1 | Program Name or Ancillary Texteere.energy.gov Water Power Peer Review Assessment of Energy Production Potential from Ocean Currents along the United States Coastline Kevin A. Haas Georgia Institute of Technology 11/3/2011

2 | Wind and Water Power Programeere.energy.gov Purpose, Objectives, & Integration Challenges and knowledge gaps addressed: –Provide a full spatial-temporal assessment of ocean currents for the U.S. coastline –A national database of ocean current energy potential that is publicly available –Interactive Geographic Information Systems (GIS) tools for users to assess the scale and the nature of ocean current power Relation to program’s mission and objectives: –Promote development of ocean current energy technology and accelerate the market

3 | Wind and Water Power Programeere.energy.gov Technical Approach Methodology: Host an ocean currents workshop to assess and revise the project methodology. Develop the ocean current energy resource potential database. –Use data to determine which model worked best for different regions. –Create joint velocity and direction probability distributions. Develop a web based interface and GIS tools for dissemination of the data. –Display GIS layers of the monthly and yearly mean and the 2% exceedance velocity. –Provide probability distributions for the velocity and direction. –Calculate the effective power using a specified number of turbines, efficiencies and dimensions. Perform an independent validation of the database. Compute the total theoretical available power.

4 | Wind and Water Power Programeere.energy.gov Technical Approach Key issues: –Spatial-temporal distribution Ocean currents are stochastic in nature; therefore, assessment must be based on probability distributions. Probability distributions require long term time series. Utilizing numerical model simulations of the ocean currents selected based on comparisons with drifter data.

5 | Wind and Water Power Programeere.energy.gov Technical Approach Key issues: –Data accessibility Provide an easy to access, user friendly interface for industry –Facilitate resource investigation Provide basic tools for industry to facilitate preliminary assessment of the ocean current power resource –Identify resources at a location –Download data for further analysis –Filter for depth and/or current speed –Total available power What is the total available power on a national scale?

6 | Wind and Water Power Programeere.energy.gov Plan, Schedule, & Budget Schedule Initiation date: 1 March 2010 Expected Completion Dates –Database/Validation: 30 June 2012 –Webpage: 31 August 2012 –Total Resource Estimate: 28 Feb 2013 This includes a 6 month NCE for doing the total resource estimate Budget: $372,627 Budget History FY2009FY2010FY2011 DOECost-shareDOECost-shareDOECost-share $56,460$158,791

7 | Wind and Water Power Programeere.energy.gov Accomplishments and Results Accomplishments: Held the Ocean Current Workshop, 5-6 May 2011 Generation of the database Decided there was no added benefit to blending additional data into the models Would instead use data to determine which model worked best for different regions Data for testing the model and validating the database Long term data sets are scarce HF radar Drifter buoys Limited ADCP data Cable data Estimating the total available power Based on percentage of kinetic power Can look at the theoretical energy balance

8 | Wind and Water Power Programeere.energy.gov Accomplishments and Results Accomplishments: Created methodology for model selection Selecting the best models for different regions of the coast Model MDRMSDRDSTDCORSKILLSCORE U (m/s) V (m/s) U (m/s) V (m/s) U (%) V (%) U (-) V (-) U (-) V (-) U (-) V (-) HYCOM JPL ROMS

9 | Wind and Water Power Programeere.energy.gov Accomplishments and Results Accomplishments: Generation of joint PDF from model time series –Sort into 10 degree and 10 cm/s (or smaller) bins –Month and year PDF’s

10 | Wind and Water Power Programeere.energy.gov Challenges to Date Challenges: 1.Accurate probability distributions at high spatial resolutions. 2.Number of depth layers to store to minimize storage requirements. 3.Correct assessment of the total available power. Approaches to resolve challenges: 1.Using numerical model simulations, requiring a minimum of 2 years of data, targeting at least 7 years. 2.Will only store depth layers with currents over 0.5 m/s or 50% of the surface current magnitude. 3.Will look at theoretical methods for estimating total power in the Gulf Stream.

11 | Wind and Water Power Programeere.energy.gov Next Steps Regional model selection and database creation –Presently happening –Complete by 5/12 Validation –Presently selecting data –Perform the analysis as the models are selected –Complete by 5/12 Webpage design –Complete by 8/12 Total theoretical/technical available resource calculation –Beginning Summer 12, complete by Fall 12