Any ideas for how to use solar to offset electricity in an apartment?
You could add a regulator (appx $88 at a local supplier) and storage battery(ies) ($77 for a 35AH, same supplier), to feed low voltage lighting ($11 per 750 mah array) at night. However, since you are paying around $0.11/KWH at the wall, it will take a long time to break even on the expense of a) battery b) regulator, c) wiring, and d) low voltage lighting. The same money spent on increased insulation would likely provide a much quicker return on your investment.