State of Direct Air Capture. Klaus S. Lackner November 19, 2015 Carbon Management Technologies Conference Sugarland, Texas

Transcription

1 State of Direct Air Capture Klaus S. Lackner November 19, 2015 Carbon Management Technologies Conference Sugarland, Texas

2 CO 2 (ppm) IPCC calls for negative emissions Hazardous Level 450 ppm Continued Exponential Growth Preindustrial Level 280 ppm Constant Emissions after % of 2010 rate 33% 10% 0% year

3 Negative carbon emissions Retrieval of carbon from environment Direct removal of CO 2 from air or ocean BECCS, Direct Air Capture, etc. Large demand for carbon dioxide disposal 100 ppm reduction implies ~400 Gt C or ~1500 Gt CO 2 Ocean will return its carbon Even zero emission must eliminate all emissions, not just 90% of coal emissions 3

4 Balancing the Carbon Budget For every ton of carbon taken from the ground another must be returned For every ton of carbon dioxide added to the atmosphere another ton must be removed Direct air capture is a valuable tool for balancing the carbon budget 4

5 Air capture is the capture of last resort can cancel out all unaddressed emissions can recover past emissions sets upper limit on the cost of carbon allows for zero or negative carbon scenarios encourages point source capture 5 Wikipedia picture

6 Why air capture? Air capture eliminates exceptions No emission source can be exempt Separates sources from sinks Carbon democratization Air capture for drawing down CO 2 Negative emissions are already unavoidable Requires vast CO 2 storage capacity Negative carbon emissions Air capture with non-fossil liquid fuels Synthetic fuel production from CO 2 and H 2 O Provides energy storage & liquid fuels Requires cheap non-fossil energy Carbon recycling Image courtesy Stonehaven production Air capture with fossil liquid fuels Carbon balanced by sequestration Requires cheap CO 2 storage Carbon balancing

7 Three Rules for Technological Fixes D. Sarewitz and Richard Nelson: Three rules for technological fixes, Nature, 2008, 456, I. The technology must largely embody the cause-effect relationship connecting problem to solution. II. III. The effects of the technological fix must be assessable using relatively unambiguous or uncontroversial criteria. Research and development is most likely to contribute decisively to solving a social problem when it focuses on improving a standardized technical core that already exists. In contrast, direct removal of CO 2 from the atmosphere air capture satisfies the rules for technological fixes. Most importantly, air capture embodies the essential cause effect relations the basic go of the climate change problem, by acting directly to reduce CO 2 concentrations, independent of the complexities of the global energy system (Rule I). There is a criterion of effectiveness that can be directly and unambiguously assessed: the amount of CO 2 removed (Rule II). And although aircapture technologies have been remarkably neglected in both R&D and policy discussions, they nevertheless seem technically feasible (Rule III).

8 Thermodynamics checks out Theoretical minimum free energy requirement for the regeneration is the free energy of mixing Gas pressure P 0 CO 2 partial pressure P x Denoted as (P 0, P x ) Separation Process CO 2 (P 0, P 0 ) involving Air (P 0, P 1 ) Sorbents Membranes etc. CO 2 depleted air (P 0, P 2 ) GG = RRRR PP 0 PP 2 PP 1 ln PP 1 PP 0 PP 1 PP 2 ln PP 2 + PP 0 PP 1 PP 0 PP 2 PP 1 PP 2 PP 0 PP 0 PP 1 PP 2 PP 0 PP 0 PP 0 PP 0 PP 0 PP 1 PP 2 ln PP 0 PP 1 PP 0 PP 2 22 kj/mol 8 Specific irreversible processes have higher free energy demands

9 Feasibility & Affordability? CO 2 in air is dilute and air is full of water Sherwood s Rule: Separation costs often scale linearly in dilution 9 Air Capture is an exception

10 Sherwood s Rule is not a Law Sherwood s rule for minerals ~ $10/ton of ore A challenge for dilute values U from seawater Air capture aspirations 10 SOURCE: National Research Council (1987)

11 Artificial kelp to absorb uranium from seawater Passive, long term exposure to water Braids of sorbent covered buoyant plastic Anchored to the floor Replaced initially active systems Low energy sorbent Laminar flow over sorbent Uptake is limited by boundary layer transport Regeneration After harvesting the strings Gross violation of Sherwood s Law Cost estimates range from $200 to $1200/kg Sherwood $3 million/kg wikipedia

12 Air capture is sorbent based Sorbent based separation of CO 2 from air Concentration ratio is 1 : 2500 Eliminates all options that perform significant work on the air Sorbents postpone work to the regeneration step All sorbents are chemical sorbents At 400 ppm physisorption is too weak Minimum free energy of binding: ΔG > 22 kj/mol Sorbents exploit carbonate chemistry Alkali hydroxides Weak and strong based amines Thermal, vacuum and reaction based recovery Humidity swing takes advantage of H 2 O CO 2 sorbent reactions 12

13 ASU Strategy for cost reductions Use passive collectors to avoid Sherwood s Rule Cost need not scale linearly with dilution no extrapolation from flue gas streams Passive collectors Match sorbent material to the problem Match swing to ambient conditions 1:2500 CO 2 1:100 H 2 O Minimum binding energy, low cost energy, good kinetics,... Harness cost reductions from mass production Learning curves can give orders of magnitude cost reductions This makes a priori cost estimates virtually impossible Take advantage of the resources in the air Wind energy, moisture content, temperature, etc. 13

