GEOTHERMAL ENERGY

decay of radioactive nuclei, residual heat, meteorite impacts

where does 70% of earth`s energy come from?

hot water reservoirs

1. hot underground water

2. for space heating than electrical production

natural stem reservoirs

hole dug into the ground can cause steam to come to the surface.

geopressured reservoirs

1. brine completely saturated with natural gas in stored under pressure from the weight of overlying rock

2. for heat and natural gas

normal geothermal gradient

1. f one digs 20,000 feet the temperature will be about 1900C above the surface temperature.

2. electricity production

3. no tech has been produced to make this one

hot dry rock

1. in 5% of US

2. gradient is 400C/km dug underground.

molten magma

1. no tech to get heat reserves here

2. best in Alaska and Hawaii

space heating
air conditioning
industrial processes
drying
Greenhouses
Aquaculture
hot water
resorts and pools
melting snow

direct uses of geothermal energy for sources below 150C

1. water is heated in earth`s well

2. heat pump » heat from underground water » house

3. water is injected back to earth

how direct uses work

ground heat collectors

This system uses horizontal loops filled with circulating water at a depth of 80 to 160 cm underground.

borehole heat exchange

This type uses one or two underground vertical loops that extend 150 meters below the surface.

sources hotter than 150C

you can generate electricity from what sources?

dry steam plantsThese are the most common plants.

These were the first type of plants created. They use underground steam to directly turn the turbines

flash steam plants

1. These are the most common plants.

2. Uses 360F hot water

3. water into chambers, steam to turbines

4. residual water is injected back

binary cycle plants

1. uses moderate heat and organic fluid

2. steam to turbines

3. no emissions

4. water temp is lower than flash steam plants

hot dry rocks

1. the simplest models have one injection well and two production wells.

2. hot rocks heat water

3. no emissions

1. soil salination

2. land subsidence = seismic activity

3. H2S “rotten eggs” gas release = fatal

4. noise pollution during drilling

5. “blowing of top”

harmful effects of geothermal

injecting back of cooled/residual water after processes

how to prevent harmful effects?

1. zinc and silica extraction

2. homegrown = more jobs = less oil reliance

3. cheaper than conventional energy

4. working all the time

5. less greenhouse gas emission

6. less land space used

advantages of geothermal

goethermal heat pumps

1. produce 4x their consumption

2. expensive to build, cheap to maintain

83.3 million barrels
40.2 million tons of CO2

Electricity generated by geothermal plants saves ______ barrels of fuel each year from being burned worldwide. This prevents _________ from being emitted into the atmosphere.

1. near volcanoes, springs, and fumaroles

where can geothermal energy be found the most?

600,000 Exajoule

It is estimated that the world could produce _________ over 5 million years.

there is enough heat radiating from the core

how can we guarantee that our human energy demands will be met for the rest of the biosphere`s lifetime?

1. hydro

2. biomass

3. geothermal

4. solar

5. wind

order of the height of energy production per energy type