Although the numbers don't look inspiringly different, here are a couple of things to consider:
First, the startup consumption is going to be a bigger part of a HDD than you would think - in order to save power, the disk spins down a lot and hence has to spin up a lot. There will be a lot of these spikes as you use the disk on an ongoing basis.
Second, consider the duration of the usage. The SSD will essentially be on/off - you request a read or a write, it services it, done. The disk will need to (potentially) start up, seek, read/write, spin down. It will be orders of magnitude slower. When running on a battery the quicker you can complete an operation and stop using the device draining power, the better - the SSD is going to win, hands down.
I won't even get into readahead semantics and random versus sequential IO, suffice it to say: the more random and sporadic your disk access is, the better the SSD is going to do. If the laptop is permanently on, reading and writing, with no down time then the difference will not be that great but that is not really a typical usage profile for a laptop.
Best Answer
I don't know of any application, but you could create the conditions you want and run this code on the command prompt:
powercfg -energy -output %USERPROFILE%\Desktop\PowerCFG_Analysis.htmlIt will monitor your system for 60 seconds and then generate an easy to read .html file on your desktop with reported findings.
Save the report, change the conditions and retest.
Source.
I just tried this out and was fairly impressed. It not only tells you about various processes but also the hardware usage.