Lennart Merkert, Antti Saarela, Alf J. Isaksson, Simo Säynevirta, ABB Opportunities in energy aware TMP scheduling Scheduling thermo mechanical pulping (TMP) production with respect to volatile energy cost Slide 1
Changing market energy markets Challenges and opportunities on electricity market Consumption & generation Renewable generation Market liberalization Covering consumption peaks Grid availability and stability Volatile energy prices source: dena Integration EE 6 5 4 3 2 1 1 3 5 7 9 11 13 15 17 19 21 23 EEX Day Ahead Price 17.3.215 Demand side management offers benefits in new market environment Slide 3
New opportunities of industrial demand side management (idsm) Saving cost with intelligent planning Using process flexibility for idsm Shifting loads of energy intensive process steps to low cost times 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 1 11 12 13 14 15 16 17 18 19 2 21 22 23 24 EEX Day Ahead Price 17.3.215 idsm allows important cost savings Slide 5
Industrial demand side management in pulp and paper industry Coordination of production planning and energy management Typical (simplified) pulping process in an integrated pulp and paper mill Pulp refiner Wood chips Pulp tank Bleaching Pulp tank Paper machine Pulp refiner Reject pulp refiner Big electricity consumer Storage for intermediate product Storages and tanks offer flexibilities for industrial demand side management Slide 6
idsm for mechanical pulp mill Considerations Need to take into account Future production plan of the paper machine(s) Total steam demand Capacity and cost of alternative steam sources The maximum production of each refiner line The minumum feasible production per refiner line Results in constrained mixed integer optimization problem Slide 7
Discrete time Resource Task Network (RTN) A flexible and versatile scheduling formulation System representation using RTN Superstructure Sets & decision variables: r R (resources), i I (tasks) and θ, t T (Time Slots) Re(r, t) R (resource excess), ξ(i, t) R (processed quantity), N(i, t) N (processing state) and Π(r, t) (incoming and outgoing resource) Interaction description using Structural Parameters: continuous interactions λ(r, i, θ) discrete interactions μ r, i, θ Resource excess balance equation r R, t T: Re r, t = Re r, t 1 r EL + (μ r, i N i, t + λ r, i ξ i, t i Task ) + Π in r, t Π out r, t Slide 8
Discrete time RTN formulation Handling of starting and stopping machines Integration into RTN superstructure A starting task taking 3 time slots Additional tasks with defined duration for starting and stopping equipment IDLE_EQ Stopping Starting EQ RA T RB Slide 9
Discrete time RTN formulation Constraints and objective function Processing Rates & Resource Storage Cost & Objective Function Processing rates Electricity cost i Production Tasks t: ElCost = Π in r = EL, t elprice(t) MinRate(i) N i, t ξ i, t MaxRate(i) N(i, t) Steam cost t Resource Storage MinVolume(r) Re r, t MaxVolume(r) SteamCost = steamprice Objective function Obj = ElCost + SteamCost t Π in r = Steam, t Slide 11
Electricity Price [ /MWh] t1 t5 t9 t13 t17 t25 t29 t33 t37 t45 t49 t53 t57 t65 t69 t73 t77 t85 t89 t93 t97 t11 t15 t19 t113 t117 t125 t129 t133 t137 t145 t149 t153 t157 t165 Electricity Price [ /MWh] t1 t5 t9 t13 t17 t25 t29 t33 t37 t45 t49 t53 t57 t65 t69 t73 t77 t85 t89 t93 t97 t11 t15 t19 t113 t117 t125 t129 t133 t137 t145 t149 t153 t157 t165 Industrial demand side management in pulp and paper industry Evaluating market opportunities for thermo mechanical pulping (TMP) mills Case study with TMP mill Real world plant and production data of a Nordic paper mill Different scenarios evaluated Scenario Energy cost Allowed pulp storage levels S No 2%-8% S1 Yes 2%-8% S2 Yes 5%-95% 8 7 6 5 4 3 2 1 8 7 6 5 4 3 2 1 Spot Market Hourly Prices (1st week, August 214) Time [hours] Spot Market Hourly Prices (1st week, December 214) Time [hours] Slide 12
t1 t5 t9 t13 t17 t25 t29 t33 t37 t45 t49 t53 t57 t65 t69 t73 t77 t85 t89 t93 t97 t11 t15 t19 t113 t117 t125 t129 t133 t137 t145 t149 t153 t157 t165 t1 t5 t9 t13 t17 t25 t29 t33 t37 t45 t49 t53 t57 t65 t69 t73 t77 t85 t89 t93 t97 t11 t15 t19 t113 t117 t125 t129 t133 t137 t145 t149 t153 t157 t165 Electricity Price [ /MWh] Industrial demand side management in pulp and paper industry Coordination of production planning and energy management Pulp production Pulp production is highly integrated with other parts of paper plant Most energy consuming production steps are moved to low cost times Paper output of plant is not reduced 8 7 6 5 4 3 2 1 4 3 2 1 Reduced pulp production Spot Market Hourly Prices (1st week, December 214) Time [hours] Running Tasks with idsm Slide 13 Shifting production to low cost times
Electricity Price [ /MWh] t1 t6 t11 t16 t26 t31 t36 t46 t51 t56 t66 t71 t76 t86 t91 t96 t11 t16 t111 t116 t126 t131 t136 t146 t151 t156 t166 Electricity Price [ /MWh] t1 t6 t11 t16 t26 t31 t36 t46 t51 t56 t66 t71 t76 t86 t91 t96 t11 t16 t111 t116 t126 t131 t136 t146 t151 t156 t166 Industrial demand side management in pulp and paper industry Evaluating market opportunities for thermo mechanical pulping (TMP) mills Case study with TMP mill Real world plant and production data of a Nordic paper mill Different scenarios evaluated Scenario Energy cost Allowed pulp storage levels S No 2%-8% S1 Yes 2%-8% S2 Yes 5%-95% 8 7 6 5 4 3 2 1 8 6 4 2 Spot Market Hourly Prices (1st week, August 214) Time [hours] Spot Market Hourly Prices (1st week, December 214) Time [hours] No of starts Savings S 8 % S1 24 6% S2 26 5% No of starts Savings S 7 % S1 34 4% S2 33 4% Slide 14
Electricity Price ( /MWh) Electricity Price [ /MWh] t1 t5 t9 t13 t17 t25 t29 t33 t37 t45 t49 t53 t57 t65 t69 t73 t77 t85 t89 t93 t97 t11 t15 t19 t113 t117 t125 t129 t133 t137 t145 t149 t153 t157 t165 Industrial demand side management in pulp and paper industry Summary & Conclusions Summary & Conclusions Resource Task Network (RTN) can be adapted for energy aware production scheduling Additional revenue stream without reduced pulp paper production Flexibility potential very often already on site Increasing price volatility will increase energy cost saving potentials >5 % cost savings possible 8 6 4 2 1 8 6 4 2-1 9.8.215 Spot Market Hourly Prices (1st week, August 214) 11-12 1.8.215 Time [hours] Spot Market Hourly Prices (Summer 215) 22-23 11.8.215 9-1 13.8.215 2-21 14.8.215 7-8 16.8.215 18-19 17.8.215 5-6 19.8.215 16-17 2.8.215 Slide 15
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