The Department, with the approval of the Department of Commerce and Economic Opportunity and the governing body of the municipality in which the redevelopment project is located, may sell and convey not to exceed 15% of all the real property which is to be used for residential purposes in the area or areas of a redevelopment project or projects to a Housing Authority created under an Act entitled “An Act in relation to housing authorities,” approved March 19, 1934, as amended, having jurisdiction within the area of the redevelopment project or projects, to provide housing projects pursuant to said last mentioned Act; provided the Department of Commerce and Economic Opportunity determines that it is not practicable or feasible to otherwise relocate eligible persons residing in the area of the redevelopment project or projects in decent, safe and uncongested dwelling accommodations within their financial reach, unless such a housing project is undertaken by the Housing Authority, and provided further that first preference for occupancy in any such housing project developed by the Housing Authority on such real property shall be granted to eligible persons from the area included in the redevelopment project or projects that cannot otherwise be relocated in decent, safe and uncongested dwelling accommodations within their financial reach.
     Any real property sold and conveyed to a Housing Authority pursuant to the provisions of this Section shall be sold at its use value (which may be less than its acquisition cost), which represents the value at which the Department determines such land should be made available in order that it may be redeveloped for the purposes specified in this Section.