Page 44 - impiantistica_5_15

carbon-free power generation scenarios, but they distributed fashion closer to population centres

have a load-flexibility lower than OCGT and exhibit (and so reducing transmission costs) as well as a

similar problems about CCS implementation. highly a high value export to countries with growing

Furthermore, implementing CCS technologies in energy demands.

such plants significantly increased electricity costs According to both the 2DS and 4DS (Degree

and further restricts their flexibility. As shown in Scenario) scenarios presented by the International

figure 2, from the point of view of the final cost of Energy Agency (IEA) in its Energy Technology

electricity (assuming a carbon tax around 50 US$/t Perspective [6], conventional and unconventional

CplOan2)t,s,CwCitGh TorawreithmouotreCCcSom[6p],etaitlitvheoutghhantheSCcPosCt natural gas will play an important role in power

generation until 2050. As a result, fully developed

[o7f]t.hTehtisonrenme oafrkCaOb2lecraepstuulrteids is lower for coal plants Sa -sCigOn2ifgicaasnttucrboninteribcuytciolens can be expected to make
explained considering in this period in providing

that both the relative net efficiency penalty due to affordable and efficient power generation with a

CCS (%) and the final net efficiency with capture very low carbon footprint and in making sustainable

(LHV, %) favour CCGT [7]. the increasing share of renewable energy sources.

It is also important to note that although advanced The development and efficient implementation of

CunOd2ercadpetvuerelopcmonecnet,pttshefyor power generation are this technology requires advancement in different
are designed for base
fields, such as combustion, turbo-machinery, heat

load. Such technologies should be rearranged exchangers, materials, oxygen production, ConOly2
capture, and also a high level of integration, not
for load flexibility, where this is possible, with

unavoidable penalties both in efficiency and costs. between the specific solutions, but also between

nInoto(tohrenrecaarlsyenso, t)scoommepCatOib2lecwapithtutrheeclooandceflpetxsibailirtey different concepts, such as renewables, nuclear,

Power2Gas (P2G), extraction of non-conventional

requirements. Hence, plants having a simpler natural gas.

layout and fully integrated CO2 capture processes
offer a major step forward.
S-CO Gas Turbine PlantsSupercri2tical fluids are those fluids above critical
The authors, as well as other research and

industrial groups in the world, do believe that

advanced gas turbine power cycles that uasneswS-eCr Oto2 point, i.e., critical pressure and temperature.
as working fluid could be an effective
F3o0r4.2C5O2K, the critical point is at 73.96 bar and
the power generation needs for the 21st century (31.1 °C). The first advantage of using

e[8ff]e. cWtioverktinegchwniothlogSy-,CwOi2thwmill inreimsuultmineanvhiriognhmly ecnotsatl a supercritical fluid in power plants is that, at this

state, a fluid is indistinguishable between being

and space impacts compared with other fossil- gaseous or liquid, with the consequent reduction

fuel-based energy conversion systems with iCnOa2 of compression work (due to both its high density
capture. This will make it easier to deploy
and low compressibility) and significant increase of

Fig. 2 - CCS impact on the

final cost of electricity for

current power plants (ETP

2014). Final net efficiency

with capture, relative net ef-

ficiency penalty due to CCS

and the cost sohfowCOn 2oncathpe-
tured are also

right axis [ETP 2013]. In this

analysis, the carbon tax is

around 50 US$/t

42 Impiantistica Italiana - Settembre-Ottobre 2015