The MARES Project: Development of a New Wave Energy Power Take-Off Based on a Superconducting Switched Reluctance Machine

Abstract

In a report published in 2021 by the Bank of America Global Research entitled "To the Moonshots: Future Tech Primer", 14 technologies for the future were listed and analyzed. One item of this list is Oceantech, including harvesting the ocean energies to also produce electricity. The report forecasted that by 2030, the ocean global economy (obviously including much more aspects than solely energy production) will be equivalent to 2010 German GDP, existing a general consensus on the tremendous impact and activity that it may generate in ocean energy generation, including that required for activities associated to the blue economy..

The ocean electric power that can be converted from an ocean planar wave is proporcional to the wave period and to the square of the wave amplitude but, to extract the maximum available power from the wave, the system must be able to be tuned which means having the availability of producing high reactive forces (proportional to its displacement or to its acceleration) which can be even higher than the required active force for producing energy. Consequently, Power Take-Offs (PTO) have always been at the focus of the research, development and innovation in the wave energy sector and they have been one of the main priorities for wave energy during the last years. As a result, the European Commission has funded several projects in recent years addressing its development and optimization under the Horizon 2020 calls, such as OPERA, WaveBoost, WETFEET, IMAGINE and SEA TITAN.

MARES is a recently granted Horizon Project proposing the development of a novel concept for a PTO able to produce the required big forces very efficiently and in a compact way (high energy density) and disregarding permanent magnets-based solutions requiring enormous quantities of rare.earth materials. The use of a simple generator topology (such as a cylindrical switched reluctance machine) and novel superconductors such as HTS or MgB₂, make the proposal even more attractive not only for wave energy conversion but also for other applications where very high force density are required.

This paper will first introduce the MARES Project to describe next the conceptual design of the superconducting generator prototype, a machine that will include both technologies of new superconductors and that will be also fabricated and tested by the MARES consortium. The project also includes the implementation analysis of this PTO into two real cases of Wave Energy Converters