GEOTHERMAL

Question 1

How is geothermal energy created?

Answer 1

Constant decay of radioactive elements. Heat escapes through rocks, water and volcanic emissions.

Question 2

What are the 3 main depth regions of geothermal?

Answer 2

Up to 100m (T<30C) - Heating produced in combination with a heat pump.

100m-1500m (30C<T<150C) - Heated rainwater, Urban heating.

1500m+ (T>150C) - Electricity generation possible, depletion possible.

Question 3

Name and describe the 3 different geothermal regions.

Answer 3

Hyperthermal - Found on tectonic plates, temperature gradient greater than 8C at 100m.

Semithermal - Dry rock areas, temperature gradient from 4C-8C at 100m.

Normal - Temperature gradient less than 4C at 100m, not cost effective for electricity generation.

Question 4

What are advantages of geothermal electricity generation?

Answer 4

Renewable
Limited CO2 emissions
Always available (good as base load)
No fuel required (cheap OpEX)

Question 5

What are the disadvantages of geothermal electricity generation?

Answer 5

Location specific (High temperature sites required)
Release of hydrogen sulfide and GHG
Risk of seismic activity (From high P water injections)
Extraction rate limited by sites ability to replenish
High CapEx for predevelopment/construction

Question 6

Name the 3 types of geothermal power plants and their operating temperatures.

Answer 6

Dry steam power plant (T 180C-350C)
Flash steam power plant (T>150C)
Binary cycle power plant (Temperatures below 180C)

Question 7

Describe a Dry steam power plant.

Answer 7

The rarest type of geothermal power plant. Water turns into steam underground, steam then exits through natural vents to power turbines.

Question 8

Describe a Flash steam power plant.

Answer 8

Water is injected into the ground at high pressure, the water then rises to surface lowering in pressure and steam is partially produced. Steam then turns the turbines and is repressurised and reinjected along with recycled water.

Question 9

Describe a Binary cycle power plant.

Answer 9

Water is injected and extracted using pumps. Water is then used to heat secondary fluid (isobutane). The steam of the secondary fluid powers turbine and is converted back to liquid.

Question 10

State Jdawgs sexuality.

Answer 10

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