On the first post in this thread there ia a group of links a little way from the top. They all go to beam comparison photos. You can figure out the power of any light you want from these links.
Click on the link under "courtesy of 2manybikes". on the left is a list of albums, click on "bike light photos"
double click on a thumbnail to get a full size photo. The photos are captioned right in the photo.

There is a 10w HID and a 15 watt halogen, and a few others. The HID is better.