Solar is completely sufficient for 99% of applications.
Do we know how to store it properly yet? How does solar pan out in case of surge ( eg : very cold winter night )
Anyway unlike fusion, seasonal thermal storage is viable and available now, and will be scaled up in immediate future. Also, with electrical vehicles inducing massive investment into the grid, there will be both pressure and resources to solve the rest.
Fine. How do you power a Europa base with Solar? A Neptune probe?
Moon base can be fine with power beamed from a satellite or plain mirrors in orbit, no atmosphere in the way. Might end up being still cheaper than hauling nuclear reactor there plus all the infra to reliably dump waste heat from it.
I guess you're right that solar is useful for 99% of spacecraft -- in that they use it currently. Not a very useful observation
"and many other applications"
Power in polar regions. How well does Solar work in Antarctica? Or Alaska for that matter?
The main difference is that literally anybody can make it, not just "oil exporting countries" and "fuel refiners". And, will. And export excess production when local tankage is full.
Either that or a place near one of the poles where you get water and lots of sunshine. A small fission reactor is a handy thing to have, however.
> Fine. How do you power a Europa base with Solar?
A lot more solar panels, or wire loops harnessing Jupiter's magnetic field and Europa's momentum, etc. Fission is still cool for that.
> A Neptune probe?
Now we enter the nuclear fission territory. Maybe fusion, some day.
For those interested in near term answer:
https://www.nasa.gov/mission_pages/tdm/fission-surface-power...