An authority shall have the right to acquire by the exercise of the power of eminent domain any real property which it deems necessary for its purposes under this chapter after the adoption by it of a resolution declaring that the acquisition of such real property described therein is necessary for such purposes. An authority, in its own name and at its own expense and cost, may prefer a petition and exercise the power of eminent domain in the manner provided in § 48-12 and acts supplementary thereto. Property already devoted to a public use may be acquired, provided no real property belonging to the municipality, the state or any political subdivision thereof may be acquired without its consent.