Focusing on the security architecture and key technologies of the NB-IoT Energy IoT, this paper first analyzes the new characteristics of the energy system under the "dual carbon" goal and the supporting role of the energy IoT to the "dual carbon" goal from four aspects: mapping carbon footprint, optimizing energy supply, optimizing energy trading, and building a two-way information flow. Then, it summarizes the characteristics and requirements of the energy IoT, and summarizes the matching relationship between NB-IoT LPWAN and the energy IoT. It explores the energy IoT security architecture including the NB-IoT security module and security service platform, and focuses on the analysis of eSIM+ESAM NB-IoT security module hardware, NB-IoT security module software based on the GlobalPlatform trusted framework, and key technologies for security management of the IoT cards based on blockchain. It can provide safe and credible LPWAN IoT solutions for energy production, transmission, storage, transaction and consumption. It also supplies credible data support for the construction of a clean, low-carbon, safe and efficient energy system, and helps achieve the "3060 dual carbon target". This work is supported by the National Natural Science Foundation of China (No. 61803345, No. 51807013, and No. 52177068).