Electricity Generation From Lignite John Weeda Director ND Plant Operations June 18, 2013

1. Electricity GenerationFrom LigniteJohn WeedaDirector ND Plant OperationsJune 18, 2013

2. Reliable, low-cost electricity • Great River Energy • 2nd largest utility in MN • 28 member cooperatives • 850+ employees (MN and ND) • 2,751 MW owned generation • 469 MW wind • 4,500+ miles transmission lines • $868.5 million 2011 operating revenue • $3.35 billion total assets • Capital markets

3. Our triple bottom line… Reliability Rates Environment • Affordable rates • Reliable electric service • Environmental stewardship

4. GRE resource portfolio

5. Types of Generation • Baseload power is available for 24-7 demand • High-capacity generating plants • Plants cost less to operate when at full efficiency • Peaking power is available when demand is highest • Higher cost to operate, but quick start-up to react to demand changes • Intermittent power is available when supply allows • Cannot be relied upon to react to level of demand

7. GRE Power Plants

8. Lignite A low-cost abundant resource for generation of electricity

9. Fort Union Lignite Over 2.0 million U.S. customers served – 850,000 Canadian customers

10. Economic Impact Every 4 megawatts of Lignite-based Electric Generation requires about 3 jobs

11. Agenda • Basics of generating electricity • Commercial generating technologies • Lignite as a fuel source • Controlling emissions • Generating electricity • Summary

12. Magnetic Field Around Bar Magnet Lines of force (Flux) N S Magnet

13. Producing Electricity From Magnetism Coil Meter (Galvanometer) Magnet

14. Basics of How Electricity is Made Producing Electricity! Which spins a magnet inside a coil of wire A source of energy such as lignite To push blades on a shaft

15. Battle of the Bulbs

16. Electricity Savings The same amount of electricity used to light up one incandescent light bulb will light up how many LED bulbs? • 2 LED bulbs • 5 LED bulbs • 10 LED bulbs • 20 LED bulbs • 50 LED bulbs

17. Electricity Savings The same amount of electricity used to light up one incandescent light bulb will light up how many LED bulbs? • 2 LED bulbs • 5 LED bulbs • 10 LED bulbs • 20 LED bulbs • 50 LED bulbs

18. Primary Sources of Energy for Generation of Electricity • Thermal generation - coal fired • Nuclear generation - reactors • Water - water wheel or water turbine • Wind Generators- wind turbines • Diesel - diesel engine • Natural gas - gas turbine

19. Wind Generators Renewable, clean but intermittent

20. Basics of How Electricity is Made A source of energy such as wind To push blades on a shaft Which spins a magnet inside a coil of wire Producing Electricity!

21. Basin Electric’s Wind Facilities PW 1 713 MW Minot Baldwin Edgeley Wilton Day County Hyde County SMSC Wind SD WindPartners Pipestone Chamberlain Lakota PWSD1 Hancock Superior Oaklane Crosswinds

22. Water-Hydro Generation Renewable, clean and reliable….but expensive and hard to build today

23. Basics of How Electricity is Made A source of energy such as water To turn blades on a shaft Which spins a magnet inside a coil of wire Producing Electricity!

24. Wind and Water Renewable but intermittent Load characteristics impact base-load units – follow the wind and water High water or wind generation – base-load units drop off

25. Diesel Generator Used for short term peaking – expensive

26. Basics of How Electricity is Made A source of energy such as a diesel engine To turn a shaft Which spins a magnet inside a coil of wire Producing Electricity!

27. Gas Turbine Natural gas is cleaner but pricing is volatile

28. Basics of How Electricity is Made A source of energy such as burning gas Which spins a magnet inside a coil of wire To turn blades on a shaft Producing Electricity!

29. Exploring lignite as a fuel sourcewith steam turbine generators

30. Most Common Commercial Technology for Large-Scale Electrical Generation Affordable, reliable, increasingly clean

31. How is Lignite Converted into Electricity?

32. How Electricity is MadeUsing a Steam Turbine Emissions Control Steam Equipment Turbine Generator Steam Pulverized Coal Water Condenser Boiler Hot Air

33. Lignite Receiving & Stockpile

34. Lignite conveyed into plant

35. Pulverizers prepare the lignite

36. Lignite-Fired Boiler Bunker Burners Coal Feeder Lift Line Pulverizer

37. Photo of pulverized coal Photo of oil during startup

38. 2,400 PSI Steam Pressure 2,400 Pounds 2,400 pounds per square inch

40. Steam turbine generator

41. Generator during assembly

42. Generator stator work

43. Modern control room with computer equipment

44. Plant Transformers • Auxiliary transformers for plant power • Step-Up transformers for sending power out

45. Power Plant Substation

46. Lignite has some challenging characteristics COAL COAL H O 2

47. Conversion Efficiency is lower due to high moisture x = 35%

48. Other Challenging Characteristics • Parameters of ND Lignite as found in nature • Heating value 6,000 to 7,000 BTU / Lb (other coals 8,000 to 12,000 BTU / Lb) • Ash content in ND lignite - 6% to 12% as burned • Sodium content high in many areas – contributes to challenges • Deposits in boiler • Other mineral constituents

49. DryFineCan Improve Lignite Coal Creek Station • Low temperature waste heat is being used to reduce moisture in lignite • System segregates unwanted portion of fuel • Increases plant efficiency and reduces emissions

50. Lignite boiler emissions in North Dakotaare controlled with up-to-date technology