Smart Electricity Systems - Multi-Energy Systems - PDF

Smart Electricity Systems MULTI-ENERGY SYSTEMS FURTHER INSIGHTS Prof. Gianfranco Chicco Dipartimento Energia “Galileo Ferraris” Politecnico di Torino © Copyright Gianfranco Chicco, 2024 INTERPRETATION OF OPERATING POINT AND FLEXIBILITY FOR TRIGENERATION Feasible operation region - Trigeneration § A graphical interpretation is used to represent the 800 average thermal power [kW t ] 600 AB contributions of the various components of a 400 trigeneration system to serve the given multi-energy 200 EDS 0 demand (W0, Q0, R0) -600 -450 -300 -150 0 150 300 450 600 average electrical power [kW e] 600 average thermal Initially, the feasible operation region of the MES power [kW t ] § 400 considering the technical limits of EDS, CHP and AB is 200 CHP drawn through Minkowski sums 0 -600 -450 -300 -150 0 150 300 450 600 average electrical power [kW e] #$,- Minkowski EDS !! sums %$"# #!"# EHP #! #$"# 1200 average thermal power [kW t ] !!"# $$"# CHP 1000 %%&'( $%&'( 800 !+,- $!"# WARG FDS 600 $) 400 AB $! !&* $&* 200 0 -600 -450 -300 -150 0 150 300 450 600 750 900 average electrical power [kW ] e Operation ranges for cooling production § The range of values that represent the electricity and heat input needed to supply the cooling demand 𝑅! = 𝑅"#$ + 𝑅%&'( from EHP and WARG is constructed, taking into account the COP and the limits (size) of the EHP and WARG § The figure shows the family of curves drawn with different values of the cooling demand to be served § The parameter is the cooling demand R0 C. Piran, A. Barale, A. Mazza, G. Chicco, Optimisation of Multi-Energy System Operation with Convex Efficiency Representation at Partial Loading, IEEE Trans. on Industry Applications, 2024, doi:10.1109/TIA.2024.3395581 Interpretation of the operation point § The next steps are then followed: 1) Start from the feasible operation region for electricity and heat 2) Introduce the point (𝑊! , 𝑄! ) with the electricity and heat demand of the user 3) Add to the point (𝑊! , 𝑄! ) the curve that represent the electricity and heat input needed to supply the cooling demand 𝑅! = 𝑅"#$ + 𝑅%&'( from EHP and WARG (the resulting range of operating conditions must remain inside the feasible operation region) 4) Draw the CHP contribution, which intersects the curve of the electricity and heat inputs needed to serve the given cooling demand R0 C. Piran, A. Barale, A. Mazza, G. Chicco, Optimisation of Multi-Energy System Operation with Convex Efficiency Representation at Partial Loading, IEEE Trans. on Industry Applications, 2024, doi:10.1109/TIA.2024.3395581 Interpretation of the operation point n For determining the CHP contribution: ü The intersection between the CHP characteristic and the range of operating conditions defines the operating point ü The location of the axes of the CHP characteristic identifies the contributions of the supply systems to serve the multi-energy demand (next steps) 700 average thermal power [kW t ] 600 500 WEDS W CHP (W0 +W EHP,Q0 +QWARG) example with CHP 400 at maximum 300 output that Q CHP supplies all the 200 thermal demand 100 (W0 ,Q0 ) (heat and cooling) 0 0 150 300 450 average electrical power [kW e] C. Piran, A. Barale, A. Mazza, G. Chicco, Optimisation of Multi-Energy System Operation with Convex Efficiency Representation at Partial Loading, IEEE Trans. on Industry Applications, 2024, doi:10.1109/TIA.2024.3395581 Interpretation of the operation point 5) Identify the contributions of CHP and EDS on the electrical side: ü CHP contribution: identified on the horizontal axis of the CHP characteristic ü EDS contribution: distance between the vertical axis of the overall figure and the vertical axis of the CHP characteristic 6) Identify the contributions of CHP and AB on the thermal side: ü CHP contribution: identified on the vertical axis of the CHP