The purposes for which bonds may be issued shall be: To acquire, purchase or improve a school site or school sites; to build a schoolhouse or schoolhouses or other building or buildings; to demolish or remove school buildings; to add to, remodel or repair any existing building; to furnish and equip any building or buildings, including all lighting, heating, ventilation and sanitation facilities and appliances necessary to maintain and operate the buildings of the district; to purchase school buses and to acquire, develop or renovate school facilities to establish, create and develop renewable energy systems as described in section 33-604, Idaho Code. The provisions of section 33-906, Idaho Code, shall not apply to bonds or portions of bonds issued to acquire, develop or renovate school energy systems as authorized in section 33-604, Idaho Code, when the school district begins to sell thermal energy for revenue as authorized in section 33-605, Idaho Code.