I've been thinking about this kind of idea lately. Isn't this technically possible? I keep wondering, why do we need to mine all the bitcoins now? Could we not

I've been thinking about this kind of idea lately. Isn't this technically possible? I keep wondering, why do we need to mine all the bitcoins now? Could we not take our time and mine using more sustainable methods? I once met someone with a small solar panel attached to their backpack. It was able to charge a phone a bit. What if that mined? What if a fraction of energy created with solar or even a stationary bicycle rigged up to generate a small amount of electricity could mine? Seems like creating power is more valuable than using a utility. Is it theoretically possible?