This paper examines thermal efficiency penalties and greenhouse gas as well as other pollutant emissions associated with pulverized coal (PC) power plants equipped with postcombustion CO2 capture for carbon sequestration. We find that, depending on the source of heat used to meet the steam requirements in the capture unit, retrofitting a PC power plant that maintains its gross power output (compared to a PC power plant without a capture unit) can cause a drop in plant thermal efficiency of 11.3-22.9%-points. This estimate for efficiency penalty is significantly higher than literature values and corresponds to an increase of about 5.3-7.7 US¢/kWh in the levelized cost of electricity (COE) over the 8.4 US¢/kWh COE value for PC plants without CO2 capture. The results follow from the inclusion of mass and energy feedbacks in PC power plants with CO2 capture into previous analyses, as well as including potential quality considerations for safe and reliable transportation and sequestration of CO2. We conclude that PC power plants with CO2 capture are likely to remain less competitive than natural gas combined cycle (without CO2 capture) and on-shore wind power plants, both from a levelized and marginal COE point of view.
Captured CO2 is a potential
feedstock to produce fuel/chemicals
using renewable electricity as the energy source. We explored resource
availability and synergies by region in the United States and conducted
cost and environmental analysis to identify unique opportunities in
each region to inform possible regional and national actions for carbon
capture and utilization development. This study estimated production
cost of synthetic methanol and Fischer–Tropsch (FT) fuels by
using CO2 captured from the waste streams emitted from
six industrial [ethanol, ammonia, natural gas (NG) processing, hydrogen,
cement, and iron/steel production plants] and two power generation
(coal and NG) processes across the United States. The results showed
that a total of 1594 million metric ton per year of waste CO2 can be captured and converted into 85 and 319 billion gallons of
FT fuels and methanol, respectively. FT fuels can potentially substitute
for 36% of the total petroleum fuels used in the transportation sector
in 2018. Technoeconomic analysis shows that the minimum selling prices
for synthetic FT fuels and methanol are 1.8–2.8 times the price
of petroleum fuel/chemicals, but the total CO2 reduction
potential is 935–1777 MMT/year.
This article uses a market-based allocation method in a consequential life cycle assessment (LCA) framework to estimate the environmental emissions created by recovering carbon dioxide (CO2). We find that 1 ton of CO2 recovered as a coproduct of chemicals manufacturing leads to additional greenhouse gas emissions of 147-210 kg CO2 eq , while consuming 160-248 kWh of electricity, 254-480 MJ of heat, and 1836-4027 kg of water. The ranges depend on the initial and final purity of the CO2, particularly because higher purity grades require additional processing steps such as distillation, as well as higher temperature and flow rate of regeneration as needed for activated carbon treatment and desiccant beds. Higher purity also reduces process efficiency due to increased yield losses from regeneration gas and distillation reflux. Mass- and revenue-based allocation methods used in attributional LCA estimate that recovering CO2 leads to 19 and 11 times the global warming impact estimated from a market-based allocation used in consequential LCA.
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