Regulatory Economist III Missouri Public Service Commission. Jefferson City, MO (573)

Transcription

1 Transmission Service Types By: Walt Cecil Regulatory Economist III Missouri Public Service Commission P.O. Box 360 Jefferson City, MO (573) November 5, 2012

2 Different Transmission Services This presentation ti is intended d to answer the question: What are the types of transmission service, and how do they differ? 2

3 Transmission Organization In the United States, electric utilities are often members of a Transmission Organization. Their duties include: (1)Planning and issuing authority to build transmission projects; and to (2)Charge and collect for transmission services using the transmission ta sso grid downed edbyt their members. 3

4 Definition: Transmission Organization Independent Transmission System Operator (ISO): an independent, nonprofit, FERC regulated organization that manages power flows, maintains i grid reliability and administers non- discriminatory transmission access to the electric transmission grid in a defined geographic region. ISOs do not own generation resources or transmission i facilities and have no economic interest in the power generated e or flowing across the transmission lines. 4

5 What is Transmission Service? Transmission Service is the reservation of capacity and transmission of energy across the transmission grid on either a firm or non-firm basis from the Point(s) of Receipt to the Point(s) of Delivery. For example, transmission service is required to move a certain amount of energy from one point on the system (usually a power plant) to another point on the esyste system (possibly (possbyacty) city) 5

6 Transmission Service Types Transmission service can generally be divided into two categories: (1)Firm Transmission Service less likely to be curtailed, given higher h priority it in when the system begins to approach its capacity; (2)Non-firm transmission service higher probability of curtailment, but scheduling is more flexible. 6

7 Firm Transmission Service Firm Transmission Service is only available when the utility has placed an advance reservation with the Transmission Organization for capacity on the transmission grid for a specific point in time and duration. Firm Transmission Service could be used for a power plant that runs almost every hour of a year. 7

8 Firm Transmission Service By buying Firm Transmission service, a utility is more likely (but not guaranteed) to be able to serve all of its customers. For example, on the hottest day of the year, there may not be enough transmission capacity to serve all transmission service requests received by the Transmission Organization. Firm Transmission service customers will have priority. 8

9 Firm Transmission Service When the sum of Transmission Service orders approaches the system s physical limit (its capacity), a Transmission Organization may require extra transmission projects to be built to meet Firm Transmission Service requests. The utility ordering Firm Transmission Service causing the system to approach its physical limit would be required to pay for those projects that become needed to expand the system s s capacity. 9

10 Non-firm Transmission Service Non-firm transmission service is provided on an as-available basis and is subject to interruption or curtailment before Firm Transmission Service. In Missouri, Non-firm Transmission Service is often used to connect wind-powered electric generating plants to the system. Wind powered generators do not generate electricity all the time. Non-firm Transmission Service may be used for a periods of time as short as an hour. 10

11 Non-firm Transmission Service If either Firm Transmission Service or Non-firm Transmission Service could be curtailed to solve a problem on the transmission i grid, Non-firm Transmission i Service would be curtailed first. 11

12 Transmission Service Curtailment When either Non-firm Transmission Service or (less likely) Firm Transmission Service is curtailed, the utility ordering the service is not compensated. 12

13 Generator Curtailment There is no compensation paid to a renewable generator (such as wind or solar powered electric generators) when they are curtailed. Consequently, Transmission Organization planning is critical: it is necessary and efficient to build the right amount of transmission capacity to meet the demands placed on the system plus an emergency reserve allowance, and with consideration for for reasonable growth into the future. 13

14 Generator Curtailment If renewable generator managers desire to reduce curtailment risk, they can order Firm Transmission Service. However, renewable generators would be paying for system capacity when they are not producing energy (for example, when there is no wind to turn the wind-turbines). 14

15 Questions? Walt Cecil Regulatory Economist III Missouri Public Service Commission P.O. Box 360 Jefferson City, MO (573)