(a) A taxpayer may, to the extent authorized pursuant to the climatetech tax incentive program established in section 16 of chapter 23J, be allowed a credit against its excise due under this chapter equal to the sum of 10 per cent of the excess, if any, of the qualified research expenses for the taxable year, over the base amount, and 15 per cent of the basic research payments determined pursuant to section 41(e)(1)(A) of the Internal Revenue Code; provided, that the terms "qualified research expenses", "base amount", "qualified organization base period amount", "basic research" and any other terms affecting the calculation of the credit shall have the same meanings as defined in said section 41 of said Code unless the context requires otherwise. In determining the amount of the credit allowable under this section, the commissioner of revenue may aggregate the activities of all corporations that are members of a controlled group of corporations, as defined by 41(f)(1)(A) of the Internal Revenue Code, and may aggregate the activities of all entities, whether or not incorporated, that are under common control as defined in section 41(f)(1)(B) of said Code.