characteristic ü AB contribution: distance between the horizontal axis of the overall figure and the horizontal axis of the CHP characteristic 700 average thermal power [kW t ] 600 WEDS WCHP (W0 +W EHP,Q 0 +QWARG) other example with 500 CHP at maximum 400 output that supplies 300 Q CHP part of the thermal 200 demand (heat and 100 cooling) Q AB 0 0 150 300 450 average electrical power [kW e] C. Piran, A. Barale, A. Mazza, G. Chicco, Optimisation of Multi-Energy System Operation with Convex Efficiency Representation at Partial Loading, IEEE Trans. on Industry Applications, 2024, doi:10.1109/TIA.2024.3395581 Maximum downward flexibility § The maximum downward flexibility corresponds to the maximum electricity input from the EDS, with: ü CHP at its minimum electricity production (to take more electricity from the EDS) ü The CHP characteristic cannot move to negative average thermal power values, and this limits the possibility of taking more electricity from the EDS 600 average thermal power [kW t ] 500 400 300 maximum 200 WEDS W CHP downward (W0 +W EHP,Q0 +QWARG) flexibility 100 Q CHP case 0 0 150 300 450 average electrical power [kW ] e C. Piran, A. Barale, A. Mazza, G. Chicco, Optimisation of Multi-Energy System Operation with Convex Efficiency Representation at Partial Loading, IEEE Trans. on Industry Applications, 2024, doi:10.1109/TIA.2024.3395581 STORAGE IN THE ENERGY HUB MODEL Storage in the Energy Hub model § Multiple energy carriers are converted, conditioned Chapterand2. stored Energyin Hubs centralized energy hubs Energy Hub transformer Electricity Electricity battery storage absorption gas turbine chiller Natural gas Cooling hot District heat water storage Heating heat exchanger Energy hub igure 2.1: Example ofwith electrical transformer, a hybrid energy hub gas turbine, that heat exchanger, contains typical ele- battery storage, hot water storage, and absorption chiller ments: electrical transformer, gas turbine, heat exchanger, Geidl M, Integrated Modeling and Optimization of Multi-Carrier Energy Systems, PhD thesis, ETH Zürich, 2007 battery storage, hot water storage, absorption chiller. Geidl M, Koeppel G, Favre-Perrod P, Klöckl B, Andersson G, Fröhlich K. Energy Hubs for the Future. IEEE Power and Energy Magazine, January/February 2007, 25-30 Q!α ditioned rage devices is and/or converted considered to consistinto another energy carrier, of an interface and which is then stored.Through al) storage. For example, pressurizedpower the interface, Interface air storage may plants be con- exchange electrical r converted Storage in the Energy Hub model power, but internally pressurized air is stored. However, when a storage into another energy carrier, which is Q then device exchanges an energy carrier α, then it isαreasonable to consider mple, pressurized it§ as The air of storage plants exchange electrical model of an energy storage unit a storage α, even if β ! = α is stored is set Therefore, internally. up by considering in the rnally pressurized the following air is stored. considerations, However, storage when content a storage anddevice. powerwith exchanged are Eα ,system, Figurestored energy 3.5: Model E a , of an the energy power Q a storage exchanged Stored theenergy external inter- es an energy carrier α, then it considered to be of the same form.is reasonable to consider ! of α, even and if β the != αinternal nal power power is stored Qα , power internally. exchangeinQα. Therefore, The § storage The interface internal can be is storage modeled similar ideal, considered to a converter and thedevice. storageTheefficiency in nsiderations, storage content and power exchanged are steady-state the input and output power values canisbe related to each other form. are stated. These relations are then merged with interface charging e of thebysame exchange and discharging modes associated to the the