Why we need the and in CO2 utilization and storage.

Why we need the ‘and’ in ‘CO 2 utilization and storage’ Curtis M. Oldenburg, Lawrence Berkeley National Laboratory, Berkeley, CA, USA While research is still needed to answer scientific and technical questions about CO 2 Capture and Storage (CCS), it is largely economic and political forces rather than technical issues that have prevented widespread deployment of CCS over the last decade. Meanwhile, the energy-climate crisis continues as fossil-fuel use grows, causing atmospheric concentrations of CO 2 to increase, along with global atmospheric temperatures and the associated measurable and costly impacts on Earth’s climate. Given the current economic and political state of affairs, it is natural to look for ways other than storage (seques- tration) by which mankind can decrease greenhouse gas (GHG) emissions. With CO 2 accounting for approximately 70% of the GHG radiative forcing from among the other main GHGs (CH 4 , N 2 O, CF 4 , C 2 F 6 , SF 6 , and HFC-23, 134a, and 152a), and with abundant fossil-fuel-combustion point sources of CO 2 available, it makes sense to focus on reducing net emissions of CO 2 by any and all means. With direct injection into the ground for permanent sequestration currently considered expensive and lacking popular support, many people concerned about energy and climate have turned to studying utilization of CO 2 – so-called CO 2 Capture, Utilization, and Storage (CCUS). In fact, the annual CCS confer- ence held for several years now in Pittsburgh changed its name this year to the 11th Annual Conference on Carbon Capture Utilization & Sequestration. Currently, CO 2 is used beneficially for a large number of purposes in the chemical, pharmaceutical, food and beverage, agricultural, healthcare, environ- mental, energy resource extraction, pulp and paper, electronic, metals, and fire safety industries . 1,2 In the area of energy resource extraction, the oil industry injects millions of tonnes of CO 2 per year for enhanced oil recovery (CO 2 - EOR). While much of the current utilization demand makes use of CO 2 as is, vast amounts of CO 2 are also converted into a variety of useful products such as urea (fertilizer), formic acid (preservative for animal feed), and syngas (fuel). Although there exist many potential large-scale uses for CO 2 , the current demand is dwarfed by the potential supply from anthropogenic sources (mostly fossil fuel combustion), and projections of increased fossil-fuel use make it difficult to envision utilization ever solving the energy-climate crisis. For example, Song 3 estimated the total potential US demand for CO 2 in the chemical and materials industries at approximately 6 MtCO 2 /yr, approximately the output of a 750 MW coal- fired power plant. CO 2 -EOR within the USA currently uses a lot more CO 2 than do the chemical and material industries, approximately 48 Mt CO 2 /yr, 3 or the output of six 1-GW coal-fired power plants. Urea production in the USA is the largest single use at 120 Mt CO 2 /yr. 2 Meanwhile, the current US power plant CO 2 emissions are estimated to be about 3 Gt CO 2 /yr, or about 15 times larger than the current US utilization rate of approximately 200 Mt CO 2 /yr. Moreover, it deserves mention here that the vast majority of CO 2 used for EOR comes from natural CO 2 reservoirs rather than anthropogenic sources. While we can envision policies arising from concern for climate that will motivate greater utilization of anthropogenic CO 2 , this greater utilization rate will occur in a future with potentially much larger rates of CO 2 emissions, assuming that global projections of increased de- mand for energy and its modes of generation are correct. Despite the raw numbers and what they reveal about the imbalance between today’s CO 2 utilization and anthropo- genic emissions, increasing CO 2 utilization is still a worthy goal. The fact is we need to start reducing CO 2 emis- sions in every way we can. The problem of global anthropogenic GHG emissions of approximately 30 Gt CO 2 /yr is so large that it demands solutions from every corner of Earth. For example, off-setting electricity production from coal by greater use of nuclear and renewable energy sources is an effective CO 2 emissions mitigation strategy, but utilization can potentially reduce CO 2 emissions even more than these fuel-substitution approaches. 4 And there is hope for large increases in utilization. First, increased application of CO 2 -EOR, along with a large-scale switchover to anthropogenic