Biomass-fired combined heat and power for district heating UET- KSK Campus Energy Engineering 2017/11/20

CASE 1: HOT WATER BOILER District heating production rate: 50 MW District heating 80 °C Preheated air Air, 30 °C, dry Condensate, 53 °C De-humidified flue gas, 53 °C District heating 50 °C Wet biofuel H2O, 170 °C, 16 bar H2O, 130 °C, 16 bar Flue gas, 120 °C District heating production rate: 50 MW Annual district heating demand: 5000 hours Fuel consumption: 2.98 kg MAF/s Power consumption: 693 kW

CASE 1: PROFITABILITY ANALYSIS Case 1: Power cost of 300 sek/MWh   Annual fuel cost [Msek] 26.1 Annual power cost [Msek] 1.04 Annual district heating revenue [Msek] 50 Cost of the flue gas condensator [Msek] 13.6 Cost of the other parts of the plant [Msek] 129.6 Total investment cost [Msek] 143.2 Depreciation [Msek] 14.3 Annual maintenace and operation [Msek] 8.07 Annual profit [Msek] 0.51 Case 3: Power cost of 700 sek/MWh   Annual fuel cost [Msek] 26.1 Annual power cost [Msek] 2.42 Annual district heating revenue [Msek] 50 Cost of the flue gas condensator [Msek] 13.6 Cost of the other parts of the plant [Msek] 129.6 Total investment cost [Msek] 143.2 Depreciation [Msek] 14.3 Annual maintenace and operation [Msek] 8.07 Annual profit [Msek] -0.87 Case 2: Power cost of 500 sek/MWh   Annual fuel cost [Msek] 26.1 Annual power cost [Msek] 1.73 Annual district heating revenue [Msek] 50 Cost of the flue gas condensator [Msek] 13.6 Cost of the other parts of the plant [Msek] 129.6 Total investment cost [Msek] 143.2 Depreciation [Msek] 14.3 Annual maintenace and operation [Msek] 8.07 Annual profit [Msek] - 0.18 Case 4: Power cost of 500 sek/MWh, no condenser   Annual fuel cost [Msek] 35.3 Annual power cost [Msek] 2.42 Annual district heating revenue [Msek] 50 Cost of the plant [Msek] 150 depreciation [Msek] 15 Annual maintenace and operation [Msek] 10 Annual profit [Msek] -13

CASE 2: REFERENCE CASE WITH STEAM CYCLE POWER PRODUCTION 20.6 MW 1-y-y’ 4 District heating 80 °C Turbine y 50 °C 1 2 Condenser FUEL DEMAND 78.1 MW y’ 3 1 HEAT PRODUCTION 50 MW Preheater2: Closed heater Preheater1: Open heater 5 1-y-y’ 9 1 8 6 Wet biofuel Preheated air 7 Flue gas y 1 11 Pump 2 Steam generator 10 y Pump 1 Trap Legend: 1 stream number y stream mass flow ratio

CASE 2: PROFITABILITY ANALYSIS INCOMES 50 MSEK/year 41.1 MSEK/year Heat production : 50 MW Power production : 20.6 MW COSTS 42.9 MSEK/year Fuel demand : 78.1 MW Capital : 57.6 MSEK/year Operation : 8.63 MSEK/year Maintenance : 10.1 MSEK/year PROFITABILITY for power price 400 SEK/MWh - 7.63 MSEK/year

CASE 3: STEAM CYCLE WITH FUEL DRYER POWER PRODUCTION 18.8 MW FF District heating FUEL DRYER 80 °C Turbine 50 °C Condenser HEAT PRODUCTION 50 MW Preheater2: Closed heater Preheater1: Open heater DRYED FUEL WET FUEL 65,85 MW Flue gas Pre-heated air Pump 2 Steam generator Pump 1 Trap

CASE 3: PROFITABILITY ANALYSIS INCOMES 50 MSEK/year 37,6 MSEK/year Heat production : 50 MW Power production : 18.8 MW COSTS 36,2 MSEK/year Fuel demand : 65.85 MW Capital : 56,4 MSEK/year Operation : 8,46 MSEK/year Maintenance : 8,88 MSEK/year PROFITABILITY for power price 400 SEK/MWh - 3,53 MSEK/year

