1 Wyoming Infrastructure Authority November 10, 2009 Superconductor Electricity Pipelines

The challenge of moving renewable power long distances needs another option 2 Todays Key Energy Challenge: Carrying 100s of Gigawatts of Green Power to Market Many Issues Multiple Sources Multiple Destinations Cost Allocation Siting Transmission Across Interconnections Losses Many Issues Multiple Sources Multiple Destinations Cost Allocation Siting Transmission Across Interconnections Losses

A New Transmission Option Combine: Conventional underground pipeline construction With two power system technologies: Superconductor cables Reduced voltage multi-terminal DC power transmission The result: A high capacity electric transmission pipeline that offers a new option for connecting diffuse sources of renewable power to remote load centers in a controlled manner Underground and easy to site Highly efficient Cost competitive with currently available options Offers underground security and siting advantages

Superconductor Advantages with DC Power When carrying DC current, superconductors themselves are perfectly lossless - Regardless of length - Regardless of power rating Benefits - No power limitations based on current-based losses - Allows lower voltage, higher current transmission - Allows underground construction Superconductors drive the economics of this transmission option

5 Superconductor Cables Projects Around the World US/Nat. Grid – 34.5kV (400m) US/DTE – 24kV (120m) JAPAN – 77kV (500m) US/EPRI – 115kV (50m) SPAIN – 10kV (30m) US/AEP – 13.8 kV (200m) DENMARK – 36kV (30m) CHINA – 35kV (30m) JAPAN – 66kV (30M) CHINA – 10.5kV (75m) US/Southwire – 12.5kV (30m) US/LIPA Phase I – 138kV (600m) KOREA – 22.9kV (100m) MEXICO – 15kV (30m) CHINA – 110 kV (30m) KOREA – 22.9kV (100m) RUSSIA – 35 kV (30m) KOREA – 22.9kV (30m) US/ENTERGY – 13.8 kV (1,600m) JAPAN – 66kV (250m) CHINA – 35 kV (30m) US/ConEd – 13.8 kV (220m) US/LIPA Phase II – 138 kV (600m) KOREA/KEPCO – 154 kV (500m) AMSTERDAM – NUON (6,000m) SPAIN – 20kV (30m) RUSSIA – 35kV (100m) Superconductor wire and cables are available from a variety of manufacturers around the world

Transmission Level Superconductor Cable 6 Application of established AC superconductor cable technology to DC is straightforward Location; Holbrook, NY (Long Island) 138kV, 2400A, 600m, 575MVA, single phase cables In service since April 2008 Figures courtesy Nexans

VSC HVDC Terminals Voltage Source Converter (VSC) based HVDC terminals available from multiple manufacturers Advantages of VSC converter topology: - Allows incorporation of multiple DC terminals on a line - Greater control and flexibility - Allows the DC line to be envisioned as a DC bus VSC converter available only at lower voltages requiring higher currents - Voltage drop - Losses 7

AC Overhead Transmission Higher power and longer distances require higher voltages Losses Limited power flow control Power transmission characteristics Public opposition 8 Courtesy Argonne National Lab Dominant form of transmission, but many challenges

DC Superconductor Cable 10,000MW in a <1m Gas Pipe Courtesy of Electric Power Research Institute Superconductor ampacity has little to no impact on cable dimensions

Operational Opportunities for DC Superconductor Cables: ELECTRICAL EFFICIENCY Overall losses 2.75% for miles (2.4% for 10GW) 10 Loss advantage increases with distance and MW rating

Operational Opportunities for DC Superconductor Cables: SIMPLIFIED SITING AND ROW 11 Underground installation addresses public and environmental concerns One pipeline can replace many overhead lines

12 Operational Opportunities for DC Superconductor Cables: SIMPLIFIED SITING AND ROW Co-location along existing right-of-way may simplify costly and complex siting procedures

Operational Opportunities for DC Superconductor Cables: GRID OPERATIONS Enhanced Grid Operation and Market Dynamics - Networked DC terminals allow aggregation of renewable sources (wind/solar) reducing variability - Opportunity for ancillary services including regulation, spinning reserve, etc Reduced Impact on Underlying Grid - Largely decoupled from underlying AC grid - Control over DC system interaction with AC grid during faults - Provides long distance wheeling without impacting regional grids 13

Operational Opportunities for DC Superconductor Cables: Redundancy Redundant cables can provide single line redundancy Loop networks, like EHV overlays, provide inherent redundancy 14

Cost Analysis 5GW, 1000mile Superconductor DC Cable System - US$8 M/mile - Costs include DC terminals, refrigeration, installation - Doubling capacity to 10GW line increases cost by less than 1/3 Cost Competitive with EHV AC - US$2.5 - $5.5 Million/mile per line - 2 to 3 lines needed for same capacity 15 Long distance, high power superconductor DC cables are cost competitive with EHV AC lines

Advantages of Superconductor Pipelines Highest power capacity Highest efficiency (lowest power losses) of any transmission technology Ideal for very long distances Capable of transferring power across the three U.S. interconnections Able to accept power from multiple distributed sources, and precisely deliver power to multiple distributed destinations Underground construction with minimum right of way requirement Simplified cost allocation due to precise controllability of DC terminals Minimizes interaction with existing AC grid, reducing costs and increasing operational flexibility Superconductor Electricity Pipelines are uniquely and ideally suited to move renewable energy to distant load centers

Tres Amigas SuperStation Project Western Interconnection Eastern Interconnection Texas Interconnection 14,400 square acres (22.5 sq. miles) of land in Clovis, New Mexico already allocated for project

Tres Amigas Project to Use Superconductor Electricity Pipeline 18

Lots of Power, Out of Sight and Easy to Site