I was pleased and surprised that the CoLab geoengineering competition chose my algae ocean proposal for voting since no credentialled scientists have expressed support for it. I would really like to do a Masters or PhD to take forward the agenda I proposed of laboratory modelling and scientific proof of concept. The dialogue on a range of questions arising from my CoLab proposal was very informative, and I hope there are further opportunities for discussion, focussed on whether the ideas can be made practical and cost-effective. Congratulations Greg and Ken, and good luck.
________________________________ From: Ken Caldeira <[email protected]> To: geoengineering <[email protected]> Cc: Greg Rau <[email protected]> Sent: Saturday, 7 September 2013 12:50 AM Subject: [geo] Climate Colab, Two of our proposals win in this round of competition .. http://climatecolab.org/web/guest/plans/-/plans/contestId/10/planId/1304174 I hadn't been lobbying heavily for this proposal largely because I deemed the process stupid an the judges likely to be biased, but now that the process and judges have selected two of our proposals, one in the Energy Power Sector and one in the Geoengineering category, I am ready to say that this process looks to me to be both thoughtful and fair. Congratulations to Greg Rau for taking on the good fight. http://climatecolab.org/web/guest/plans/-/plans/contestId/10/planId/1304174 http://climatecolab.org/web/guest/plans/-/plans/contestId/20/planId/1304119 The full set of winners of this round, competing for the Grand Prize can be found here: http://climatecolab.org/community/-/blogs/2012-2013-climate-colab-contest-winners?_33_ I note that there was no "judges" choice under the category of "geoengineering", which seems to be limited to CDR-type techniques: http://climatecolab.org/resources/-/wiki/Main/Comments+by+Expert+Reviewers+on+the+Geoengineering+Proposals http://climatecolab.org/web/guest/plans/-/plans/contestId/10/planId/1304174 Proposal for Electric power sector by The Planet Doctors Spontaneous Conversion of Power Plant CO2 to Dissolved Calcium Bicarbonate Pitch As in SO2 mitigation, spontaneously remove CO2 from power plant flue gas using wet limestone scrubbing. Description SummaryCarbonate mineral weathering is a major absorber of excess CO2 at planetary scales: CO2 + H2O + CaCO3 --> Ca(HCO3)2aq. However, relying on this very slow natural process to consume excess CO2 would in the interim commit us to many millennia of climate impacts and ocean acidity (1). It is therefore relevant to find ways of cost-effectively accelerating this proven, natural (geo)chemistry in order to more quickly mitigate of our CO2 emissions, while also trying to rapidly transition to non-fossil energy sources. Modeling and lab studies have shown that contacting CO2-enriched gas with water and limestone is an effective way of spontaneously capturing and storing CO2 as dissolved calcium bicarbonate (2-7). This is termed Accelerated Weathering of Limestone – AWL. In laboratory tests, up to 97% of the CO2 in a dilute gas stream was removed using this method (11). Seawater would appear the best option for such systems, although other non-potable water sources (wastewater, saline ground water) could also be relevant at inland sites. An AWL total cost of <$30/tonne CO2 avoided has been estimated, with <$20/tonne being more likely at coastal power plants that already pump massive quantities of seawater for condenser cooling. The preceding mitigation cost ranges are a fraction of that reported for more conventional capture and underground storage of concentrated CO2 (CCS) when retrofitted to existing power plants (8). CO2 mitigation is not the only potential benefit of AWL. As in natural carbonate weathering, the dissolved Ca(HCO3)2 added to the ocean by the process will help to chemically offset the effects of CO2-induced ocean acidification (9-11). Despite its potential, AWL is lacking a demonstration at a scale that would prove its cost effectiveness, safety, and net environmental and societal benefit. It is proposed that these issues be evaluated and tested at a relevant scale by a team of scientists, engineers, and environmental, economics, legal, and social experts. gregrau Owner kencaldeira Member philrenforth Member http://climatecolab.org/web/guest/plans/-/plans/contestId/20/planId/1304119 Proposal for Geoengineering by Planet Physicians Saving the Planet, v2.0 Pitch Interested in air CO2 removal, carbon-negative fuel, saving the ocean, and redrawing the global energy map? Read further. Description SummaryRegardless of our CO2 emissions, Nature eventually will return global CO2 to pre-human levels primarily via base (carbonate and silicate) rock weathering (1). Nature’s 100,000 year time frame for this process, however, means that unless we quickly intervene, the earth will unacceptably fry and acidify in the interim. Thus, it is of interest to consider building on and accelerating this proven, global scale geochemical CO2 mitigation process while we also strive to transition from our carbon-positive energy existence. We propose to research a process that simultaneously addresses both of these issues by merging rock weathering and renewable energy in a novel electrochemical process. It has been demonstrated (2-5) that strategically placing common rock minerals around the acidic anode of a standard, functioning saline water electrolysis cell not only produces H2, and O2 or Cl2, but also generates a solution that is strongly absorptive of air CO2. This spontaneously converts the CO2 to stable bicarbonates and/or carbonates in solution. The preceding points the way toward employing common rock minerals, salt solutions (seawater, brines), and renewable energy (e.g., wind, solar, ocean, geothermal) in a system that can remove CO2 from air while also generating a carbon-negative fuel, H2. The global abundance of these reactants and energy sources suggest that the process could be conducted at a significant scale. Furthermore, as in natural rock weathering, the (bi)carbonates added to the ocean by the process will help to chemically offset the effects of CO2-induced ocean acidification (6-8). It is proposed that the cost-effectiveness, capacity, environmental impact/benefit, social desirability, and geopolitical implications of this novel, carbon negative fuel production method be evaluated by an international team of scientists, engineers, and environmental, legal, and social experts. C.Negative Owner gregrau Member kencaldeira Member platzer Member _______________Ken CaldeiraCarnegie Institution for Science Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 [email protected] http://dge.stanford.edu/labs/caldeiralab @kencaldeira -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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