The global prevalence of Internet of Things devices is projected to exceed 18 billion by 2024 and double within a decade. This rapid growth presents significant cybersecurity and sustainability challenges. We will investigate the intersection of security and power consumption, aiming to optimize energy-efficient security protocols. We will explore technology options for IoT applications, focusing on low-power long-range communication and evaluate the trade-offs between power consumption, security, and reliability. Emphasizing both quantitative and qualitative metrics, we will address the need for comprehensive security features in low-cost IoT devices and the significant impact of their cumulative power consumption on global sustainability.