HARNESSING DEEP SEA GEOTHERMAL RESOURCES FOR

MULTIPLE ISLANDS IN THE LESSER ANTILLES

Jim Shnell, President,Ocean Geothermal Energy Foundation

Seafloor Geothermal Energy

• High-temperature, baseload resource to reverse climate change• Supercritical resource carries 5 to 10 times as much energy as steam• Drives a highly efficient, supercritical CO2 turbine• The energy can also produce hydrogen by electrolysis• Enough electricity to balance wind and solar power• Enough energy to replace fossil fuels• Can reverse climate change globally, stop the rise of sea levels

Current State of the Art

• Currently accessible geothermal energy globally is insufficient• Not enough of it• Not hot enough

• Recent attempts to develop enhanced geothermal systems• Drilling deep in rock is too difficult and expensive• Still not hot enough

• But 100 million quads of geothermal energy is usable globally

Iceland’s Advantage

• Iceland’s vast geothermal energy costs about 4₵ per kWh• Iceland is located on the Mid-Atlantic Ridge• Estimated temperatures can exceed 550° to 650° C• Tried to drill 4,000 to 5,000 meters to get critical pressure• Instead, drilled into 900° C magma at 2,000 meters depth • Goal is supercritical fluids that carry 10 times as much power

Opportunity in the Lesser Antilles

• Not a rift zone, but a volcanic island arc, with similar characteristics• 19 potentially active volcanoes (6 erupted in the last 400 years)• Magma rises through the crust• Very high temperatures• Deep water nearby

Heat flow in the Lesser Antilles island arc and adjacent back arc Grenada basin

Geochemistry, Geophysics, GeosystemsVolume 13, Issue 8, Q08007, 16 AUG 2012 DOI: 10.1029/2012GC004260http://onlinelibrary.wiley.com/doi/10.1029/2012GC004260/full#ggge2294-fig-0001

Access to Seafloor Geothermal Energy

• Drill wells adjacent to magma under seafloor 2000+ meters deep• Many of the volcanoes are on the west side of the island• The seafloor drops off rapidly to the west of the southern islands• Kick-em Jenny too shallow?• Drill 2,000 meters into the crust to get resources over 500°C• Lower submersible turbine-generators onto wells

• Transmit electricity to land by high-voltage direct current line• Remote-controlled

• Retrieve turbine-generators periodically for maintenance• Standardize turbine-generators to facilitate replacement

Advantages of Seafloor Geothermal Energy

• High heat flow, so reservoirs are more sustainable thermally• Generating stations can be placed close together

• Reduce risks and costs of exploration• Enable use of one transmission line for many stations

• New HVDC lines built for 1.2 MV can transmit 10 GW for 3,000 km• Standardized equipment will cost less

Energy to Replace Petroleum

• Replacing petroleum will further reduce climate change• Electricity to charge batteries on electric cars• Electrolysis using geothermal electricity for hydrogen

• Geothermal resources allow supercritical electrolysis - more efficient• Place electrolysis stations on seafloor near generating stations• New catalysts cost less, are more efficient

Conclusion• Seafloor geothermal energy will replace the use of petroleum,

unifying electricity and transportation into a single energy industry• Seafloor geothermal energy can also supply the balancing energy to

keep the grid reliable when it uses large amounts of solar and wind power, so all 3 renewables can grow quickly and not limit each other

For more info, see Ocean Geothermal Energy Foundation’s website at http://www.OceanGeothermal.org

or send us an email at oceangeothermal@gmail.com

Thank You!