Muon-catalyzed nuclear fusion, once called cold fusion before that name was usurped by pseudo-scientific theories in the 1970s, became the leading source of energy in the post-peak oil world, generating enormously abundant energy despite its initial expense. The first fully functioning reactor of this type was the Atmos Ring in Griswall, adapted from the Aurelia Superconducting Synchrotron Laboratory particle accelerator. A joint project between the government and Neucom, the Atmos Ring pioneered the use of muons only as an initial catalyst to create a positive feedback loop in which temperatures inside the magnetically-confined reactor rise as deuterium-tritium fusion takes place, quickly negating the need for more muons. The reactor was designed to be replicable on other particle accelerators, and Neucom's conversion of several aging particle accelerators in Osea and Usea into fusion reactors revolutionized Western electrical infrastructure, and although General Resource focused on building new fission plants in the 2020s, they too began utilizing fusion power in the next decade.
Despite the abundance of energy brought about by the rise of nuclear fusion, it has also resulted in new disputes over resources. The key role of lithium-6 in distilling tritium brought another valuable use to the rare metal, which grew increasingly scarce throughout the 21st Century due to its applications in electronics, fuels, and alloy production. Neucom's heavy investment in Leasath, however, supplied them with constant lithium exports while General Resource's puppet governments in the southern Verusan continent mined for the metal extensively with varying degrees of success.