- Email: [email protected]
Advanced Metering Infrastructure and Determination of the Operability of Demand Response Devices
Mary M. Straub is Principal Load Research Analyst in the Pricing and Regulatory Services Department of the Baltimore Gas and Electric Company. She has been with the Company for 20 years and has worked at BGE in Load Research and Demand-Side Management. Her prior experience includes work at the Potomac Electric Power Company. Ms. Straub received an M.S. in Agricultural and Resource Economics from the University of Maryland, College Park. Sheldon Switzer is Manager, DSM Evaluation, Measurement and Verification, at the Baltimore Gas and Electric Company. He has been with the Company for more than 27 years and has worked at BGE in other capacities including Pricing and Tariffs, Load Research and DemandSide Management. Prior regulatory background includes work at the Maryland Public Service Commission and the U. S. Federal Trade Commission. Mr. Switzer served as a member of BGE’s negotiating team for electric restructuring and was the lead issue manager for electric price unbundling. His experience includes the analysis of competitive issues in the telecommunications, gas, electric, and energy industries. Mr. Switzer received a B.A. in Economics from the State University of New York at Albany and an M.A. in Economics from the University of Maryland, College Park.
May 2013,
Vol. 26, Issue 4
Advanced Metering Infrastructure and Determination of the Operability of Demand Response Devices In the past, Baltimore Gas and Electric Company has observed the degradation of load control operability over time. While it is prohibitively expensive to periodically conduct a site visit to the home of every participant in the Company’s PeakRewards program to identify inoperable devices, AMI affords a new opportunity to focus the search. Mary M. Straub and Sheldon Switzer
I. Introduction ‘‘An investment in knowledge always pays the best interest.’’ – Benjamin Franklin
On Jul. 13, 2009, the Baltimore Gas and Electric Company (BGE or ‘‘the Company’’) filed an application for Authorization to Deploy a Smart Grid Initiative with the Public Service Commission of Maryland. The
three major components of the initiative are: (1) A two-way communication network (utilityto-meter-to-premise); (2) advance metering infrastructure (AMI) – ‘‘smart’’ meters with ZigBee communications capabilities; and (3) a Smart Energy Rewards Program (a pricing structure to encourage customers to reduce loads under conditions needed for system reliability or for
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
45
economic reasons when wholesale energy prices are high). The Department of Energy awarded BGE $200 million under the American Recovery and Reinvestment Act (ARRA) – Smart Grid Investment Program Funding Opportunity Announcement (DE-FOA0000058). Subsequently, the Commission issued Order No. 83531, Case 9208 on Aug. 13, 2010. In this Order the commission indicated that BGE may proceed with its deployment of its AMI proposal, subject to certain conditions: (1) BGE was authorized to establish a regulatory asset with recovery of costs to occur in a traditional rate case. (2) Cost recovery to occur when benefits start to accrue after BGE has delivered a cost-effective AMI system. (3) No mandatory TOU rates. (4) BGE to submit an updated customer education plan and messaging that it will provide to customers prior to meter installation and before the Smart Energy Rewards Program begins. (5) BGE and other parties are to submit to the Commission for approval a set of metrics to track the progress and performance of the AMI initiative. his article will briefly describe some of the metrics that are being developed, but the primary focus will be a discussion of BGE’s PeakRewards Program (direct load control of customers’ air conditioners and water heaters) and the innovative use of AMI data to indicate the operability of individual customer devices.1
T
46
II. AMI Performance Metrics ‘‘Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.’’ – Albert Einstein
The Maryland Public Service Commission established a working group whereby stakeholders were directed to develop and submit for approval a comprehensive set of metrics to
BGE used AMI data in an innovative way to indicate the operability of individual customer devices. allow the Commission to assess the progress and performance of the Smart Grid Initiative. The members of the working group include, among others, BGE, Potomac Electric Power Company, the staff of the Maryland Public Service Commission, the Office of People’s Counsel, the Maryland Energy Administration and AARP. Phase I metrics are designed to measure progress during the deployment phase; Phase II metrics will track the realization of AMI benefits after deployment. he four overall Phase I objectives to be measured during the deployment phase
T
include: (1) customer education; (2) installation and activation of the advanced metering infrastructure on schedule and within budget; (3) realization of initial operational benefits; and (4) results from forward looking PJM capacity market auctions and calculations of future value. Customer education metrics include such items as the percent of customers who are aware and understand AMI technology and benefits (via survey instruments), tracking of customer outreach through the media, newsletters, customer organizations and newsletters, and the number of communication methods deployed. Other metrics in Phase I include tracking the progress and costs of meter installation, testing for meter accuracy, reductions in meter operations cost and avoided costs for replacement or maintenance relating to the older metering system. Phase II metrics include the realization of benefits once the AMI system is operational. Such benefits include outage management, remote connection and disconnection of service, remote meter reading, presentation of Web-based information to customers and dynamic pricing. These operations yield financial benefits (capital and O&M cost savings) and improved customer service (greater reliability, billing accuracy, better information to respond to customer inquiries, etc.). One additional benefit was not initially recognized and this will be the focus of the remainder of this
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
The Electricity Journal
article: The benefit is derived from the AMI-enabled ability to detect whether specific customer direct load control equipment installed under the Company’s PeakRewards program is operational.
