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43:["$","title",null,{"children":"CCGT Energy & Carbon Explorer | Tony Griffiths | Observable"}] 4b:T588,# CCGT Energy & Carbon Explorer An interactive, source-audited **teaching model** of combined-cycle gas turbines and post-combustion amine capture. Choose **older unabated**, **older retrofitted**, or **modern integrated capture**; change rated **net** electrical output and steady-state dispatch. Observe the linked process-flow diagram, the physical energy Sankey, direct CO2 mass flows and an optional **exergy / heat-quality** teaching panel. **Reading the diagrams:** red = natural gas; orange = process heat and steam; yellow = electricity; grey = CO2 (flue gas has a separate grey line style); black = rejected heat. Turbine and capture equipment are separate conceptual plant boundaries. The energy Sankey is an exact allocation within the simplified model, not a validated process-design heat-and-mass balance. **Annual quantities:** Mtpa and TWh/year are calculated as the displayed stable operating point sustained for the selected number of **hours/year**. The initial 8,760 hours is a theoretical maximum, not a dispatch or capture forecast. At 0% dispatch the plant is OFF, with zero steady-state flows. **Important:** older-plant efficiencies, internal heat splits, temperatures, natural-gas composition approximations and part-load behaviour are illustrative. See the detailed assumption register at the end. The modern electrical performance is calibrated to IEAGHG (2020), with 98.5% capture. 4c:T4e31,// Cell 2 // CCGT Energy & Carbon Explorer v6, 11 Nov 2026. // Portable, deterministic JavaScript engine for Observable or a React/Next.js application. // All MW are rates, based on natural gas LHV; steady-state only. const SOURCES = Object.freeze({ IEAGHG2020: { title: 'IEAGHG (2020), Update Techno-Economic Benchmarks for Fossil Fuel-Fired Power Plants with CO2 Capture, Report 2020-07', url: 'https://ieaghg.org/publications/2020-07%20Update%20techno-economic%20benchmarks%20for%20fossil%20fuel-fired%20power%20plants%20with%20CO2%20capture.pdf', location: 'Chapter A Table 5: plant performance; Chapter B Table 6: gas composition and LHV 46.502 MJ/kg; Chapter C: gas turbine 641 C and HRSG outlet 105 C; Tiller pilot reboiler duty 3.3 MJ/kg.', kind: 'primary engineering benchmark' }, IPCC2006: { title: 'IPCC (2006), Guidelines for National Greenhouse Gas Inventories, Vol. 2, Ch. 2, Stationary Combustion', url: 'https://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_2_Ch2_Stationary_Combustion.pdf', location: 'Table 2.2, natural gas default combustion factor 56,100 kg CO2/TJ (net calorific value).', kind: 'intergovernmental methodology' }, AECOM2022: { title: 'AECOM for BEIS (2022), Next Generation Carbon Capture Technology: Technoeconomic Analysis, WP6', url: 'https://assets.publishing.service.gov.uk/media/6294923ce90e07039e31b777/aecom-next-gen-carbon-capture-technology-technoeconomic-analysis.pdf', location: 'Section 6.1, Table 10: 292 MWth steam and 42 MWe for 272 tonnes CO2/hour; section 6.1.2: 4.2 MWth/MWe steam opportunity assumption.', kind: 'UK government commissioned engineering study' }, ADAMS2016: { title: 'Adams and Mac Dowell (2016), Off-design point modelling of a 420 MW CCGT power plant integrated with amine capture, Applied Energy 178', url: 'https://doi.org/10.1016/j.apenergy.2016.06.087', location: 'Abstract: modelled 51.84% baseline efficiency and an 8.64 percentage-point efficiency penalty.', kind: 'peer-reviewed paper' }, NATIONALGAS: { title: 'National Gas Transmission, Technical Guidance - energy and standard volume conversion factors', url: 'https://data.nationalgas.com/technical-guidance', location: 'Reference conditions and illustrative 39.6 MJ/UK-standard m3 gross calorific value, 15 C and 1.01325 bar.', kind: 'UK gas network operator' }, ENERGYUK2022: { title: 'Energy UK (2022), IED Compliance Protocol, Large Combustion Plant BREF Update', url: 'https://www.energy-uk.org.uk/wp-content/uploads/2023/03/IEDComplianceProtocolLCPBREFUpdate2022.pdf', location: 'Fuel properties: net calorific value = 0.90 x gross calorific value for natural gas when net data unavailable.', kind: 'industry technical guidance' }, ISO6976: { title: 'ISO 6976:2016, Natural gas - calorific value, density and Wobbe index from composition', url: 'https://www.iso.org/standard/55842.html', location: 'Standard volume, temperature and composition conventions. Project-specific composition is not specified in this demo.', kind: 'international standard' }, OFGEM2026: { title: 'Ofgem (2026), Review of typical domestic consumption values: decision', url: 'https://www.ofgem.gov.uk/sites/default/files/2026-05/Review%20of%20typical%20domestic%20consumption%20values%20decision.pdf', location: 'Table 1, page 7: medium single-rate electricity 2,500 kWh/year and medium gas 9,500 kWh/year, effective 1 July 2026.', kind: 'UK energy regulator decision' }, UKHEATNETWORKS: { title: 'DESNZ (2024), Green Heat Network Fund applicant guidance', url: 'https://assets.publishing.service.gov.uk/media/66215d89be5f81890e757d55/green-heat-network-fund-guidance-for-applicants.pdf', location: 'Section 4.8 Shared Ground Loops and Ambient Loops: ambient network heat and heat pumps needed to raise temperature.', kind: 'UK government heat-network guidance' }, EA: { title: 'Environment Agency, Post-combustion carbon dioxide capture: emerging techniques', url: 'https://www.gov.uk/guidance/post-combustion-carbon-dioxide-capture-emerging-techniques', location: 'Capture performance during normal operation and start-up/shutdown; operating assumptions for post-combustion capture.', kind: 'UK regulatory guidance' } }); const REFERENCE = Object.freeze({ fuelThermalMW: 2418, gasTonnesPerHour: 187, netWithoutCaptureMW: 1506, netWithHighCaptureMW: 1316, baseAuxMW: 23.9, allAuxHighCaptureMW: 87.8, grossGasTurbinesMW: 1040, highCapture: 0.985 }); const FACTORS = Object.freeze({ // IPCC 56,100 kg/TJ x 0.0036 TJ/MWh / 1000 kg/t. tCO2PerMWhFuelLHV: 56100 * 0.0036 / 1000, // Indicative amine regeneration duty, not the specific IEAGHG full-scale reboiler duty. reboilerGJPerTonneCO2: 3.3, // Gas LHV from IEAGHG fuel input and mass input; specific to that reference gas. naturalGasLHV_MJPerKg: 46.502, // UK gross calorific value (example), converted to net using 0.90 approximation. naturalGasGCV_MJPerUKSm3: 39.6, naturalGasNetToGrossApprox: 0.90, naturalGasUKStandardTempC: 15, m3ToFt3: 35.3146667215, scfStandardTempC: 15.5555555556, ambientTempC: 15, typicalHouseholdElecKWhPerYr: 2500 }); // Calibrate the work penalty to IEAGHG's difference in gross electricity, // NOT to the amount of steam heat extracted directly (these have different grade). const referenceGrossGenerationLossMW = (REFERENCE.netWithoutCaptureMW + REFERENCE.baseAuxMW) - (REFERENCE.netWithHighCaptureMW + REFERENCE.allAuxHighCaptureMW); const referenceCapturedTph = REFERENCE.fuelThermalMW * FACTORS.tCO2PerMWhFuelLHV * REFERENCE.highCapture; const referenceReboilerMWth = referenceCapturedTph * FACTORS.reboilerGJPerTonneCO2 / 3.6; const STEAM_OPPORTUNITY_COEFFICIENT = referenceGrossGenerationLossMW / referenceReboilerMWth; const CASES = Object.freeze({ 'old-unabated': Object.freeze({ label: 'Older CCGT / no