1. Wood chip drying in connection with combined heat and power or solar energy in Finland Samuli Rinne Henrik Holmberg Tiina Järvinen Kaisa Kontu Sanna Syri Aalto University

9. Source: bing.com/maps

10. Condensing power 100 92 47 42

11. Combined heat and power District heating Replaces mainly conventional condensing power 55 92 100 33

12. Photo: Mika Karppinen A state of the art-CHP-system

13. The Finnish electricity production, hourly averages in 2006-2009, MW

14. Electricity production in EU27 in 2010 and 2020, TWh Nuclear Coal, peat Natural gas Solar

15. The targets of the wood fuel drying in this concept: 1. Better energy efficiency 2. More flexible CHP production 3. Profitable operation

17. Lower heating value of wood chips per loose m 3 Bark Sawdust Forest residues

18. Lower heating value of wood chips per loose m 3

20. Combined heat and power + fuel drying with CHP heat District heating More electricity production with the same amount of fuel

21. The studied CHP system

22. The targets of the wood fuel drying in this concept: 1. Better energy efficiency 2. More flexible CHP production 3. Profitable operation

23. Simulated power production in Finland in a week on March, MW. Nuclear and industrial CHP omitted. The nominal effect of wind power is 8000 MW in this future scenario (about 50% of the total Finnish power production capacity).

24. Flexibility in the district heating networks with CHP 1. A lot of wind/solar (+nuclear) production → low electricity price. CHP production is decreased: - heat storages are discharged - demand side management: the heating of buildings is decreased if possible 2. A little of wind/solar (+nuclear) production → high electricity price. CHP production is increased: - heat storages are charged - condensing turbines (which are connected to the CHP turbines) and even auxiliary coolers are used - demand side management: the heating of buildings is increased if possible - snow melting is put in operation - fuel dryers using CHP heat are used

25. The targets of the wood fuel drying in this concept: 1. Better energy efficiency 2. More flexible CHP production 3. Profitable operation

26. To make CHP production more profitable, it should be concentrated more to the moments when the electricity price is high

27. Net production cost of heat (NPC) pf CHP heat = Fuel cost + variable O&M cost – income from electricity sales amount of heat 20 e/MWh fuel + 1 e/MWh fuel – 49 e/MWh electricity * 0,33 = 0,55 = (in average, in this case) 9 e/MWh heat

28. Dryer properties 100% 80 o C 60%40% Evaporation Losses

29. The Nordpool electricity price in Finland in 2011, e/MWh and the marginal cost limit for the drying NPC < 12 e/MWh NPC > 12 e/MWh

30. The optimisation of the dryer use

34. The net production cost of heat in the different alternatives, 1000 e/a The maximum input heat effect of the dryer, MW

35. The net production cost of heat in the different alternatives, also with solar heat, 1000 e/a D = The maximum input heat effect of the dryer, MW S = The aperture area of the solar collectors, hectares

36. Dryer performance: 6% more energy in m 3. 56 GWh 80 o C 34 GWh Evaporation Losses MC 45% 556 GWh MC 28% 590 GWh 22 GWh

37. The next steps in the research -more dryer investment data -more test years and a future scenario -better consideration of power plant ramping rates - maintenance costs of the dryer? - effects to the system level emissions?