III. PeakRewards: Direct Load Control of Air Conditioning and Electric Water Heating ‘‘Summer afternoon – Summer afternoon. . . the two most beautiful words in the English language.’’ – Henry James
Summer afternoons are indeed quite nice, except when the temperature is approaching the high 908s in Baltimore. Then subject to other considerations, it may be time to activate BGE’s PeakRewards program. BGE’s air conditioning and water heater control programs are designed to reduce peak demand during emergency events on the PJM system or for economic benefits when the wholesale price of electricity is very high. Details of BGE’s program can be found in Rider 15 of BGE’s Electric Retail Service Tariff – Demand Response Service.2 A. Air conditioning control Residential customers may contract with BGE to permit the installation, operation, and maintenance, at the Company’s expense, of radio-controlled equipment on the customer’s central air conditioning or heat May 2013,
Vol. 26, Issue 4
pumps. The control devices are either a smart thermostat or a switch by which the Company can control the operation of the air conditioning to achieve a net reduction in load on the Company’s system. ustomers may choose from three cycling options – 50 percent, 75 percent, or 100 percent; the customer’s cooling unit will operate only 50 percent of the time, 25 percent of the time, or will be
C
Customers are encouraged to participate not only for the bill credits, but also for the ability to contribute to environmental goals and system reliability. shut down, respectively, during PJM3-declared emergency events. If control is used for economic reasons (when wholesale market prices are very high) or for local area emergency events, a cycling strategy up to 50 percent will be used. Corresponding to the cycling strategy chosen by the customer, the Company will provide an annual bill credit of $50, $75, or $100, payable in four monthly installments as bill credits in the months of June, July, August, and September. A onetime annual enrollment incentive equal to the annual customer incentive is also available to encourage customer participation.
B. Water heater control Residential customers may contract with the Company for the installation of a control device such that service to their electric water heaters is subject to interruption at any time. During a control event, the electric service to the water heater is shut down yielding a net reduction in load on the Company’s system. Participating customers receive an annual bill credit of $25, payable in equal installments over four winter months, and there is also a onetime enrollment incentive of $25. C. PeakRewards: a successful program BGE has been very successful in achieving high participation rates for the PeakRewards program. In addition to the bill credits, the Company emphasizes the environmental benefits such as reducing the need for additional power generation plants, reducing emissions, and reducing the need for additional electric delivery infrastructure such as electric distribution and transmission lines. Thus customers are encouraged to participate not only for the bill credits, but also for the ability to contribute to environmental goals and system reliability. During a PJM Interconnection emergency event, when regional electricity demand is close to surpassing regional supply, BGE is obligated to activate its PeakRewards program. Participants in PJM’s capacity
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
47
Table 1: Participation and Peak Reduction as of Mar. 1, 2013. Air Conditioning Enrolled customers
329,926
76,229
Enrolled devices % participation of eligible customers
363,846 37%
77,889 16%
Demand reduction (MWs)
market must be prepared to accurately forecast and commit demand response capacity resources that can be dispatched by PJM. For the duration of an emergency event customers cannot override their participation, exit the program or change the committed cycling level if an air conditioning control participant. PJM needs to be able to determine the amount of Emergency DR resources that it has available to dispatch during an emergency event. GE may operate its PeakRewards program at other times – when wholesale prices are high or for local control of load within BGE’s service territory. During these nonemergency events, air conditioners will be cycled up to the 50 percent level. Participants in the air conditioning and electric water heater demand response programs may override an interruption event up to two times during a calendar year, except that no overrides are permitted during a PJM-declared emergency event. BGE is clearly a national leader in the marketing and implementation of utility direct load control programs. The Company ranks as one of the top three utilities in terms of total
B
48
Water Heater
486
16
participants in direct load control programs as well as residential customer participation rates.4 Table 1 summarizes, as of Mar. 1, 2013, the participation by customers and the peak demand reduction from the air conditioning5 and electric water heater water control programs. D. Operability of direct load control devices PJM’s current protocol for the determination of the operability of direct load control devices is a load research utility-specific study conducted every five years. In accordance with PJM’s Manual 19, Attachment B: Load Research Guidelines, BGE has recently conducted a switch operability study for its residential PeakRewards air conditioner program. Using the standard of 90 percent confidence with 10 percent accuracy (as stated in the guidelines), BGE was required to assess the operability status of at
least 68 points. For research purposes, BGE split the entire population into cycling bins, and drew three sets of randomly selected samples of homes to be visited. The results of that study are shown in Table 2. ased upon this study, BGE will be using a switch operability of 86 percent for its residential PeakRewards air conditioner program over the 2013 PJM-defined Delivery Year, beginning Jun. 1, 2013. The 86 percent operability factor is a weighted average of the three sample results using the overall population of devices.6 Over time the degradation in operability can be due to many factors such as equipment failure or removal/tampering with the control devices. Given 363,846 enrolled devices as of Mar. 1, 2013, and applying an 86 percent operability factor indicates that approximately 50,000 switches/ thermostats are not operating. The challenge is to be able to identify customers with inoperable devices and take appropriate corrective action. Sending out a person to check on each switch and thermostat on BGE’s system in order to locate equipment that is not performing would be prohibitively expensive;
B
Table 2: BGE PeakRewards Air Conditioner Operability Study. Cycling
Device Population
Sample
Percent
as of 12/31/2012
Visited
Failed
Percentage
50%
239,397
70
11
59
84%
75% 100%
44,052 61,084
72 77
5 10
67 67
93% 87%
Overall
344,533
219
26
193
86%
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
Passed
Passed
The Electricity Journal
yet it is also extremely costly to pay credits to customers who are not providing the load reduction expected when control is implemented. However, for the first time BGE is able to identify those devices that are likely to be inoperable using AMI data.