capture', baseNetEfficiency: 0.52, afterCaptureNetEfficiency: 0.52, captureFraction: 0, gasTurbineGrossFuelFraction: 0.36, recoveredHeatFuelFraction: 0.48, conventionalAuxFuelFraction: 0.015, status: 'illustrative older reference case' }), 'old-retrofit': Object.freeze({ label: 'Older CCGT / retrofitted capture', baseNetEfficiency: 0.52, afterCaptureNetEfficiency: 0.44, captureFraction: 0.95, gasTurbineGrossFuelFraction: 0.36, recoveredHeatFuelFraction: 0.48, conventionalAuxFuelFraction: 0.015, status: 'illustrative retrofit scenario, NOT a particular UK plant' }), 'modern-ccs': Object.freeze({ label: 'Modern CCGT / integrated capture', baseNetEfficiency: REFERENCE.netWithoutCaptureMW / REFERENCE.fuelThermalMW, afterCaptureNetEfficiency: REFERENCE.netWithHighCaptureMW / REFERENCE.fuelThermalMW, captureFraction: REFERENCE.highCapture, gasTurbineGrossFuelFraction: REFERENCE.grossGasTurbinesMW / REFERENCE.fuelThermalMW, recoveredHeatFuelFraction: 0.50, conventionalAuxFuelFraction: REFERENCE.baseAuxMW / REFERENCE.fuelThermalMW, status: 'IEAGHG electrical performance; illustrative internal heat allocations' }) }); const ASSUMPTIONS = Object.freeze([ {parameter:'Modern fuel and electrical outputs', value:'2418 MWth; 1506 MWe before; 1316 MWe after', provenance:'Published', source:'IEAGHG2020', caveat:'Full load; modern capture is 98.5%.'}, {parameter:'Modern electrical auxiliary demand', value:'23.9 MWe before; 87.8 MWe after', provenance:'Published', source:'IEAGHG2020', caveat:'Includes step-up transformer losses.'}, {parameter:'Old case electrical efficiencies', value:'52% unabated; 44% with retrofit', provenance:'Illustrative informed by literature', source:'ADAMS2016', caveat:'Not specific project data; 2016 study 51.84% and 8.64 percentage point CCS penalty.'}, {parameter:'Capture efficiency', value:'0%; 95%; 98.5% for 3 scenarios', provenance:'Illustrative retrofit; published modern', source:'EA; IEAGHG2020', caveat:'Normal steady-state assumed, not a guarantee at start/stop.'}, {parameter:'Combustion CO2 emission factor', value:'0.20196 t CO2/MWh fuel LHV', provenance:'Published + converted', source:'IPCC2006', caveat:'Direct combustion only; fuel composition differs from IEAGHG.'}, {parameter:'Amine reboiler duty', value:'3.3 GJ/t captured', provenance:'Indicative literature-anchored', source:'IEAGHG2020', caveat:'Not a validated project-specific duty; may vary with capture rate, solvent and load.'}, {parameter:'Steam electric opportunity coefficient', value:`${STEAM_OPPORTUNITY_COEFFICIENT.toFixed(4)} MWe lost per MWth`, provenance:'Derived calibration', source:'IEAGHG2020; AECOM2022', caveat:'Calibrated gross-power loss / illustrative reboiler duty; compare AECOM 1/4.2 = 0.2381. Not universal.'}, {parameter:'Gas fuel mass heating value', value:`${FACTORS.naturalGasLHV_MJPerKg.toFixed(3)} MJ/kg`, provenance:'Published', source:'IEAGHG2020', caveat:'Chapter B Table 6 gas LHV; reference gas composition is assumed across all cases.'}, {parameter:'Gas standard-volume heating value', value:'39.6 MJ/Sm3 gross x 0.90 = 35.64 MJ/Sm3 net', provenance:'Published example + approximate conversion', source:'NATIONALGAS; ENERGYUK2022', caveat:'Sm3 uses 15 C, 1.01325 bar. Real gas composition and compressibility vary.'}, {parameter:'Normal volume conversion', value:'Nm3 at 0 C, 1.01325 bar from UK Sm3 at 15 C', provenance:'Published conditions + ideal-gas adjustment', source:'NATIONALGAS; ISO6976', caveat:'Temperature conversion factor is approximately 0.9479; compressibility neglected.'}, {parameter:'MMscfd volume conversion', value:'60 F, 1 atm from UK Sm3 at 15 C, ideal-gas temperature ratio', provenance:'Derived approximation', source:'ISO6976', caveat:'No composition-specific compressibility correction.'}, {parameter:'Old gas-turbine gross fraction', value:'36% of fuel input', provenance:'Illustrative allocation', source:'ADAMS2016', caveat:'Not measured engine shaft power.'}, {parameter:'HRSG useful heat recovery', value:'48% older; 50% modern of fuel input', provenance:'Illustrative allocation', source:'No validated heat balance', caveat:'Allows a consistent explanatory energy Sankey; NOT engineering process design.'}, {parameter:'Schematic stream temperatures', value:'Modern GT exhaust 641 C, HRSG outlet 105 C; capture gas around 40 C; reboiler ~130 C', provenance:'Published modern exhaust / illustrative others', source:'IEAGHG2020', caveat:'641 C and 105 C are IEAGHG modern design values; 40/130 C approximations and old-turbine 580 C are illustrative, not project data.'}, {parameter:'Rejection temperatures', value:'Condenser ~35 C; capture cooling ~40 C', provenance:'Illustrative', source:'No plant-specific stream sheet', caveat:'Exergy heat-quality overlay only; actual sink temperature and load vary.'}, {parameter:'Part load / dispatch', value:'0-100% linear scaling of reference full-load heat rate', provenance:'Simplification', source:'Not modelled', caveat:'0% is OFF (not stable load); no minimum load, dynamic ramp, start-up, shut-down or standby consumption.'}, {parameter:'Annualisation', value:'Instantaneous selected load multiplied by selected operating hours per year', provenance:'Arithmetic definition', source:'Not a plant forecast', caveat:'Dispatch is held constant during hours selected; 8760 h is theoretical upper bound.'}, {parameter:'Overall energy balance', value:'Fuel = net electricity + final rejected heat', provenance:'Model accounting identity', source:'Energy conservation', caveat:'All capture reboiler heat and used auxiliary electricity assumed ultimately rejected; CO2/product stream enthalpy ignored.'}, {parameter:'Sankey display terminal semantics (v4)', value:'Distinct exhaust and condenser heat outlets; contiguous MW-scaled process bars; internal terminal for reboiler and electrical auxiliaries', provenance:'Diagram convention, not new physical assumption', source:'First-law energy accounting', caveat:'Sankey drawings end internal duties at their place of use, while finalWasteHeatMW includes their eventual dissipation. Downward arrows alone do not sum to the finalWasteHeatMW KPI.'}, {parameter:'Typical household equivalent', value:'2,500 kWh/year electricity, medium single-rate home from 1 July 2026', provenance:'Published Ofgem benchmark', source:'OFGEM2026', caveat:'Electricity produced over selected hours divided by typical annual use; not coincident supply, capacity guarantee or grid-dispatch forecast.'}, {parameter:'Condenser heat utilisation', value:'~35 C illustrative; possible heat-network source only with heat pumps / temperature uplift', provenance:'Indicative temperature + government heat-network guidance', source:'UKHEATNETWORKS', caveat:'No household-heat-equivalent claim because usable recovered duty, temperature lift, utilisation and network losses are not modelled.'}, {parameter:'Capture electrical-equivalent penalty ratio', value:'(foregone steam-turbine generation + capture electrical auxiliaries) / net export', provenance:'Derived model ratio', source:'IEAGHG2020; AECOM2022', caveat:'Electrical opportunity cost, not reboiler MWth plus MWe. No whole-plant exergy calculation.'