Scott Adams (yes, that Scott Adams) has compiled some research on new technologies that would allow homeowners to get completely off the power grid. These technologies include advances in solar panels, lithium-ion batteries made with silicon nanowires, and even micro-nuclear reactors. Oddly, he does not mention residential wind turbines, an existing technology with a long history of improvement.
One issue with these residential power sources is conversion. Most of these technologies produce 12-volt DC, which must be converted to 110-volt AC. Ironically, of course, many household appliances, such as computers, convert that 110 AC back to 12-volt DC. A lot of energy is wasted in those conversions. So to maximize the efficiency of these systems, homes should be wired to accommodate 12-volt DC appliances.
Getting off the power grid is entirely possible — but still prohibitively expensive for most people.