Understanding Demand Response

What Is Demand Response?

Demand response is a set of programs and mechanisms through which electricity consumers voluntarily modify their consumption at the request of a grid operator, utility, or demand aggregator. In exchange for agreeing to curtail load when called upon, participants receive financial compensation — either as a direct capacity payment, an energy market revenue share, or a bill credit.

From the grid operator's perspective, demand response is an alternative to building more peaking generation capacity. Instead of investing billions in power plants that run only a few hundred hours per year during peak conditions, the grid operator pays consumers to reduce load temporarily. The net cost to the grid is far lower, and the environmental benefit — avoiding operation of inefficient peaking plants — is significant.

Demand response programs have existed in various forms for decades. The market has grown substantially as grid operators have formalized DR participation through wholesale capacity and energy markets — allowing aggregated consumer loads to compete directly with generating resources for the same market revenues.

Types of Demand Response Programs

Demand response programs span a range of types, differentiated by what triggers curtailment, how fast the response must be, and what compensation is available:

• 1
  Emergency Demand Response

  Activated during grid emergencies — when reserves fall below a minimum threshold and reliability is at risk. Emergency DR programs typically offer higher compensation but require fast response times (30 minutes or less) and reliable curtailment delivery. Penalties for non-performance can be significant.

• 2
  Economic Demand Response

  Activated when wholesale electricity prices rise above a threshold — not because of a grid emergency, but because reducing load is economically optimal for both the participant and the market. Economic DR events are more frequent but typically offer lower per-event compensation than emergency programs.

• 3
  Capacity Market DR

  Participants commit curtailment capacity to the forward capacity market in exchange for an annual capacity payment. They must be available to curtail when called upon during defined peak periods. Capacity market DR is common in ISO markets such as PJM and ISO-NE.

• 4
  Ancillary Services DR

  Providing fast-responding load reduction as a grid stability service — frequency regulation, spinning reserves, or non-spinning reserves. These programs require the fastest response times (seconds to minutes) and are most accessible to loads with automated control systems.

Problems with Traditional Demand Response

Traditional demand response programs rely on manual processes — a facility manager receiving a notification, manually adjusting thermostats or overriding the BAS, and then restoring normal operations after the event. This approach is plagued by several structural problems:

• Missed curtailments:

  Manual processes fail. Facility managers are not always at their desks when event notifications arrive. Staff turnover, competing priorities, and simple human error result in a meaningful percentage of DR events going unexecuted. In programs with non-performance penalties, missed curtailments can turn the DR program from a revenue source into a net cost.

• Insufficient curtailment:

  Manual setpoint adjustments are imprecise. The curtailment amount delivered may be substantially less than the committed amount — creating partial non-performance and reducing net revenue.

• Post-event demand spikes (the rebound problem):

  During a DR event, building temperatures rise as HVAC is curtailed. The moment the event ends and normal setpoints are restored, every thermostat simultaneously calls for cooling — creating a demand spike (the "post-event peak" or "rebound") that can be larger than the building's normal peak demand. This post-event spike creates a new, higher demand charge that can eliminate or exceed the DR incentive payment.

• Occupant comfort complaints:

  Crude temperature setpoint increases during DR events often cause occupant discomfort. Retail customers may leave early. Office workers complain. The operational and reputational costs of temperature excursions are difficult to quantify but can be substantial.

The Math Problem: Traditional DR and Net Revenue Losses

The post-event peak problem creates a fundamental financial math issue that makes traditional demand response economically questionable for many commercial buildings.

Consider a typical DR scenario. A commercial building commits to curtailing 100 kW during a 4-hour DR event on a hot summer afternoon. The DR incentive payment might be $500–$800 for the event. During the event, HVAC is partially curtailed and building temperatures rise 3–5 degrees.

When the event ends at 7:00 PM, all thermostats simultaneously call for maximum cooling. The building's HVAC demand spikes to 150–200% of its normal level — well above the peak demand recorded earlier that month. That new post-event peak becomes the demand charge basis for the month. At a demand rate of $15/kW, a 150 kW post-event peak above the previous monthly maximum adds $2,250 to the demand charge — more than three times the DR incentive payment.

Why Small Sites Are Excluded from Traditional Programs

Traditional demand response programs were designed for large industrial and commercial loads — sites that can individually commit hundreds or thousands of kilowatts of curtailment capacity. Most utility and ISO-managed DR programs have minimum participation thresholds of 100–500 kW, effectively excluding the vast majority of commercial buildings.

A typical quick-serve restaurant, bank branch, or mid-size retail store might have total electrical demand of 30–80 kW. These sites simply cannot meet the minimum enrollment requirements for most traditional DR programs — even though, when aggregated across hundreds of locations, they represent enormous controllable demand.

This exclusion means that the owners and operators of large commercial portfolios — national retail chains, banking networks, restaurant franchisors — have historically been unable to participate in demand response programs despite having more aggregate controllable load than many industrial facilities. Aggregation-based DR platforms solve this problem by combining many small sites into a single program participant.

The Automated DR Solution

Automated demand response addresses each of the structural problems that make traditional manual DR economically problematic:

• Guaranteed curtailment delivery:

  Automated systems execute curtailment the moment a DR signal is received — without human intervention, consistently, every time. Curtailment amounts are precisely controlled to match committed capacity, eliminating partial non-performance.

• Predictive modeling precooling:

  Intelligent precooling pre-cools the building before a DR event begins, reducing the temperature differential that must be managed during curtailment. Building temperatures stay within acceptable ranges throughout the event, eliminating comfort complaints and reducing the post-event rebound.

• Managed post-event recovery:

  Automated systems manage the transition back to normal operation after the event ends, staggering equipment restarts using the same queuing technology as IDO to prevent the post-event peak. The demand spike that eliminates traditional DR revenue is eliminated.

• Aggregation enables small site participation:

  By aggregating sites as small as 10 kW into a coordinated DR resource, automated platforms allow small commercial sites to participate in programs that previously required 100+ kW minimum commitments. Franchise operators, restaurant chains, and banking networks gain access to DR revenue streams that were previously unavailable.