This type of layout has many advantages. Obviously, you can reduce the costs to transmission. A distributed system like this is also very robust; in one generator breaks, the house will just use more power from the grid, without causing any major problems. If the systems of use are diversified, they will also be robust to loss of one source of Energy (such as a drop in the wind). On the flip side, the generating systems are as unlikely to be as efficient due to their small size.
There are currently attempts in the UK, to ease planning regulations for this sort of generation system.