This article is about a 19% drop in the last 2 months. Alternative energy methods didn’t increase in popularity/use enough in the last 2 months to cause that much of a drop. The article uses a decent amount of actual data analysis and sources and shows a pretty clear causality between the growth of supply and the stagnation of demand that led to the price drop.
Renewable energy has definitely led to an overall drop in price over the last 15 years but it wouldn’t cause a drop this drastic without a huge increase in use or improvement in technology.