I just read in Wikipedia that Arizona does not observe DST due "in large part … to energy conservation since the temperature in and around Phoenix and Tucson is hotter than any other large U.S. metropolitan area during the summer, resulting in more poiwer usage from air conditioning units and evaporative coolers in homes and businesses. An extra hour of sunlight while people are active would cause people to run their cooling systems longer, thereby using more energy".
Whether that's true or not, it was an interesting data point, since one of the benefits of Daylight Saving Time was to conserve energy (e.g. by requiring less electricity for illumination). By that standard, if not observing DST is what will conserve more energy, it would make sense not to observe it, by the same rationale as other locations observing it to conserve energy.