I would go to March 1886, Great Barrington, Massachusetts, and I would seek out William Stanley Jr.
Stanley had already built the first practical transformer and was demonstrating a complete high voltage AC transmission system. In 1886, his system transmitted electricity along Main Street and stepped it down for individual businesses. This was one of the critical technological foundations of the modern electric grid.
From there, I give him the conceptual roadmap for the electrical civilization that follows his work. I know enough about how modern renewables work to give him some good ideas. Oh and involving Westinghouse would be important and pretty much inevitable. This would be easier if I could prepare like, a binder, but I could still potentially help with just what I happen to know.
The goal is to go back when petrochemicals as an industry were still weak enough to be slain. If I were successful it would be one of the most outsized positive impacts I could have on the course of human history.