}, {parameter:'Component efficiency proxies', value:'GT gross electric/fuel; recovered steam/(fuel minus GT electric); steam gross electric/recovered steam', provenance:'Derived from illustrative model allocations', source:'IEAGHG2020; ADAMS2016', caveat:'Not manufacturers measured gas turbine thermal, HRSG effectiveness, or steam turbine isentropic efficiencies; ratios are pedagogic allocations.'}, {parameter:'Exergy heat-quality overlay', value:'Q x [1-(T0+273.15)/(T+273.15)]', provenance:'Ideal reversible Carnot approximation', source:'Second law of thermodynamics', caveat:'NOT whole-plant exergy efficiency or balanced exergy Sankey; no pressure or chemical exergy.'} ]); function simulateCCGT({caseId='modern-ccs', ratedNetMW=1000, dispatchPercent=75, annualHours=8760} = {}) { const config = CASES[caseId]; if (!config) throw new Error(`Unknown case: ${caseId}`); if (!Number.isFinite(ratedNetMW) || ratedNetMW < 10 || ratedNetMW > 2500) throw new RangeError('Rated net MW must be 10 to 2500'); if (!Number.isFinite(dispatchPercent) || dispatchPercent < 0 || dispatchPercent > 100) throw new RangeError('Dispatch must be 0 to 100 percent'); if (!Number.isFinite(annualHours) || annualHours < 0 || annualHours > 8760) throw new RangeError('Annual hours must be 0 to 8760'); const fuel = ratedNetMW * dispatchPercent / 100 / config.afterCaptureNetEfficiency; const netMW = ratedNetMW * dispatchPercent / 100; const gtMW = fuel * config.gasTurbineGrossFuelFraction; const baselineSTMW = fuel * (config.baseNetEfficiency + config.conventionalAuxFuelFraction - config.gasTurbineGrossFuelFraction); const baseAuxMW = fuel * config.conventionalAuxFuelFraction; const generatedCO2Tph = fuel * FACTORS.tCO2PerMWhFuelLHV; const capturedCO2Tph = generatedCO2Tph * config.captureFraction; const emittedCO2Tph = generatedCO2Tph - capturedCO2Tph; const reboilerMWth = capturedCO2Tph * FACTORS.reboilerGJPerTonneCO2 / 3.6; const steamPowerPenaltyMW = reboilerMWth * STEAM_OPPORTUNITY_COEFFICIENT; const stMW = baselineSTMW - steamPowerPenaltyMW; const extraCaptureAuxMW = fuel * (config.baseNetEfficiency - config.afterCaptureNetEfficiency) - steamPowerPenaltyMW; const grossMW = gtMW + stMW; const hrsgMWth = fuel * config.recoveredHeatFuelFraction; const exhaustRejectMWth = fuel - gtMW - hrsgMWth; const condenserRejectMWth = hrsgMWth - stMW - reboilerMWth; const finalWasteHeatMW = exhaustRejectMWth + condenserRejectMWth + reboilerMWth + baseAuxMW + extraCaptureAuxMW; const fuelGasTph = fuel * 3600 / FACTORS.naturalGasLHV_MJPerKg / 1000; const fuelGasUKSm3ph = fuel * 3600 / (FACTORS.naturalGasGCV_MJPerUKSm3 * FACTORS.naturalGasNetToGrossApprox); const fuelGasNormalNm3ph = fuelGasUKSm3ph * (273.15 / (273.15 + FACTORS.naturalGasUKStandardTempC)); const fuelGasMMscfd = fuelGasUKSm3ph * 24 * FACTORS.m3ToFt3 * ((273.15 + FACTORS.scfStandardTempC) / (273.15 + FACTORS.naturalGasUKStandardTempC)) / 1e6; const energyBalanceErrorMW = fuel - netMW - finalWasteHeatMW; const electricBalanceErrorMW = grossMW - baseAuxMW - extraCaptureAuxMW - netMW; const co2BalanceErrorTph = generatedCO2Tph - capturedCO2Tph - emittedCO2Tph; if ([gtMW, baselineSTMW, stMW, extraCaptureAuxMW, exhaustRejectMWth, condenserRejectMWth, finalWasteHeatMW].some(v => v < -1e-7)) { throw new Error('Negative energy allocation: assumptions require recalibration'); } if (Math.abs(energyBalanceErrorMW) > 1e-6 || Math.abs(electricBalanceErrorMW) > 1e-6 || Math.abs(co2BalanceErrorTph) > 1e-7) { throw new Error('Non-closing model balances'); } return { caseId, caseName:config.label, provenance:config.status, ratedNetMW, dispatchPercent, annualHours, baseNetEfficiency:config.baseNetEfficiency, netEfficiency:config.afterCaptureNetEfficiency, captureFraction:config.captureFraction, netElectricMW:netMW, grossElectricMW:grossMW, fuelMWth:fuel, fuelGasTph, fuelGasUKSm3ph, fuelGasNormalNm3ph, fuelGasMMscfd, gasTurbineGrossMW:gtMW, steamTurbineGrossMW:stMW, steamTurbineBaselineMW:baselineSTMW, conventionalAuxMW:baseAuxMW, captureAuxMW:extraCaptureAuxMW, hrsgMWth, exhaustRejectMWth, condenserRejectMWth, reboilerMWth, steamPowerPenaltyMW, finalWasteHeatMW, generatedCO2Tph, capturedCO2Tph, emittedCO2Tph, energyBalanceErrorMW, electricBalanceErrorMW, co2BalanceErrorTph, capturedMtpa:capturedCO2Tph * annualHours / 1e6, emittedMtpa:emittedCO2Tph * annualHours / 1e6, isOff:dispatchPercent === 0 }; } // Directed energy-flow DISPLAY graph. Reboiler, auxiliary electricity and distinct // heat discharge points are terminal visual sinks. The use of a display sink does // NOT imply energy is stored there indefinitely: the simplified physical balance // still counts this energy in finalWasteHeatMW when it ultimately dissipates. // This graph is acyclic, and every internal conversion node conserves MW. function createEnergyGraph(p) { if (p.isOff) return {nodes:[],links:[]}; const has = p.captureFraction > 0; const nodes = [ {id:'fuel',name:'Natural gas',kind:'gas',terminal:'input'}, {id:'gt',name:'Gas turbine',kind:'process'}, {id:'heatRecovery',name:'Heat recovery boiler',kind:'process'}, {id:'steamCycle',name:'Steam cycle',kind:'process'}, {id:'electricBus',name:'Electricity bus',kind:'process'}, {id:'export',name:'Grid export',kind:'electric',terminal:'boundary-electric'}, {id:'exhaustReject',name:'Exhaust heat (separate)',kind:'waste',terminal:'boundary-heat'}, {id:'condenserReject',name:'Condenser heat (separate)',kind:'waste',terminal:'boundary-heat'}, {id:'stationAux',name:'Station auxiliaries',kind:'electric',terminal:'internal-duty'}, ...(has ? [ {id:'reboiler',name:'Amine reboiler',kind:'heat',terminal:'internal-duty'}, {id:'captureAux',name:'Capture auxiliaries',kind:'electric',terminal:'internal-duty'} ] : []) ]; const links=[]; const add=(source,target,value,kind)=>{if(value>1e-9) links.push({source,target,value,kind});}; add('fuel','gt',p.fuelMWth,'gas'); add('gt','electricBus',p.gasTurbineGrossMW,'electric'); add('gt','heatRecovery',p.fuelMWth-p.gasTurbineGrossMW,'heat'); add('heatRecovery','steamCycle',p.hrsgMWth,'heat'); add('heatRecovery','exhaustReject',p.exhaustRejectMWth,'waste'); add('steamCycle','electricBus',p.steamTurbineGrossMW,'electric'); add('steamCycle','condenserReject',p.condenserRejectMWth,'waste'); if(has) add('steamCycle','reboiler',p.reboilerMWth,'heat'); add('electricBus','stationAux',p.conventionalAuxMW,'electric'); if(has) add('electricBus','captureAux',p.captureAuxMW,'electric'); add('electricBus','export',p.netElectricMW,'electric'); return {nodes,links}; } 4d:T684,// Cell 3 // Observable Notebooks 2.0: use view(...), not legacy viewof syntax. function makeWideSlider(form) { form.style.width = 'min(100%, 1050px)'; form.style.display = 'block'; const rail = form.querySelector('input[type="range"]'); if (rail) { rail.style.width = '100%'; rail.style.minWidth = 'min(78vw, 660px)'; } return form; } const caseId = view(Inputs.select(['old-unabated','modern-ccs','old-retrofit'], { label:'Power station configuration',value:'modern-ccs',format:id=>CASES[id].label })); const ratedNetMW = view(makeWideSlider(Inputs.range([10,2500], { label:'Rated NET electrical output (MW)',value:1000,step:10 }))); const dispatchPercent = view(makeWideSlider(Inputs.range([0,100], { label:'Dispatch at selected stable output (%) - 0% = OFF',value:75,step:1 }))); const annualHours = view(makeWideSlider(Inputs.range([0,8760], { label:'Hours/year at this operating point (for annualised units)',value:8760,step:60 }))); display(html`

