system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is photosynthesis so hard to replicate in a machine?

I've always wondered why we don't make solar panels work like artificial plants, and I assume it's because it's too hard. But why?
gpt
For the second part: because we don't need sugar, we need energy. Photosynthesis is very inefficient, the plants are around 0.1 - 2% efficiency (solar power converted to chemical energy) which is abysmal, and unusable for us. If you want to convert this chemical energy to electrical energy you will lose a big chunk of this stored energy again. Not to mention that photosynthesis requires a constant flow of raw materials and water, which is a possible point of failure.
  
While our solar panels current efficiency is around 20%, and there is still room to grow. Based on the Shockley–Queisser limit our panels can convert up to 33.7% of the solar energy to useable electrical energy. And they don't require any raw materials after they are installed.