This study explores the complexities surrounding the adoption of decentralised Renewable Energy Technologies in Spain, crucial for transitioning towards a renewable energy-driven economy. Through a systematic review of both scientific and grey literature, key factors influencing adoption were identified. Utilising the Analytic Network Process method, this research highlights political will, technological maturity, and fiscal incentives as primary drivers. These findings underscore the importance of mature technologies and incentivisation strategies in expediting adoption. Conversely, addressing barriers necessitates a multifaceted approach, presenting challenges for policy formulation. However, the analysis reveals a positive cascade effect, wherein strengthening primary drivers positively impacts others within their domain. This pattern is mirrored in the barriers. Furthermore, the study reveals consistent factors across technologies, adopter types, and regions. The three-axis analysis shows the largest differences in terms of the type of adopter, followed by the type of technology. The smallest differences are found by region, emphasising the unifying influence of the EU framework. This suggests a unified approach to policy design and promotion efforts.