Per Maj. Tom's post and other research, this is how I found the answer for my system. I hope someone finds this helpful.
I found the following 3 commands (run in a terminal window) to be very useful:
"pmset -g"
"pmset -g log"
"pmset -g | grep Assertion"
These commands helped me identify that "Address Book Source Sync" was keeping my MBP from sleeping. I found 20,000+ entries in 1 week -- 1 every 30 seconds!!!
"2014-10-14 00:05:44 -0500 Assertions PID 17685(AddressBookSour) Released PreventUserIdleSystemSleep "Address Book Source Sync" 00:00:30 id:0x100001ab2 [System: No Assertions] "
The counterintuitive thing is that I did not have my Contacts set to sync with iCloud. So I checked the box to sync Contacts with iCloud and for the past few days my MBP has been sleeping well and using very little battery power to do so. See the timestamps of the 3 "Charge: xx%" messages in the excerpt from "pmset -g log" below:
Time stamp Domain Message Duration Delay
========== ====== ======= ======== =====
UUID: D5905EA6-89A9-4E0F-8556-54433B1607F5
2014-10-27 21:00:23 -0500 Sleep Entering Sleep state due to 'Clamshell Sleep': Using BATT (Charge:79%) 4229 secs
2014-10-27 21:00:27 -0500 PM Client Acks Delays to Sleep notifications: [com.apple.apsd is slow(3636 ms)]
2014-10-27 22:10:50 -0500 Kernel Client Acks Delays to Sleep notifications: [powerd is slow(3641 ms)] [AppleThunderboltNHIType1 driver is slow(msg: WillChangeState to 2)(2071 ms)] [en0 driver is slow(msg: WillChangeState to 0)(2147 ms)]
2014-10-27 22:10:52 -0500 DarkWake DarkWake [CDN] due to EC.SleepTimer/SleepTimer: Using BATT (Charge:78%) 0 secs
2014-10-27 22:10:52 -0500 Kernel Client Acks Delays to Wake notifications: [en0 driver is slow(msg: DidChangeState to 2)(1871 ms)]
2014-10-27 22:10:52 -0500 Sleep Entering Sleep state due to 'Maintenance Sleep': Using BATT (Charge:78%) 35162 secs
2014-10-27 22:10:53 -0500 PM Client Acks Delays to Sleep notifications: [discoveryd is slow(1281 ms)] [com.apple.apsd is slow(1789 ms)]
2014-10-28 07:56:47 -0500 Kernel Client Acks Delays to Sleep notifications: [AppleThunderboltNHIType1 driver is slow(msg: WillChangeState to 2)(2071 ms)] [PRT0 driver is slow(msg: SetState to 2)(429 ms)] [AppleHDADriver driver is slow(msg: SetState to 1)(413 ms)] [AppleHDADriver driver is slow(msg: SetState to 1)(468 ms)] [AppleIntelFramebuffer driver is slow(msg: SetState to 2)(729 ms)] [NVDA driver is slow(msg: SetState to 2)(795 ms)]
2014-10-28 07:56:48 -0500 Notification Display is turned on
2014-10-28 07:56:54 -0500 Wake Wake from Standby [CDNVA] due to EC.LidOpen/Lid Open: Using BATT (Charge:78%) 316 secs
2014-10-28 07:56:54 -0500 HibernateStats hibmode=3 standbydelay=4200 rd=330 ms
2014-10-28 07:56:54 -0500 Kernel Client Acks Delays to Wake notifications: [en0 driver is slow(msg: DidChangeState to 2)(1876 ms)]