This chapter introduces concepts to understand, formulate, and solve a microgrid design and optimal sizing problem. First, basic concepts of energy potential assessment are introduced, in order to determine if a location is suitable for PV and wind generation systems implementation. Second, different modeling approaches are presented and the required characteristics for the optimal microgrid sizing problem are discussed. Third, basic concepts about load estimation for the design and sizing of microgrids are introduced. Fourth, the most common microgrid sizing criteria are presented and classified according to the type of analysis. Fifth, basic concepts related to multi-objective optimization are introduced and some common design approaches and optimization algorithms are presented, emphasizing into multi-objective genetic algorithms. In addition, microgrids design commercial software is reviewed. Sixth, some IEEE standards related to the design, operation, and implementation of microgrids are presented. Finally, the chapter concludes with key remarks on microgrid design and sizing problem.

Reliability analyses are essential for the design of hybrid photovoltaic/wind/battery systems. The selection of design criteria is an important task and has to ensure proper reliability and optimal configuration. In the literature, loss of power supply probability (LPSP) and loss of load hours (LOLH) are the most common reliability criteria used for this matter. This study presents a comparative analysis on LPSP and LOLH design criteria based on a Monte Carlo simulation, taking into consideration uncertainties in the variables involved in the design process. Moreover, two new statistical design criteria are proposed, aiming to avoid over-sizing of the optimal configuration. According to the obtained results, LOLH is a stricter design criterion compared with LPSP, leading to a more reliable energy system. In addition, the optimal configuration selected by using the proposed statistical design criteria showed better performance when compared with the solution based on LPSP or LOLH.

Currently, the trend of micro-grids and small-scale renewable generation systems implementation in urban environments requires to have historical and detailed information about the energy potential resource in site. In Colombia, this information is limited and do not favor the design of these applications; for this reason, must be made detailed studies of the energy potential in their cities. In this paper is presented the wind and solar energy resource assessment for the city of Bucaramanga, based on the monitoring on four strategic points during the years 2010, 2011 and 2012. According to the analysis, is evidenced a significant solar resource throughout the year ascending on average to 1 734 kWh/m², equivalent to 4.8 kWh/m²/day. Also, from a wind statistical study based on the Weibull probability distribution and Wind Power Density (WPD) was established the wind potential as Class 1 according to the scale of the Department of Energy of the United States (DOE), since the average speed is near 1.4 m/s. Due this, it is technically unfeasible the using of micro-turbines in the city, even so their potential for natural ventilation of building was analyzed. Finally, is presented a methodology to analyze solar harvesting by sectors in the city, according to the solar motion and shadowing caused by existing structures.