initial results demonstrate that the ability to use AMI data is a powerful tool for the determination of load control device operability.
IV. Identifying Direct Load Control Devices that may not be Operating using AMI Data
The study of air conditioning load control device operability was based on the examination of
‘‘Next to knowing when to seize an opportunity, the most important thing in life is to know when to forego an advantage.’’ – Benjamin Disraeli
A
MI data affords BGE the opportunity to identify load control devices that are likely to be inoperable. AMI meters allow BGE to collect data on whole house loads before, during, and after a load control event. ‘‘Judgment’’ is the applicable approach in determining algorithms for the identification of possible devices that may not be operating. The algorithms can then be revised (with criteria tightened or loosened) based on results from the subsequent field investigations. BGE is currently in the beginning stages of installing AMI meters throughout its service territory. As such, the data reported herein are based on a relatively small number of customers who have both an AMI meter and a load control device. Notwithstanding the need for continual enhancement, these May 2013,
Vol. 26, Issue 4
A. Assessment of air conditioning control operability
For the first time BGE is able to identify those devices that are likely to be inoperable using AMI data. individual customer premise loads during two event days when air conditioner control was invoked in the summer of 2012 – Jul. 17 and Jul. 18. Hourly data was available for 27,000 installed and certified AMI meters. Merging the AMI and the PeakRewards customer lists resulted in 8,319 customers with data available for both event days. The process for evaluating the data and identifying a list of potential non-operational devices is described below. Identify customers that appear to have their air conditioner off by reviewing the variation in whole house usage over the hour before the event,
during the hours of the event and the hour after the event. If the usage appears flat or quite low, then it is assumed that the customer is not cooling their home on that particular event day. (Maximum usage below 1.05 kW, or a coefficient of variation below 0.08). Identify customers that appear to have their air conditioners on where data indicates that there is a load response to the event: * Develop a payback ratio, by comparing the electricity use during the first hour after the event to the last hour of event. If this ratio is above 10 percent, then assume the air conditioner was cycled. * Develop an event ratio, by comparing the minimum usage during the event to the usage that occurred just prior to the event. If this ratio shows a 10 percent reduction or greater, then assume the air conditioner was cycled. Remaining customers are placed in the uncertain category. Table 3 details the findings. 86 percent of the customers have consistent classifications over the two event days (7,1398,319), with 96 percent of these customers suggesting a load drop on both Jul. 17 and Jul. 18 (6,8737,139). 46 homes were characterized as uncertain for both event days and were targeted for a site visit. One home was removed due to some missing data. Table 4 provides a summary of the device type at the homes that were scheduled to be visited. Table 5 indicates a summary of the results from visits for the
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
49
Table 3: Identifying Customers with Inoperable Devices. 17-Jul.
