water power peer review

1 | Program Name or Ancillary Text eere.energy.gov

Water Power Peer Review

Direct Drive Wave Energy Buoy Ken Rhinefrank

[Columbia Power Technologies, Inc.][[email protected]][November 2, 2011]

Manta Direct Drive Wave Energy Converter

2 | Wind and Water Power Program eere.energy.gov

Purpose, Objectives, & Integration

Challenges-Barriers-Knowledge Gaps

Wave energy is the only renewable energy source that is not commercially installed. Numerous designs and concepts exist and most are early stage with limited knowledge concerning the actual CoE or ability to operate and survive in this harsh environment.

Furthermore the systems can be complex in design, non-linear in performance and include numerous cost uncertainties such as grid integration and permitting. In real sea conditions, numerical energy predictions can be off by over 40%. Until prototypes are designed built and tested we will not know the true cost of energy or be able to reliably forecast methods of cost reduction.



How Solving Problem Relates to Program Mission

The design and development of a wave energy system is complex and detailed. Only through a staged project development approach, where actual performance and operation are measured and observed experimentally at a sufficiently large scale and where complete system designs are developed, built and tested, can the actual cost of energy can be assessed.



Integration of this Project

Results from this project are used to inform the utility-scale design process, improve cost estimates, accurately forecast energy production and to observe system operation and survivability. Knowledge and experience gained from this project is applied to major program objectives including:

• Design and certification of the commercial-scale system• Land-based test of a commercial-scale generator, bearing and seals• Open-ocean deployment of a commercial-scale DDR WEC in

conjunction with a recognized independent testing center.


Technical Approach

Project Approach

The primary goal of this project is an intermediate-scale (1:7) bay/ocean test of a novel Direct-Drive Rotary Wave Energy Converter (DDR WEC). Key tasks include:

• WEC Optimization– Shape, CG, inertial using AQWA and Wave Dyne numerical models– PTO Controls Optimization

• 33rd scale tank testing, performance and survival analysis• 7th scale testing at sea (design, build, deployment and experiments)• Data analysis of 7th scale results• Integration of findings into Commercial Scale Design


• WEC body optimization complete• AQWA numerical optimization• Over 368 unique shape simulations• 311 unique CG and inertia simulations• 1700+ hours of computer simulation time• “Gen 3.1” 230% energy capture improvement versus

“Gen 3 “ 15th scale• PTO Controls Optimization• Ballast Optimization• Interim Optimization Report complete

Technical Approach


• 33rd scale tank testing and performance analysis complete• Design & Fabrication complete• Testing services and test plan contracted and completed• Regular waves, irregular waves, 50 year and 100 year storm waves• Wave data has been analyzed• Performance measures and RAO’s assessed• Numerical and experimental comparisons in progress, example RAO below

Technical Approach


Technical Approach

• 7th scale Testing at sea (design, fabrication, ops. and experiment)

SEA TRIAL UNDERWAY

Seattle

Deployment Site


Technical Approach

• Data Analysis• Data Collection and Deployment ongoing

Wave occurrence is ~40% of the time in winter Remote WEC data collection through 3G network AWAC data collection through periodic site visits 7-24 surveillance camera Solar power small waves in summer Periodic service visits Periodic battery charges

• Analysis Methodology is developed Third-party review of approach ongoing Statistical characterization of waves Assessment of data quality

• Integrate Findings into Commercial Scale Design• Design in progress


Plan, Schedule, & Budget

Schedule

• Initiation date: December 1, 2009

• Planned completion date: March 26, 2011

– Deployment extended beyond May 2011 by up to nine months to collect more data

• Milestones

FY10 WEC Optimization 33rd scale wave tank experiment 7th scale design

FY11 Permits approved 7th scale fabrication complete Deployment Underway WEC Recovery Data Analysis Commercial design integration


Plan, Schedule, & Budget

• Go/no-go decision pointsFY12/FY13– Performance and cost assessment – Utility scale prototype site selection– Project funding availability for major tasks:

• PTO test• Commercial scale build and deployment

Budget: • Remaining budget will be utilized during remainder of deployment period• 71% of budget utilized to date.

Budget History

FY2009 FY2010 FY2011

DOE Cost-share DOE Cost-share DOE Cost-share

0 0 $573K $573K $601K $601K


Accomplishments and Results

• 230% increase in energy capture

• Successful Design/Fabrication, Puget Sound-Deployment

Knowledge gained through the design, fabrication, test and deployment of a 7 ton intermediate scale WEC is extensive and has proven to be an essential and valuable stage in our technology readiness level.

• Continued operation at sea for over eight months

This milestone is demonstrating a viable technology for extracting energy from ocean waves and provides confidence in our design as we move toward an open-ocean utility-scale demonstration. Preliminary indications of energy generation are on track with

numerical estimates.


Challenges to Date

Prototype Power draw very high

Causes: • Active/Standby design load 60/40 W, design creep and deviation from spec ->105W• 105W = 95 kW full scale equivalent -> “Instrumentation does not scale down well”• Original charge frequency 20 to 25 days with average WEC shaft power of 45W• Deployment extension into summer months (less wave energy)• Power electronics failure

Solutions:• $3k battery charges at 2x per week• Installation of Solar panels kept electronics working all summer without charges• Upgrades to wave energy power electronics• Future systems installed in small scale wave climates need more storage and backup

energy sources.


Challenges to Date

DDR voltage and power variance and high demand on electronics eventually caused failure

Causes: • Cyclic speed and voltage with average levels an order of magnitude lower than peak.• Possible damage due to thermal overload• No commercially viable solution that fit the prototype needs requiring a custom

solution at this scale. • Accelerated design path to meet schedule

Solutions:• Original design and backup designs planned for this failure and applied linear

damping controls even in failed conditions which allowed for continued collection of performance data.

• Redesigned and repaired power electronics.• Commercial design includes cost tradeoffs between voltage peak reduction and over-

specified power electronics.• Post deployment autopsy to find possible cause


Challenges to Date

Wave data analysis at 1:7 scale is difficult in ocean setting

Causes: • Relatively deep water (22m) decreased high frequency response of AWAC• 7th scale spectrum is at the high frequency limit of commercially available and

deployable wave monitoring instruments that were practical at this location.• Regionally available intermediate scaled (1:4 to 1:10) wave climates do not support

larger than 1:7 scale tests.• Lager scales too expensive to test for this level of readiness.

Solutions:• Accept imperfection while assuring data is sufficient (marginally met at Nyquist rate)• Mount AWAC on a mid column buoy to increase frequency response.• Monitor data from AWAC through acoustic modem to WEC and then to shore• Post process time series data into spectral format using in-house code


Challenges to Date

Evaluating 1:7 scale wave data Regions where shipping traffic produces relatively large waves introduce post processing requirements not normally associated with tank testing or utility scale ocean testing scenarios.

Solutions:• Creative post processing

Data collection requirements (frequency and quantity) Prototype test requirements exceed those expected for a final utility application. Data collection and storage for prototype testing requires very high reliability.

Solutions:• Not satisfied with dSpace/PC based solution used this time, alternatives are under

investigation


Next Steps

Continue deployed testing & determine when data is sufficientDaily monitoring, post processing, WEC battery charges, AWAC servicing

WEC RecoveryRemove all equipment

Data Analysis

Commercial design integration

Final report

water power peer review

Documents