Fire in the Ice: Methane Hydrates

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Fire in the Ice Methane Hydrates
Methane hydrates (Clathrates) New Fuel or Major
Threat for Increased Global Warming, Huge Slumps
and Disastrous Tsunamis?
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Clathrates (methane hydrates)

• What are clathrates?
• What is the origin of the methane in clathrates?
• Beasties living off decaying clathrates
• Where do clathrates occur naturally?
• How much clathrates are there?
• Clathrates as possible fuel source
• Clathrates as a cause of tsunamis/ climate change

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What are Methane Hydrates?

• Methane Hydrates are one example of clathrates
• Clathrates are compounds which consist of a cage
  structure, in which a gas molecule is trapped
  inside a cage of water molecules
• Methane (CH4) is trapped in Water (H2O) forming
  an ICE

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Greycarbon Greenhydrogen in CH4 Red
oxygen White hydrogen in H2O
1 m3 of hydrate -gt 170 m3 methane gas (STP)
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Pentagonal dodecahedron
Cage made of water molecules - may contain CH4 or
CO2 (a bit like a bucky ball made of Carbon)
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Origin of natural methane

• Bacterial degradation of organic matter in
  low-oxygen environments within sediments
• Thermal degradation of organic matter, dominantly
  in petroleum (e.g., Gulf of Mexico)

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Where do clathrates occur?How much clathrate is
there?

• Methane and water must be available (organic
  matter produced by biota in oceans close to
  continents)
• Clathrate must be stable (ice) cold and/or high
  pressure

High latitudes (permafrost) In medium deep sea
sediments (300-2000 m)
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Hydrate Stability
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Hydrate Stability
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clathrates discovered
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Gas Hydrate on the Sea floor
Beasties!
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Organisms living on cold gas seeps
The lair of the ice worm
Beasties!
Tube worms and crab
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How does the foodchain in these seep
communities function?
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How much hydrate is there?

• Estimates vary widely globally 600,000 to
  2,000,000 Tcf (trillion cubic feet)
• 1 Tcf 1 quadrillion Btu (quad)
• World energy use (2000) about 375-400 Quad 500
  Tcf hydrate gas per year
• US gas hydrates estimated at about 100,000 to
  600,000 Tcf
• Gas hydrates abundant in oil-poor countries
  (Japan, India)

VERY MUCH !
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Clathrates as fuel

• Problems how to collect the gas -in a controlled
  way?
• Small recoverable?
• Need to be treated as synfuels to get
  oil-equivalent

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Climate change/Tsunamis

• Methane is a strong greenhouse gas
• If clathrates are destabilized, huge amounts of
  methane are added to the atmosphere (55 106 years
  ago??)
• Sediments loose strengthgtslip downslopegt
  slumpsgt tsunamis
• Methane is rapidly oxidized to CO2, also a
  greenhouse gas

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Have clathrates ever been destabilized in the
past?

• Increase in temperature, decrease in pressure
  (drop sea level)
• At the end of the last ice age, mega-slumps
  occurred in regions with gas hydrates

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Methane hydrates

• Possibly LARGE fuel source (natural gas) more
  than twice all other fossil fuels
• Unknown difficulties in recovery
• Production may cause major slumps, tsunamis, and
  exacerbated greenhouse effect