the low free board of wave-energy devices, which makes them undetectable
either by eyesight or by radar (Shaw 1982, 170). An oil tanker striking a wave energy generator
could produce catastrophic results.
For ocean current energy to be utilized successfully at a commercial scale, a number of potential
technical challenges need to be addressed to minimize environmental costs, including prevention
of marine growth buildup and resistance to corrosion without degradation of the marine environ-
ment (Armaroli and Balzani 2011, 244; Mueller and Wallace 2008), and protection of fish and
marine species from injury from turning turbine blades. These are environmental costs of all ocean
technologies, except as noted above. Other uses of the ocean environment for shipping routes,
commercial fishing, and present recreational uses, such as sport fishing and diving, will need to
be considered when siting turbines. Other environmental costs include potential large-scale risks
of slowing a current flow by extracting energy. Local effects, such as changes of estuary mixing
that result in potential temperature and salinity modifications, might affect species in estuaries
(USDOI 2006a).
Appropriate spacing of OTEC plants in tropical oceans will be necessary to mitigate potential
negative environmental costs on ocean temperatures and marine life (USDOE 2011). The envi-
ronmental costs of discharges of large volumes of both warm and cold water from OTEC power
plants into the ocean are not well known (Trenka 1994, 16), but have been found problematic when
associated with other technologies ( Calvert Cliffs Coordinating Committee v. AEC 1971). There is
also a risk of discharge of low-boiling-point fluids such as ammonia or freon to the environment
from leaks. OTEC power plants may conflict with other uses of the ocean, such as commercial
shipping, recreational boating, and commercial fishing (Trenka 1994, 16).