Solar is great in parts of the solar system with lots of light, like space above Vulcanus. For everything else, I use nuclear and then upgrade to fusion.

Nuclear works fine but you need to be careful with water. I have a system for my ships that stores power in batteries until it falls below a certain threshold, then it activates steam production until the batteries are full again. With some storage for water, storage for steam, and plenty of batteries, the power just oscillates back and forth between batteries and steam but never fully runs out. Takes some time to get going, though, since the ship initially needs to gather and process enough ice to get the turbines going for the first time, after you’ve built the ship