Transcript Geothermal Energy “Digging Deep to Discover the Power”

Geothermal Energy
“Digging Deep to
Discover the Power”
Michelle Kennedy & Caitlin Sloan
What is Geothermal Energy?
• Heat produced by molten rock under
the Earth’s crust
• Wells are drilled deep into rock to
stimulate water flow
• Earthquakes & magma movement
break rock covering allowing water to
flow
• Hot springs & geysers occur as a result
Where is it Found?
• Highest underground temperatures
found in regions with active volcanoes
• The Pacific Rim has many “hot spots”
• Easiest to access in mountainous
areas such as western United States
How is it Harnessed?
• A conversion apparatus must be built to
convert the heat in steam into electricity
• Most common process  “Hydrothermal
Convection”
• Another process  “Hot Dry Rock”
• Proposed plan:
– Drill into heated bedrock
– Create open reservoir
– Pump water into it to be heated
Three Main Designs
• Dry Steam
Three Main Designs
• Flash Steam
Three Main Designs
• Binary Cycle
• Design depends on the resource
• Largest geothermal system in
operation is steam-driven plant  The
Geysers
– Located north of San Francisco,
California
– The heat used for energy is all steam, not
hot water
Ideal Iceland
• Nearly every building is heated by hot
spring water
• 85% of homes are heated by
geothermal energy
• Geothermal produces 18% of
country’s electricity
• Cost of this energy will continually
drop
What is the Cost?
• Conversion apparatus turns heat into
electricity at $1,700 per kilowatt
• More than 100 gigawatts could be
produced for $1 billion over next 40
years
– Equal to:
• The cost of just one coal-fired power plant
• One third the cost of a new nuclear generator
Fun Facts
• Electricity produced annually  greater
than solar & wind combined
• Amount of heat within 10,000 meters of
Earth’s surface contains 50,000 times more
energy than all the oil & gas resources in
the world
• Ground source heat pumps
 72% more efficient than
electric heating & air
conditioning
Pros of Geothermal Energy
• Renewable resource
• The process of extraction produces
low emissions  contained
underground
• Compatible with many environments
• Works 24/7
• Minimal cost
• Clearly feasible (Iceland)
Cons of Geothermal Energy
• Apparatuses must reach at least 5,000
feet underground
• Geothermal steam naturally contains
hydrogen sulfide
• Building power plants can trigger
earthquakes
• Type of rock limits location of drilling
The Future of Geothermal
Energy
• It could succeed anywhere
• Cost of electricity from these systems
is declining
• Geothermal development likely to
increase
• 2007 MIT study  first in 30 years
• Bright future for home & building
heating
The End