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michael_nielsen's profile
michael_nielsen
michael_nielsen
michael_nielsen
@michael_nielsen

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michael_nielsen

@michael_nielsen

Searching for the numinous. Co-purveyor of https://quantum.country/ 

San Francisco, CA
michaelnielsen.org
Joined July 2008

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    1. michael_nielsen‏ @michael_nielsen Feb 20
      • Report Tweet

      The reason this is interesting: looking at the NAS's recent report on negative carbon emission technologies, many cost less than $20 per tonne of CO2 removed. The US produces ~5 Gt of CO2/yr. If the $20 was scalable, that would be well under 1% of GDP. ( https://www.nap.edu/catalog/25259/negative-emissions-technologies-and-reliable-sequestration-a-research-agenda … )

      4 replies 13 retweets 54 likes
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    2. michael_nielsen‏ @michael_nielsen Feb 20
      • Report Tweet

      Of course "If scalable" is bearing a huge load in that tweet!

      1 reply 0 retweets 3 likes
      Show this thread
    3. Matt Guttman‏ @RealtimeAI Feb 20
      • Report Tweet
      Replying to @michael_nielsen

      Are tech solutions more likely to increase or decrease in cost over time?

      1 reply 0 retweets 0 likes
    4. Scott Leibrand‏ @scottleibrand Feb 20
      • Report Tweet
      Replying to @RealtimeAI @michael_nielsen

      Scott Leibrand Retweeted Scott Leibrand

      Most of the <~$20/tCO2 solutions have limited capacity (land constraints etc.). DAC is the major exception, which costs ~$100/tCO2 and has ~unlimited capacity and is instead limited by capex and energy costs, both of which will come down over time.https://twitter.com/scottleibrand/status/1095478861880389633?s=21 …

      Scott Leibrand added,

      Scott Leibrand @scottleibrand
      Replying to @Marcusdstewart @ramez @jgkoomey
      Global thermostat claims they’ll hit $100/ton at their Huntsville plant that is already under construction, and could do $75/ton if they put it near a source of waste heat: https://physicstoday.scitation.org/doi/pdf/10.1063/PT.3.4018 …
      1 reply 0 retweets 4 likes
    5. michael_nielsen‏ @michael_nielsen Feb 20
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      Replying to @scottleibrand @RealtimeAI

      Thanks. I don't have a good handle yet on scalability - there seem to be a lot of potential options, many are in their early days, and (ofc) most won't pan out. Ofc, most don't need to.

      2 replies 0 retweets 3 likes
    6. Scott Leibrand‏ @scottleibrand Feb 20
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      Replying to @michael_nielsen @RealtimeAI

      This 350-page free PDF does an excellent job of covering everything in way more detail than I’ve seen anywhere else. I’ve only read the DAC section so far, and it’s very good. Looking forward to the others. Thanks for sharing it.

      1 reply 0 retweets 2 likes
    7. Scott Leibrand‏ @scottleibrand Feb 20
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      Replying to @scottleibrand @michael_nielsen @RealtimeAI

      The key insight that most people seem to be missing is that $100/tCO2 DAC puts an upper bound of about $1/gallon of gasoline/kerosene/diesel on what it’ll cost to fully decarbonize and get to net zero CO2 emissions, even w/o new tech for aviation, steel, cement, agriculture, etc.

      1 reply 0 retweets 2 likes
    8. michael_nielsen‏ @michael_nielsen Feb 20
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      Replying to @scottleibrand @RealtimeAI

      Yeah. It's interesting to think about other options at prices below that. Nearing $1/t it starts to make sense for single affected countries (say the Netherlands or some consortium) to consider just paying for a solution outright. Like a defense budget, but for water.

      1 reply 0 retweets 3 likes
    9. michael_nielsen‏ @michael_nielsen Feb 20
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      Replying to @michael_nielsen @scottleibrand @RealtimeAI

      The budget for water infrastructure in the Netherlands, Venice, New Orleans etc already runs into the billions I believe.

      1 reply 0 retweets 2 likes
    10. Scott Leibrand‏ @scottleibrand Feb 20
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      Replying to @michael_nielsen @RealtimeAI

      One close analogy might be ocean alkalization / alkalinization, which could allow countries like Australia to protect the alkalinity of waters around important reefs while permanently sequestering CO2. But apparently that was outside the scope of this document.

      1 reply 0 retweets 2 likes
      michael_nielsen‏ @michael_nielsen Feb 20
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      Replying to @scottleibrand @RealtimeAI

      Fascinating to look at existing numbers. The Netherlands' defense budget is 10+ billion EU. Australia spends AUS 500+ million on the reef. Looks as though typical costs in places like Venice, New Orleans are on the order of 1 billion per year.

      7:39 PM - 20 Feb 2019
      • 2 Likes
      • ScipioAcheronus Scott Leibrand
      1 reply 0 retweets 2 likes
        1. New conversation
        2. michael_nielsen‏ @michael_nielsen Feb 20
          • Report Tweet
          Replying to @michael_nielsen @scottleibrand @RealtimeAI

          All very approximate, and will likely go up in the near future. Reading up on flood insurance it's growing like gangbusters. NETs aren't practical at scale yet, but we're not so far off, either.

          1 reply 0 retweets 2 likes
        3. michael_nielsen‏ @michael_nielsen Feb 20
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          Replying to @michael_nielsen @scottleibrand @RealtimeAI

          Reminds me of the situation with solar, where it was just too expensive, and then subsidies helped bring the price down so much that now it really is competitive. I wonder if there's a similar way to get NETs started, & start bringing the price down.

          1 reply 0 retweets 2 likes
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