18-Jul. AC OFF
AC Cycled
Total
Jul. 17 Percent
220 83
503 6,873
78 244
801 7,200
10% 87%
Uncertain Total
6 309
266 7,642
46 368
318 8,319
4%
Jul. 18 percent
4%
92%
4%
Table 4: Device Types. Device Type
Count
50% Switch
32
100% Switch 50% T-Stat
5 5
75% T-Stat 100% T-Stat
1 2 45
45 sites identified. Eight control devices were operating; several issues were discovered with respect to signal strength, wiring or programming; difficulties in gaining access to homes to check on thermostats were encountered; and 24 control units (or slightly more than half of the devices) were found to be missing or tampered. B. Assessment of electric water heater control operability The study of electric water heater load control7 device operability was conducted for the event days indicated in Table 6. ome complicating factors impacting the evaluation of load drops: All event days lasted only 1 hour, and without an extended period of load drop, the event
S
50
Uncertain
AC OFF AC cycled
Total
load makes up a much smaller share of whole premise data, especially when the customer heats with electricity. For air conditioner load reductions, a 1 kW to 2 kW load reduction is expected when the average whole premise load is around 4 kW. With a winter water heater event under extreme weather, a 1 kW reduction is expected out of a 5.5 kW load. However, when customers are identified as electric heating and non-electric heating, the prospects of finding inoperable devices improves. iven the very limited duration of the events in Jan. 2013, the focus of the analysis is on only those customers that do not heat their homes with electric devices so as to determine the impact of water heater control. Also, for purposes of this initial analysis, all customers with electric loads greater than 4 kW
payback would be difficult to detect if the water heater was not ‘‘scheduled’’ to be on during the event, or masked by the other variable loads in the house for that hour. The load curtailment occurred for an integrated hour on only one event day, Jan. 23. This is important as the hourly integrated AMI data for the other two events contains the impact of the load control event and payback in the same hour. As compared to air conditioning load, water heater
G
Table 5: Summary of Site Visits. Site Visit Findings
Count
Percent
Operating as expected
7
16%
Operating but extra AC units not controlled Signal strength
1 5
2% 11%
1 20
2% 44%
Missing
4
9%
Thermostat and unable to gain access to home Not wired properly; tech fixed
3 3
7% 7%
Device on wrong unit; tech investigating
1
2%
Not programmed; tech fixed Tampered
Table 6: Event Days. Water Heating Control
Start Time
End Time
Length
Event Temperature
Jan. 22 Jan. 23
100% 100%
6:45 PM 7:00 AM
7:46 PM 8:01 AM
1 hrs 1 min 1 hrs 1 min
198 138
Jan. 25
100%
7:45 AM
8:45 AM
1 hrs 0 min
178
Date
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
The Electricity Journal
were excluded. Under other circumstances, with longer duration events, it would be more likely that load impacts could be observed even in the presence of electric home heating or larger premise loads. he evaluation process is otherwise similar to that used for the air conditioning operability study. Customers were identified for which the water heater was not likely to be operating from the hour before the event through the hour after the event. Customers that appear to have their water heaters operating where data indicates that there is a load response to the event: * Develop a payback ratio, by comparing the electricity use during the first hour after the event to the last hour of event. If this ratio is above 10 percent then assume the water heater was shut off during the event. * Develop an event ratio, by comparing the minimum usage during the event to the usage that occurred just prior to the event. If this ratio shows a 10 percent reduction or greater then assume the water heater was shut off during the event. Remaining customers are placed in the uncertain category. Thirty-two customers were determined to be in the uncertain category for all three events and, as such, scheduled for site visits to determine the control switch operability. As of Apr. 1, 2013, 27 verifications of the switches have been conducted: 3 were deemed working; 22 were deemed missing;
T
May 2013,
Vol. 26, Issue 4
and 2 were deemed tampered. Five customers did not respond to BGE’s request for a site visit.
Conclusion ‘‘Measure not the work until the day’s out and the labor done.’’ – Elizabeth Barrett Browning
The analyses presented in this article represent a first step towards developing a process by which AMI load data can successfully be used to indicate the operability of automatic load control equipment. Operability is important – simply because BGE pays customers through bill credits to deliver reductions in peak loads. These peak load reductions become part of BGE’s obligation to deliver firm capacity in the event of a system emergency, as the load control capability is bid into PJM’s capacity market, known as the Reliability Pricing Model (RPM). In the past, BGE has observed the degradation of load control operability over time. While it is prohibitively expensive to periodically conduct a site visit to the home of every participant in the Company’s PeakRewards program to identify inoperable devices, AMI affords a new opportunity to focus the search. The algorithms for examining equipment performance during an event can be further refined, with parameters adjusted to either tighten or loosen the thresholds used for identifying potential sites to visit.&
Endnotes: 1. The thermostats or switches used to control the air conditioners and water heaters receive a one-way radio signal. If there were two-way communications between the control devices and the Company’s operations center, then BGE would be able to know how each device was performing. In the absence of two-way communications capability, AMI data can be evaluated to indicate the performance of the control devices. A site visit is then required to accurately determine the operability of the control equipment. 2. See http://www.bge.com/ myaccount/billsrates/ratestariffs/ electricservice/pages/default.aspx 3. PJM Interconnection is the regional transmission organization (RTO) that coordinates the movement of electricity in all or parts of 13 states and the District of Columbia. PJM operates a competitive wholesale electricity market and manages the high-voltage electricity grid to ensure reliability. Its long-term regional planning process provides for costefficient improvements to the grid to ensure reliability and economic benefits on a systemwide basis. 4. Jonathan Nelson and Rachel Reiss Buckley, Hot or Not? DLC Program Benchmarking, Results from 2012 E Source Direct Load Control Program Study, Aug. 16, 2012. 5. Generation level MW for 5 PM at 83.2 WTHI. Reported load reduction assumes a 100 percent operability rate for PeakRewards air conditioning program participants. Per PJM requirements, BGE will reflect an operability rate of 86 percent based on a sample analysis of customers. This change, effective Jun. 1, will result in an approximate reduction of the program impact of 68 MW. 6. The study was conducted from late Nov. 2012 to mid-Jan. 2013. PJM reviewed the study and indicated approval on Mar. 6, 2013. 7. 100 percent cycling of a water heater means that electric supply to the water heater is completely shut off for the duration of any event.
