Professor Wilfred Elders explains super critical water and why it can make the power of a geothermal well 10x stronger. There are many favorable conditions for generating power in deep water on the mid ocean ridges. Most important is achieving super critical water. That is when the combination of high pressure (220 bars) and high heat (375c) make a fluid that is highly efficient at transferring heat to a turbine. Go to 5:20 in the video.