Demand Response and Grid-Interactive Building Controls

Overview

Demand Response (DR) programs allow building operators to reduce electrical consumption during peak grid periods in exchange for financial incentives. Grid-Interactive Efficient Buildings (GEBs) take this further by dynamically adjusting loads to support grid stability. This guide covers DR program types, implementation in BAS, OpenADR protocol, and measurement and verification.

What is Demand Response?

Demand response is a voluntary reduction in electricity consumption during peak demand periods, typically triggered by utility signals. Buildings receive advance notice (minutes to hours) and reduce load through HVAC setpoint adjustments, lighting reductions, and equipment staging changes.

DR Program Types

Program Type	Trigger	Response Time	Duration	Typical Incentive
Peak Shaving	Utility signal at system peak	1-4 hours notice	2-6 hours	$50-200/kW/year
Load Shifting	Time-of-use pricing	Scheduled	Daily	Rate arbitrage
Frequency Regulation	Grid frequency deviation	Seconds	Minutes	$15-40/MW/hour
Emergency DR	Grid emergency	30 min notice	2-4 hours	$500-1000/MW/event

OpenADR Protocol

OpenADR (Open Automated Demand Response) is the standard protocol for communicating DR signals between utilities and buildings.

Architecture

VTN (Virtual Top Node): Utility-side server that issues DR events. VEN (Virtual End Node): Building-side client that receives events and reports compliance.

OpenADR Event Structure

<!-- Example DR Event Signal -->
<oadrEvent>
  <eventID>DR-2026-0215-001</eventID>
  <signalType>SIMPLE</signalType>
  <signalPayload>
    <level>MODERATE</level>  <!-- NORMAL, MODERATE, HIGH, SPECIAL -->
  </signalPayload>
  <activePeriod>
    <start>2026-02-15T14:00:00Z</start>
    <duration>PT4H</duration>  <!-- 4 hours -->
  </activePeriod>
</oadrEvent>

Implementing DR in BAS

Pre-Cooling Strategy

The most effective DR strategy for commercial buildings. Cool the building below normal setpoint before the DR event, then allow temperature to drift up during the event.

Sequence:

Phase 1: Pre-Cool (2 hours before event)
  - Lower cooling setpoint by 2-4F
  - Run chillers at maximum capacity
  - Charge thermal mass

Phase 2: DR Event Active
  - Raise cooling setpoint by 4-6F from normal
  - Reduce fan speeds to 70%
  - Shed non-critical lighting 30%
  - Disable reheat coils

Phase 3: Recovery (after event)
  - Gradually return to normal setpoints over 30-60 min
  - Stagger equipment restart to avoid demand spike
  - Resume normal scheduling

Load Shedding Priorities

Priority	Equipment	Typical Reduction	Comfort Impact
1 (First)	Non-critical lighting	30-50%	Low
2	HVAC setpoint adjustment	20-30% of HVAC load	Moderate
3	Fan speed reduction	10-15%	Low-Moderate
4	Chiller staging	15-25%	Moderate
5 (Last)	Elevator operations	5-10%	High

BAS Programming Example (Niagara)

// DR Event Handler
IF DR_Signal = MODERATE THEN
  Cooling_SP_Offset = +4.0F
  Lighting_Shed = 30%
  Fan_Speed_Max = 70%
  Reheat_Enable = FALSE
  
ELIF DR_Signal = HIGH THEN
  Cooling_SP_Offset = +6.0F
  Lighting_Shed = 50%
  Fan_Speed_Max = 60%
  Reheat_Enable = FALSE
  Chiller_Stage_Limit = N-1

ELIF DR_Signal = NORMAL THEN
  // Recovery mode
  Cooling_SP_Offset = 0.0F
  Lighting_Shed = 0%
  Fan_Speed_Max = 100%
  Reheat_Enable = TRUE
ENDIF

Measurement and Verification

Baseline Calculation

DR performance is measured against a baseline (what consumption would have been without the DR event).

IPMVP Approach:

Baseline_kW = Average of 10 similar non-event days
Adjustment = Weather normalization (outdoor temp correlation)
DR_Reduction = Baseline_kW - Actual_kW during event
Savings($) = DR_Reduction(kW) x Event_Duration(hrs) x Incentive_Rate($/kWh)

Trending Requirements

Point	Interval	Purpose
Building total kW	1 min	Verify load reduction
Chiller kW	1 min	HVAC component
Lighting kW	5 min	Lighting component
Zone temperatures	5 min	Comfort monitoring
Outdoor temperature	5 min	Weather normalization

Grid-Interactive Efficient Buildings (GEB)

GEB extends DR to continuous grid interaction through thermal energy storage (ice/chilled water), battery energy storage systems, electric vehicle charging management, and solar PV with smart inverters.

GEB Architecture

Occupant Communication

Before DR Event:

• Email notification 24 hours ahead
• Digital signage in lobbies
• Building app push notification

During Event:

• Display current DR status on dashboards
• Show estimated end time
• Provide comfort override option (limited)

After Event:

• Share results (kW reduced, incentive earned)
• Thank occupants for participation

Common Pitfalls

• Baseline Errors: Using wrong comparison days inflates or deflates savings
• Rebound Effect: Post-event demand spike from simultaneous equipment restart; stagger recovery
• Comfort Complaints: Always communicate with occupants before events
• Weather Sensitivity: Hot days have highest DR value but also highest comfort risk
• Equipment Limits: Do not shed critical systems (data centers, labs, operating rooms)

Annual Savings Estimate

200,000 sqft Office Building:

• Peak shaving: 15-20 events/year x 200 kW reduction x 4 hrs = 12,000-16,000 kWh
• Incentive: 200 kW x $100/kW/year = $20,000/year
• Energy savings: $1,500-2,000/year from shifted consumption
• Total: $21,500-22,000/year with minimal equipment cost