Huh? Solar power generation at scale is exactly such a thing. Wind power, too. Also hydroponics are a thing at the industrial scale now as is desalination of seawater. These are not magic bullets but they do fix a lot of things.

because we know how solar, wind works and that is "reality". Basing a model on some imaginary future technology that we don't know is possible or not shouldn't happen in my opinion. It is one thing to think or create different models with possible future technologies taken into it and other to be certain about that happening based on that imaginary technology.