Ocean Energy Overview: Wave Power & Tidal Power May 10, 2007

2 Wave Power

3 Waves Generated by Wind Over Water Wave generating area Stochastic resource but possibly predictable 1 to 3 days in advance Waves are a concentrated form of solar energy Temperature and pressure differences give rise to wind Wind blowing over water generates waves

4 Wave Power Overview  What is wave power?  For PG&E, opportunity to extract renewable energy from waves along northern coast of California  Most wave energy conversion (‘WEC’) devices are deployed on surface of water Like wind turbines, multiple WEC devices are aggregated in ‘farms’ Operate in varying depths ( feet) Nascent technology (mostly pre-commercial)  California has high potential  PG&E service territory borders 600 miles of Pacific coastline High wave power densities suggest good economics Potential annual energy production could be as high as 48,000 GWh  Wave power could make a significant contribution to future RPS goals  Permitting of wave power plants follows FERC hydropower licensing process  Many stakeholders – environmentalists, fishermen, surfers, etc.  Roughly 5 year process expected for development license grant

5 Wave Power Project Overview Activities completed  Hired EPRI to evaluate and screen potential California sites  Hired consultant to confirm EPRI evaluation methodology  Filed FERC preliminary permit applications for Humboldt & Mendocino  Began stakeholder outreach Current activities  Launching feasibility studies  Confirm wave power resources  Consider immediate constraints (shipping, grey whale migration, fishing, etc)  Identify possible technologies  Understand installation, operations, and maintenance  Develop energy production and economic models  Continuing outreach

6 Potential California Wave Power Generation  Selection criteria for initial sites  Grid interconnection  Wave resource  Port infrastructure (deepwater ports shown in green)  Local support  PG&E filed two FERC preliminary permit applications (40MW each)  Humboldt County (Eureka)  Mendocino County (Fort Bragg)  Wave power plant  Multiple wave energy conversion devices arranged in an array  Leading devices float on surface of water  miles offshore  Connected to land via subsea cable Humboldt Bay Noyo Harbor Bodega Bay SF Bay Area Half Moon Bay Monterrey Bay Morro Bay Santa Barbara Los Angeles San Diego

7 Mendocino and Humboldt WaveConnect Projects

8 WaveConnect Project Overview  PG&E is lead project developer  PG&E obtains site control and conducts initial feasibility analyses  PG&E develops infrastructure to evaluate, test, and deploy various WEC devices  Open process for device selection  Individual WEC device developers only responsible for device- specific permitting  Project is scaled up to 40 MW total  Contributes to post RPS goals PG&E Substation Junction Box Pilot Plant Device A Pilot Plant Device B Demo Device A Demo Device B Demo Device C Shared O&M Facilities Wave Direction WEC Device A Offshore InfrastructureOnshore Infrastructure Representative aids to navigation Subsea Transmission Cable WEC Device B WEC Device C PG&E Substation Junction Box Pilot Plant Device A Pilot Plant Device B Demo Device A Demo Device B Demo Device C Shared O&M Facilities Wave Direction WEC Device A Offshore InfrastructureOnshore Infrastructure Representative aids to navigation Subsea Transmission Cable WEC WEC Device

9 Overview – Wave Technologies OPD Pelamis Wave Plant (‘Farm’) UK Wave Hub Wavebob Ocean Power Delivery Pelamis Ocean Power Technology PowerBuoy TM AquaEnergy AquaBuOY Devices and technologies pictured for illustration / discussion only Does not reflect or imply any PG&E preference

10 Tidal Power

11 Tides Governed by Earth-Moon-Sun Tidal changes in sea level occur as Earth rotates beneath bulges in ocean envelope, which are produced by solar and lunar gravitational forces and centrifugal forces MOON’S ORBIT North Pole Earth rotates counter-clockwise Resource Variable but Predictable Greatest range occurs when sun and moon pull in same direction (spring tide) Weakest when sun and moon in opposition (neap tide)

12 North America Tidal Power Potential Tacoma Narrows, WA Power density = 1.7 kW/m 2 Site energy flux = 0.93 TWh/yr Western Passage, ME Power density = 2.9 kW/m 2 Site energy flux = 0.91 TWh/yr Muskeget Channel, Martha’s Vineyard, MA Power density = 0.95 kW/m 2 Site energy flux = 0.12 TWh/yr Knik Arm, Anchorage, AK Power density = 1.6 kW/m 2 Site energy flux = 1.0 TWh/yr Golden Gate, San Francisco,CA Power density = 3.2 kW/m 2 Site energy flux = 2.08 TWh/yr Many good sites Southeast AK and BC Minas Passage, NS Power density = 4.5 kW/m 2 Site energy flux = 8.9 TWh/yr Head Harbor, NB Power density = 0.94 kW/m 2 Site energy flux = 0.2 TWh/yr Many good sites in NB and NS A few good sites in Puget Sound

13 Tidal Power Overview  What is tidal power?  For PG&E, opportunity to extract renewable energy from tidal flows entering and exiting San Francisco Bay  For SF Bay, tidal turbines are most likely technology Deployed underwater, totally submerged Like wind turbines, multiple turbines are aggregated in ‘farms’ Nascent technology (mostly pre-commercial)  SF Bay has been identified as a high potential site for tidal power  Permitting of wave power plants follows FERC hydropower licensing process  Many stakeholders – environmentalists, fishermen, commercial shipping, etc.

14 Tidal Power Turbines Verdant Power Turbine – East River Project – Installation Illustration MCT Seaflow- SeaGen Turbines – UK Installation Devices and technologies pictured for illustration / discussion only Does not reflect or imply any PG&E preference

15 USGS Bathymetry Map of SF Bay Ocean Bay maximum depth = 377 feet Source:

16 USGS Bathymetry Map of SF Bay Bay Ocean Source: maximum depth = 377 feet