The CO2 emissions from the ERCOT coal fleet (a) and total ERCOT electric grid (b) are different for each scenario
Figure 4. The CO2 emissions from the ERCOT coal fleet (a) and total ERCOT electric grid (b) are different for each scenario. (a) The emissions from the scenario-specific coal-fired plants are highest for scenarios 3 and 4 that, by definition, include more coal-fired power plants. (b) To conceptualize the quantity of CO2 captured in each scenario, we show two baseline results for comparison in which no CO2 is captured. 'Baseline: no emissions penalty, no sales price, no CO2 capture' compares to scenarios 1 and 3 in which there is no emissions penalty. 'Baseline: $60/tCO2 emissions penalty with no CO2 capture' estimates the emissions from ERCOT generators when an emissions penalty exists but no generators have CO2 capture.
This letter compares several bounding cases for understanding the economic viability of capturing large quantities of anthropogenic CO2 from coal-fired power generators within the Electric Reliability Council of Texas electric grid and using it for pure CO2 enhanced oil recovery (EOR) in the onshore coastal region of Texas along the Gulf of Mexico. All captured CO2 in excess of that needed for EOR is sequestered in saline formations at the same geographic locations as the oil reservoirs but at a different depth. We analyze the extraction of oil from the same set of ten reservoirs within 20- and five-year time frames to describe how the scale of the carbon dioxide capture, utilization, and storage (CCUS) network changes to meet the rate of CO2 demand for oil recovery. Our analysis shows that there is a negative system-wide net present value (NPV) for all modeled scenarios. The system comes close to breakeven economics when capturing CO2 from three coal-fired power plants to produce oil via CO2-EOR over 20 years and assuming no CO2 emissions penalty. The NPV drops when we consider a larger network to produce oil more quickly (21 coal-fired generators with CO2 capture to produce 80% of the oil within five years). Upon applying a CO2 emissions penalty of 60$2009/tCO2 to fossil fuel emissions to ensure that coal-fired power plants with CO2 capture remain in baseload operation, the system economics drop significantly. We show near profitability for the cash flow of the EOR operations only; however, this situation requires relatively cheap electricity prices during operation.