Regional evaluation of brine management for geologic carbon sequestration

Regional evaluation of brine management for geologic carbon sequestration Hanna M. Breunig a,b , Jens T. Birkholzer c , Andrea Borgia c , Curtis M. Oldenburg c , Phillip N. Price a , Thomas E. McKone a,d,∗ a Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 90R2002, Berkeley, CA 94720, USA Department of Civil and Environmental Engineering, University of California, 1 Cyclotron Road, 74R316C, Berkeley, CA 94720, USA c Earth Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 74R316C, Berkeley, CA 94720, USA d School of Public Health, University of California, Berkeley, USA b Abstract Large scale deployment of carbon dioxide (CO2) capture and sequestration (CCS) has the potential to significantly reduce global CO2 emissions, but this technology faces social, economic, and environmental challenges that must be managed early on. Carbon capture technology is water-, energy-, and capital- intensive and proposed geologic carbon sequestration (GCS) storage options, if conducted in pressure- constrained formations, may generate large volumes of extracted brine that require costly disposal. In this study, we evaluate brine management in three locations of the United States (US) and assess whether recovered heat, water, and minerals can turn the brine into a resource. Climate and aquifer parameters varied between the three regions and strongly affected technical feasibility. We discovered that the levelized net present value (NPV) of extracted brine can range from −$50 (a cost) to +$10 (a revenue) per ton of CO2 injected (mt-CO2 ) for a CO2 point source equivalent to emissions from a 1000 MW coal-fired power plant (CFPP), compared to CCS NPV ranging from −$40 to −$70 per mt-CO2. Upper bound scenarios reflect assumed advancements in current treatment technologies and a favorable market and regulation landscape for brine products and disposal. A regionally appropriate management strategy may be able to treat the extracted brine as a source of revenue, energy, and water. 1. Introduction Carbon dioxide (CO 2 ) capture and sequestration (CCS) is designed to prevent anthropogenic CO 2 from entering the atmo- sphere. Geologic carbon sequestration (GCS) is the injection of CO 2 into geologic formations such as sedimentary basins (Gale, 2004; Holloway, 2005). The large storage capacities of saline aquifers within sedimentary basins in the United States (US) make them a promising choice for GCS. Unfortunately, because the pore space in saline aquifers is already filled with brine, the injection of large quantities of CO 2 can lead to widespread and lasting pres- sure perturbation in the subsurface (Birkholzer et al., 2012; Nicot, 2008). Potential impacts related to elevated formation pressure include: (1) caprock fracturing and fault reactivation, and (2) pressure-driven leakage of CO 2 and brine (Rutqvist et al., 2008). One developing technique for mitigating pressure concerns is GCS with brine extraction, whereby CO 2 is injected into a saline ∗ Corresponding author at: Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 9R2002, Berkeley, CA 94720, USA. Tel.: +1 510 642 8771; fax: +1 510 642 5815. E-mail address: temckone@lbl.gov (T.E. McKone). formation and resident brine is brought to the surface through extraction wells to direct CO 2 plume flow and to manage forma- tion pressure (Bergmo et al., 2011; Birkholzer et al., 2012; Buscheck et al., 2012). While brine extraction is not required and may not be necessary for most GCS sites, it is useful to explore methods for reducing dis- posal costs for sites where pressure constraints require that brine be extracted. Buscheck et al. (2012) provide a qualitative overview of potentially viable options including: desalination; saline water for cooling towers; makeup water for enhanced oil recovery (EOR) systems; and geothermal energy production. Various industries provide evidence that brine-sourced heat, minerals, and water are marketable products that present an opportunity for considering the brine as a resource in certain regions of the country (Ahmed et al., 2001; Aines et al., 2011; Buscheck et al., 2011; Frick et al., 2010; Harto and Veil, 2011; Sullivan et al., 2011; Veil et al., 2004). Aside from desalination, there is currently no method for explor- ing the feasibility, cost, or benefit of brine management for GCS (Bourcier et al., 2011). Our objective is to develop a spatially resolved method for quan- tifying the costs and environmental impacts of brine management. We assume that the GCS projects studied require extraction of brine at an extraction ratio of one (i.e., volume of CO 2 injected equals