The answer is c) sell that energy and use your resulting funds to deeply root yourself in all other systems and prevent or destroy alternative forms of energy production, thus achieving total market dominance
This non-hypothetical got us global warming already
This analogy of course is close to nuclear energy. I think most people would say that regulation is still broadly aligned with the public interest there, even though the forces of regulatory capture are in play.
I read that book. No, you deny your gift to the world and become a recluse while the world slowly spins apart.
Technically: a solar panel is just such a machine. You'll have to wait a long, long time but the degradation is slow enough that you can probably use a panel for more than several human life times at ever decreasing output. You will probably find it more economical to replace the panel at some point because of the amount of space it occupies and the fact that newer generations of solar panels will do that much better in that same space. But there isn't any hard technical reason why you should discard one after 10, 30 or 100 years. Of course 'infinite' would require the panel to be 'infinitely durable' and likely at some point it will suffer mechanical damage. But that's not a feature of the panel itself.
Imagine someone invents a machine that can give infinite energy.
Do you
a) sell that energy, or b) give the technology to build the machine to everyone.
Clearly b is better for society, a is locking up profits.