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carbon capture

below are notes and excerpts from howard j. herzog’s book “carbon capture” (2018). i was mostly interested in learning what the systems were, how effective they are, and if there are any particular reasons to use one over the other.

ch 1: climate change

  • carbon dioxide capture and storage, or CCS, is the process of taking CO₂ from our environment and human processes and figuring out a way to store, or otherwise utilize it.
  • preindustrial CO₂ concentration in parts per million: 275. current levels are now over 400.
  • the oceans have feedback loops: dark parts of the ocean absorb more heat, which melts more ice, which creates more water that will heat up more, and so on. oh yeah, 40% of earths population (humans that is) live close or near an ocean. the oceans contain 60x the amount of carbon in the atmosphere, and 80% of the anthropogenic CO₂ will eventually end up in the ocean.
  • mitigation: reduction of the greenhouse gases that go into the atmosphere due to human activity
  • adaptation: the changing of human activity and behavior in response to the changing earth systems
  • geoengineering
    • carbon dioxide removal (CDR): removing CO₂ from the atmosphere
    • solar radiation management (SRM): deployment of programs to increase the amount of solar radiation that reflecting immediately back into space


  • mitigation is stopping things at the source
  • carbon however stays in our atmosphere for a long time (centuries)
  • paris agreement specifies how much the global temperature can rise
    • in order to meet this, a carbon budget is established
    • the carbon budget is measured in gigatonnes (Gt; billion tonnes)
    • in 2013, a 50% of containing global temperature rise to 2°C would mean a carbon budget of 1550 GtCO₂
    • which will be exceeded around 2056 at the current estimate of 36 GtCO₂ per year

mitigation can be broken down into 3 general categories:

  • reduced energy use
  • shifting to low (or no) carbon energy sources
  • carbon dioxide capture and storage (CCS)

reduced energy use

  • LED lightbulbs instead of incandescent bulbs
  • more efficient machines, cars, computers, heating, etc
  • between 1949 and 2017, the energy intensity as measured energy use per unit of GDP decreased at a rate of roughly 1.5% per year
  • this will need to be at least doubled

shifting to low (or no) carbon energy sources

  • nuclear - but slowly winding down and unlikely the world will turn back to it. as it winds down, we will have to continue to replace it with these alternative energy systems, so its doubled edged since it is the biggest carbon free energy source in use today.
  • hydro, wind, solar, geothermal, biomass
    • in 2016, wind = 6% and solar = 1% of electric sector power production
  • shifting from coal to natural gas
    • while this is better than nothing, it wont help us meet our bigger goals
    • highly dependent on local economics of coal to gas prices (per watt-hourof electricity produced)

carbon dioxide capture and storage

  • continue to burn fossil fuels
  • however capture CO₂ before it reenters the atmosphere
  • biggest opportunities are power plants, refineries, and other large industrial systems
  • sometimes the captured CO₂ can be utilized but its more likely that it will be pumped underground instead


  • adaptation is inevitable
  • mitigation has costs bore by the mitigator, with benefits to the world
  • adaptation however has costs and benefits that are more immediate
    • e.g. flood control prevention
    • easier to sell
    • dont even need to blame climage change™

carbon dioxide removal (CDR)

  • interest in CDR grows as people realize that we will likely not mitigate or adapt quickly enough
  • however CDR is more expensive since you’re taking CO₂ out of the atmosphere
  • interest is coming from both a desire to be able to get back to the 2°C rise (i.e. the paris agreement) if we go over our carbon budge, as well as some type of implicit admittance that we are not sufficiently mitigating (globally)
  • while the 2°C change wouldn’t literally be the end of the world, it increases all future costs of adaptation (in dollars? yes; in human lives; definitely), as well as mitigation, and could cause a runaway greenhouse gas effect (e.g. from the melting of the permafrost which would let out methane)

implementing carbon dioxide removal

  • jargon: negative emissions technologies (NETs)
  • many NETs deal with natural “carbon sinks” such as vegetation, soils, and oceans
  • planting trees is a simple example; they fix atmospheric carbon into the soil and their biomass
  • agricultural practices like no-till farming, which can increase carbon storage in the soil
  • others range from fertilizing the ocean, enhancing the weathering of minerals that will form carbonate rocks, or converting biomass into biochar and adding that to soil
  • the scale, cost, and efficiency of all of these are dubious

solar radiation management (SRM)

  • most controversial of the above
  • block incoming sunlight to the earth
  • inspired by volcanoes, whose ash/sut blocks sunlight and cools the earth with effects that can last years
  • an example being a volcanic winter event
  • proponents say that injecting particles high in our atmosphere is a cheap and easy way to buy more time while the carbon budget is dealt with other strategies
  • opponents suggest it is a huge experiment with unknown consequences ranging from geopolitical issues to, uh, the destruction of our ozone
  • SRM would also fail to affect ocean acidification
  • it may also change weather patterns, cause unforeseen droughts or floods, and may also cause people to mentally chose to not mitigate since they have falsely bought “more time”
  • proponents argue again, however, that given how slowly we are currently mitigating, we need to investigate and research SRM technology now regardless

ch 2. fossil fuels

fossil fuel history and consumption

  • in 2021, fossil fuels supplied 82% of the world’s commercial energy
  • modern petroleum industry started in pennsylvania in 1859 (first oil well)
  • another name for fossil fuels: hydrocarbons
  • primarily carbon, hydrogen, smaller amounts of sulfur, nitrogen
  • combustion combines with O_2 and creates CO_2, H_20 , and trace components of sulfur dioxide (SO_2) and nitrous oxides (NO_X)
  • carbon intensity is the amount of CO_2 emissions per unit of energy in the fuel
  • rule of thumb coal, oil gas == 5:4:3
  • 2016: the US used 103 exajoules of energy
  • exajoule == a trillion megajoule
  • a gallon of gasoline == 120 MJ
  • one kilowatt-hour of electricity, from a coal fired power plane, is about 10 MJ
  • a US household uses about 8800 kilowatt-hours in a year
  • 2016 (US): transportation fuel use is 92% oil
  • 2016 (US): fuel input for electricity: coal (34%), natural gas (27%), nuclear (22%), renewables (15%)
  • 2016 (US): electricity output : coal (31%), natural gas (33%), nuclear (21%), renewables (15%)

fossil fuel futures

  • peak oil, predicted in 1919, 1956, 1971, probably next year
  • reserves == “generally taken to be those quantities that geological and engineering information indicates with reasonable certainty can be recovered in the future form known reservoirs under existing economic and operating conditions”
  • 5 decades worth of reserves for oil and gas, a century of coal (this is coming from BP)
  • however new reserves are added every year
  • resources == “potentially recoverable with foreseeable technological and economic developments”
  • if you take BPs word for it, 100,000,000+ years worth of fossil fuels left before peak oil
  • to stabilize at 2C or less, we need to leave 50% of reserves in the ground, and 90% of all resources
  • if we ran out of the reserves by burning it all, we’d be up 9C
  • in short, peak oil and oil shortages, at an ecological level, aren’t impetus realistically to change anything
  • the author argues that stronger policy is needed, and if carbon capture systems become good enough, we can still use fossil fuels without going over our budgets

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