IPCC
(2005) opererer med intervallet 24-40%
for kulfyrede kraftværker (Pulverized Coal plants).
IEA
(2004) 39%
I en artikel (januar 2009): The
energy penalty of post-combustion CO2 capture & storage and
its implications for retrofitting the U.S. installed base
(Kurt Zenz House, Charles F. Harvey, Michael J. Aziz and Daniel
P. Schrag) konkluderer forfatterne, at merenergiforbruget i forbindelse
med eftermonterede (retrofit) CCS anlæg på
kulkraftværker er i størrelsesordenen 50-80%
og at merenergiforbruget i praksis vanskeligt kan bringes under
25%.
Conclusion
Achieving substantial reductions in CO2 emissions requires
either shutting down a large fraction of the current installed
base
of coal-fired power plants or retrofitting those plants for CCS.
Previous studies have estimated that the additional fuel
required
(f2) to maintain constant work output for a PC retrofit is between
50% and 80%. An analysis
of the thermodynamic limit indicates
those values might be improved by harnessing more of the
available waste heat and by improving the 2nd-law efficiency of
temperature-swing separation systems. It appears difficult,
however, to improve f2 for post-combustion capture
to below
25% in practice. Our most
likely efficiency scenario indicates
that offsetting the energy penalty incurred from capturing
and storing 80% of the U.S. coal fleet’s CO2 emissions will
require either an additional 390–600 million tonnes of
coal, an
additional 69–92 gigawatts of CO2-free-baseload power,
or
a 15%–20% reduction in overall electricity use. (NOAHs understregning)
I en Panel Presentation, (maj 2007): CO2 Compression
Opportunities in Fossil Fueled Power Plants. Session Chairs:
Richard Dennis and Manfred Klein hedder det bl.a.:
"When 90 % CO2 capture is implemented in a precombustion
decarbonization IGCC and CO2 is compressed to 2,200 psia, the
auxiliary power load increases by about 40%,
compared to the non-capture case."
I et abstract af artiklen Carbon capture and storage:
Fundamental thermodynamics and current technology af
S.C. Page, A.G.Williamson og I.G.Mason hedder det:
"Carbon capture and storage (CCS) is considered a leading
technology for reducing CO2 emissions from fossil-fuelled electricity
generation plants and could permit the continued use of coal and
gas whilst meeting greenhouse gas targets. However considerable
energy is required for the capture, compression, transport and
storage steps involved. In this paper, energy penalty information
in the literature is reviewed, and thermodynamically ideal and
‘‘realworld’’ energy penalty values are
calculated. For a sub-critical pulverized coal (PC) plant, the
energy penalty values for 100% capture are 48.6%
and 43.5% for liquefied CO2, and for CO2 compressed
to 11MPa, respectively. When assumptions for supercritical plants
were incorporated, results were in broad agreement with published
values arising from process modelling. However, we show that energy
use in existing capture operations is considerably greater than
indicated by most projections. Full CCS demonstration plants are
now required to verify modelled energy penalty values. However,
it appears unlikely that CCS will deliver significant CO2 reductions
in a timely fashion. In addition, many uncertainties remain over
the permanence of CO2 storage, either in geological formations,
or beneath the ocean. We conclude that further investment in CCS
should be seriously questioned by policy makers."
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