Intel has recently said that its new platform, the one to replace quite successful Calpella, simply codenamed Huron River, is supposed to have better battery life.
The heart of the platform is 32nm CPU with GPU in dual and quad-core versions and this CPU should have better thermals than the existing Arrandale 32nm CPU with 45nm graphics.
This is something that you could easily suspect but we expect that most of the TDP savings will come from the graphics side, as in Sandy Bridge GPU is a monolithic part of the same chip while in Arrandale we are talking about two cores on the same socket, and graphics is stuck at 45nm which is obviously more hot and bigger than 32nm.
We don’t know the exact percentage and how much lower Huron River can go, but we are quite sure that it won’t be a miraculous number, simply as you cannot save that much compared to Arrandale's quite low TDPs.
Sandy bridge also have De-Muxed EDP to provide concurrency with discrete graphics that is supposed to reduce the power consumption, but this is another story altogether.