14 Anionic Exchange Resins Solid carbonate solution Quaternary ammonium ions form strong-base resin Positive ions fixed to polymer matrix Negative ions are free to move Negative ions are hydroxides, OH - Dry resin loads up to bicarbonate OH - + CO 2 HCO 3 - (hydroxide bicarbonate) Wet resin releases CO 2 to carbonate 2HCO 3- CO CO 2 + H 2 O Novel GRT photomoisture driven CO 2 swing 14

15 The Moisture Swing Tao Wang et al 15

16 Free energy from water evaporation Water evaporation can drive CO 2 capture Liquid Water Dry air Separation Process involving Sorbents Membranes etc. CO 2 enriched air Moist air Free energy of water evaporation at a relative humidity RH: G = RT ln(p/p sat ) = RT ln(rh) Ball park estimate: 2.5 kj/mol 140 MJ/m 20 /m /kwh 16

17 Many other alternatives to DAC Field without public support moved to start-ups Looking for CO 2 markets ASU and its new center aim for public demonstration Working with private companies and other universities Many different approaches are being pursued Liquid and solid sorbents Inorganic and organic Passive and active air flow (low pressure drop) Thermal swings Moisture driven swings Vacuum swings Combinations of different swings Shaped after large industrial processes Emulating the mass production paradigm 17

18 CO 2 Markets Merchant CO 2 Markets are small and distributed Chemical commodities E.g. urea, often attached to point sources Biomass production Greenhouse, algae reactors Limit water consumption, produce food/fuels Operate with CO 2 enriched air Enhanced oil/gas recovery Air capture aims at small fields, exploratory work in the absence of pipelines Synthetic renewable fuels Input is excess, intermittent renewable power, often distributed Energy rather than CO 2 drives cost Sequestration Remote locations engender less resistance Air capture has a competitive advantage in satisfying small, distributed or remote demands 18

19 Developments and Research Private companies capturing CO 2 Carbon Engineering Climeworks Global Thermostat Infinitree Skytree Sorbent Research ASU, Georgia Tech, Columbia, Zhejiang and more Systems Research Technical challenges are system s challenges Systems constraint will drive component research 19

20 Center for Negative Carbon Emissions Demonstrating a new approach to carbon management Demonstration Basic Science Policy-Outreach Field deployed prototypes Establish rapid prototyping capability Continuous improvement and continuous operation Learning by doing in multiple iterations Sorbent chemistry, physics and thermodynamics Separation Science System engineering, scaling and automation, techno-economics Sustainability science, human interfaces Study policy implications of air capture technology Move policy makers to a zero-emission world Connect to industry and venture capital Seek support from foundations & sovereign wealth funds Creating IP Pool 20

21 Low cost comes with experience $600 APS (low tech, first-of-a-kind) Per ton CO 2 $500 cost of lighting fell 7000 fold in the 20 th century $400 price dropped fortyfold $300 GRT (first-of-a-kind) $200 $100 $0 Practical interest price dropped hundredfold Raw material and energy limit (frictionless cost) The Power of the Learning Curve Ingredient costs are already small small units: low startup cost Wikipedia pictures

22 Finding Market Niches

23 365 ton/year plant in Squamish, BC Uses known reaction used for paper mill processing to follow industrial scale Produces pure CO 2 for synthetic fuels

24 Innovative modular design Demonstrator CO 2 Collector CO 2 Capture Plants 2 t CO 2 /y Online since 12/ t CO 2 /y Full scale module Online since 08/ t CO 2 /y Modular, turnkey, standalone 3 units sold 2 units sold 2 sales contracts closed 24

25 Operational & Tested Since October 2010 at 500 tonnes CO2 / year 54% capture efficiency 160 kwh/tonne electricity, 4.4 GJ/tonne of 95 C heat Assumptions: $0.07 / kwh electricity; $3.50 / MMBtu heat (US market price of natural gas); 10% capital depreciation Number of units to achieve under $50 per tonne: less than 1,000,000 tpy fleet capacity ~10% currently installed liquid amine capacity Emphasis on low grade heat and its careful use

26 Moisture swing based technology to feed CO 2 to plants in enclosed spaces First product planned for 2016

27 Starting in the consumer market (mass production)

28 Center for Negative Carbon Emissions Outside prototype Working towards a public demonstration

29 Atmospheric CO 2 Capture and Membrane Delivery CO 2 CO 2 Large-scale algae cultivation (courtesy of Joule ) Bioplastics ASU LIGHTWORKS: SUSTAINABLE FUELS AND PRODUCTS Rittmann and Lackner, DOE TABB29

30 Conclusion Air Capture is technically feasible Powerful tool in fighting climate change Costs are starting to come down Operational units raise confidence Start-ups find economic niches Starting small opens specialty markets Learning will lower costs Public support needed for policy relevant answers Knowledge gap noted by National Academy study can be fixed Air Capture and Point Source Capture Air capture supplements point source capture 30