CASE 4: STEAM CYCLE WITH LOWER STEAM DATA POWER PRODUCTION 19 MW P=0.7 bar H=2.56MJ/kg m=23kg/s P=65 bar T=510 ̊C H=3,44MJ/kg m=27kg/s 4 + - District heating 80 °C Turbine 50 °C 1 2 Condenser FUEL DEMAND 79 MW 3 HEAT PRODUCTION 50 MW Preheater2: Closed heater Preheater1: Open heater 5 9 10Kg/sec 8 6 Wet biofuel Preheated air 7 Flue gas 11 Pump 2 Boiler 10 Pump 1 Trap

CASE 4: PROFITABILITY ANALYSIS INCOMES 50 MSEK/year 66,5 MSEK/year (for price of 700sek/MWh) Heat production : 50 MW Power production : 19 MW COSTS 43,5 MSEK/year Fuel demand : 79 MW Capital : 53,2 MSEK/year Operation : 7,9 MSEK/year Maintenance : 9,8 MSEK/year PROFITABILITY for power price 700 SEK/MWh 2 MSEK/year

CASE 5: STEAM CYCLE WITH FLUE GAS CONDENSER POWER PRODUCTION: 22.1 MW HEAT PRODUCTION: 50MW District heating 50 C Dry biofuel District heating 50 C Condensate 53 C Flue gas 120 C Preheated air District heating 80 C Flue gas to chimney 100 bars 540°C 25°C WASTE HEAT RECOVERY: 12.2 MW FUEL DEMAND: 82.1 MW

CASE 5: PROFITABILITY ANALYSIS INCOMES 50 MSEK/year 33.2 MSEK/year 59.2 MSEK/year Heat production : 50 MW Power production : 22.1 MW Waste heat recovery : 12.2 MW Total annual revenue : 114.4 MSEK/year COSTS 45.2 MSEK/year Fuel demand : 82.1 MW Annuity : 63 MSEK/year Operation and maintenance : 21.4 MSEK/year Total operating cost : 129.5 MSEK/year PROFITABILITY (@300SEK/MWh): -15.MSEK/year

CASE 6: STEAM CYCLE WITH FLUE GAS CONDENSER AND INLET AIR HUMIDIFIER POWER PRODUCTION: 21,8 MW HEAT PRODUCTION: 50MW District heating 50 C Wet biofuel Flue gas condenser District heating 50 C Condensate 53 C Flue gas 120 C Preheated air District heating 80 C Humidifier for inlet air Condensate 30 C Inlet air humidifier 40 C Saturated Air 30 C (dry) De-humidified flue gas to chimney 100 bars 540°C 25°C WASTE HEAT RECOVERY: 17,86 MW FUEL DEMAND: 82,5 MW

CASE 6: PROFITABILITY ANALYSIS INCOMES 50 MSEK/year 65,3 MSEK/year 17,9 MSEK/year Heat production : 50 MW Power production : 21,8 MW Waste heat recovery : 17,9 MW Total annual revenue : 133,1 MSEK/year COSTS 45,4 MSEK/year Fuel demand : 82,5 MW Capital : 66,7 MSEK/year Operation and maintenance : 22,4 MSEK/year Total operating cost : 134,4 MSEK/year PROFITABILITY for power price 400 SEK/MWh : -1,3 MSEK/year

CASE 7: SMALL SCALE STEAM CYCLE 480/62 Power 5,1 MW Biomass Fuel 28.4 MW Heat power 17,7 MW

CASE 7: PROFITABILITY ANALYSIS INCOMES 17,7 MSEK/year 15,5 MSEK/year Heat production : 17,7 MW Power production : 5,1 MW COSTS 15,6 MSEK/year Fuel demand : 28,4 MW Capital : 15,7 MSEK/year Operation : 2,39 MSEK/year Maintenance : 3,55 MSEK/year PROFITABILITY for power price 400 SEK/MWh -4,48 MSEK/year

PROFITABILITY ANALYSIS

MAIN CONCLUSIONS It is profitable with… steam cycle if power price > 500 SEK/MWh fuel drier if 500 SEK/MWh < power price < 850 SEK/MWh waste heat recovery if power price > 400 SEK/MWh If inlet air humidifier is added to a flue gas condenser