converter § Inmodel general,fromthese the efficiencies !24 preceding Q = may depend sections e Q on in resulting power a and complete energy (3.12)energy hub Chapter 3 erface can be modeled similar to a converter α α αdevice. The outputemodel ut and where power including values describes α how conversion can andtostorage. be related much the power each other with the system exchanged Storage affects the energy stored. This factor generally depends on the direction of powerQ!flow, α = i.e., eα Qifα the storage is charged or discharged: (3.12) Eα 3.3.1 " Storage Element ibes how much the power e+α exchanged if Qα ≥ 0 with the system (charging/standby) !α e gy stored. ThisAfactor α = generally depends on the direction (3.13) Q general model 1/e − α for else energy(discharging) storage devices is developed based on Fig-.e., if the storage ure 3.5. is charged The storage devices is considered to consist ofInterface or discharged: an interface and an internal (ideal) storage. Through the interface, power may Qα be con- + eα ≥ 0 (charging/standby) if Qαditioned and/or converted into another energy carrier, which is then (3.13) 1/e− α else stored. (discharging) For example, pressurized Figure 3.5: air Modelstorageof anplants energyexchange electrical storage device. Stored energ Geidl M, Integrated Modeling and Optimization of Multi-Carrier Energy Systems, PhD thesis, ETH Zürich, 2007 power, but internally pressurized air nalispower stored. Q! αHowever, when a storage , power exchange Qα. device exchanges an energy carrier α, then it is reasonable to consider rk 3.6model including conversion and efficiencies storage. + − Power generally Taking aand energy depends closer lookondependent onthe energy storage stored and technology emakes α ,its eα time = f (Q clear α , Eα ) can derivative.be included insuch theasequations above, + − to keep the complexity but in eorder Power and orage performance, energy dependent charging andefficiencies discharging , eα = f (Qα , Eα ) can be α efficiencies, ly dependsofincluded 3.3.1 the on the the Storage of dependent constant Storage in the Energy Hub model optimization inenergy optimization throughout problems the equations stored Element problems above, and this thesis. reasonably its but reasonably − ! low, to timein derivative order they keep aretheassumed. complexity low, they are assumed to be to be and energy efficiencies e+α , eα = f (Qα , Eα ) can be constant throughout d in the§ The equations above, but this thesis.to!keep the complexity ininaorder The energy stored energystored after the period certain (0, 24 operating depends T) period on thethe initial T equals Ch A general optimization The model problems stored energyfor energy reasonably after a storage low, certainthey devices are operatingassumedis perioddeveloped to T be equals based the on Fig- initial initial energy content and on the integral of power in the storage content plus the time integral of the power: ure nt throughout 3.5. The this storage storage thesis. content ! devices plus the time is integral consideredof the topower: consist of an interface and period (ideal) storage. Through the an internal !T interface, power may be con- Storage ored energy after a certain operating period T !T " the initial equals ditioned and/or converted Eα (T )into = Eanother α (0) + Qα (t) dtcarrier, which is energy (3.14) thenEα e content plus the time integralEof α (Tthe) =power: " Eα (0) + Qα (t) dt (3.14) stored. For example, pressurized air storage 0 plants exchange electrical Q! α !T 0 power, but internally The internal power flow Q pressurized air " α correspondsis stored. to the However, time when a storage derivative of the "" Interface device E α (T The exchanges ) internal = E power an α (0) + energy Q (t) flow Qαcarrier dt α corresponds α, thento the it is (3.14) time derivative reasonable to ofconsider the stored energy. For steady-state considerations, power is approximated Qα stored energy. Forpower steady-state considerations, inpower is of approximated by The it§ as internal athestorage change of in α, 0 is even energy ∆E the!