Drilling operations in deep and ultradeep water are increasing around the world The development of these substantial prospects provides many challenges and requires the integration of knowledge with prudent designs at different stages of the well development. Also, more wells are drilled in rotary steerable mode and other instrumented bottom-hole assemblies. All of these tools need power which is stored in batteries. Because the downhole power supply is limited for these tools, an alternate mode of energy supply is needed so that these tools can remain downhole for 1 ng hours. This paper examines a new energy source extraction method using the hydraulic energy obtainedfrom the circulated drilling fluid when downhole motors are used.