# Future Renewable Energy Communities Based Flexible Power Systems
## 1 Introduction  
In order to approach how renewable energy sources are essential to human life, it is important to consider what people need to survive. These needs are related to air (pure), water (clean), food (healthy and nutritious), space (comfortable to live), limited reproduction (to guarantee the continuity of the species), and the amount of energy required per capita (preferably renewable in order to maintain sustainable conditions) [1, 2, 3]. If any of these items are missing, the human being does not survive, which means that climate change threatens our existence. According to World Wild Life (WWF), some of the long-term effects of global climate change are temperature rise, frost-free season lengthen, change in precipitation patterns, droughts and heatwaves, hurricanes, sea-level rise, and arctic ice-free. Recent events such as the COVID-19 pandemic, fires in Australia and gas shortage in Texas uncovered the need to bolster resilience through sustainable development. In 2015, the Paris Agreement was a landmark in which 196 countries committed to lower their greenhouse gas emissions in order to limit global warming to 1.5 \({}^{\circ}\)C [4, 5]. Since then, the number of private companies publicly committing to reduce their carbon footprint is rising. According to the Science-Based Targets initiative (SBTi), 1494 companies are taking climate action, 744 with science-based targets and 589 committed to limitingclimate change to 1.5 \({}^{\circ}\)C [4]. Therefore, it can be inferred that, besides threatening humans' existence, climate changes are affecting the global economy. Climate change has a direct relationship with carbon dioxide concentrations. The amount of CO\({}_{2}\) in the atmosphere has increased along with the consumption of energy from fossil fuels and it was accelerated by the Industrial Revolution. Although the energy matrix has been transitioning from a relatively homogeneous to a diverse range of sources in the past years, fossil fuels are still the planet's main energy source [6]. Thus, prioritizing technologies that accelerate the energy transition from sources coming from the sun instead of those coming from the earth (uranium, petrol, and coal) is essential to guarantee a sustainable planet. According to the United Nations, in order to achieve Sustainable Development it is necessary to work on climate action (Goal 13), to prioritize clean and affordable energy (Goal 7) and to build sustainable cities and communities (Goal 11) [7]. Therefore, greater focus should be given on the importance of the rational local use of energy sources. The local resources can fall into three categories: those coming from the sun, those coming from the earth, and ambiguous ones. Those coming from the sun are welcome, as that is the case with hydroelectric, wind, photovoltaic, thermocouples, tides, sea waves, magneto-hydrodynamics, and others such thermosolars and piezoelectric. Those coming from the earth, such as fossils (oil, gas and coal) and uranium are not welcome because they are polluting and they are limited resources. Ambiguous energies are those that can be welcomed or not, depending on how they are used, but all of them, welcome, not welcome, and ambiguous, depend on good management. In a changing world impacted by global warming, reducing our carbon footprint and consuming renewable energy is not enough. It is definitely necessary to build a resilient system to guarantee energy supply and, consequently, sustainable cities and communities. However, because of the energy landscape's transformation, in which the world is transitioning from centralized to distributed energy resources (DER), it is necessary to improve the current power systems. This paper discusses new aspects of the managing technologies in order to guarantee system efficiency, public satisfaction, and reliability under renewable sources to mitigate climate changes.