IEEE PES Dis)nguished Lecture Pacific Northwest Na)onal Laboratory 07 September 2010 Saifur Rahman Virginia Tech Advanced Research Ins)tute A residental customer daily load curve Source: G. Celli at all (University of Cagliari, Italy) Impact of Load Curves in the Distributed Generation Optimal Siting and Sizing sg.cier.org.uy/cdi/cier-zeus.nsf/.../$file/307.pdf
Source: BPA www.bpa.gov 2,500.0 2,500.0 2,000.0 2,000.0 1,500.0 1,000.0 1,500.0 Series1 1,000.0 Series1 500.0 500.0 0.0 1 3 5 7 9 11 13 15 17 19 21 23 0.0 1 3 5 7 9 11 13 15 17 19 21 23 01 Jan 2008 02 Jan 2008 Installed Capacity 4,541 MW 4
According to United States Department of Energy s modern grid initiative, an intelligent or a smart grid integrates advanced sensing technologies, control methods and integrated communications into the current electricity grid. 5 Components of the Smart Grid Source: NIST
Source: NIST Source: NIST
Demand response: A reduction in the consumption of electric energy by customers from their expected consumption in response to an increase in the price of electric energy, or to incentive payments designed to induce lower consumption of electric energy Dispatchable DR: Planned change in consumption agreed to by the customer (e.g. direct control of HVAC) Non-dispatchable DR: Customer decides whether and when to reduce consumption based on retail rate (e.g. dynamic pricing program) FERC definition does not include Voluntary action by the consumer
Demand Response A broader definition Demand Response is a customer action to control load to meet a certain target. Here the customer chooses what load to control and for how long. This is different from DSM where the load is controlled by the electric utility and the customer has no control beyond the initial consent. 12
Some major benefits of DR are: Saving in generation investment, deferring T&D upgrades Energy efficiency Facilitating renewable energy integration Better equipment use (e.g. increase in load factor) DR and Smart Grid: Smart Grid technologies (e.g. smart meter) facilitate DR Potential (FERC): Why demand response? Benefits & potential Existing DR capability: Can reduce 4% of US peak demand (810,000 MW in 2009) DR could shave about 32,000 MW off US peak load in 2010 Based on current industry best practices: 9% US electricity demand can be saved With improved DR: peak shaving could reach 14-20% of the peak The proposed DR scheme Offers customers flexible participation in DR program Is an intelligent program, i.e. at any time the system operator knows with certainty how much load reduction can be achieved (active two-way communication with customers) Lets customers control their end-use appliances according to their need (except under grid emergency situations) Encourages customer participation by enabling automatic in-home power consumption management, along with real-time pricing and power-use information display/alert
4-phase scheme: Phase 1: Determination of amount of demand reduction desired by the grid Phase 2: Allocation of desired demand reduction to substations Phase 3: Each substation distributes requests to its customers to achieve the demandreduction quota Phase 4: Each customer decides whether and how to reduce their consumption & responds through their Home Management System (HMS) The amount of load reduction is determined for the entire network based on a set of criteria: Voltage Frequency Generation cost Transmission constraints Renewable energy contribution Environmental factor, etc.
System operator allocates the amount of load to be shed to substations Criteria for allocation: Substation load factor Network topology and loading condition Distribution power loss Other criteria The process is carried out in the form of request and response Each substation selects feeder(s) where load-reduction is to be performed It then sends messages to the target customers via the smart meter Message content: Load reduction amount and price/ incentive It collects customer responses to determine if the desired load reduction is achievable and reports to the grid operator
Upon receiving the message from grid substation Customer decides whether to accept the substation offer Customer sends a reply to the substation and performs load reduction (if the offer is accepted) Reply content: YES/NO, if yes achievable load reduction amount and duration This is performed automatically using a power management system called Home Management System (HMS) Home Management System: Is an intelligent device that manages power consumption of end-use appliances at the customer property (house, building) Has a two-way communication capability Is equipped with certain sensor and control devices Has an user-friendly interface (a display and input options)
Home Management System 1) Calculates a satisfactory power consumption plan for the house 2) Communicates with the substation during loadcontrol process 3) Controls major household appliances to achieve the agreed level of power consumption amount 4) Controlled appliances: HVAC, PHEV, water heater, clothes dryer (240V loads) HMS operation aims to meet three objectives: To ensure the end user s comfort To achieve a target load saving and ensure effective operation of the controlled appliances To minimize end user discomfort during grid emergency
Source: http://www.geconsumerproducts.com/pressroom/press_releases/company/company/smart_meter_pilot09.htm Possible communication protocols for HMS and controlled appliances are: Wi-fi Based on the IEEE 802.11 standards Most widespread WLAN (wireless local area network) class today Zigbee A suite of high level communication protocols using small, low-power digital devices Based on the IEEE 802.15.4-2003 standard for WHAN (wireless home area network) Examples: wireless light switches with lamps, electrical meters with in-homedisplays, consumer electronics equipment via short-range radio Sources: 1) IEEE Standards Association: http://standards.ieee.org 2) Wi-fi Alliance: http://www.wi-fi.org 3) Zigbee Alliance: http://www.zigbee.org
ZigBee HAN Digital Home Design Line http://www.digitalhomedesignline.com/ 212200388%3Bjsessionid=4NSYMR40EYQKKQSNDLRCKH0CJUNN 2JVN?printableArticle=true ZigBee Network Connections Venture Beat http://venturebeat.com/2009/04/07/ember-lands-8m-for-a-hefty-sliceof-the-smart-grid/ Infrastructure support necessary for the flexible DR scheme include: Controlled appliances to have two-way communication capability If smart appliances: may already have Other appliances: need upgrade Cost issues need to be considered Upgrade cost could be lower with wide-spread use
4-phase scheme: Grid Substation Customer End-use equipment control by HMS Saifur Rahman Professor and Director Virginia Tech Advanced Research Ins)tute srahman@vt.edu