Wave

Wave energy is on the cutting edge of new technologies being developed to harvest the planet’s renewable resources. Although the technologies are not quite ready to be deployed, wave energy holds incredible promise for Nova Scotia, in both energy production and technology and manufacturing sectors.

Applications

There are many forms of wave energy technology and some of the most promising technologies are being produced right here in Nova Scotia by Wave Energy Technologies (WET). In general, these generators work by capturing the energy from the rise-and-fall motion of waves off the coast, which are converted to electricity and transmitted to shore by underwater cable to the electrical grid onshore.
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There have been dozens of methods proposed for capturing and converting the energy contained in ocean waves. Of over fifty competing designs, WET believes that approximately seven different technologies exist today which are approaching commercially viable status. They identify the following companies as the most commercially advanced:
• Pelamis (Scotland)
• Oceanlinx (Australia)
• Aquabuoy (US/Canada)
• PowerBuoy (US)
• Archimedes Wave Swing (Denmark/Scotland)
• Wavebob (Ireland)
• Limpet (Scotland).

The producers estimate the costs to produce electricity from these near-term commercial devices range from $0.17 to $0.40 per kilowatt hour (kWh).

WET predicts that by 2011 electricity can be produced at a cost of $0.09 to 0.11 per kW hour with its WET EnGen™ technology in locations where there is a resource of greater than 25 kW per metre of wave front. As the production cost of the WET EnGen™ diminishes over time, it will become possible to deploy wave farms closer to the coast which will decrease the cost further by decreasing the “line loss” through transmission.

Potential Resource
From a practical perspective the wave energy resource lies almost entirely off the Atlantic Coast where wind-generated waves have had the time and distance to build up energy over vast expanses of open sea from storms in the North Atlantic Ocean.

Experts estimate that the resource reaches a level of 25 kW/m at approximately 100 kilometers off shore. This value is an annual average. In the fall, winter and spring months the average will be higher due to stronger winds generating higher waves, while in the summer months the resource will be lower.

The economically viable wave energy resource in Nova Scotia appears to be restricted to the Atlantic coast from Cape Sable in the south to Scatarie Island, Cape Breton in the north. Wave resources are directly influenced by water depth. The depth of the Scotian Shelf is a key factor. The average wave energy resource off Sable Island is approximately 20-25 kW per metre of wave front (per metre of coastline when near shore) while the average wave energy resource in near shore locations (0.5 - 2 km from shore) such as Halifax and Liverpool may be 8-12 kW/m.

The data cited indicates that we can estimate the resource at a distance of 40 km offshore at 15 kW/m. Over a total distance of 600 kilometers the wave energy resource available totals 9000 megawatts (MW) of available energy. Realistically only a fraction of the available resource might be harvested due to a competition for sea space by navigation, fishing, environmental considerations, and other complicating factors. Based on an assumption of 20% availability, it would amount to 1800 MW of energy. The conversion efficiency of the WET EnGen™ generator is estimated to be 25%, resulting in total energy converted to 450 MW of energy.

NOTE: If wave farms were installed at the outer edge of the Scotian Shelf in deeper water, where the wave energy resource doubles to 25-35 kW/m this would also double the power generated.

The Case for 100% Renewable in Nova Scotia

Read more about the case for 100% Renewable Energy in our 2008 submission to the Department of Energy, Renewed Energy Strategy + Climate Action Plan consultations. Download 2008 Submission Document.