“…Some researchers have focused on economic aspects (e.g., [12,13]), while others have analyzed policy (e.g., [14,15]) and management dimensions (e.g., [16,17]). Many empirical studies have appeared in different contexts, not only based on a variety of countries, for example, Germany [15], Zimbabwe [18], and Thailand [17], but also type of application, for example, on-grid (e.g., [19,20]) and off-grid systems (e.g., [21,22]). For several decades, technology and costs were assumed to be not commercially competitive compared with conventional energy sources (see e.g., [23]).…”