the gist of carbon capture for investors without time (Q4–2019)

We need to capture ~38 years of our current CO2 emissions.

At Impact Science .dev we offer advisory services to investors. And we love to work with investors interested in climate change. What follows is a recent gist of Carbon Capture and Storage (CCS) we prepared for a client. It is aimed to help triage a first reaction of any CCS investment within this huge, complicated and under-funded space.

How much to capture:

• We have ~1300 gT of CO2 to capture. (gT is gigaton)
• We pump ~34gT/year currently. Only ~20% of that (but increasing) is currently tax/offset, at prices of ~10$/T (10$–100$ range. varies by policy of emitter & buyer’s location).
• There is a long tail of contributors, but of those 34 gT:
  - 10gT comes from just 4k known fossil fuel power plants (half are pulverized coal plants)
  - 1gT come from 1k known cement production sites.
• As of 2019 there are 17 operating CCS projects in the world, capturing 31.5Mt of CO2 per year, of which 3.7Mt is stored geologically

When to capture it:

• Post combustion. From flue gas (chimney). 90% efficient, but also reduces 25% plant efficiency.
• Pre combustion. When gasified, the syngas (CO,H2) is added steam to get H2 and CO2 that is split.
• Oxyfuel. Burn with pure oxygen instead of air, cooled with closed loop flue gas. Output is pure CO2 to be captured.
• From the air. e.g. Company “Carbon Engineering” They are doing it since 2015 and have 2 main test sites. Costs 100–200$/tone of CO2.
• From the ocean. We haven’t seen much on this. E.g. Using algaes

How to capture it:

• Absorption. Using amines, most common. Can capture up to 90%, needs high pressure, low oxygen. Uses high-ish energy 3 MJ/kgCO2.
• Adsorption, (CO2 sticks to it, then scrub it via temperature or pressure cycle).
• Membrane gas separation. Good but slow.
• Fuel Cells. Flue gas is pumped into a superheated catalyzer. High potential, biggest risk corrosion due to super heated operation.
• Using organisms:
  - To pump carbon into the soil, enriching it. Part of “Regenerative Agriculture”. E.g. “Indigo ag” uses microbes to increase carbon within the soil, which increases crop yield (Additionally, they sell those credits and pay farmers 15$/ton CO2, capturing 1 ton of CO2 with microbes takes ~5 acre/year).
  - While also making energy (Negative Emission Tech, or NETs): This is the Bioenergy with carbon capture and storage (BECCS): Carbon negative, energy positive. Captures by photosynthesis (Corn/sugarcane). See below on what to do with the biomass.
  — BECCS Carbon efficiency: 50% biomass to power. 25% biomass to biofuel.
  — BECCS Energy efficiency: 11% biomass to power. 26% biomass to biofuel.

Overall cost to capture and store:

• ~2/3 of cost with current options is on capture (except mineral storage)
• Roughly, the avoidance costs is 30–70$/tCO2 for Gas and coal plants. (meaning cost of same energy with or without CCS). This is ~3x current price of CO2 credits.
• Capture coal- gas 15/75$ tCO2.

What to do with what you capture:

• Keep in mind transport costs: 1–10$/ tCO2 (not too sensitive to distance)
• Store geologically Cost 0.5–7$/tCO2
• Inject on spent oil reservoirs to get more, it’s called Enhanced Oil Recovery, or EOR. Pays 10$/tCO2 (but produces CO2 when oil is used).
• Inject and fix in minerals, like (coal mines, Calcite, manganese ). Most durable, non-burnable solution. Costs 50–100 $/tCO2. (There’s storage stock for 2k gT)
• Sell the CO2: Currently Industry buys 120Mt, excluding EOR. 2/3 for urea (fertilizers, back in air in months).
• Dump in ocean: Not a good idea since it acidifies the ocean.
• Convert to Methanol, adding H2. 2x more expensive than methanol from oil ($565.54 per ton of methanol)
• If CO2 is superheated to 2.4KC, splits into CO and O. CO can be made hydrocarbons via Fischer-Tropsch.
• If CO2 is captured into biomass:
  - You can use Clostridium thermocellum which is a promising bacteria that turns cellulose into ethanol, but we don’t know yet how to scale it.
  - BECCS has scale problems (if ¼ of all CCS uses plants, it uses up to 80% of cropland). BECCS needs $30–$280 per ton of CO2 to make it profitable.
  - Make plastic, biofuels, concretes, … “Bio CCS Algal Synthesis” is example to make fuel via alga.

Did we miss something? Do you disagree? Want to offer your expertise?

If your are interested in the sources, have questions, or want to work together, contact us.

Coal storage in Aboño, Asturias.