= if βduring derivative α aistime stored period time internally. ∆t; the the dE /dtin Therefore, slope α by the energy theisfollowing change in stored, energy ∆E approximated considerations, during storage a time by∆t, the period variations content and ∆t; the power slope dE exchanged α /dt are ternal power assumed flow is assumed " Q to be constant corresponds to during the time what derivative Figure corresponds of 3.5: α to be constant during ∆t, what corresponds to constantthe Model of to an constant energy storage device. Store energy.considered Q"αto : be of the same form. power " For steady-state power Qα : considerations, power is approximated ! nal power Qα , power exchange Qα. dE dEα ∆t;α ∆E α changeThe in energy storage ∆E during acan interface Q""αbe time Q α= =period modeled ≈≈∆E theα slope similar! ĖαdE !Ėto a α /dt converter device.(3.15) (3.15) The med tosteady-state be constantinput during dt ∆t to constant α and∆t, what power output corresponds dt ∆t values can beare exchange related stated.to each These other are then merged relations " Qα : by§ Then: model from the preceding sections resulting in a co 3.3.2 dEα in " αStorage ∆EEnergy in Energy Hubs eα Qα model including (3.15) conversion and storage. 3.3.2Q Storage α ! α =Hubs = ≈ !Q Ė (3.12) dt ∆t where Energyeα hubs Energy describes hubs may contain how much contain multiple multiple the storage power elements. storage exchanged with elements.InInprinciple, thestor- principle, system stor- 3.3.1 Storage Element affects Storageage Geidl the ageM,can in energy be canEnergy beModeling Integrated stored. connected and Hubs toThis to Optimization the ofthe factor hubEnergy hub Multi-Carrier generally inputs, inputs, the Systems, the PhD hubdepends hub thesis, outputs, outputs, ETH onorthe Zürich, 2007 direction orbetween between converters of power converters flow,connecting connecting inputs i.e., if theinputs storage andis and outputs. charged outputs. AItwill It will or bebeshown shown discharged: general model that that for thethe energy cor- devices is devel cor- storage responding storage responding storage powerpower flow flow can canbe betransformed transformed ure 3.5. The totoeither either storage side of of side devices the is the considered to consist Storage in the Energy Hub model § The storage can be connected at the input or output of the hub § Example (three inputs, three outputs, storage at one input and one output) storage #̇$!& %$! !! "! !$! "%! storage H #̇%"& %%" !" "" !$" "%" !# "# !$# "%# "! &! !""# = % !&"# § The central (shaded) part has a matrix representation "# &# where the inputs and outputs are linked by the connection matrix H "!" $̇%"' § With storage, the matrix representation +%" − &%" $̇!# !"!# + '&!# ( = * ! +%# ( for the complete system becomes "!$ +%$ Storage in the Energy Hub model § Starting from the matrix equation storage "!" $̇%"' +%" − &%" #̇$!& !"!# + $̇!#'& ( = * ! +%# ( %$! !! "! !# !$! "%! "!$ +%$ the model is developed as storage "!" 0.%" '̇%"* ) H #̇%"& %%" !"!## + %'̇!#*) + = - !.%# # − - % 0 %"+ !$" !" "" "%" !# "!$ 0.%$ 0 "!" &%" ̇ *%"- 0 ,%" !# "# ̇ ! "!## = % !&%## − (% ) 0 / + )*!#-, /1 !$# "%# !# "!$ &%$ 0 0 "!" &%" 1, 0 0 0 1̇%" +%" 0 0 !"!# # = % !&%## − (% ) 0 1 0 0. + )0 ,+!# 0.0 ) 1̇!#. "!$ &%$ 0 0 0 0 0 0 0 1' 0 0 0 0 0 &!" § By introducing the storage coupling matrix ! = # $ 0 1 0 0) + $0 '&#$ 0) 0 0 0 0 0 0 "!" &%" *̇%" the final matrix equation is !"!# # = % !&%## − ( ) *̇!# - "!