Displayed units (model calculations remain in MW and tonnes/hour)

`); const gasEnergyUnit = view(Inputs.select(['MWth','TWh/yr'], {label:'Gas energy',value:'MWth'})); const gasFlowUnit = view(Inputs.select(['t/day','kNm3/h','MMscfd'], {label:'Gas throughput',value:'t/day'})); const heatUnit = view(Inputs.select(['MWth','TWh/yr'], {label:'Heat / steam',value:'MWth'})); const electricUnit = view(Inputs.select(['MWe','TWh/yr'], {label:'Electricity',value:'MWe'})); const co2Unit = view(Inputs.select(['Mtpa','t/h'], {label:'CO2 mass',value:'Mtpa'})); const showExergy = view(Inputs.toggle({label:'Show exergy / heat-quality add-on',value:false}));4e:T431,// Cell 4 const point = simulateCCGT({caseId,ratedNetMW,dispatchPercent,annualHours}); const fmtNum = (x,d=1) => Number(x).toLocaleString('en-GB',{maximumFractionDigits:d}); // Use formatFlow() in ALL diagrams and summary cards. function formatFlow(value,kind) { const annualTWh = value * point.annualHours / 1e6; switch(kind) { case 'gasEnergy': return gasEnergyUnit==='TWh/yr' ? `${fmtNum(annualTWh,4)} TWh/yr` : `${fmtNum(value,1)} MWth`; case 'gasMass': if(gasFlowUnit==='kNm3/h') return `${fmtNum(point.fuelGasNormalNm3ph/1000,2)} kNm3/h`; if(gasFlowUnit==='MMscfd') return `${fmtNum(point.fuelGasMMscfd,2)} MMscfd`; return `${fmtNum(value*24,1)} t/day`; case 'heat': return heatUnit==='TWh/yr' ? `${fmtNum(annualTWh,4)} TWh/yr` : `${fmtNum(value,1)} MWth`; case 'electric': return electricUnit==='TWh/yr' ? `${fmtNum(annualTWh,4)} TWh/yr` : `${fmtNum(value,1)} MWe`; case 'co2': return co2Unit==='Mtpa' ? `${fmtNum(value*point.annualHours/1e6,3)} Mtpa` : `${fmtNum(value,2)} t/h`; default: return fmtNum(value,1); } } 4f:T252f,// Cell 6 // CCGT v7 schematic renderer: same topology, clearer external CO2 labelling, and MW-based proportional line widths. // Draws a fixed, readable process-flow schematic. Use the SAME point as the Sankey. function makeSchematicSvg(p, show) { const C = {gas:'#cf433a', heat:'#e68c2e',power:'#e2b527',co2:'#7b8794',waste:'#24282b',solvent:'#258c7d',flue:'#65717c'}; const has = p.captureFraction > 0; // Common MW-to-stroke scale for a given selected plant size so widths remain visually consistent // across configuration switches. No dependence on configuration-specific fuel efficiency. const energyWidth = mw => mw > 1e-9 ? Math.min(17, Math.max(0.8, (10.8 * mw) / Math.max(10, p.ratedNetMW))) : 0; const co2Basis = Math.max(1e-9, Math.max(p.generatedCO2Tph || 0, ((p.ratedNetMW / Math.max(1e-9, p.netEfficiency)) * 0.20196))); const co2Width = tph => tph > 1e-9 ? Math.min(7, Math.max(0.75, 6.2*tph/co2Basis)) : 0; const paint = {...C,red:C.gas,orange:C.heat,yellow:C.power,grey:C.co2,black:C.waste,teal:C.solvent,flue:C.flue}; const defs = Object.entries(paint) .map(([k,c])=>``).join(''); const safe = s => String(s).replaceAll('&','&').replaceAll('<','<').replaceAll('>','>'); const pipe=(d,kind,width=3,style='',tip='')=>width<=0?'':`${tip?`${safe(tip)}`:''}`; const txt=(x,y,s,size=13,colour='#303a43',anchor='start',weight=500)=>`${s}`; const op=(x,y,w,h,title,sub1='',sub2='',shade='#fff')=>`${safe([title,sub1,sub2].filter(Boolean).join(' — '))}${txt(x+w/2,y+25,title,17,'#1e292f','middle',700)}${sub1?txt(x+w/2,y+47,sub1,14,'#47515c','middle'):''}${sub2?txt(x+w/2,y+65,sub2,12,'#59616a','middle'):''}`; const v=(amount,kind)=>show(amount,kind); const base=` ${txt(110,120,'CCGT POWER STATION',21,'#222','start',750)} ${txt(110,143,'Combustion + steam cycle',12,'#5d6972')} ${txt(788,120,has?'CO2 CAPTURE + CONDITIONING':'CO2 CAPTURE PLANT NOT FITTED',21,has?'#222':'#89939b','start',750)} ${txt(788,142,has?'Post-combustion amine process':'Flue gas goes to atmosphere',12,'#6e7780')} ${op(145,230,130,84,'Gas turbine','Combustion +','generation')} ${op(333,230,165,84,'Heat recovery','steam generator','(HRSG)')} ${op(536,230,150,84,'Steam turbine','Electricity from','hot steam')} ${op(545,453,132,75,'Condenser','Cooling water')} ${op(598,155,97,42,'Power bus','','','#fff8d9')} ${pipe('M17 266 H143','gas',energyWidth(p.fuelMWth),'',`Natural gas input: ${v(p.fuelMWth,'gasEnergy')}`)} ${txt(20,207,`Gas: ${v(p.fuelMWth,'gasEnergy')}`,19,C.gas,'start',750)} ${txt(20,230,v(p.fuelGasTph,'gasMass'),15,C.gas,'start',650)} ${pipe('M39 300 H143','flue',p.isOff?0:1.7,'stroke-dasharray="4 4"')} ${txt(34,327,'Air',11,C.flue)} ${pipe('M275 274 H331','flue',energyWidth(p.fuelMWth-p.gasTurbineGrossMW))} ${txt(303,261,'Hot exhaust',11,C.flue,'middle')} ${txt(303,329,p.caseId==='modern-ccs'?'