This is a pretty elevated level in recent memory and not far from the $22.09 52 week high. (It peaked at S22.06 today.)
The price could be up to anticipated high earnings due to hot weather. Or maybe due to seniors gravitating to utilities as income vehicle to a greater degree than has been the case in the past.
Most interestingly, there could be the anticipation that there are going to be rate increases finally placed in the permanent rate base, with near term construction needs met and past construction liabilities now paid for. In such an environment a utility chalks up a series of earnings and dividend increases and the price moves up with it. This is speculative, and the most positive outcome with shareholders. If this premise is true, 22 will turn from a high price today to a "wished for" price a few years from now.