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
51
May 2013,
Vol. 26, Issue 4
Advanced Metering Infrastructure and Determination of the Operability of Demand Response Devices In the past, Baltimore Gas and Electric Company has observed the degradation of load control operability over time. While it is prohibitively expensive to periodically conduct a site visit to the home of every participant in the Company’s PeakRewards program to identify inoperable devices, AMI affords a new opportunity to focus the search. Mary M. Straub and Sheldon Switzer
I. Introduction ‘‘An investment in knowledge always pays the best interest.’’ – Benjamin Franklin
On Jul. 13, 2009, the Baltimore Gas and Electric Company (BGE or ‘‘the Company’’) filed an application for Authorization to Deploy a Smart Grid Initiative with the Public Service Commission of Maryland. The
three major components of the initiative are: (1) A two-way communication network (utilityto-meter-to-premise); (2) advance metering infrastructure (AMI) – ‘‘smart’’ meters with ZigBee communications capabilities; and (3) a Smart Energy Rewards Program (a pricing structure to encourage customers to reduce loads under conditions needed for system reliability or for
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
45
economic reasons when wholesale energy prices are high). The Department of Energy awarded BGE $200 million under the American Recovery and Reinvestment Act (ARRA) – Smart Grid Investment Program Funding Opportunity Announcement (DE-FOA0000058). Subsequently, the Commission issued Order No. 83531, Case 9208 on Aug. 13, 2010. In this Order the commission indicated that BGE may proceed with its deployment of its AMI proposal, subject to certain conditions: (1) BGE was authorized to establish a regulatory asset with recovery of costs to occur in a traditional rate case. (2) Cost recovery to occur when benefits start to accrue after BGE has delivered a cost-effective AMI system. (3) No mandatory TOU rates. (4) BGE to submit an updated customer education plan and messaging that it will provide to customers prior to meter installation and before the Smart Energy Rewards Program begins. (5) BGE and other parties are to submit to the Commission for approval a set of metrics to track the progress and performance of the AMI initiative. his article will briefly describe some of the metrics that are being developed, but the primary focus will be a discussion of BGE’s PeakRewards Program (direct load control of customers’ air conditioners and water heaters) and the innovative use of AMI data to indicate the operability of individual customer devices.1
T
46
II. AMI Performance Metrics ‘‘Do not worry about your difficulties in Mathematics. I can assure you mine are still greater.’’ – Albert Einstein
The Maryland Public Service Commission established a working group whereby stakeholders were directed to develop and submit for approval a comprehensive set of metrics to
BGE used AMI data in an innovative way to indicate the operability of individual customer devices. allow the Commission to assess the progress and performance of the Smart Grid Initiative. The members of the working group include, among others, BGE, Potomac Electric Power Company, the staff of the Maryland Public Service Commission, the Office of People’s Counsel, the Maryland Energy Administration and AARP. Phase I metrics are designed to measure progress during the deployment phase; Phase II metrics will track the realization of AMI benefits after deployment. he four overall Phase I objectives to be measured during the deployment phase
T
include: (1) customer education; (2) installation and activation of the advanced metering infrastructure on schedule and within budget; (3) realization of initial operational benefits; and (4) results from forward looking PJM capacity market auctions and calculations of future value. Customer education metrics include such items as the percent of customers who are aware and understand AMI technology and benefits (via survey instruments), tracking of customer outreach through the media, newsletters, customer organizations and newsletters, and the number of communication methods deployed. Other metrics in Phase I include tracking the progress and costs of meter installation, testing for meter accuracy, reductions in meter operations cost and avoided costs for replacement or maintenance relating to the older metering system. Phase II metrics include the realization of benefits once the AMI system is operational. Such benefits include outage management, remote connection and disconnection of service, remote meter reading, presentation of Web-based information to customers and dynamic pricing. These operations yield financial benefits (capital and O&M cost savings) and improved customer service (greater reliability, billing accuracy, better information to respond to customer inquiries, etc.). One additional benefit was not initially recognized and this will be the focus of the remainder of this
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
The Electricity Journal
article: The benefit is derived from the AMI-enabled ability to detect whether specific customer direct load control equipment installed under the Company’s PeakRewards program is operational.
