Utility Horizons - Second Quarter 2013 - (Page 50)

REGULATION de Rigueur... Stress On the Distribution Grid Most articles on distributed generation do not discuss competing with the fuel cost of central station power. Instead they discuss the added reliability of having generation at the site of the load. Indeed, that local reliability is probably justification for the 30 GW of distributed generation installed in California, providing reliability to the owner of the distributed generator. Some people point to distribution as causing 99% of the customer outages on a utility system and that distributed generation could help with this situation. But since distributed generation is generally not owned by the franchised utility, there needs to be a way to transfer funds from the consumer to the owner of the distributed generation. There needs to be a special tariff applicable to those times when the distribution system is impaired or during the very few hours a year when central station power is incapable of meeting the demands of all consumers. The concept of a small group of customers being served by distributed generation is often referred to as a micro-grid. Most of the time, a micro-grid will be connected to the system grid, and will look like a standard utility distribution circuit or network, albeit with more distributed generation embedded in it. However, the concept of a micro-grid is most important when it is not connected to the system grid. It is during this period of stress that this special tariff needs to be applicable. The major job of a system operator is to match supply and demand, having equal amounts of generation and load. When they are out of balance, bad things can happen; the most discussed being that system frequency varies from the 60 Hertz standard. When there is too much generation, the frequency goes higher than 60 Hertz. When there is not enough generation, the frequency declines below 60 Hertz. System operators generally discuss the issues as if they will be controlling generation to match load, much as I did in the previous two sentences. But system operators readily acknowledge that they sometimes must control load to match available generation. the case during a disaster recovery or under other circumstances when the communications infrastructure is damaged or otherwise constrained. This communications backbone is usually an integral part of the SCADA/EMS (Supervisory Control And Data Acquisition/Energy Management System), which is the automation system that balances generation with demand in real time and extensively supports Smart Grid operations. However, in the absence of a fully operational SCADA/EMS central dispatch program, the participants on the micro-grid still need ways to decide when to increase or decrease generation and/or shed load. Thus, a special tariff can provide the participants with a way to mimic the control orders that would normally come from the system operators. Special Tariff I suggest that there should be a special tariff that is applicable during periods of stress, such as when the SCADA systems are unavailable. The special tariff would specify a real-time price that varies inversely with the frequency on the micro-grid, such as is demonstrated below. As the frequency goes up, the price goes down. The price varies slightly within a small range about 60 Hertz, but then varies greatly as system frequency moves further away from 60 Hertz. There also needs to be a setpoint that determines the price at 60 Hertz. For discussion purposes, I will use a setpoint of $30/MWH, which creates the second, upper curve in the graph. The dispatch price would be applicable to both The most critical operation of a micro-grid will often occur when telecommunications equipment is unavailable, as is frequently Some people have argued that a micro-grid requires that the local utility be disenfranchised. A special tariff eliminates the need to disenfranchise the utility, since the utility would still be the entity buying and selling electricity. 1 50 • UTILITY HORIZONS • Q2 - 2013 www.UtilityHorizons.com  http://www.UtilityHorizons.com

Table of Contents for the Digital Edition of Utility Horizons - Second Quarter 2013

Utility Horizons - Second Quarter 2013
Publisher’s Message
Contents
The Queue
Automation Rising!
Inside Tracks
Focal Point
Automation and Innovation at Epcor Water Services
BLeading Edge: Advanced Technology Perspectives
Consumer Engagement: The Future Goes Mobile
Demand Response: Why the Future Is in the Cloud
Building Paths to Smarter Water Management
Bullet-Proofing Your Scada System Against the Evil-Doers
Education Matters
Standard Bearings
Regulation De Rigueur
On the Horizon
Purviews
Intersections
Eventualities
Thinking It Through With Sparky Flamedrop
Loose Ends

Utility Horizons - Second Quarter 2013

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