Planetside, apparently, TUU provides for stupendously safe, efficient and reliable energy extraction from fusion power and natural renewables (solar, tidal, GT).
ST-IV: “Shortly before the fusion age, there was a brief flirtation with nuclear fission”
ST-TNG-Encounter at Farpoint: “Our planet has been blessed with great reserves of geothermal energy”
I mean, the Sun outputs a prodigious amount of energy. As long as they’re pulling TUU out of their sleeves, they can declare it builds a powersat that turns 99.99% of the whole spectrum that hits it, from longwave radio to gamma, into electricity, and beams it down to Earth safely on a subspace whatchamacallitphased beam.
And the mentality behind Trek would NOT put a large M/A reaction chamber on the surface of an inhabited planet. If the containment field fails, you can’t jetisson, and as soon as the antimatter touches the floor, you just detonated the nuke to end all nukes. So M/A is more likely to be used in space, by starships and the like, than to light up cities. As to where they get the antimatter, in our corner of space the tricky part is holding on to antiparticles generated from atomic decay and collissions long enough to actually add up to something – it probably involves dilithium, the “magic ingredient” of Trek technology; and somewhere, the Federation equivalent of the NRC has some huge particle-accelerator plants orbiting close to stars, sucking up prodigious amounts of their energy in order to turn hydrogen into antihydrogen.
BTW, given proper planning/zoning, population control, AND a world in which “income distribution” and “resource allocation” are trivially dispatched by TUU, you could theoretically optimize Earth into pleasant habitable cities and large green areas without deliberately purging the proles. And in the TUU vision it’s more likely that the method was entire fields of endeavour being overregulated out of existence on Earth and people just leaving for where they could, say, be prospectors, salesmen, miners… or even, play lawn darts, ride bikes w/o helmets, smoke. Part of the Rodenberrian utopia is that on Earth not only do we no longer have to be a part of the financial rat race, but neither do we do anything that’s “bad for us” (Wesley wondering to Tasha how could anyone do drugs :rolleyes: ). THAT is where, to me, it runs into bitchin’ verosimilitude problems.