III. PeakRewards: Direct Load Control of Air Conditioning and Electric Water Heating ‘‘Summer afternoon – Summer afternoon. . . the two most beautiful words in the English language.’’ – Henry James
Summer afternoons are indeed quite nice, except when the temperature is approaching the high 908s in Baltimore. Then subject to other considerations, it may be time to activate BGE’s PeakRewards program. BGE’s air conditioning and water heater control programs are designed to reduce peak demand during emergency events on the PJM system or for economic benefits when the wholesale price of electricity is very high. Details of BGE’s program can be found in Rider 15 of BGE’s Electric Retail Service Tariff – Demand Response Service.2 A. Air conditioning control Residential customers may contract with BGE to permit the installation, operation, and maintenance, at the Company’s expense, of radio-controlled equipment on the customer’s central air conditioning or heat May 2013,
Vol. 26, Issue 4
pumps. The control devices are either a smart thermostat or a switch by which the Company can control the operation of the air conditioning to achieve a net reduction in load on the Company’s system. ustomers may choose from three cycling options – 50 percent, 75 percent, or 100 percent; the customer’s cooling unit will operate only 50 percent of the time, 25 percent of the time, or will be
C
Customers are encouraged to participate not only for the bill credits, but also for the ability to contribute to environmental goals and system reliability. shut down, respectively, during PJM3-declared emergency events. If control is used for economic reasons (when wholesale market prices are very high) or for local area emergency events, a cycling strategy up to 50 percent will be used. Corresponding to the cycling strategy chosen by the customer, the Company will provide an annual bill credit of $50, $75, or $100, payable in four monthly installments as bill credits in the months of June, July, August, and September. A onetime annual enrollment incentive equal to the annual customer incentive is also available to encourage customer participation.
B. Water heater control Residential customers may contract with the Company for the installation of a control device such that service to their electric water heaters is subject to interruption at any time. During a control event, the electric service to the water heater is shut down yielding a net reduction in load on the Company’s system. Participating customers receive an annual bill credit of $25, payable in equal installments over four winter months, and there is also a onetime enrollment incentive of $25. C. PeakRewards: a successful program BGE has been very successful in achieving high participation rates for the PeakRewards program. In addition to the bill credits, the Company emphasizes the environmental benefits such as reducing the need for additional power generation plants, reducing emissions, and reducing the need for additional electric delivery infrastructure such as electric distribution and transmission lines. Thus customers are encouraged to participate not only for the bill credits, but also for the ability to contribute to environmental goals and system reliability. During a PJM Interconnection emergency event, when regional electricity demand is close to surpassing regional supply, BGE is obligated to activate its PeakRewards program. Participants in PJM’s capacity
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
47
Table 1: Participation and Peak Reduction as of Mar. 1, 2013. Air Conditioning Enrolled customers
329,926
76,229
Enrolled devices % participation of eligible customers
363,846 37%
77,889 16%
Demand reduction (MWs)
market must be prepared to accurately forecast and commit demand response capacity resources that can be dispatched by PJM. For the duration of an emergency event customers cannot override their participation, exit the program or change the committed cycling level if an air conditioning control participant. PJM needs to be able to determine the amount of Emergency DR resources that it has available to dispatch during an emergency event. GE may operate its PeakRewards program at other times – when wholesale prices are high or for local control of load within BGE’s service territory. During these nonemergency events, air conditioners will be cycled up to the 50 percent level. Participants in the air conditioning and electric water heater demand response programs may override an interruption event up to two times during a calendar year, except that no overrides are permitted during a PJM-declared emergency event. BGE is clearly a national leader in the marketing and implementation of utility direct load control programs. The Company ranks as one of the top three utilities in terms of total
B
48
Water Heater
486
16
participants in direct load control programs as well as residential customer participation rates.4 Table 1 summarizes, as of Mar. 1, 2013, the participation by customers and the peak demand reduction from the air conditioning5 and electric water heater water control programs. D. Operability of direct load control devices PJM’s current protocol for the determination of the operability of direct load control devices is a load research utility-specific study conducted every five years. In accordance with PJM’s Manual 19, Attachment B: Load Research Guidelines, BGE has recently conducted a switch operability study for its residential PeakRewards air conditioner program. Using the standard of 90 percent confidence with 10 percent accuracy (as stated in the guidelines), BGE was required to assess the operability status of at
least 68 points. For research purposes, BGE split the entire population into cycling bins, and drew three sets of randomly selected samples of homes to be visited. The results of that study are shown in Table 2. ased upon this study, BGE will be using a switch operability of 86 percent for its residential PeakRewards air conditioner program over the 2013 PJM-defined Delivery Year, beginning Jun. 1, 2013. The 86 percent operability factor is a weighted average of the three sample results using the overall population of devices.6 Over time the degradation in operability can be due to many factors such as equipment failure or removal/tampering with the control devices. Given 363,846 enrolled devices as of Mar. 1, 2013, and applying an 86 percent operability factor indicates that approximately 50,000 switches/ thermostats are not operating. The challenge is to be able to identify customers with inoperable devices and take appropriate corrective action. Sending out a person to check on each switch and thermostat on BGE’s system in order to locate equipment that is not performing would be prohibitively expensive;
B
Table 2: BGE PeakRewards Air Conditioner Operability Study. Cycling
Device Population
Sample
Percent
as of 12/31/2012
Visited
Failed
Percentage
50%
239,397
70
11
59
84%
75% 100%
44,052 61,084
72 77
5 10
67 67
93% 87%
Overall
344,533
219
26
193
86%
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
Passed
Passed
The Electricity Journal
yet it is also extremely costly to pay credits to customers who are not providing the load reduction expected when control is implemented. However, for the first time BGE is able to identify those devices that are likely to be inoperable using AMI data.
initial results demonstrate that the ability to use AMI data is a powerful tool for the determination of load control device operability.
