Basic Research Needs for Geosciences - Energetics Meetings and ...

APPENDIX 1: TECHNICAL PERSPECTIVES RESOURCE DOCUMENTinjected 1 MMt of CO 2 per year for ten years (Arts et al. 2004). In that context, the technicalneeds for geological carbon sequestration involve questions of scale (both spatial and temporal).Greater scientific understanding is required to develop tools, regulations, and operationalprotocols for deployment of multi-million ton injections in thousands of wells nationwide andworldwide across a range of geological settings. This need requires that future suitable sites areconfidently identified, atmospheric isolation of CO 2 is effective during injection and long after,and that the subsurface environment is effectively monitored. These expectations in turn requirethat large volumes of subsurface rock formation can be adequately characterized, and that theperformance of the storage reservoir can be predicted, simulated, and verified. Hazards thatpresent potential risks must be identified and the risks quantified. Underlying these concerns arequestions of fundamental petrophysics, hydrology, geochemistry, and reservoir characterization.Given the limited data sets from geological carbon sequestration operations at scale and theheightened interest in the technical feasibility of sequestration, additional fundamental researchshould lead to significant enhancements in the scientific and technical understanding needed forlarge-scale deployment. While substantial understanding currently exists, it can be betterquantified, characterized, used, and validated through addressing remaining important scientificand technical questions.CARBON CAPTURE AND STORAGE OVERVIEWCarbon capture and storage involves three components: capture and separation, transportation,and geological sequestration. Industry has substantial experience with each of these components,chiefly from operation of hydrogen plants, fertilizer plants, refineries, and natural gas processingfacilities, as well as from enhanced oil recovery operations. CO 2 has been separated fromindustrial flue streams at scales greater than 1 MMt CO 2 /y (270,000 t C/y), large pipelinestransport millions of tons of CO 2 hundreds of kilometers, and millions of tons of CO 2 and otheracid gases are injected into geological formations every year. Similarly, CO 2 has been separatedfrom small-scale power plants, and technology to scale these operations to plants of 200 MW orgreater exists.In considering the technical needs for geological carbon sequestration deployment, it is helpful toconsider a reference case of a 500 MW coal-fired power plant with its carbon capture and storageneeds (MIT 2007). Such a plant, burning bituminous coal with an 85% capacity factor and 90%capture, will require injection of 3 MMt CO 2 /y and approximately 200 MMt CO 2 over itsexpected lifetime of roughly 60 years. For targets of interest and a normal geothermal gradient,this mass will require a storage volume equivalent to 60,000–100,000 bbl/d (~10,000–16,000m 3 ), and ~1.4–2.3 billion barrels (~200–400 million m 3 ) over the same time. For injection into asedimentary rock layer of 30 m thickness, 70% net injectivity, 10% porosity, and where only 5–50% of the pore volume can be accessed effectively due to heterogeneity, the resulting CO 2plume would have a 7–70 km final radius and displace an equivalent volume of pore fluid. Forplants where the sulfur species are co-sequestered at ~0.03% of the injected volume,~8500 tons/y of sulfur could be injected as SO x or H 2 S.There are over 1500 coal-fired power plants in the United States today generating 330,000 MWof electricity. There are over 5,500 natural gas fired power plants generating over 430,000 MWof electricity. To achieve substantial reductions of CO 2 emissions, well over 1 Gt C (emissionsfrom 600,000 MW of electricity 3.7 Gt CO 2 ) must be injected annually. Injection will beproposed for a range of geological formations, including those with some understanding basedBasic Research Needs for Geosciences: Facilitating 21 st Century Energy Systems Appendix 1 • 5