$ &%$ 0 The Energy Hub Model including storage § In general, storage is represented with the storage coupling matrix S and the array 𝐞̇ of the derivatives in time of the energy stored § For the whole system, the compact matrix model is: vo = [H −S][vi 𝐞]̇ T where the coupling matrix H contains the efficiencies (or COPs) of the components and considers the topology of the interconnections inside the energy system, represented by using dispatch factors at the bifurcations of the outputs § The matrices H and S can be constructed by visual inspection of the system M. Geidl, G. Koeppel, P. Favre-Perrod, B. Klöckl, G. Andersson, K. Fröhlich, Energy Hubs for the Future. IEEE Power and Energy Magazine 5 (1), 25–30 (2007). Electricity Electricity Example 3.2 In this example, derivation of (3.18) and (3.24) is out lined using a simple energy hub. Consider the hub shown in Figure 3. Natural gas Example of Storage in the Energy Hub which contains two converters and two storage devices: gas turbine an heat exchanger, and gas tank and hot water storage, respectively. Th Districtgas heatturbine is characterized by Heat its gas-electric and gas-heat efficiencie § System with gas turbine ηGT, GT heatGT exchanger HE and two storages (gas ge and ηgh , respectively. The heat exchanger operates with an effi tank at the natural gas input, ciencyandHE ηhh hot water at. Efficiencies of the heat output) the storage devices are eg and eh , for th Figure 3.7: Examplegas hubtank withand gastheturbine, heat exchanger, heat storage, gas tank, respectively. The electrical connectio § Three inputs and and twoheat outputs storage. input and output is assumed to be lossless. The in between (the coupling matrix is represented a converters ar 28 non-square form) Chapter 3. Modeling described by the following coupling matrix:   The storage devices exchange Electricity the powers Electricity 1 ηge GT 0 H C=   (3.25 GT 1 GT HE 0 ηgh ηhh(3.26a) Natural gas Qg = · Ėg eg 1 output-to-input coupling matrix District heat Heat Mh = · Ėh (3.26b) HE eh without storage Figure With § 3.7: storage: Example Nowwith hub (3.18) gascan be formulated: turbine, heat exchanger, gas tank, and heat storage.   ! "   Pe GT Le 1 ηge 0   The storage devices exchange the powers =   Pg − e1 · Ėg  (3.27) 1 Lh + · Ėh GT HE  g  eh 0 ηgh ηhh Ph 1 Qg = · Ėg (3.26a) eg outputs inputs 1 the hub can be described according to (3.24). Therefore Alternatively, Mh = · Ėh (3.26b) input-side Geidl M, Integrated Modeling e andh output-side and Optimization storage of Multi-Carrier Energy flow Systems, PhDhave thesis, to ETHbe transformed Zürich, 2007 to equiv- alent output-side flows: Now (3.18) can be formulated:   GT ' () * ' () * ' () * Meq S Ė Alternatively, the hub can be described according to (3.24). Th Example of Storage in the Energy Hub matrix S is denoted storage coupling matrix. It describes how nges of the storage energies affectinput-side the hub and output output-side storage flow have to be transformed to flows. In other alent output-side ds, it maps all storage energy derivatives flows: output- into equivalent System § entries flows. The sαβwith are gas turbine derived GT, heat according exchanger to (3.22). Finally, HE a and two storages (gas GT tion includingtank hub at the natural input gasflows and output input,asand 28 wellhot as water the storage eq ηge at the heat output)Chapter 3. Modeling Me = Ėg gy derivatives can be achieved by including § Alternatively, using the model (3.23) in (3.20): eg -. Electricity Electricity GT + , P eq ηgh GT 1 L=H CP P − S Ė = C H −S M = (3.24) Natural gas h Ė g + Ėh Ė eg eh District heat Heat relation§ represents a completeFrom With storage: modelthese of anequations, energy hub theinclud- storageHEcoupling matrix can be extra converter and storage elements. The following example outlines the 3.4. Energy Transmission GT  vation of (3.24) for a given hub layout. ηge turbine, heat exchanger, gas tank, Figure 3.7: Example hub with gas 1' 0 0 0 0 ! = #$ ! & ) + $0 1'Finally, and heat storage. eg ) the flows through S =   GT the energy hubcan be formulated as (3.2 mple 3.2 In this example, 0 derivation 0 of & (3.18) " and (3.24) is out- ηgh 1   d using a simple energy hub. Consider the hub The shown in Figure storage devices 3.7 theepowers exchange g eh Pe ch contains two converters and two storage devices: gas turbine  and   ! " 1 GT ηge  Pg (3.26a) exchanger, and gas tank and hot water storage, respectively. 