Is chrome OS as energy efficient as mavericks?

Has anyone done a battery life test comparing runtime and normalizing with the wh of the batteries used and chips used?

The haswell parts are 15w tdp correct? That's the same as the 15w tdp i5 models on the macbook airs, but do those still use more energy because they are higher tier?

I'm curious because even with the improvements with the surface 3, battery life in apples OS still seems to mop the floor compared to windows, so if chrome OS can perform similarly or better, it would make it even more appealing for people demanding max battery life and not wanting to go high end on the apple side.

Imagine a 13-15" chromebook with a 60-80 WH battery, high quality 1080p display, with just enough energy efficiency to do as well as if not better than the macbook airs? Durable plastic construction for lighter weight, no license fees for software. It could be the perfect browsing machine. The chromebooks don't have to stay ultra low end, the only one so far with a decent display is the hp model, and you sacrifice battery life and raw performance.

Why can't google just make a chasis like that 15" chromebook concept posted in another thread

https://www.youtube.com/watch?v=IGC6zBPPL9A

And just fill it with this y series intel i3 part that has an even lower than 15w tdp

http://ark.intel.com/products/76609/Intel-Core-i3-4020Y-Processor-3M-Cache-1_50-GHz

Why do they continue to only play on the absolute gutter level bottom end, they could charge hundreds more and still win people over if they offered enough value.