Solar doesn't much compete with petroleum. Its main effect is to reduce prices for coal. You'd expect that this might start to affect the profitability of coal companies eventualy....

For solar to affect petroleum, whose primary use is transport, we'll need to solve the storage problem. Tesla notwithstanding that has not happened. Electric vehicle sales were 0.66% of unit auto sales in 2015, and actually represented a sharp numeric decrease from 2014.

(The dollar volume is higher given the higher price of electrics, but it's unit sales you want to watch.)