Cold fusion is a means of producing energy at the atomic level. On Hadante, Linea used her "activators" which interacted at the sub-atomic level within the cells of the tare root to create organically based cold fusion. The activators spirit the sub-atomic particles to combine within the cells of the tare root, and as new material is made, energy is released, flowing through the tendrils of the plant. Linea and SG-1 were able to use her cold fusion energy source to power the stargate, allowing them to manually dial the gate and escape from Hadante prison.
Cross Reference: Hadante, Linea, Manual Dial
Episode Reference: Prisoners