NOMA has emerged as a promising multiple access technique for accommodating a massive number of devices in future wireless networks, owing to its superior spectral efficiency. Simultaneous wireless information and power transfer (SWIPT) offers a sustainable solution by enabling energy-constrained devices to simultaneously harvest energy and decode information from received signals. In this chapter, the integration of SWIPT with cooperative NOMA (CNOMA) is studied under the realistic condition of i-CSI. The system model considers a multi-tier downlink heterogeneous cellular network comprising MBSs and femto-base stations (FBSs), whose spatial locations are modeled using a PPP to capture network irregularities. Unlike traditional approaches where energy harvesting (EH) is performed solely using the superimposed NOMA signal, this work introduces a novel scheme in which the cooperating user node harvests energy not only from the intended signal but also from interference originating from neighboring base stations. This approach allows for enhanced energy harvesting capabilities and supports sustained cooperative communication. Analytical expressions are derived for key performance metrics such as outage probability and system throughput at the NOMA-served user pair, which includes a CCU and a CEU. The proposed EH-aided CNOMA system is compared against existing benchmarks to highlight its advantages in terms of reliability and efficiency. Furthermore, extensive Monte Carlo simulations are conducted to corroborate the analytical findings, validating the accuracy and effectiveness of the proposed model under practical network conditions.