Energy from Ocean Floor Geothermal Resources

Abstract

The need for large increments of new electric generating capacity to replace fossil fuels will increase as the world replaces petroleum with either electricity or hydrogen to fuel transportation, whether to charge the batteries of electric cars or to provide hydrogen through electrolysis. Such replacement transportation energy, by consuming off-peak electricity, will make base-load electricity even more important in the future. A solution to the global need for baseload renewable power can be achieved through several inter-related innovations, which adapt and use existing technologies to access geothermal resources in the deep sea floor. Geothermal energy is the only form of clean, renewable energy that can provide enough baseload electricity to replace coal, petroleum, natural gas and nuclear power as the primary sources of electricity and transportation power. The use of geothermal energy is currently limited in scope and location to a relatively few areas on land that provide limited resources. Access to vast amounts of geothermal energy can, however, be gained through the ocean floors, under which abundant geothermal resources can be found in a supercritical state. Supercritical geothermal resources will enable the generation of electricity on an efficient, economical and highly reliable basis through the first innovation, the use of remote-controlled turbine generators on the ocean floor that will supply both the grid's demand for electricity and, by operating during off-peak hours, the power needed to replace existing transportation fuels. These stations will incorporate a further innovation, the use of turbines powered by supercritical CO2 as the working fluid, which is still in the research and development stage for nuclear power plants and has not previously been considered for geothermal plants. These advancements in geothermal technology, to develop a very high-temperature and therefore very efficient form of geothermal generation, will make geothermal energy (already highly reliable, with availability factors over 90%, and very friendly to the environment, with no negative effect on the land surface or the atmosphere) more affordable, by reducing the levelized cost of geothermal power below the levels of other forms of generation. Such generation, being both bountiful and inexpensive, will form the foundation for a further innovation, the direct use of supercritical geothermal resources to provide hydrogen by electrolysis. This advance will enable the restructuring of the transportation and electrical energy industries so that the provision of inventories of transportation energy (in accordance with current industry practice) serves as a buffer for the load following demands of the grid for electricity. In addition, the ocean geothermal system can be operated in coordination with other energy sources such as wind and solar power or on a stand-alone basis to transform the energy generation and delivery industries. Geothermal resources are accessible in the ocean floor all around the globe. Abundant resources are easily available near Iceland and the West Coast of North America, but such resources in fact wrap around the globe. This paper will describe the conceptual design for the ocean-floor geothermal system and provide the well drilling cost analysis, manufacturing cost analysis and life cycle cost analysis of the system.