On the other hand, if your system keeps your RAM always full (as Mavericks appears to do), it can save SSD energy. I guess battery consumption increase will be marginal in Mavericks, but benchmarks are needed for a real life evaluation.
It will use more battery in the same way as carrying around a small bottle of water in your car will increase the fuel consumption due to the extra weight. The amount of energy used by the RAM is negligible compared to the major heavy lifters in the laptop - the screen, the CPU and the GPU (assuming one is fitted). These things dwarf everything else inside the machine in terms of power draw. The next closest things I would wager would be the SSD during writes, and the USB controller if you have something plugged in that requires a lot of juice (like charging an iPad or similar).
Someone should be worrying about how much battery a better processor would use up. Not this. People should really just enjoy their machines.
I'm sorry but I can't believe this thread. If you're worried about the impact of ram on battery life.. man.. I guess that's one of the problems with the internet. Minutia become mountains.
While every hardware addition may change it slightly, shouldn't be a significant amount either way. Apple's battery life claims and however they arrive at the numbers have been altered in the recent years (remember when all the MBP line had a 10 hour claimed battery life?) for the better, as every device we see released seems to exceed the claimed by quite a bit. I'm sure part of their testing is to test all possible configurations simultaneously and make sure they all fall close enough to each other to claim 8 hours across the board. Even still, I don't think there's necessarily more hardware for the 16GB configs, just denser chips that may have the same power rating as the less dense chips.