U.S.-Ireland R&D Partnership: Control Co-Design of Heterogeneous Arrays of Wave Energy Converters

This project promotes the progress of science and advances national prosperity, by studying novel approaches to renewable ocean wave energy harvesting. Oceans are colossal reservoirs of energy. Ocean wave energy converters capture wave power and convert it to electric power.

Despite its potential, this technology is not yet mature, and the current cost of wave power is high compared to other renewable energy sources. Wave energy converters are usually deployed in the form of arrays of identical units. These units are controlled to increase the efficiency of the array in harvesting power at a lower cost.

However, there is a lack of appropriate science and technology to conceptualize and design for the deep interdependencies among the several units in the array and the ocean. To address these challenges, this project establishes collaboration among researchers in the United States, Republic of Ireland, and Northern Ireland that aims to generate innovation and enable wave energy converters to produce power at a lower cost.

The project investigates the wave energy converter arrays from a new perspective in which the array of units is designed and controlled to change the wave field in a favorable way. The results from this research will benefit the national economy and society. This project also links education and research, providing international experience for undergraduate students, and positively impacts society via an outreach program that aims to raise the knowledge level among high school students.

In arrays of wave energy converters, automatic control is one of the most pressing problems and least studied because of dynamic modelling difficulties. Another challenge is the need for reactive power in the power take-off units; that is, take-off units should put power into the ocean at times such that more power can be harvested at other times. This award aims to connect efforts to address these challenges analytically, numerically, and experimentally on a fundamental level.

A new modeling approach will be investigated that assumes the surface pressure as input to the model, instead of the classically used wave elevation. The impact of simultaneously optimizing both geometry and control, among different array units, on its collective performance will be analyzed. Nonlinear hydrodynamic forces will be leveraged for improved performance of this heterogeneous array.

To achieve these objectives, three interlaced approaches will be developed: optimal control analysis, numerical control co-design optimization, and experimentation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.