IV. Identifying Direct Load Control Devices that may not be Operating using AMI Data
The study of air conditioning load control device operability was based on the examination of
‘‘Next to knowing when to seize an opportunity, the most important thing in life is to know when to forego an advantage.’’ – Benjamin Disraeli
A
MI data affords BGE the opportunity to identify load control devices that are likely to be inoperable. AMI meters allow BGE to collect data on whole house loads before, during, and after a load control event. ‘‘Judgment’’ is the applicable approach in determining algorithms for the identification of possible devices that may not be operating. The algorithms can then be revised (with criteria tightened or loosened) based on results from the subsequent field investigations. BGE is currently in the beginning stages of installing AMI meters throughout its service territory. As such, the data reported herein are based on a relatively small number of customers who have both an AMI meter and a load control device. Notwithstanding the need for continual enhancement, these May 2013,
Vol. 26, Issue 4
A. Assessment of air conditioning control operability
For the first time BGE is able to identify those devices that are likely to be inoperable using AMI data. individual customer premise loads during two event days when air conditioner control was invoked in the summer of 2012 – Jul. 17 and Jul. 18. Hourly data was available for 27,000 installed and certified AMI meters. Merging the AMI and the PeakRewards customer lists resulted in 8,319 customers with data available for both event days. The process for evaluating the data and identifying a list of potential non-operational devices is described below. Identify customers that appear to have their air conditioner off by reviewing the variation in whole house usage over the hour before the event,
during the hours of the event and the hour after the event. If the usage appears flat or quite low, then it is assumed that the customer is not cooling their home on that particular event day. (Maximum usage below 1.05 kW, or a coefficient of variation below 0.08). Identify customers that appear to have their air conditioners on where data indicates that there is a load response to the event: * Develop a payback ratio, by comparing the electricity use during the first hour after the event to the last hour of event. If this ratio is above 10 percent, then assume the air conditioner was cycled. * Develop an event ratio, by comparing the minimum usage during the event to the usage that occurred just prior to the event. If this ratio shows a 10 percent reduction or greater, then assume the air conditioner was cycled. Remaining customers are placed in the uncertain category. Table 3 details the findings. 86 percent of the customers have consistent classifications over the two event days (7,1398,319), with 96 percent of these customers suggesting a load drop on both Jul. 17 and Jul. 18 (6,8737,139). 46 homes were characterized as uncertain for both event days and were targeted for a site visit. One home was removed due to some missing data. Table 4 provides a summary of the device type at the homes that were scheduled to be visited. Table 5 indicates a summary of the results from visits for the
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
49
Table 3: Identifying Customers with Inoperable Devices. 17-Jul.
18-Jul. AC OFF
AC Cycled
Total
Jul. 17 Percent
220 83
503 6,873
78 244
801 7,200
10% 87%
Uncertain Total
6 309
266 7,642
46 368
318 8,319
4%
Jul. 18 percent
4%
92%
4%
Table 4: Device Types. Device Type
Count
50% Switch
32
100% Switch 50% T-Stat
5 5
75% T-Stat 100% T-Stat
1 2 45
45 sites identified. Eight control devices were operating; several issues were discovered with respect to signal strength, wiring or programming; difficulties in gaining access to homes to check on thermostats were encountered; and 24 control units (or slightly more than half of the devices) were found to be missing or tampered. B. Assessment of electric water heater control operability The study of electric water heater load control7 device operability was conducted for the event days indicated in Table 6. ome complicating factors impacting the evaluation of load drops: All event days lasted only 1 hour, and without an extended period of load drop, the event
S
50
Uncertain
AC OFF AC cycled
Total
load makes up a much smaller share of whole premise data, especially when the customer heats with electricity. For air conditioner load reductions, a 1 kW to 2 kW load reduction is expected when the average whole premise load is around 4 kW. With a winter water heater event under extreme weather, a 1 kW reduction is expected out of a 5.5 kW load. However, when customers are identified as electric heating and non-electric heating, the prospects of finding inoperable devices improves. iven the very limited duration of the events in Jan. 2013, the focus of the analysis is on only those customers that do not heat their homes with electric devices so as to determine the impact of water heater control. Also, for purposes of this initial analysis, all customers with electric loads greater than 4 kW
payback would be difficult to detect if the water heater was not ‘‘scheduled’’ to be on during the event, or masked by the other variable loads in the house for that hour. The load curtailment occurred for an integrated hour on only one event day, Jan. 23. This is important as the hourly integrated AMI data for the other two events contains the impact of the load control event and payback in the same hour. As compared to air conditioning load, water heater
