@ the OP: I think the technology is here now. I don’t believe that New Jersey, USA is known for being a particularly sunny location, but some NJ home owners have installed solar panels to offset the majority of their monthly electricity bill.
From a 3-year old Wall Street Journal article:
$170 over 6 weeks prorates to $113.00 and change over 4 weeks. So, per the above Wall Street Journal article, Frank Corradi’s monthly electric bill drops from $140 to $27.00 a month because of his solar panels. ( ETA: Oops! I misread the article. This is partially because at a "green party" I went to over the summer, I met a contractor who designs systems just powerful enough to offset costs but not generate cash flow. IIRC, he did this to minimize the amount of cash the home owner would have to outlay for the system. But in the WSJ article, the home owner who was interviewed made a different choice.)