Supplying power to offshore oil platform facilities is a challenging task due to the high power demands and long distances involved. While it is possible to supply power by ac submarine transmission cable to a nearby offshore load, this becomes impractical for loads with long distances and/or high power demands. This paper examines technically and economically two alternatives for subsea transmission: high-voltage alternating current and high-voltage direct current (HVdc). The most effective solution is determined to supply approximately 530 MW of load for several proposed offshore fields (from a few kilometers up to 100 km from the shore). Additionally, this paper sheds some light on voltage source converter technology and how it positively impacts the HVdc setup and efficiency, improving the economics of supplying electrical power to offshore installations.