I was referring to the extension in 2007, which if anything has
increased energy usage.
One study in one state showed an increase in energy consumption of 1%.
Another study, performed nationally after the most recent change, showed a decrease of 0.5%.
These studies may have an error that's greater than the increase or decrease, and what you'll find is that some organizations and individuals will push one study and not the other based on their personal or organizational bias.
At best you might be able to say that it's unclear whether DST saves energy or not, but as I've shown up above regarding automobile accidents there may be other benefits, including the additional hours of daylight after work that people seem to enjoy.