FUD Zilla writes Intel's one-chip Haswell platform will have a TDP of 11.5W and a "scenario design power" of 7.5W. Devices based on this upcoming SoC will promise a battery life of eight to ten hours. You can expect products based on Intel's one-chip Haswell ULT in Q4 2013.
Intel also referred to this chip as part of its Y-processor line of products, with a 11.5W maximum TDP and scenario design power of 7.5W. This is quite exceptional considering that this is the TDP of the complete SoC. In contrast, the Ivy Bridge Y-processor line had a 13W TDP (7W SDP), and that was only the CPU.
The point of having a BGA package and making a SoC is to lower the production cost, lower TDP and footprint. Haswell ULT is the chip meant for Ultrabooks and tablets where footprint, TDP and lower cost play a key role. This is probably why Intel plans to further drop the Haswell Ultrabooks pricing, as mentioned here.