Section 4
SEC. 4. This franchise shall continue for a period of twenty-five years from the date of approval of this Act and is subject to the express condition that the same shall be null and void unless the construction of said plant be begun within one year from the date of approval of this Act and be completed within two years from said date, except when prevented by an act of God or force majeure, martial law, riot, civil commotion, usurpation by military power or any other cause beyond the grantee's control.