Numerous

Leonel took a cautious step outward, his hair standing on end. However, no matter how he swept his gaze or his Internal Sight, he couldn't catch a wisp of anything. As far as he could tell, there really was nothing but a single expansive road headed toward that beautiful blue star surrounded by a cage of rotating silver. 

The Dyson Sphere was something Leonel had only read about in science fiction novels. Even 25th century Earth had never been able to accomplish such a thing. 

According to a scientist by the name of Kardashev, civilizations could be separated in strength by their energy resources. At the lowest Type I level, a civilization could be capable of making perfect usage of Nuclear Fusion, the energy of the stars. By this logic, Earth of the 21st century was not yet Type I as it could only use the much less efficient Nuclear Fission.