摘要：This work analyses the carbon dioxide (CO2) capture system operation within the Electric Reliability Council of
Texas (ERCOT) and Great Britain (GB) electric grids using a previously
developed first-order hourly electricity dispatch and pricing model. The grids
are compared in their 2006 configuration with the addition of coal-based
CO2 capture retrofits and emissions penalties from 0 to 100 US dollars per metric ton of
CO2 (USD/tCO2).
CO2 capture flexibility is investigated by comparing inflexible
CO2 capture systems to flexible ones that can choose between full- and zero-load
CO2 capture depending on which operating mode has lower costs or higher profits. Comparing these
two grids is interesting because they have similar installed capacity and peak demand, and
both are isolated electricity systems with competitive wholesale electricity markets. However,
differences in capacity mix, demand patterns, and fuel markets produce diverging behaviours of
CO2 capture
at coal-fired power plants. Coal-fired facilities are primarily base load in ERCOT for a large range
of CO2 prices but are comparably later in the dispatch order in GB and consequently
often supply intermediate load. As a result, the ability to capture
CO2 is more important for ensuring dispatch of coal-fired facilities in GB than in ERCOT when
CO2 prices are high. In GB, higher overall coal prices mean that
CO2 prices must be slightly higher than in ERCOT before the emissions savings of
CO2 capture offset capture energy costs. However, once
CO2 capture is economical,
operating CO2 capture on half the coal fleet in each grid achieves greater emissions reductions
in GB because the total coal-based capacity is 6 GW greater than in ERCOT.
The market characteristics studied suggest greater opportunity for flexible
CO2 capture to improve operating profits in ERCOT, but profit improvements can be offset by a
flexibility cost penalty.