G
Table 5: Summary of Site Visits. Site Visit Findings
Count
Percent
Operating as expected
7
16%
Operating but extra AC units not controlled Signal strength
1 5
2% 11%
1 20
2% 44%
Missing
4
9%
Thermostat and unable to gain access to home Not wired properly; tech fixed
3 3
7% 7%
Device on wrong unit; tech investigating
1
2%
Not programmed; tech fixed Tampered
Table 6: Event Days. Water Heating Control
Start Time
End Time
Length
Event Temperature
Jan. 22 Jan. 23
100% 100%
6:45 PM 7:00 AM
7:46 PM 8:01 AM
1 hrs 1 min 1 hrs 1 min
198 138
Jan. 25
100%
7:45 AM
8:45 AM
1 hrs 0 min
178
Date
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
The Electricity Journal
were excluded. Under other circumstances, with longer duration events, it would be more likely that load impacts could be observed even in the presence of electric home heating or larger premise loads. he evaluation process is otherwise similar to that used for the air conditioning operability study. Customers were identified for which the water heater was not likely to be operating from the hour before the event through the hour after the event. Customers that appear to have their water heaters operating where data indicates that there is a load response to the event: * Develop a payback ratio, by comparing the electricity use during the first hour after the event to the last hour of event. If this ratio is above 10 percent then assume the water heater was shut off during the event. * Develop an event ratio, by comparing the minimum usage during the event to the usage that occurred just prior to the event. If this ratio shows a 10 percent reduction or greater then assume the water heater was shut off during the event. Remaining customers are placed in the uncertain category. Thirty-two customers were determined to be in the uncertain category for all three events and, as such, scheduled for site visits to determine the control switch operability. As of Apr. 1, 2013, 27 verifications of the switches have been conducted: 3 were deemed working; 22 were deemed missing;
T
May 2013,
Vol. 26, Issue 4
and 2 were deemed tampered. Five customers did not respond to BGE’s request for a site visit.
Conclusion ‘‘Measure not the work until the day’s out and the labor done.’’ – Elizabeth Barrett Browning
The analyses presented in this article represent a first step towards developing a process by which AMI load data can successfully be used to indicate the operability of automatic load control equipment. Operability is important – simply because BGE pays customers through bill credits to deliver reductions in peak loads. These peak load reductions become part of BGE’s obligation to deliver firm capacity in the event of a system emergency, as the load control capability is bid into PJM’s capacity market, known as the Reliability Pricing Model (RPM). In the past, BGE has observed the degradation of load control operability over time. While it is prohibitively expensive to periodically conduct a site visit to the home of every participant in the Company’s PeakRewards program to identify inoperable devices, AMI affords a new opportunity to focus the search. The algorithms for examining equipment performance during an event can be further refined, with parameters adjusted to either tighten or loosen the thresholds used for identifying potential sites to visit.&
Endnotes: 1. The thermostats or switches used to control the air conditioners and water heaters receive a one-way radio signal. If there were two-way communications between the control devices and the Company’s operations center, then BGE would be able to know how each device was performing. In the absence of two-way communications capability, AMI data can be evaluated to indicate the performance of the control devices. A site visit is then required to accurately determine the operability of the control equipment. 2. See http://www.bge.com/ myaccount/billsrates/ratestariffs/ electricservice/pages/default.aspx 3. PJM Interconnection is the regional transmission organization (RTO) that coordinates the movement of electricity in all or parts of 13 states and the District of Columbia. PJM operates a competitive wholesale electricity market and manages the high-voltage electricity grid to ensure reliability. Its long-term regional planning process provides for costefficient improvements to the grid to ensure reliability and economic benefits on a systemwide basis. 4. Jonathan Nelson and Rachel Reiss Buckley, Hot or Not? DLC Program Benchmarking, Results from 2012 E Source Direct Load Control Program Study, Aug. 16, 2012. 5. Generation level MW for 5 PM at 83.2 WTHI. Reported load reduction assumes a 100 percent operability rate for PeakRewards air conditioning program participants. Per PJM requirements, BGE will reflect an operability rate of 86 percent based on a sample analysis of customers. This change, effective Jun. 1, will result in an approximate reduction of the program impact of 68 MW. 6. The study was conducted from late Nov. 2012 to mid-Jan. 2013. PJM reviewed the study and indicated approval on Mar. 6, 2013. 7. 100 percent cycling of a water heater means that electric supply to the water heater is completely shut off for the duration of any event.
1040-6190/$–see front matter # 2013 Elsevier Inc. All rights reserved., http://dx.doi.org/10.1016/j.tej.2013.04.001
51