Relative efficiency of different commute bike setups
Jan Heine performed some wind tunnel tests of "Real World Aerodynamics" a few years ago. A link to a blog post (and the results published in Bicycle Quarterly) can be found here. Those tests cover only one component (the aero drag component) of commuter-type bicycles vs. "racing" bikes.

If you want to make your own apples-to-apples comparisons of performance potential between any number of bikes of any type there are five pieces of information you need to know:


how much power you produce on that particular bike;
how much (you and) the bike weighs;
the Crr for that bike;
your CdA on that bike; and
how much of your power is lost in the drivetrain.


With those five bits of information you can compare the performance of a road racer to a TT bike to a penny farthing to a velomobile to a MTB; on a hill, on the flat, on a descent, on a velodrome. Of course, those five variables won't tell you if the bike fits, or if it handles well, or if it has a way to carry your groceries and laptop and change of clothing, but as far as performance goes, that's all you need to know.

A good bathroom scale will help you measure 2). Since you have a power meter, there are field test methods and protocols that will help you determine 3) and 4).

1) explores whether you can produce more power on one bike than another, because of positioning (for example, many riders find they produce lower power in a TT position than in a traditional road racing position) or crank length or gearing (for example, some riders find they produce less power on a single-speed than on a multi-geared bike).

Finally, 5) measures losses in the drive train, such as in a fixed-gear or with an internally-geared hub like the Alfine. In general, measuring losses in the drive train can be expensive because you need a way to measure power at each end of the drive train. See Kyle and Berto here, for an example of a rig used to measure losses. A similar rig was used by Spicer here. However, if you have a crank-based power meter (and, if you're using an Alfine then I suspect you must), it is possible to use the crank-based power meter to measure power at one end of the drive train and then use "virtual elevation" methods to measure the power at the driving wheel. A detailed description of the protocol is long but a quick description is to climb the same hill on a calm day with different configurations. Since the hill is the same and the conditions are calm you know that the "virtual elevation" should match the true elevation profile of the hill; so if you can measure power at the crank then differences in observed VE must be the result of differences in losses in the drive train.