1. 12/10/13Homeostatic Utility Control1 Homeostatic Utility Control in Retrospect J.L. Kirtley Jr. kirtley@mit.edu Gridwise Architecture Council 4 th Transactive Energy Workshop

2. 12/10/13Homeostatic Utility Control2 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

3. 12/10/13Homeostatic Utility Control3 There were three basic elements of Homeostatic Utility Control: Frequency Adaptive Power Utility Regulator (FAPER): Fast control The Energy Marketplace Marketplace Interface to Customer

4. 12/10/13Homeostatic Utility Control4 Frequency Adaptive Power Utility Regulator (FAPER): Fast control The Energy Marketplace Marketplace Interface to Customer

5. 12/10/13Homeostatic Utility Control5 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

6. 12/10/13Homeostatic Utility Control6 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!

7. 12/10/13Homeostatic Utility Control7 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

8. 12/10/13Homeostatic Utility Control8 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

9. 12/10/13Homeostatic Utility Control9

10. 12/10/13Homeostatic Utility Control10 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’

11. 12/10/13Homeostatic Utility Control11 ‘Power Signal’ could be derived from frequency Or it could be an area power error signal Separating high and low frequency signals

12. 12/10/13Homeostatic Utility Control12 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

13. 12/10/13Homeostatic Utility Control13 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

14. 12/10/13Homeostatic Utility Control14 Frequency Adaptive Power Utility Regulator (FAPER): Fast control The Energy Marketplace Marketplace Interface to Customer

15. 12/10/13Homeostatic Utility Control15 This is the Energy Marketplace as envisioned by Schweppe in 1980 Note ‘Utility Generation’ is in the ‘Regulated Industry’

16. 12/10/13Homeostatic Utility Control16 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

17. 12/10/13Homeostatic Utility Control17 Later work on Spot Pricing: Jiankang Wang Here we have a pretty generic explanation of why you want to get the final price right

18. 12/10/13Homeostatic Utility Control18 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)

19. 12/10/13Homeostatic Utility Control19 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

20. 12/10/13Homeostatic Utility Control20 Better search methods can find the balance

21. 12/10/13Homeostatic Utility Control21 Frequency Adaptive Power Utility Regulator (FAPER): Fast control The Energy Marketplace Marketplace Interface to Customer

22. 12/10/13Homeostatic Utility Control22 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

23. 12/10/13Homeostatic Utility Control23 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 Market Interface to Customer

24. 12/10/13 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)

25. 12/10/13Homeostatic Utility Control25 Current work: using an office building for ancillary services (Young-Jin Kim) Solar Cells Electric Car Charging Air Conditioner Modulation

26. 12/10/13Homeostatic Utility Control26 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.