For the shadow to be significantly larger than the shading object, the object must be significantly closer to the light source. For Earth, in solar orbit, that

For the shadow to be significantly larger than the shading object, the object must be significantly closer to the light source. For Earth, in solar orbit, that means you'd have to get inside the orbit of Venus. Then you have a huge energy cost in keeping your shading object in the correct position relative to Earth. Its natural orbit is not going to work at all.