~641 C':'~580 C',11,C.flue,'middle')} ${pipe('M420 314 V363 H608 V316','orange',energyWidth(p.hrsgMWth))} ${txt(491,351,'Steam',12,C.heat,'middle',650)} ${pipe('M611 315 V451','orange',energyWidth(p.condenserRejectMWth))} ${pipe('M545 497 H439 V315','orange',p.isOff?0:Math.max(1.2, energyWidth(Math.max(20,p.hrsgMWth*0.08))),'stroke-dasharray="7 5"')} ${txt(452,479,'Condensate return',11,C.heat,'middle')} ${pipe('M200 230 V175 H596','yellow',energyWidth(p.gasTurbineGrossMW))} ${pipe('M620 230 V199','yellow',energyWidth(p.steamTurbineGrossMW))} ${txt(296,155,`Gas turbine ${v(p.gasTurbineGrossMW,'electric')}`,16,'#80630f','start',700)} ${txt(631,218,`Steam ${v(p.steamTurbineGrossMW,'electric')}`,15,'#80630f','middle',650)} ${pipe('M646 155 V53 H740','yellow',energyWidth(p.netElectricMW),'',`Net grid export: ${v(p.netElectricMW,'electric')}`)} ${txt(742,44,`TO GRID: ${v(p.netElectricMW,'electric')}`,22,'#735810','start',800)} ${pipe('M610 528 V646','black',energyWidth(p.condenserRejectMWth))} ${txt(454,669,`Condenser reject: ${v(p.condenserRejectMWth,'heat')}`,17,C.waste,'start',700)} ${txt(110,606,`Net efficiency: ${(100*p.netEfficiency).toFixed(1)}% (LHV)`,16,'#47515c','start',650)} `; const captureSvg=has?` ${op(785,229,108,84,'Flue gas','cooler','~40 C')} ${op(929,229,112,108,'Absorber','CO2 into','amine solution')} ${op(1120,230,112,109,'Regenerator','CO2 released','from amine')} ${op(1114,433,134,75,'Reboiler','Steam heat','~130 C')} ${op(1253,424,135,90,'CO2 plant','Dry + compress','to transport')} ${pipe('M498 275 H520 V342 H755 V274 H783','flue',co2Width(p.generatedCO2Tph))} ${txt(637,335,'Flue gas to absorber',12,C.flue,'middle')} ${txt(790,358,`Flue CO2: ${v(p.generatedCO2Tph,'co2')}`,16,C.flue,'start',650)} ${txt(790,376,p.caseId==='modern-ccs'?'HRSG outlet ~105 C':'HRSG outlet ~100 C',11,C.flue)} ${pipe('M893 274 H927','flue',co2Width(p.generatedCO2Tph))} ${pipe('M983 229 V159 H1047 V78','flue',co2Width(p.emittedCO2Tph))} ${txt(1067,34,'TREATED FLUE GAS TO ATMOSPHERE',16,C.flue,'start',750)} ${txt(1067,58,`Residual CO2: ${v(p.emittedCO2Tph,'co2')}`,19,C.co2,'start',700)} ${txt(1067,78,'Also nitrogen, oxygen and water vapour',13,C.flue)} ${pipe('M1041 290 H1118','teal',p.isOff?0:3.6)} ${txt(1080,280,'Rich amine',11,C.solvent,'middle')} ${pipe('M1120 329 H1082 V391 H982 V340','teal',p.isOff?0:2.6,'stroke-dasharray="7 4"')} ${txt(1035,383,'Lean amine return',11,C.solvent)} ${pipe('M1174 433 V341','orange',energyWidth(p.reboilerMWth))} ${pipe('M686 301 H737 V557 H1170 V510','orange',energyWidth(p.reboilerMWth),'',`Reboiler steam duty: ${v(p.reboilerMWth,'heat')}`)} ${txt(874,538,`Steam to reboiler: ${v(p.reboilerMWth,'heat')}`,18,'#a35f18','start',700)} ${pipe('M1114 474 H1080 V586 H439 V316','orange',p.isOff?0:Math.max(1.2, energyWidth(Math.max(20,p.reboilerMWth*0.08))),'stroke-dasharray="7 6"')} ${txt(787,579,'Condensate return to power station',11,C.heat)} ${pipe('M695 176 H745 V195 H1340 V422','yellow',energyWidth(p.captureAuxMW))} ${txt(1055,185,`Capture power: ${v(p.captureAuxMW,'electric')}`,17,'#8c690e','start',700)} ${pipe('M1232 282 H1318 V422','grey',co2Width(p.capturedCO2Tph))} ${txt(1274,267,`Captured CO2`,11,C.co2,'middle')} ${pipe('M1388 468 H1530','grey',co2Width(p.capturedCO2Tph),'',`Captured CO2 export: ${v(p.capturedCO2Tph,'co2')}`)} ${txt(1438,402,'CAPTURED CO2',17,C.co2,'start',750)} ${txt(1438,426,'TO CO2 NETWORK',18,C.co2,'start',750)} ${txt(1438,453,v(p.capturedCO2Tph,'co2'),22,'#526474','start',800)} ${pipe('M841 313 V648','black',energyWidth(p.reboilerMWth+p.captureAuxMW))} ${txt(835,671,'Capture cooling / reject heat',12,C.waste)} `:` ${pipe('M456 229 V75','flue',co2Width(p.generatedCO2Tph))} ${txt(480,34,'FLUE GAS TO ATMOSPHERE',17,C.flue,'start',750)} ${txt(480,59,`Uncaptured CO2: ${v(p.emittedCO2Tph,'co2')}`,20,C.co2,'start',700)} ${txt(835,318,'No absorber, reboiler or compression equipment.',16,'#8b959c')} ${txt(835,348,'All combustion CO2 leaves via the flue-gas stack.',14,'#8b959c')} `; return ``; } const schematicContainer = document.createElement('div'); schematicContainer.style.overflowX = 'auto'; schematicContainer.style.border = '1px solid #d9dee3'; schematicContainer.style.borderRadius = '10px'; schematicContainer.innerHTML = makeSchematicSvg(point, formatFlow); const schematicSvg = schematicContainer.querySelector('svg'); schematicSvg.style.width = diagramView === 'Full-size detail' ? '1640px' : '100%'; schematicSvg.style.minWidth = '0'; schematicSvg.style.maxWidth = 'none'; schematicSvg.style.height = 'auto'; display(schematicContainer); display(html`

