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at temperatures relevant for Concentrated Solar State-of-the-art on S-CO2 Gas
Turbine Cycles
Power applications, bridging the gap that the

CSP plants have in acting in fast-acting “peaker”

applications.

sTohme eS-rCeOce2net xbprloeiatakttihornoutgohpsic. is also related to Although excellence can be found in some
As known, shale
tseecchtonroslo(gey.g, .t,hehreeatareexcsthilal nugneerxsp)loinrveodlvoepdpoinrtSun-CitiOes2
gas extraction is founded on hydraulic fracturing

(“fracking”) of shale formations by using a especially in the semi-closed cycle configuration.

large amount of fresh water. The importance of In US, under the CSP program of the Department

unconventional natural gas in the global energy otefsEtender,gdy,eam1o0nMstWratSin-gCOth2etuhrbiginhe was successfully
efficiency of the
scenario is widely accepted and it is easy to

In 2012, some scientists from Kyoto predict that the shale strategy under conditions and at a scale relevant
gas extraction will
University in Japan, lead by Dr. to commercial Concentrating Solar Power projects

continue more and (project ended in November 2013).

Tsuyoshi Ishida [13], found a new way more in the next On the international level, both the US and Japan,

to enhance and make sustainable the years. As the recent in a consortium in which Toshiba and Net Power

shale gas extraction using rSe-aCl Osc2.aTleh,is US experience are the main partners, have been working on the
method, if applicable on
teaches, fresh-water Sye-aCrOs.2 oxy-combustion “Allam cycle” for nearly 5
Constraints have been found with this cycle
consumption and
could be a “three-dimensional” solution contamination are
due to the high turbine inlet temperature (1100-

to save fresh water, enhance the shale the most important 1200 °C), that requires challenging blade cooling
gas production and finally, use the topics related with
the environmental solutions and, due to the thermal dependency of
shale formatiotencshansolCoOgi2ess.torage in CCS footprint of the shale
gas extraction. the Air Separation Unit (ASU) from which some

heat is recovered, thus limiting operational flexibility.

Articles available in literature show the potential high

Furthermore, S-CgOas2 efficiency of the Allam cycle and large technological
semi-closed
advancement involved. In particular, Net Power

turbines with oxy-combustion could be used finished oxy-combustion tests at 300 bar in an

to extract shale gas in desert regions where no tbShu-eCildAOli2ltasmefinrCsvitryo5cn0lem,MeoWnthteeifrnaccy2ilci0tyl1e3inco2an0nfi1dg5u.irsaIntpioclanonsnnt(rianasgstthttooe

water is available.

In 2012, some scientists from Kyoto University

in Japan, lead by Dr. Tsuyoshi Ishida [13], found one developed in Enea) may be designed to show

a new way to enhance and make sustainable primary advantages. For example, configurations

the shale gas extraction reuasl insgcalSe-,CcOo2u. ldThbies that do not require a continuous heat supply from
method, if applicable on
the ASU, thus permitting asynchronous operation

a “three-dimensional” solution to save fresh between the power cycle and the ASU, are

water, enhance the shale gas production and preferable to gain higher operational flexibility.

fininaCllyC, Susetecthhenoslohaglieesf.orFmuartthioenrsmoarse,COth2estsohraalgee- Echogen Power Systems has been developing

a closed power generation cycle for CSP, WHR,

gas formations could become a major utilization Combined Heat & Power and geothermal

option for carbon sequestration [14, 15]. Some aTphpeliAcautsiotrnasli.anThReeynbeuwiltabale6-E8nMerWgye unit in 2013.
Agency (Arena)
Corporations from US (GE) and Norway (Statoil

ASA) already joined their forces in a 10-billion is funding a consortium consisting of Sandia

US$ research program [16] aimed aant dusiningfraSc-kCinOg2 National Laboratories, National Renewable Energy
in Enhanced Oil Recovery (EOR)
Laboratory (NREL) from US, University of Sydney

instead of water. and Queensland University of Technology for the

It is finally observed that the Sa-CppOli2cateticohnnsolaongdy project named “Solar-driven seuxppeercctreitdicapl roCjeOc2t
can be exploited in different Brayton Cycle”. Among the

sectors to enhance their decarbonisation. benefits, the consortium declares: “Much less

Compactness and other features make such pususoipwnegerrcariiirtsicinaretl yqpCuiiOcrea2dl gBatrosaytctuoornbminpceryesc,slsethetchroeembyCpiaOnrc2erdeinawstinhitghe

technology exploitable in power, oil & gas, and

transport sectors (in the transport sector a

reduction of at least 60% in GHGs is required by the overall amount of electricity produced by about

2050, with respect to 1990). mInarpitaimrtiecultarra,nSs-pCoOrt2. 30%. This higher efficiency also means that the
cycles are exploitable in
capital cost is much less because fewer mirrors are

This is interesting since the GHG emissions of required and the receivers and towers are smaller”.

international maritime transport is increasing and The involvement and know-how in Europe is low

aemccisosuinotnss.foLraasbt,obuut t4n%otolef agslot,bsaul cmhaan-tmecahdneolCoOgy2 at present, but the interest is growing very quickly

and some communities already formed, e.g.,

can be exported to countries with growing energy the CO2ReTurn Project Group coordinated by

demands. these authors (Enea) within the European Turbine

Impiantistica Italiana - Settembre-Ottobre 2015 45