AMSC’s PLANNED ANALYSIS OF ECONOMICS OF HTS GENERATORS FOR WIND TURBINES prepared for

1. AMSC’s PLANNED ANALYSIS OF ECONOMICS OF HTS GENERATORS FOR WIND TURBINES prepared for 18-19 May 2009 meeting of the ExCo of the IEA Implementing Agreement for a Co-Operative Program for Assessing the Impacts of High -Temperature Superconductivity on the Electric Power Sector prepared by A.M. Wolsky HTS Agreement Operating Agent (most recently revised 1 May 2009)

2. this talk will present a few words about:• the appeal of HTS generators for wind • the competition: NdFeB • what AMSC has been doing • AMSC’s recently announced plans

3. the appeal of HTS generators for wind

4. WIND TURBINES DRIVE LOW RPM SHAFTS AT THE TOP OF TOWERS Towers support the weight of the generator system. These towers , particularly off-shore towers, can be expensive.

5. HOW DOES fmechanical = 0.5 Hz BECOME felectrical = 50 Hz ?

6. HOW DOES fmechanical=0.5 Hz BECOME fmechanical=50 Hz, TODAY ? by using three kinds of equipment • a gearbox, often 1:50 • a 4 or 6 pole generator, • power electronics AC –> DC –> AC induction generator gearbox for 1.5 MW turbine 1.5 MW Vestas

7. 1 electrical rotation 1 mechanical rotation 2 2/ 6 2/ 6 mechanical rotation mechanical rotation 1 – 6 gear ratio 12 pole electrical machine MECHANICAL GEARS or MULTIPOLE MACHINE ?

8. TODAY’s GEARBOXES ARE HEAVY BUT HEAVY GEARBOX and CHEAP LIGHT WEIGHT GENERATOR ARE TODAY’s BEST OFF–THE–SHELF COMBINATION Turbine drives 30 rpm shaft power passes thru gear box (e.g., 1:50) and then runs a 4 pole generator Turbine drives 1:2 gearbox thatdrives 100 pole generator 1 electrical rotation 1 mechanical rotation 2 2/ 6 2/ 6 mechanical rotation mechanical rotation 12 pole electrical machine 1 – 6 gear ratio gearbox for 1.5 MW turbine with two high speed shafts Too heavy and expensive with today’s Cu & Fe TODAY

9. AN Bonus 1.3MW/62 wind turbine’s gearbox being tested at METSO HTS PROMISES TO GREATLY REDUCE THE WEIGHT OF MULTIPOLE ROTOR SYSTEMS (120 MT HTS vs. 300 MT Cu) Many–pole rotors may eliminate the expensive and heavy gearbox Gearbox–generator weight savings enables either • more powerful wind turbine and generator on the same structure • support the lighter weight with a less expensive tower

10. the competition: permanent magnets, NdFeB

11. Near Future improvements are sought from using NdFeB magnets instead of Cu coils on the generator rotor* * ABB offers up to 60 poles, up to 5 MW Alstom offers up 100 poles, up to 1.5 MW Siemens up to 3.6 MW NdFeB magnets offer simplicity vs. Cu coils • NdFeB was very expensive (e.g., 55 €/kg 2003) but prices are coming down (e.g., 20$/kg 2006) • NdFeB conducts so eddy current losses cannot be neglected • NdFeB is always “on”, spinning rotor always wants to put a voltage across stator’s armature coils SUPPLIERS SEEK WAYS TO DEVELOP MORE POWERFUL WIND TURBINES HTS will compete with NdFeB “PERMANENT MAGNET” GENERATORS ATTRACT INTEREST

12. what AMSC has been doing

13. AMERICAN SUPERCONDUCTOR WANTS TO SERVE THE MARKET FOR WIND GENERATED ELECTRICITY AMSC • offers power electronics for use by Wind Farms • owns a German, subsidiary, AMSC WindTec, that designs and assembles wind turbines (0.65 – 10.0 MW) also licenses designs in several countries (e.g., Canada, China, Turkey) • states it has strong ties with wind turbine manufacturers – Hyundai Korea – Sinovel China – TECO Taiwan

14. AMERICAN SUPERCONDUCTOR HAS BEEN CONSIDERING COMPONENTS OF HTS GENERATORS FOR WIND TURBINES AMSC • in 2007, received 3.7 million $ from National Institute of Science and Technology (Advanced Technology Program) • began work, in Oct. 07, in collaboration with TECO-Westinghouse Motor Co • to develop HTS and related technology that would enable construction of a 10 MW generator without gearbox ( i.e., a direct drive generator) • has experience from its work with other motor manufacturers which resulted in – prototype synchronous compensators (8 MVA) for utility – prototype motor (36.5 MW) for the US Navy

15. AMERICAN SUPERCONDUCTOR & TECO HAVE BEEN WORKING TO REDUCE COST OF GENERATOR four topics have AMSC’s attention • REBaCuO tape AMSC yield is up price depends on length ordered and other factors • pancake coils made from REBaCuO tape AMSC slitting to 10 mm wide tape (not 4 mm) for coils in order to reduce number of coils otherwise needed and thus reduce cost • cryogenics • stator, conventional materials TECO working on stator

16. AMSC’s recently announced plans

17. AMERICAN SUPERCONDUCTOR WILL ANALYZE ITS ECONOMICS WITH A VIEW TOWARD BUILDING A PROTOTYPE 8 MW HTS GENERATOR AMSC • will collaborate with DOE’s National Renewable Energy Lab’s National Wind Technology Center (NWTC) • during the next 12 months • AMSC Windtec will estimate the full cost of a future 8 MW turbine – 8 MW direct drive HTS generator – blades – hub – nacelle – tower – controls – power electronics • National Wind Technology Center will evaluate the system’s economics – initial cost – overall cost of energy AMSC’s effort is “intended as a prelude to follow-on programs aimed at building and testing a full-scale prototype.”