1 The GTQg = ηge · 0 e − egĖ g 0 Le    Ph   § The complete model turbine is characterized by its gas-electric and gas-heat becomes =  efficiencies 1 g GT    (3. L h GTMh η=hhHE · Ė gh η − h eg − e1h   GT and ηgh , respectively. The heat exchanger operates with an0 effi- ηgh eh  Ėg (3.26b)   HE cy ηhh. Efficiencies of the storage devices Now are (3.18) eg and canebeh , formulated: for the Ėh tank and the heat storage, respectively. The electrical connection   From Geidl M, Integrated Modeling and Optimization of Multi-Carrier ween input and output is assumed to be lossless.! The converters Energythis formulation Systems, PhD thesis, " it ETH is obvious Zürich, are GT 2007 that  energyPe storage present in hub resultsLein additional1degrees ηge of0 freedom   in its operation. ! ribed by the following coupling matrix: =    Pg − e1 · Ėg    (3.27) Lh + e1 · Ėh g   h 0 η GT η HE gy Eiα(t at + 1) Periodtime periods. E t refers to different iα ored at erent timethe end of E 50periods. period t t. to refers Chapter 4. Optimization Time-dependent Storage in the Energy Hub iα nd of period t. Eiα iod: § The storage is considered in period t for the energy hub i: ! " Sti Ėti = §St Eti −is the t energy (t−1) stored at the(4.10) stb end of period t E Eiα " 50 i + E i (t−1) Chapter 4. Optimization − Ei § + Ei are the standby stb (4.10) losses in period t 1, the vector Eti denotes (t−1) the Eiα stored energies at t Eiα represents E i denotes the standby stored energyatlosses per period energies standby energy losses per period t Eiα (t − 2) (t − 1) t (t + 1) Period inequality constraints have to be included in (t−1) nstraints wer have to and Figure energy beStorage limits. 4.1: included Minimal E iα energyin Eand iα atmaximaldifferent time periods. Eiα t refers to gy limits. Minimal e regarded. For the and thesake maximal energy stored at the of simplicity, it end is as-of period t. or the element orage sake of simplicity, is available it isinas- (t − 2) the hub(t −for 1) each t (t + 1) Period nisbe available connected in the The §be recharged at hub4.1: equivalent any Figure forStorage side in each each storage of the period: energy power hub.Eiα At atflowthevector different time is periods. Eiα t refers to d at carriers ergy any side ρof∈the E arehub. At the the stored, energy stored at the end of period t. lower and! upper " ∈ E are stored, lower to be regarded, respectively. and equpper t Mi =AtSithe t t Ėi = output t S Ei side t − Ei (t−1) + Ei stb (4.10) , respectively. At be therecharged outputinside each period: ergy carriers σ ∈ E are stored, the correspond- !t " σ ∈ E are As stored, indicatedthe correspond- in Figure 4.1, eq t thet vectort t Ei t denotes (t−1) thestb stored energies (4.10) at apply. The power limits corresponds Mi = Si Ėto i =energy S Ei − Ei + Ei wer limits corresponds the Geidl end M, of period Integrated toand Modeling Estb t;energy represents Optimization i the standby of Multi-Carrier Energy Systems, PhD energy losses thesis, ETH Zürich, 2007 per period y determine how much the storage energy can how muchinthe hubstorage energyincan i. As indicated Figure 4.1, the vector Eti denotes the stored energies at d.erBesides power (or energy (orend the ramping), energy of theperiodramping), stor-t; Estb i the stor- represents the standby energy losses per period

Smart Electricity Systems - Multi-Energy Systems - PDF

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