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, Geosystems
Volume 13, Issue 8, Q08007, 16 AUG 2012 DOI: 10.1029/2012GC004260
http://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!