The reason there have not been new refineries is the enormous cost. Exxon and others have been expanding existing refineries. But if you’ve got the bucks, knock yourself out
One of the major cost is, as everyone knows, regulation.
One of the major gripes that the oil industry as with Chemical and Electric generation is ever changing regulation.
The regulations in place when you first draw up plans for a plant are not likely to be the regulations in place when you are ready to come on line.
Thus, the plant that you designed at the outset is not the plant that start production. A company is often re-engineering a plant all through construction because the EPA or some other regulator changes governing regulations at some point after they had approved construction.
One of Trump’s platform planks was streamlining regulations. Freezing regulations at the time of construction permit would be a great boon to industry. Even better would be having regulations for a plant frozen for the first 10 years of production.
Pass laws like that and watch the economy grow!