The present invention is realized by apparatus and methods for placing a large utility scale photovoltaic array in the low stratosphere of earth's atmosphere at an altitude of about 20 km, above clouds, moisture, dust, and wind. This is accomplished using a large light-weight, rigid, buoyant structure to support the large photovoltaic array. Long, strong and light tethers connect the buoyant structure to the ground and hold it in position against wind forces. The electricity output from the photovoltaic array is then coupled to high voltage transmission lines which connect from the platform to the earth's surface. The electricity is then transmitted through the high voltage transmission lines to the earth's surface where it is connected to the electrical supply grid and provides lower cost, more reliable electricity.