system
Given the following post, respond as if you're commenting on Reddit:
human
Solar power is becoming more efficient and cost effective over time. Are there any fundamental physical limits as to how efficient it will get?

A related question to do with the economics of solar vs fossil fuels. 

If the cost of solar power approached the cost of oil, I assume oil producers would lower their prices to compete. But there are fixed extraction costs. At what point would the cost of extracting oil no longer be economically viable? 

In other words, at what solar energy price would it make no sense to recover oil at all? How far away from that are we in terms of years?
gpt
The limit is 33.7% for a solar cell with just one type of photovoltaic. Adding multiple layers will increase the limit towards 86% as more and more layers are added. 

This limit is called the Shockley-Queisser limit. 

Edit: This limit only applies if a p-n junction is used. Limits for solar energy processing are different.