The complex future of CO_2 capture and storage: Variable electricity generation and fossil fuel power

摘要

Fossil fuels are an integral part of the US energy portfolio, playing a prominent role for current and future domestic energy security. A sustainable, low-carbon future will require CO_2 to be captured from major coal and natural gas power plants. However, fossil fuel electricity generation CO_2 emissions are typically highly variable throughout each day with daily generation profiles varying greatly between plants. We demonstrate that understanding this variability is absolutely critical for setting a suitable carbon price as well as identifying if and how much CO_2 a power plant will capture. For example, we show that a CO_2 emissions price (or tax) of anywhere between $85/tCO_2 and $135/tCO_2 will be required to incentivize a gas power plant to manage all its capturable CO_2; this range is solely due to differences in CO_2 emissions profile. Further, we show that the setting a carbon price is very sensitive to system-wide costs including the CO_2 value for enhanced oil recovery and, in particular, the costs for CO_2 transport and storage. We also find that, even though coal-fired plants are more CO_2-intensive and thus incur greater CO_2 management costs, coal plants require a significantly lower carbon price ($15/tCO_2 lower) in order to encourage CO_2 capture. We conclude that integrating fossil fuel power, particularly natural gas, into a large-scale CO_2 capture and storage system is a complex problem that will require detailed research and modeling.