Homeostatic Utility Control in Retrospect

1. Homeostatic Utility Control in Retrospect Gridwise Architecture Council 4thTransactive Energy Workshop J.L. Kirtley Jr. kirtley@mit.edu Homeostatic Utility Control

2. Homeostatic Utility Control • Arose from an initiative of Fred C. Schweppe and his colleagues in the late 1970’s • Was actually named by Richard Tabors • Was part of Schweppe’s efforts to re-invent the electric utility system • Was intended to make the grid work better • Was developed in the context of regulated public utilities • When first presentation, was rather roundly ridiculed • Has provoked quite a lot of research Homeostatic Utility Control

3. There were three basic elements of Homeostatic Utility Control: • Frequency Adaptive Power Utility Regulator (FAPER): Fast control • The Energy Marketplace • Marketplace Interface to Customer Homeostatic Utility Control

4. Frequency Adaptive Power Utility Regulator (FAPER): Fast control • The Energy Marketplace • Marketplace Interface to Customer Homeostatic Utility Control

5. FAPER • Intended to replace (or supplement) ‘Spinning Reserve’ • Fast (virtually instantaneous) control • Takes advantage of ‘average power’ or ‘energy’ type loads • Works only within the hysteresis band of an energy load • Within that band, turns load on or off according to frequency Homeostatic Utility Control

6. FAPER would help the system, but why would customers want to install them? • There is some expense • Probably negligible impact on comfort of equipment operation • Here is Schweppe’s suggestion for compensation • Charge less when frequency is high and more when frequency is low! Homeostatic Utility Control

7. Later work on FAPERs at MIT: Kevin Brokish • Surprisingly large fractions of consumer loads are amenable to FAPER operation • Brokish assumed operation to be a modification of setpoint in a hysteresis type control Homeostatic Utility Control

8. Brokish recognized • an instability that can arise with a lot of FAPERS controlling loads by switching them on and off • Loads synchronize with each other • Solution is like Ethernet communications: use probabilistic delay • White band is the dead band • Outside dead band, lighter blue is higher probability of switching Homeostatic Utility Control

9. Homeostatic Utility Control

10. More Transactive Energy Work: Olivia Leiterman on Storage • FAPER like action need not depend on frequency • Signals from the utility system can initiate change in interchange • Energy Storage is the ultimate in ‘energy’ type load • Here is some motivation for involving real energy wiggles in ‘ancillary services’ Homeostatic Utility Control

11. ‘Power Signal’ could be derived from frequency Or it could be an area power error signal Separating high and low frequency signals Homeostatic Utility Control

12. Separation of high frequency and low frequency variations • Energy Duration tells what your energy storage is doing • Ramp Duration tells what your other (slower) regulation resources are doing Homeostatic Utility Control

13. Here is the bottom line: • More to this than can be quickly explained • Longer (slower) frequency cutoff reduces mean ramp rate for thermal units • But it also means more storage energy is required Homeostatic Utility Control

14. Frequency Adaptive Power Utility Regulator (FAPER): Fast control • The Energy Marketplace • Marketplace Interface to Customer Homeostatic Utility Control

15. This is the Energy Marketplace as envisioned by Schweppe in 1980 Note ‘Utility Generation’ is in the ‘Regulated Industry’ Homeostatic Utility Control

16. In The Energy Marketplace: • There would be a mix of regulated and unregulated generation • Regulation to ensure return to capital and prevent monopoly pricing • Separate ‘buy’ and ‘sell’ prices for customer generation • ‘Time of Day’ pricing was recognized as insufficient • Anticipated automation in customer premises • Recognized that there would be issues with customer acceptance and privacy • And anticipated (maybe incorrectly) that two-way communication with meters might be impractical Homeostatic Utility Control

17. Later work on Spot Pricing: Jiankang Wang Here we have a pretty generic explanation of why you want to get the final price right Homeostatic Utility Control

18. In a deregulated market, System operators must buy electricity and keep the system balanced • Elasticity Matrix describes • instantaneous elasticity of demand • cross-elasticity (from one time period to others) Homeostatic Utility Control

19. Demand is determined by a balance • Unit Commitment • Economic Dispatch • Price Elasticity predicts change in demand • But see there are numerous ways things might not balance Homeostatic Utility Control

20. Better search methods can find the balance Homeostatic Utility Control

21. Frequency Adaptive Power Utility Regulator (FAPER): Fast control • The Energy Marketplace • Marketplace Interface to Customer Homeostatic Utility Control

22. Market Interface to Customer (MIC) • Need to get ‘price’ or ‘prices’ to Customer • Requirement may be only 5 to 10 minutes • Anticipated that there might need to be a confirming signal in reverse • Automation at the customer premises was anticipated • Some form of ‘smart meter’ was also anticipated Homeostatic Utility Control

23. Market Interface to Customer • To avoid this fellow (who Scheweppe anticipated) • Smart Meter does not report on customers in real time • Measures power, multiplies by price, integrates the result Homeostatic Utility Control

24. Later work at MIT: • ‘The Energy Box’ • Richard Larson and students: • Dan Livengood • Woei Ling Leow • Anticipates forecasts of price, weather, etc. will be required This is an image from Livengood’s thesis, (taken without permission) Homeostatic Utility Control

25. Current work: using an office building for ancillary services (Young-Jin Kim) Solar Cells Electric Car Charging Air Conditioner Modulation Homeostatic Utility Control

26. Discussion • This work was presented to the IEEE Power Engineering Society Summer Meeting in Vancouver • Charles J. Frank of EPRI told us we were idiots • None of the group had any experience with running a utility • We don’t know what spinning reserve is (misuse the term) • FAPER would cost $60k • Robert W. Alford of Siemens-Allis said that • Indirect load control would not be effective • Complicated pricing structures require too much customer participation • Confirmation of prices posted every 5 minutes would require too much bandwidth • The Electric Utility Business is not as mature as it used to be. Homeostatic Utility Control