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

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