

A staple of Sci-fi like Star Trek is that not just power generation, but storage and transmission are also trivial. They have any number of ways to transmit energy across large distances, between ships etc.
As an example, this already exists: In a First, Caltech’s Space Solar Power Demonstrator Wirelessly Transmits Power in Space
I imagine one of the ways for planet level energy generation would be solar panels in space and transmitting to earth somehow. I don’t know whether that is feasible IRL anytime in the next 200 years but in a “sci fi setting” its probably the most reasonable idea that is not just “magic” IMO.
So maybe one realy big solar panel array, or a planet wide coverage of many smaller arrays coordinated for sharing load with dozens of transmission points down to Earth would be my solution to your question.
I don’t get the point of this comparison with China unless you also look at Chinese computer industry in the same time period.
Whatever criticism you may have of the USSR’s rate of adoption how is this comparable to the Chinese experience in the 21st century? China can only have a computer industry at all because of the decades they spent being friendly with the west, having all their factories at home and proactively not giving a shit about patents and copyright.
If the USSR had the opportunity to have iPhone factories in Moscow perhaps history would be different too otherwise what is the point?