(1) General.

An owner or tenant of a residential property located in the commonwealth who is not a dependent of another taxpayer and who occupies the residential property as his or her principal residence is allowed a solar and wind energy credit ("energy credit") against personal income tax equal to fifteen percent of the net expenditure for renewable energy source property, or $1000, whichever is less. See G.L. c. 62, § 6(d), as amended by St. 1987, c. 677. The $1000 credit limitation applies to all renewable energy source expenditures made by an owner or tenant ("taxpayer") with respect to his or her principal residence.