FUD Zilla reports the chipset of Intel's 2013 Haswell platform will have a significantly lower power consumption:
Intel has shared some new details with its notebook partners indicating that Lynx Point, a chipset that matches Haswell CPUs in Shark Bay 2013 platform, has a significantly improved power profile. You should expect 25 percent lower TDP and 50 percent lower average power than Panther Point chipset of Chief River 2012.
A word of warning - these are just projected numbers as the chipset has not yet been tested. Remember, Shark Bay is expected in 1H 2013 probably a year from late April 2012 when Chief River, Ivy Bridge 2012 notebook platform hits the market.