Is a green cryptocurrency possible?

Could it really be feasible to develop a cryptocurrency that is environmentally friendly, or is this just a pipe dream? With the massive energy consumption associated with traditional cryptocurrency mining, it's a legitimate concern. But is there any hope for a green alternative? Could we potentially harness renewable energy sources, or even develop innovative consensus mechanisms that drastically reduce the carbon footprint? The question remains: is a green cryptocurrency truly a viable option, or is it just wishful thinking?