Current Obstacles to Wide Implementation of Wave

EnergyAlex Ruane

10/27/05

Overview

• Level of Development Progress– Output Capabilities

• Construction and Maintenance

• Local Impact of Devices– Scenic– Economic– Ecologic– Geologic

Stan?

Level Of Development Progress

• “Ocean energy today probably is about where wind energy was in 1974” – Engineering News-Record Editorial, 7/6/2004

• Most projects are still in development and prototype stages

– most prototypes have only been tested in wave tanks at scale

• Cannot meet the needs of a large population (see stats)

– current output ranges on the order of 1 MW– on average, generate 16 kW per meter of coastline– not yet economically competitive with fossil fuel

From Clement et al., 2002, a 120 kW prototype 1.5 km off Nansei Town, Japan

Construction and Maintenance

• Hawaiian Department of Business, Economic Development, and Tourism report, 2002:

– “By a comfortable margin, the most money and effort being spent worldwide on wave energy development employs the OWC”

• Falcao, 2004:– Civil construction dominates costs of OWC plants– Long-term maintenance and lifetimes are unknown– High-energy areas require high construction/materials costs– Difficult (and sometimes dangerous) to construct devices in high-wave areas

• Blast cliff away and leave natural dam?• Construct in dry dock and tow to proper location?

– The largest plant ever constructed (OSPREY plant in Scotland) was destroyed by the sea shortly after installment (1996)– Integrating OWC plants into breakwater is best option, as construction costs are shared

• Already done in Japan and India

Local Impact of Devices

• Visual impact can be large for TAPCHAN and OWC devices, less so for the “Mighty Whale” and offshore devices

– Strategic placement away from tourist areas a good idea– Noise can also be disruptive for OWC devices

• Offshore devices require cables linking bottom anchor to onshore grid as well as anchor-device tether

– could disrupt transportation and recreation activities• Offshore buoys would be invisible to most radar

• Accelerates coastal erosion on construction, then reduces it during lifetime

– Affects coastal property and sedimentation

Local Impact of Devices

• Ecological effects could be drastic in small areas– Offshore buoy farms could reduce wave action in sensitive tidal zones]

• Lower energy areas could provide shelter to wildlife (like kelp forests?)

– Large sections of shoreline would be destroyed for onshore OWC and TAPCHAN facilities

• Devices would also be more effective if shallows were dredged deeper

• Installation of offshore devices would require extensive cable-laying operations

• Danger of providing opening for colonization by invasive species

Final Thoughts

• Estimates of high energy resource potential are often misleading

– Not all coastlines are suited for development• need high wave energy and suitable coastal features

– Energy supplied is variable and inefficient– Much more research and development is required

• Variable and small-scale energy source– Better suited to compliment larger projects or to power small/local communities

• Pacific Islands, not Nebraska