Energy independence makes life offshore more fun. No one wants to stress over the voltmeter or run an engine for hours. In the old days, independence meant going without, but modern solar energy technology can make life not that different offshore.
Energy, like any problem of consumption, involves balancing generation and consumption. You will be in a deficit if you don't generate at least as much as you consume. To a degree, you control both sides of the equation on your boat. You must minimize consumption by consuming only what you need as efficiently as possible. This means using things like LED lighting, efficient refrigeration, and turning things off when you aren't using them, as your mom always told you.