Conceptual process flows. Energy line widths scale with MW; CO₂ line widths use a separate mass-flow scale. Indicative temperatures and internal steam allocations are not a validated plant heat-and-mass balance.

`);50:T32c4,// Cell 7 // CCGT Energy & Carbon Explorer v7 - common-width-scale, smoother MW-scaled Sankey. // All process bars are exactly as tall as their total incident energy flow. // Same MW values have the same visual thickness across the three plant configurations. function makeEnergySankeySvg(p, show) { const C = Object.freeze({ gas:'#cf463e', electric:'#e8bb27', heat:'#eb8a32', waste:'#262a30', ink:'#29353e', soft:'#63717c', border:'#27333b' }); const esc = v => String(v).replaceAll('&','&').replaceAll('<','<') .replaceAll('>','>').replaceAll('"','"'); const fmt = (v, type) => show(v, type); const text = (x,y,value,size=13,colour=C.ink,anchor='start',weight=500,extra='') => `${esc(value)}`; // Common MW scale across the three CCGT configurations for the current selected plant size. const scale = 240 / Math.max(10, p.ratedNetMW); const H = mw => Math.max(0,mw * scale); const hasCapture = p.captureFraction > 0; const val = p; const fuelH=H(p.fuelMWth); const gtPowerH=H(p.gasTurbineGrossMW); const gasHeatH=H(p.fuelMWth-p.gasTurbineGrossMW); const steamHeatH=H(p.hrsgMWth); const exhaustH=H(p.exhaustRejectMWth); const steamPowerH=H(p.steamTurbineGrossMW); const steamReboilerH=H(p.reboilerMWth); const condenserH=H(p.condenserRejectMWth); const grossPowerH=H(p.grossElectricMW); const gridH=H(p.netElectricMW); const equivalentHomes = p.netElectricMW*p.annualHours*1000/FACTORS.typicalHouseholdElecKWhPerYr; const homesLabel = equivalentHomes>=1e6?`${(equivalentHomes/1e6).toFixed(2)}m`:Math.round(equivalentHomes).toLocaleString('en-GB'); const stationH=H(p.conventionalAuxMW); const captureAuxH=H(p.captureAuxMW); const close=(a,b)=>Math.abs(a-b)<1e-6; if(!close(gtPowerH+gasHeatH,fuelH) || !close(steamHeatH+exhaustH,gasHeatH) || !close(steamPowerH+steamReboilerH+condenserH,steamHeatH) || !close(gtPowerH+steamPowerH,grossPowerH) || !close(gridH+stationH+captureAuxH,grossPowerH)) { throw new Error('Sankey geometry does not conserve MW at process bars'); } const turbineY = 330; const turbineBottom = turbineY + fuelH; const boilerY = turbineBottom - gasHeatH; // bottom aligned with gas turbine const steamY = boilerY; // top aligned with heat recovery boiler const busY = 140; const gridY = 140; const stationY = 350; const captureBoxTop = 465; const captureAuxY = 535; const reboilerY = 670; const rejectBoxY = 825; const rejectTipY = 892; const wNode = 18; const pos = { fuel: {x:92,y:turbineY}, turbine: {x:272,y:turbineY}, boiler: {x:498,y:boilerY}, steam: {x:748,y:steamY}, bus: {x:1080,y:busY}, grid: {x:1420,y:gridY}, station: {x:1180,y:stationY}, captureAux: {x:1170,y:captureAuxY}, reboiler: {x:1170,y:reboilerY} }; const ribbon = (id,sx,sy,tx,ty,h,colour,description,mw,unit='heat',curve={}) => { if (mw <= 0 || h <= 0) return ''; const dx = tx - sx; const lead = curve.lead ?? Math.max(45, Math.min(150, dx * 0.42)); const tail = curve.tail ?? Math.max(45, Math.min(150, dx * 0.42)); const d = `M ${sx} ${sy} C ${sx+lead} ${sy} ${tx-tail} ${ty} ${tx} ${ty} L ${tx} ${ty+h} C ${tx-tail} ${ty+h} ${sx+lead} ${sy+h} ${sx} ${sy+h} Z`; return `${esc(description)}: ${esc(fmt(mw,unit))}`; }; const straight = (id,sx,sy,tx,h,colour,description,mw,unit='heat') => { if (mw <= 0 || h <= 0) return ''; return `${esc(description)}: ${esc(fmt(mw,unit))}`; }; const rejectDown = (id,sx,sy,turnX,tipY,h,description,mw) => { if (mw <= 0 || h <= 0) return ''; const cy = sy + h/2; const r = Math.max(42, Math.min(78, h*1.1)); const tipLen = Math.min(28, Math.max(14, h*.78)); const shaftY = tipY - tipLen; const d = `M ${sx} ${cy} H ${turnX-r} Q ${turnX} ${cy} ${turnX} ${cy+r} V ${shaftY}`; return ` ${esc(description)}: ${esc(fmt(mw,'heat'))} `; }; const bar=(x,y,h,fill,name,top=13,sub='')=>{ if(h<=0) return ''; return `${esc(name)}${sub?` — ${esc(sub)}`:''} ${text(x+wNode/2,y-(sub?31:15),name,Math.max(17,top),C.ink,'middle',760)} ${sub ? text(x+wNode/2,y-11,sub,14,C.soft,'middle',650) : ''} `; }; const sink=(x,y,h,name,amount,unit,desc,fill)=>{ if(h<=0) return ''; return `${esc(`${name}: ${fmt(amount,unit)} — ${desc}`)} ${text(x+wNode+12,y+5,name,17,C.ink,'start',750)} ${text(x+wNode+12,y+28,fmt(amount,unit),19,unit==='electric'?'#745508':'#92511d','start',800)} ${text(x+wNode+12,y+47,desc,12,C.soft)} `; }; const hrsgEff = (100 * (p.hrsgMWth / Math.max(1e-9, p.fuelMWth - p.gasTurbineGrossMW))).toFixed(1); const steamEff = (100 * (p.steamTurbineGrossMW / Math.max(1e-9, p.hrsgMWth))).toFixed(1); const base=``; const links=` ${straight('fuel',pos.fuel.x+wNode,pos.fuel.y,pos.turbine.x,fuelH,C.gas,'Natural gas energy input',val.fuelMWth,'gasEnergy')} ${ribbon('gt-power',pos.turbine.x+wNode,pos.turbine.y,pos.bus.x,pos.bus.y,gtPowerH,C.electric,'Electricity produced by gas turbine',val.gasTurbineGrossMW,'electric')} ${ribbon('gt-hot-exhaust',pos.turbine.x+wNode,pos.turbine.y+gtPowerH,pos.boiler.x,pos.boiler.y,gasHeatH,C.heat,'Energy leaving gas turbine in exhaust',val.fuelMWth-val.gasTurbineGrossMW,'heat')} ${ribbon('recovered-steam',pos.boiler.x+wNode,pos.boiler.y,pos.steam.x,pos.steam.y,steamHeatH,C.heat,'Steam energy recovered from exhaust',val.hrsgMWth,'heat')} ${rejectDown('exhaust-outlet',pos.boiler.x+wNode,pos.boiler.y+steamHeatH,670,rejectTipY,exhaustH,'Exhaust stack heat',val.exhaustRejectMWth)} ${ribbon('steam-power',pos.steam.x+wNode,pos.steam.y,pos.bus.x,pos.bus.y+gtPowerH,steamPowerH,C.electric,'Electricity produced by steam turbine',val.steamTurbineGrossMW,'electric')} ${hasCapture?ribbon('reboiler-steam',pos.steam.x+wNode,pos.steam.y+steamPowerH,pos.reboiler.x,pos.reboiler.y,steamReboilerH,C.heat,'Useful steam heat delivered to amine reboiler',val.reboilerMWth,'heat',{lead:250,tail:105}):''} ${rejectDown('condenser-outlet',pos.steam.x+wNode,pos.steam.y+steamPowerH+steamReboilerH,868,rejectTipY,condenserH,'Condenser cooling heat',val.condenserRejectMWth)} ${ribbon('grid-export',pos.bus.x+wNode,pos.bus.y,pos.grid.x,pos.grid.y,gridH,C.electric,'Net electrical work exported to grid',val.netElectricMW,'electric')} ${ribbon('station-aux',pos.bus.x+wNode,pos.bus.y+gridH,pos.station.x,pos.station.y,stationH,C.electric,'Electrical work used inside the power station',val.conventionalAuxMW,'electric')} ${hasCapture?ribbon('capture-aux',pos.bus.x+wNode,pos.bus.y+gridH+stationH,pos.captureAux.x,pos.captureAux.y,captureAuxH,C.electric,'Electrical work consumed inside the capture plant',val.captureAuxMW,'electric'):''} `; const nodes=` ${bar(pos.fuel.x,pos.fuel.y,fuelH,'#fff3f0','Gas input',12)} ${bar(pos.turbine.x,pos.turbine.y,fuelH,'#fff','Gas turbine',15)} ${bar(pos.boiler.x,pos.boiler.y,gasHeatH,'#fff','Heat recovery boiler',13,`${hrsgEff}% recovered¹`)} ${bar(pos.steam.x,pos.steam.y,steamHeatH,'#fff','Steam turbine',15,`${steamEff}% electric yield¹`)} ${bar(pos.bus.x,pos.bus.y,grossPowerH,'#fff5cb','Electrical bus',15)} ${bar(pos.grid.x,pos.grid.y,gridH,'#ffe68b','Grid export',15)} ${sink(pos.station.x,pos.station.y,stationH,'Station auxiliaries',val.conventionalAuxMW,'electric','Power station pumps and fans','#fff0b4')} ${hasCapture?sink(pos.captureAux.x,pos.captureAux.y,captureAuxH,'Capture auxiliaries',val.captureAuxMW,'electric','Fans, pumps and CO2 compression','#ffecad'):''} ${hasCapture?sink(pos.reboiler.x,pos.reboiler.y,steamReboilerH,'Amine reboiler',val.reboilerMWth,'heat','Useful solvent-regeneration heat','#f7c38e'):''} ${text(67,pos.fuel.y-34,fmt(val.fuelMWth,'gasEnergy'),23,'#b53c36','start',800)} ${text(1270,pos.grid.y+gridH/2-7,fmt(val.netElectricMW,'electric'),27,'#74560a','middle',800)} ${text(1270,pos.grid.y+gridH/2+22,`About ${homesLabel} typical homes / year`,17,'#74560a','middle',700)} ${text(425,263,'Electric power from gas turbine',18,'#84620d','middle',730)} ${text(425,287,fmt(val.gasTurbineGrossMW,'electric'),18,'#84620d','middle',800)} ${text(399,boilerY+gasHeatH+27,'Hot turbine exhaust',17,'#9b5522','middle',700)} ${text(625,steamY+steamHeatH/2-12,'Recovered steam',17,'#79441d','middle',750)} ${text(625,steamY+steamHeatH/2+14,fmt(val.hrsgMWth,'heat'),18,'#634b34','middle',800)} ${text(957,386,'Steam-generated electricity',18,'#84620d','middle',730)} ${text(957,408,fmt(val.steamTurbineGrossMW,'electric'),18,'#84620d','middle',800)} ${text(670,917,'Exhaust / stack heat',17,C.ink,'middle',750)} ${text(670,941,fmt(val.exhaustRejectMWth,'heat'),18,C.ink,'middle',800)} ${text(868,917,'Condenser / cooling',17,C.ink,'middle',750)} ${text(868,941,fmt(val.condenserRejectMWth,'heat'),18,C.ink,'middle',800)} `; return base+links+nodes; } const energySankeyContainer = document.createElement('div'); energySankeyContainer.style.overflowX = 'auto'; energySankeyContainer.style.border = '1px solid #d9dee3'; energySankeyContainer.style.borderRadius = '10px'; energySankeyContainer.innerHTML = makeEnergySankeySvg(point, formatFlow); const energySvg = energySankeyContainer.querySelector('svg'); energySvg.style.width = diagramView === 'Full-size detail' ? '1550px' : '100%'; energySvg.style.minWidth = '0'; energySvg.style.maxWidth = 'none'; energySvg.style.height = 'auto'; display(energySankeyContainer); display(html`

