So, let us assume for a moment that the Singularity is going to happen. We are all going to get eyes that can see UV, near-infrared, have infinite zoom, and biomechanical chips in our head will allow us to record and upload anything we see to a matrix that will make the Internet look like the telegraph. Synthetic myomers and carbon fiber nanotubes will allow us to become faster, stronger, and have greater endurance than the heroes of myth. Sort of like the Borg, but with better fashion sense.
And our caloric intake is absolutely going to go through the damned roof! Really, short of implanting nuclear batteries, or converting our spleens into fuel cells, we are going to need some way of providing energy for all these wonderful new toys. So, what about solar power?
Last night I was reading yet another article on sunscreen, and Point 4 combined with Comment #7 and Comment #12 deep in my sub-conscious, and then burst forth right as I turned out my light and my head hit the pillow. What if, instead of simply absorbing UV radiation and releasing it as stray electrons, sunscreen was made up of nanomaterials that could absorb the radiation and instead of releasing it, concentrated the electrons and stored them, or channeled them into whatever bionic doodad needed it?
These solar collectors could be part of the standard nanotech package that every transhuman child receives, and would act foremost as protection against the malignant rays cast upon our planet by the Evil Daystar!
These nanomachines would pull double duty as solar cells, channeling energy into devices that needed it, but their efficacy would be limited by their relatively scarcity in the body. However, if a person finds that they have a huge demand of power, or their fuel-cell spleen is in need of a recharge and no cheap whiskey is available, the nanomachine sunscreen could be directly applied to the skin providing a significant boost of power. Cheap brands would lose efficiency and be flushed from the body after a period of 6-8 hours, but more expensive sunscreen would actually permanently boost a person's power generation capabilities and resistance to UVA and UVB radiation.
Now, I just hope the Singularity gets here before I die of old age.