Background: Large-scale fusion reactors using hydrogen isotopes as fuel are still under development at several places in the world. These types of fusion reactors use tritium as fuel for the T +D reaction. However, tritium is not a sustainable fuel to use, since it will require fission reactors for its production, and since it is a dangerous material due to its radioactivity. Thus, fusion relying on tritium fuel should be avoided, and at least two better methods for providing the nuclear energy needed in the world indeed exist already. The first experiments with sustained laser-driven fusion above break-even using deuterium as fuel were published already in 2015.Results: The well-known muon-induced fusion (also called muon-catalyzed fusion) can use deuterium as fuel. With the recent development of a high intensity (patented) muon source, this method is technically and economically feasible today. The recently developed annihilation energy generation uses ordinary hydrogen as fuel. Conclusions: muon-induced fusion is able to directly replace most combustion-based power stations in the world, giving sustainable and environmentally harmless power (primarily heat), in this way eliminating most CO2 emissions of human energy generation origin. Annihilation-based power generation has the potential to replace almost all other uses of fossil fuels within a few decades, also in most mobile applications including spaceflight, where it is the only method which gives relativistic rocket propulsion.