When away from a power socket, I use Safari instead of Chrome. Saves battery a LOT. Was able to run 11" Air with 19 tabs on Safari and with vim (on iTerm). 2hrs later still had 95% battery left.
Were you comparing Safari with 0 extensions vs. Chrome with 0 extensions? Or does each have a different extension load?
I will often fall back to Safari if a page doesn't render properly in Chrome, but that's because I installed a bunch of extensions on Chrome and have consciously left Safari pure as the driven snow. It's a different problem domain, but I know certain extensions can use resources in surprising ways.
What's especially obnoxious about that behavior is that if you disable the dGPU, it works just fine. So what's the point?
Also, one would expect Chrome's own Web Store to work well in Chrome... but Google's attitude toward long-standing bugs is anything but exemplary.
Chrome burns 90% of a CPU on one thread, and another 40% on another. Coconut reports about 32 Watts used. Safari maxes at about 12% plus 8%, and tops at about 15 Watts. Base usage on this machine with the current screen brightness and applications that happen to be open is 10-12 Watts. I get approximately the same results with Incognito mode, which suggests the problem is core Chrome rather than add-ons.