Transmission Transporting Electricity by Wire Darcy Neigum Montana-Dakota Utilities Co.

1. TransmissionTransporting Electricity by WireDarcy NeigumMontana-Dakota Utilities Co.

2. Electric Supply System Substation Power Transformer Coal Station Storage Distribution Substation Primary Transmission Lines Residential Transmission Commercial Substation

4. The electricity market has some features in common with just about any other market: • Product • Sellers • Buyers • Transportation

5. Market Features • Product – electricity is there 24/7 • Sellers – generators must continually match load • Buyers control the light switch • Transportation – transmission system must reliably deliver electricity from Sellers to Buyers

6. No way to store electricity Production = Consumption Transmission grid is the ultimate “just in time” manufacturing

7. History – 1880-1900 • Edison’s Pearl Station produced Direct Current (DC) power • Westinghouse’s power plant at Niagara Falls used Alternating Current (AC) power AC became the standard because of its ease in stepping up (transmission) or stepping down voltages (distribution)

8. Transmission Choices • Since distribution systems are also AC, it’s easy to distribute power from AC transmission lines • The majority of U.S. transmission of electricity is by alternating current (AC) • DC transmission lines have less line loss than AC but require conversion facilities – so DC is used for long distances with no distribution systems between conversion points

9. High voltage AC transmission lines

10. New Transmission Line Costs • Bulk of transmission costs are initial capital expenditures. Secondary cost is on-going maintenance • $125,000 per mile for 60 KV lines • $250,000 per mile for 115 KV lines • $375,000 per mile for 230 KV lines • $1,000,000 per mile for 345 KV lines

13. Three Power Grids • Operate independently, but connected in a few places by direct-current (DC) ties • The Eastern and Western Interconnects have limited interconnections with each other • DC ties bridge the national electric system by taking AC electricity on one side, converting it to DC, and then converting it back to AC so that it is synchronized with the AC electricity on the other side of the system separation

14. Delivery of electricity to consumers, usually transmitted over long distances through overhead power lines It is complex, costly and critical to the economy and way of life Due to the large amount of power involved and to reduce losses, transmission normally takes place at high voltages Electricity follows the “path of least resistance” Electric Power Transmission

15. Sounds Simple, What’s the Catch? • Electricity cannot be stored so supply (generation) must be produced exactly when needed to meet customer demand or risk system failure • Level in “lake” must be kept constant at all times • Laws of physics dictate that power flows on a path of least resistance, not necessarily where we’d like it to

16. Let’s Add Some Complexity • Lake levels must remain the same • Streams must remain within their banks • What if some beavers built a dam across one of the streams? Immediately water has to flow to keep customers happy—yet the water level in the lakes must remain constant and the rivers must not overflow their banks • In the electric system all of this is happening at the speed of light Reliability of design

21. Blackout of 2003 Congressional action for North American Electric Corporation (NERC) Reliability Standards for the Bulk Electric System - “NERC Standards” August 14, 2003, 11:15 p.m. EST About 9 hours after blackout

22. Current Transmission Challenges Facing Region • The current transmission system was developed to move power from a power plant to a utility’s service area

23. Issues Facing North Dakota • Bottleneck occurs between North Dakota and other states • Adding generation in ND can aggravate other bottlenecks in the region

24. Issues Facing North Dakota • Demand for new wind generators to access market • Wind generation ultimately built to serve load to the east • Transmission constraints • Competition with existing generators • Age of existing system

25. Adding or upgrading transmission is difficult Physical constraints – Long distances, complex system, stability, overloads, and voltage limitations Regulatory constraints & uncertainties Cost of $1,000,000 per mile for 345 kV Financial risk! Who pays? Issues Facing North Dakota

26. Siting Quagmire Exists • Struggle between states and federal government • Federal Energy Regulatory Commission has ‘backstop’ siting authority if states refuse to site critical facilities • Only one utility has attempted to initiate the FERC siting process • Fourth Circuit Court of Appeals held that FERC’s limited authority is not available where a state agency has denied an application on a timely basis

27. Initiatives • MISO Regional Generation Outlet study • Determine how to transmit wind across the MISO footprint • MISO RECB Task Force • Develop equitable cost-sharing methodology • Upper Midwest Transmission Development Initiative (UMTDI) – • Five-state study (ND, SD, MN, IA & WI) • Encourage construction of interstate transmission lines • Develop equitable cost-sharing methodology

28. MISO Regional Generation Outlet Study $15 to $30 Billion of needed transmission upgrades

29. Other Material • http://videos.howstuffworks.com/medialink/3049-how-the-power-grid-works-video.htm