Wave energy converters (WECs) can optimize energy production by capturing the full force of ocean waves. Over time, however, the powerful charge of waves can wear down a device. While the operation of a WEC in normal conditions is relatively well understood, how devices can best survive extreme ocean conditions is a major question in early-stage wave energy research—and one being pursued by researchers at the Department of Energy and national labs.
To understand a WEC’s experience over a 20-year deployment lifetime when encountering large waves, Sandia National Laboratories and the National Renewable Energy Laboratory developed the WEC Design Response Toolbox (WDRT). Launched in 2016, the WDRT is an open-source analysis tool that provides industry with the ability to perform extreme response and fatigue analyses. WDRT features include:
- Environmental Characterization: Metocean environmental analysis and statistics
- ShortTermExtreme: Analysis of short-term (sea-state specific) extreme responses
- LongTermExtreme: Analysis of long-term (design life) extreme responses
- Fatigue: Fatigue analysis
- Most-Likely Extreme Response (MLER): Focused-wave construction for efficient high-fidelity modeling.
Earlier this month, researchers updated the WDRT with new functionality in the environmental characterization module. Previously, the tool used a single method to analyze wave climates—which is how researches talk about the characteristics of waves in a given area over a particular time period. The update offers additional methods to provide a more comprehensive picture of wave predictions.
With more than 50% of the U.S. population living within 50 miles of coastlines, creating huge energy demand, vast potential exists to serve this population with locally captured wave energy. Yet every ocean can become violent, and before a cost-efficient industry can develop, devices must be able to survive extreme conditions—without costly over-design—and provide reliable power.
Under extreme conditions, WECs experience large-amplitude motions, wave overtopping, wave slamming, and other physical phenomena that are difficult to simulate. These extreme conditions often dictate how strong a device should be to survive. Predicting extreme loads is a critical step in the device design process.
WDRT provides a solution for researchers and device developers from across the sector to analyze WEC survival. The sector can use WDRT in conjunction with WEC-Sim—another DOE-funded project to model and develop wave energy devices—or with any other numerical or experimental modeling approach or tool. WDRT also provides deployment-focused developers with functionality needed to provide survivability analysis when working with certification bodies.
Sandia National Laboratories and the National Renewable Energy Laboratory are planning to host a webinar to summarize WDRT and demonstrate applications in late spring or early summer. Information about that webinar, when available, will appear here.
The Office of Energy Efficiency and Renewable Energy accelerates development and deployment of energy efficiency and renewable energy technologies and market-based solutions that strengthen U.S. energy security, environmental quality, and economic vitality. Visit water.energy.gov to learn more about the Water Power Technologies Office.