The Benq Zowie XL2735 and the XL2540 certainly do not consume a lot of energy. Despite the fast panels they are remarkably high up on the list. All of the red bars (= wqhd-models) are at the bottom, with the exception of the Dell S2716DG and the XL2735. The last one is slightly more economic when it comes to power consumption.
The power consumption at equal brightness is a relatively new test, which means there are less models in the graphs. Nevertheless the Benq models perform well here. Especially the 20 watt of the wqhd XL2735 is impressive.