Page 52 - Impiantistica Novembre-Dicemvre 2015

Table 6 - Near-zero emission plants

PCC + biomass Efficiency % pt. TPC €/kW LCOE €/MWh CAC €/t change
% change €/kW change €/MWh change €/t -0.3
2887 65.1 -2.5
34.6 -0.6 +115 100.5 +5.8 -3.3
2823 58.3
(100% abatement) 35.3 -0.4 +62 94.2 +2.6
Oxy-combustion 3203 92.5

(97.6% capture) 34.1 -0.8 +128 119.2 +4.8
IGCC

(98.6% capture)

seawater cooling instead of natural draught cooling coal plant with post combustion capture. The re-
towers increases the thermal efficiency of plants
with CCS by up to 0.7 percentage points and using sults would be similar for the oxy-combustion plant.
air cooling reduces the efficiencies by up to 0.7 per-
centage points and both of these cooling systems Coal price can vary over a wide range due to local
have little impact on the capital cost. However, at
higher ambient temperatures the impact of air coo- coal availability and mining costs to market varia-
ling is expected to be more negative.
bility, which is difficult to predict. Varying the coal

price by ±1.5 €/GJ from the base case of 2.5 €/GJ

changes the LCOE by ±15.5 €/MWh.

The operating capacity factor of the plant may be

lower than the 90% base case assumption in this

Economic sensitivities paper, either because of poor reliability and availa-

bility of the plant or because of electricity system

The costs of CCS depend on economic parame- constraints, i.e. other power generators with lo-

ters, which will vary over time and between different wer marginal operating costs being operated in

plant locations. It is therefore important therefore to preference to CCS plants at times of low power

consider the sensitivity of costs to variations in the demand. Reducing the capacity factor can have

parameters. The sensitivity to the coal price, econo- a substantial effect of the LCOE, figure 4 shows

mic discount rate, plant life, cost ofaf cCtoOr2 transport that reducing the capacity factor from 90% to 70%
and storage, operating capacity and cost
would increase the LCOE by 15.6 €/MWh.

tpieesnawlteyreforasnsoens-sceadptfuorreadllCoOf 2theemmisasiinonsst.udSyencsaitsiveis- If the plant operates at a low capacity factor becau-

se of electricity system constraints the impacts on

and the results for each parameter are presented plant profitability and rate of return may be much

in [2]. As an example, the sensitivities to all of the less significant because the times when the plants

parameters are shown in figure 4 for the pulverised are forced to not operate would by definition be

times of low electricity prices, so the impacts on

net revenues and rates of return of not operating at

such times may be small. However, this is difficult

to assess because the electricity prices depend on

the costs of the other generating plants in the ove-

rall electricity system.

Costs of cCoOns2idtrearnasbplyorbt eatnwdeesntordaigffeeraernet expected
to vary sites. At

shiatenscewdhoerilereCcOo2vecray,n be sold, for example for en-
the net cost may be zero or

even negative. If trheelatCivOel2y has to be transported a
long distance in a small pipeline for offsho-

re storage the cost would be substantially greater

than the 10 €/t base case scenario in this paper.

Fig. 4 - Sensitivities of Levelised Cost Of Electricity (plant with post combustion capture) Sensitivities to costs in the range of zero to 20 €/t

ocof CstOs 2msatoyrebde are shown in figure 4 but the range of
higher in some circumstances.

The main economic evaluation in this paper does

not include a cost Ifnocr luedminitgtinagcnoosnt -thcaapt itsureeqduaClOto2
to the atmosphere.

t6Th5hee€c/LotCsCtOOoEf2,CiswOore2ulaaldbtiavineteclymreiaensnseet nbthsyietCivLCeCStOoinEintbhcyirse6aps€lai/nnMgt,Wti.hhee..

plant life from 25 to 40 years, because of the effects

of economic discounting.

The sensitivities eocf oCnOom2 aicvopiadraanmceetecrossat r(eCAshCo)wton
variations in the

in figure 5. It can be seen that variations iimn tphaecCt oOn2
emission cost, which has relatively little

Fig. 5 - Sensitivities of CO2 avoidance cost (plant with post combustion capture) the LCOE of the plant with capture, has by far the

50 Impiantistica Italiana - Novembre-Dicembre 2015