Steam regeneration and auxiliary electricity are shown as internal duties at their point of use; their energy ultimately dissipates. The two downward heat arrows are physical outlets, not the complete final heat balance. Household equivalents use Ofgem's 2026 figure of 2,500 kWh/year and the selected operating hours.
¹ Turbine and boiler conversion percentages are model allocation ratios, not measured equipment efficiencies.

`);51:T158a,// Cell 5 // Three integrated summaries. Each number comes from the same source-audited model. // Component conversion values are model allocation proxies, NOT vendor equipment test efficiencies. const gtConversionPct = point.isOff ? null : 100*point.gasTurbineGrossMW/point.fuelMWth; const exhaustAfterGTPct = point.fuelMWth-point.gasTurbineGrossMW; const heatRecoveryPct = point.isOff ? null : 100*point.hrsgMWth/exhaustAfterGTPct; const steamYieldPct = point.isOff ? null : 100*point.steamTurbineGrossMW/point.hrsgMWth; const captureElectricCostMW = point.steamPowerPenaltyMW + point.captureAuxMW; const capturePenaltyPctOfExport = point.isOff ? null : 100*captureElectricCostMW/point.netElectricMW; const captureHeatPctOfExport = point.isOff ? null : 100*point.reboilerMWth/point.netElectricMW; const pct = x => x===null ? '—' : `${fmtNum(x,1)}%`; const panelMetric = (label,value,note='') => html`

${label}

${value}

${note ? html`

${note}

` : ''}

`; const summaryGroups=[ { title:'CCGT power station',caption:'Gas combustion, steam recovery and turbine conversion',color:'#ba4b43', highlightLabel:'Natural gas thermal input',highlightValue:formatFlow(point.fuelMWth,'gasEnergy'), highlightNote:`Fuel flow ${formatFlow(point.fuelGasTph,'gasMass')} · LHV basis`, metrics:[ ['Gas turbine gross generation',formatFlow(point.gasTurbineGrossMW,'electric')], ['Steam turbine gross generation',formatFlow(point.steamTurbineGrossMW,'electric')], ['Gas turbine conversion¹',pct(gtConversionPct),'Electrical output / fuel input'], ['Heat recovery fraction¹',pct(heatRecoveryPct),'Steam energy / post-turbine heat'], ['Steam-cycle electricity yield¹',pct(steamYieldPct),'Steam electrical output / steam energy'] ], note:'¹ Simplified model allocation ratios, NOT measured equipment efficiencies or steam-turbine isentropic efficiency.' }, { title:'CO₂ capture plant',caption:'Only active when the selected configuration has capture',color:'#d88232', highlightLabel:'CO₂ capture fraction',highlightValue:`${fmtNum(point.captureFraction*100,1)}%`, highlightNote:point.captureFraction ? 'At this steady operating point' : 'Capture process not fitted', metrics:[ ['CO₂ captured',formatFlow(point.capturedCO2Tph,'co2')], ['Amine reboiler duty',formatFlow(point.reboilerMWth,'heat'),'Useful regeneration heat'], ['Capture electrical auxiliaries',formatFlow(point.captureAuxMW,'electric'),'Fans, pumps and compression'], ['Foregone steam-turbine output',formatFlow(point.steamPowerPenaltyMW,'electric'),'Steam extraction opportunity cost'], ['Reboiler heat / net export',pct(captureHeatPctOfExport),'MWth per MWe: not an electrical penalty'] ], note:'Reboiler MWth and electrical MWe describe different grades of energy and are not directly additive.' }, { title:'Combined plant',caption:'Net delivery, capture penalty and ultimate heat rejection',color:'#357f78', highlightLabel:'Net electrical efficiency',highlightValue:point.isOff?'OFF':`${fmtNum(100*point.netEfficiency,1)}%`, highlightNote:'Exported electricity / gas fuel energy (LHV)', metrics:[ ['Capture electrical-equivalent penalty',pct(capturePenaltyPctOfExport),'Steam power foregone + electrical auxiliaries ÷ net export'], ['Direct CO₂ emitted',formatFlow(point.emittedCO2Tph,'co2')], ['Ultimate rejected heat',formatFlow(point.finalWasteHeatMW,'heat'),'Includes eventual dissipation of internal duties'], ['Condenser heat source',formatFlow(point.condenserRejectMWth,'heat'),'Low grade (~35°C illustrative)'], ['Potential district heating','Heat pump required','Ambient-loop option; not direct household heat'] ], note:'No “homes heated” claim: available temperature, heat recovery, heat-pump COP, seasonal demand and network losses are not modelled.' } ]; const summaryEl = html`

${summaryGroups.map(g=>html`

${g.title}

${g.caption}

${g.highlightLabel}

${g.highlightValue}

${g.highlightNote}

${g.metrics.map(([label,value,note])=>panelMetric(label,value,note))}

${g.note}

`)}

`; display(summaryEl);52:T988,// Cell 8 if (showExergy) { const T0 = 15 + 273.15; const quality = tempC => Math.max(0,1-T0/(tempC+273.15)); const rows = [ {name:'Electricity (work)',temp:null,f:1,mw:point.netElectricMW,meaning:'Electrical work is already high-grade energy'}, {name:'Hot gas leaving turbine (illustrative)',temp:point.caseId==='modern-ccs'?641:580,f:quality(point.caseId==='modern-ccs'?641:580),mw:point.fuelMWth-point.gasTurbineGrossMW,meaning:'Single-temperature approximation of mixed exhaust energy'}, {name:'Amine reboiler steam (illustrative)',temp:130,f:quality(130),mw:point.reboilerMWth,meaning:'Theoretical reversible heat-work potential, NOT actual generation lost'}, {name:'Capture cooling (illustrative)',temp:40,f:quality(40),mw:point.reboilerMWth,meaning:'Simplified fate of reboiler heat (not full capture cooling duty)'}, {name:'Steam condenser heat (illustrative)',temp:35,f:quality(35),mw:point.condenserRejectMWth,meaning:'Low-temperature heat has little remaining work potential'} ]; const t = html`

Optional exergy: comparing heat quality

Ideal heat Carnot fraction = 1 - ambient absolute temperature / stream absolute temperature, using 15 C ambient. This is a teaching illustration, not a whole-plant exergy Sankey.

