# Rotational Speed Control Using ANN-Based MPPT for OWC Based on Surface Elevation Measurements
## 1 Introduction  
Global energy transformation is the key to reduce climate damages. This transformation would help achieve a cheaper renewable power, reduction of emissions and air pollution, and increase welfare and growth. The World Meteorological Organization declared that the 20 hottest years recorded have all transpired during the last 22 years and the highest four took place in the last four years only [1]. In fact, the IPCC special report on the impacts of global warming of 1.5 \({}^{\circ}\)C states that during the latest decade (2009-2018) the average temperature was about 0.93 \({}^{\circ}\)C more than the pre-industrial baseline, and during the five years (2014-2018) it was 1.04 \({}^{\circ}\)C more than the baseline [2]. For these reasons, many efforts have been invested to reduce the damages of the climate change which can be seen in the objectives set by the Kyoto Protocol (1997) to decrease polluting emissions of five greenhouse gases (GHG); methane, nitrogen oxide, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride aside from the carbon dioxide to a minimum of 5% against the emissions documented in 1985 [3], and later with the objectives set by the 20-20-20 agenda which states that every European Country needs to achieve by 2020 a 20% emission level decrease on GHG from the 1990 numbers, a 20% renewables in the final energy consumption, and a 20% improvement of energy efficiency [4]. Despite these efforts, the average energy that are related to CO\({}_{2}\) releases have escalated 1.3% yearly in the past five years widening the gap between registered emissions and the required emissions levels to reach the globally fixed climate goals [5]. Considering the accelerating climate change damages, the transformation of the global energy system requires significant acceleration to reach the goals of theParis Agreement [6]. Those goals consist of keeping the increase in average global temperatures lower than 2 \({}^{\circ}\)C and preferably to restrict warming to 1.5 \({}^{\circ}\)C during this century. Electrification based on renewables while combined with energy efficiency is the key ingredient of a successful energy transition that can guarantee a lower overall energy demand. This concept can start to reduce energy-related CO\({}_{2}\) emissions immediately and substantially. Moreover, it decreases air pollution and raises health benefits, beneficial socio-economic advantages and can turn into an important factor to form a connected and digitalized economy and society. In this sense, governments should enforce further forceful climate, renewable energy and energy efficiency strategies and goals. Notably, governments ought to line up climate and sustainability objectives with power plans [5]. To fulfill the Paris Agreement on Climate Change, the Ocean Energy Forum established a strategic roadmap to build an ocean energy system for Europe which will guarantee around 10% of power demands of Europe through wave and tidal energy by 2050 [7]. The roadmap highlights the importance of Research and Development to speed up testing and validation of numerous ocean technologies to achieve a commercial maturity and secure industrial deployment [7]. According to the European Marine Energy Centre, many countries have been engaged in projects which concentrate on the development of the Wave Energy Converter (WEC) industry for instance United Kingdom (26 projects), Norway (14), Denmark (9), Spain (9), Ireland (7), Sweden (5), France (4), Finland-Germany-Portugal (2), and Greece (1) [8]. However, since many countries, which are developing WECs, are at various phase of development there exist no mutual ground to define the best configuration, Power Take-Off (PTO) system and control strategies in light of implementation intricacies. Hence, the central point of research, in next years, must change from large scale WECs to the difficulties of developing WECs and adapted projects proper to promote the development of niche markets [9].