HDR/HWR can be one of the major sources of energy for the world in the 21st century because of the size of HDR/HWR resources and the environmental benefits offered by clean HDR/HWR energy. Over the last 25 years, significant advances have been made in the creation and operation of stimulated reservoirs, but little is yet known about the details of joint structure within the body of the reservoir. Continued developments and improvements to the technologies that support HDR/HWR development are essential to increase our understanding of these reservoirs.