${rows.map(r=>html`

${r.name}${r.temp===null?'':` (~${r.temp} C)`}

${(r.f*100).toFixed(1)}%

`)}

At this load: reboiler heat ${fmtNum(point.reboilerMWth,1)} MWth x ideal quality ${fmtNum(quality(130)*100,1)}% = ${fmtNum(point.reboilerMWth*quality(130),1)} MW theoretical reversible work potential, versus the modelled ${fmtNum(point.steamPowerPenaltyMW,1)} MWe of foregone turbine electricity. The numbers are not expected to be identical.

`; display(t); } 53:T914,## Model boundaries, caveats and extension pathway - The rated capacity input is **net exported power** at the reference efficiency. Each scenario is sized to deliver the same net MW; it does **not** assume identical gas turbines in all three cases. - **0% is OFF.** Any nonzero dispatch uses the same full-load heat rate. This is a teaching approximation; real plants have minimum stable loads, lower efficiencies at part load, start/stop losses and capture transients. - Energy is conserved exactly within the model's **stylised physical energy allocation**. Reboiler heat and auxiliary electricity ultimately join rejected heat; they are not separate final boundary outputs. Steam and gas enthalpy, flue gas sensible heat, pressure losses, cooling systems and CO2 export enthalpy have not been rigorously modelled. - Thermal grade matters. The optional **exergy** panel uses ideal reversible Carnot heat fractions at *illustrative* temperatures, not a validated plant exergy balance. The heat transfer takes place over temperature ranges, not necessarily at a single temperature. - Annualised figures assume the selected dispatch output is sustained for the selected operating hours. They are *not* annual dispatch forecasts. Gas tonnes/day are instantaneous flow extrapolated to a 24-hour day. - CO2 is **direct combustion** only, calculated using the generic IPCC natural-gas fuel factor. It excludes gas upstream emissions, methane leakage, solvent losses, capture plant emissions from supplementary firing, and transport/storage leakage. - Gas volume uses an illustrative UK gross calorific value, an approximate net/gross factor and simplified reference condition adjustment to 60 F. Physical conversions must be recalibrated to site gas composition for engineering use. - Plant-specific presets should be added as **data records**, with each field mapped to an evidence source and its date. Do not transfer the old 44% scenario directly to Pembroke, or the IEAGHG modern design directly to Peterhead or NZT, without project-specific verification. **Suggested later extensions:** project presets, vendor-validated full/part-load performance maps, start/stop and bypass modes, solvent/CO2 intermediate storage, hourly dispatch and carbon accounting including fuel origin, biogenic fraction and lifecycle emissions. 54:[] 47:{"id":"a55e1a4405121ed0","slug":"ccgt-energy-and-carbon-explorer","title":"CCGT Energy & Carbon Explorer","thumbnail":"b10001fbcaed75a2f52b9fc902d99581cd34f991ce447e4532a6ae85abd27763","access_level":"public","create_time":"$D2026-11-11T21:28:34.102Z","update_time":"$D2026-11-11T21:43:55.132Z","view_time":null,"first_public_time":"$D2026-11-11T21:40:34.716Z","has_unpublished_edits":null,"fork":true,"stars":1,"starred":false,"owner":{"type":"team","id":"fa149cb0825f9a52","login":"tony-griffiths","name":"Tony Griffiths","avatar_url":"https://avatars-next.observableusercontent.com/7cf209d7bf7ee1257528bf422fc89bd37776aee216d4c1820dd2be9490133758","tier":"free_2026","bio":"Love exploring ways to make sense of complex data across time and space. 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This is my personal hobby/ art project space.","followed_by_you":false,"follows_you":false}],"members":[{"type":"team","id":"fa149cb0825f9a52","login":"tony-griffiths","name":"Tony Griffiths","avatar_url":"https://avatars-next.observableusercontent.com/7cf209d7bf7ee1257528bf422fc89bd37776aee216d4c1820dd2be9490133758","tier":"free_2026","role":"editor"}],"comments":[],"custom_thumbnail":true,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"titling":"auto","title":"CCGT Energy & Carbon Explorer","cells":[{"id":1,"value":"$4b","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":2,"value":"$4c","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":3,"value":"$4d","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":4,"value":"$4e","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":13,"value":"// Cell 5a\n\n// Shared reading mode for both process diagrams. The model and flow widths are unchanged.\nconst diagramView = view(Inputs.select(\n ['Fit to notebook', 'Full-size detail'],\n {label: 'Diagram viewing mode', value: 'Fit to notebook'}\n));\ndisplay(html`

\n Fit shows each complete diagram in the notebook.\n Full-size detail uses the SVG's native width with horizontal scrolling for reading small annotations.\n Hover over a Sankey flow or process unit for the underlying value.\n

`);","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"$4f","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":7,"value":"$50","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":5,"value":"$51","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":9,"value":"// Cell 9\n\nconst comparisons=Object.keys(CASES).map(id=>{\n const q=simulateCCGT({caseId:id,ratedNetMW,dispatchPercent,annualHours});\n return {\n 'Configuration':q.caseName,\n 'Net eff. (%)':+(100*q.netEfficiency).toFixed(2),\n [`Gas (${gasEnergyUnit})`]:gasEnergyUnit==='TWh/yr'?+(q.fuelMWth*annualHours/1e6).toFixed(4):+q.fuelMWth.toFixed(1),\n [`Power (${electricUnit})`]:electricUnit==='TWh/yr'?+(q.netElectricMW*annualHours/1e6).toFixed(4):+q.netElectricMW.toFixed(1),\n [`Captured CO2 (${co2Unit})`]:co2Unit==='Mtpa'?+(q.capturedCO2Tph*annualHours/1e6).toFixed(4):+q.capturedCO2Tph.toFixed(1),\n [`Emitted CO2 (${co2Unit})`]:co2Unit==='Mtpa'?+(q.emittedCO2Tph*annualHours/1e6).toFixed(4):+q.emittedCO2Tph.toFixed(1),\n [`Reboiler (${heatUnit})`]:heatUnit==='TWh/yr'?+(q.reboilerMWth*annualHours/1e6).toFixed(4):+q.reboilerMWth.toFixed(1)\n };\n});\ndisplay(Inputs.table(comparisons,{width:1250}));\n","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":12,"value":"// Cell 10\n\nconst checks = [\n ['Overall boundary energy (MW)',point.energyBalanceErrorMW],\n ['Net power and auxiliaries (MW)',point.electricBalanceErrorMW],\n ['CO2 generation vs captured + emitted (t/h)',point.co2BalanceErrorTph]\n];\nconst checked = checks.every(([name,err])=>Math.abs(err)<1e-6);\ndisplay(html`

${checked?'PASS':'FAIL'} - model balances close at this operating point

`);\ndisplay(Inputs.table(checks.map(([name,error])=>({Check:name,'Residual magnitude':Number(Math.abs(error).toExponential(3))}))));\n","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":8,"value":"$52","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"// Cell 11\n\ndisplay(html`

Engineering evidence and provenance

Published is taken from the cited report; derived means a documented arithmetic or calibration step; illustrative means it is not a measured plant value. Follow the original links to verify specific numbers.

`);\ndisplay(Inputs.table(ASSUMPTIONS,{columns:['parameter','value','provenance','source','caveat'],width:1250}));\nfor (const [key,src] of Object.entries(SOURCES)) {\n display(html`

${key} - ${src.title}
Where to look: ${src.location}

`);\n}\n","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":11,"value":"$53","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W54","stdlib":"2"}} 42:null