Demand response is a system where electricity customers reduce or shift their power usage during periods of high demand, high prices, or grid stress. Instead of firing up additional power plants to meet a spike in electricity use, grid operators call on homes, businesses, and factories to temporarily cut back. It’s one of the most cost-effective tools for keeping the lights on during extreme conditions, and it played a visible role during California’s September 2022 heat wave, when an emergency text alert to residents produced a 2,000 MW drop in energy demand within 20 to 30 minutes.
How Demand Response Works
The basic idea is straightforward: peak electricity demand lasts only a small fraction of the year (roughly 5% or less of total hours), but meeting those peaks requires expensive, often carbon-intensive backup power plants. Demand response flips the equation. Rather than building more supply for those brief spikes, it trims the demand side instead. Customers who participate agree to use less electricity when the grid needs relief, and they’re compensated for doing so through bill credits, direct payments, or lower rates during off-peak hours.
Grid operators, like ISO New England or California’s CAISO, monitor supply and demand in real time. When wholesale electricity prices surge or reliability is at risk, they trigger a demand response event. Participating customers then reduce consumption, either manually or through automated systems that adjust equipment on their behalf.
Two Main Types of Programs
Demand response programs fall into two broad categories: price-based and incentive-based.
Price-based programs pass wholesale electricity price swings directly to customers. If power costs three times more at 4 p.m. than at midnight, you see that difference on your bill. Common structures include time-of-use pricing (set rate tiers for different parts of the day), critical peak pricing (much higher rates during grid emergencies), and real-time pricing (rates that change hour by hour based on the wholesale market). The logic is simple: when you pay more for peak-hour electricity, you naturally shift flexible tasks like laundry, dishwashing, or EV charging to cheaper hours.
Incentive-based programs pay you on top of your normal electricity rate for agreeing to reduce load when called upon. These include direct load control, where the utility can remotely cycle your air conditioner or water heater for short periods, and interruptible service contracts, where large commercial customers accept occasional shutdowns in exchange for lower rates year-round. Other versions let businesses bid their available load reductions into wholesale energy markets, earning revenue the same way a power plant would.
What It Looks Like for Homeowners
For most residential customers, participation starts with a smart thermostat or a similar connected device. ENERGY STAR smart thermostats are designed to work with utility demand response programs, learning your preferences and automatically adjusting temperature settings based on occupancy and conditions. During a demand response event, the utility sends a signal to your thermostat, which nudges the temperature up a few degrees for a limited window. You can typically override it if you need to.
The load reductions from individual homes are modest but meaningful in aggregate. Direct load control programs targeting residential air conditioning have reported reductions of about 0.4 to 1.5 kilowatts per customer during an event. Water heater programs typically reduce 0.3 to 0.6 kW per household. In one Florida program, customers who allowed control of multiple loads (air conditioning, water heating, pool pumps) saw average peak reductions of 40% during critical periods. A study of 220 homes with smart thermostats found an average reduction of 0.64 kW per household during critical peak days, a 27% cut in peak usage, with about two-thirds of the savings attributed to the thermostat itself.
Compensation varies by utility and program. Some offer a flat annual bill credit for enrollment, others pay per event, and “pay-for-performance” designs reward you based on how much you actually reduce when called upon. The financial benefits combine direct incentive payments with bill savings from using less electricity during the most expensive hours.
How Industries Participate
Industrial demand response operates at a much larger scale and often involves more creative strategies. Agropur, a dairy processor, responds to demand response events by setting back cooler and freezer temperatures, reducing lighting, turning off forklift charging stations, and temporarily shutting down its wastewater treatment plant. During natural gas demand events in Minnesota winters, the company switches its entire fuel load from natural gas to propane.
Steel manufacturer Cleveland-Cliffs takes a two-pronged approach. First, the shop floor gets a call from management and shuts down or reduces non-critical equipment. Second, the facility ramps up its own generation. The steelmaking process produces blast furnace gas, which normally feeds an internal steam system. During a demand response event, they push blast furnace gas production higher to generate more of their own electricity, pulling less from the grid.
Across industries, common tactics include adjusting HVAC setpoints, dimming lights, slowing or stopping non-critical pumping processes, and pausing battery-charging equipment. Many facilities use sensors that detect high-peak conditions automatically and trigger load reductions through building control systems without waiting for a phone call.
Grid Reliability and Environmental Benefits
Demand response directly improves grid reliability by reducing the chance of blackouts during extreme conditions. The California 2022 heat wave is the clearest recent example. On top of existing demand response and conservation programs, CAISO issued an unprecedented emergency text alert to millions of residents. The 2,000 MW drop that followed was enough to help the state avoid rolling blackouts during one of its most severe grid emergencies.
The environmental payoff comes from displacing the dirtiest power plants. Grid operators typically meet peak demand by running “peaker” plants, which are fast-starting but often gas-fired and less efficient than baseload generators. Every megawatt reduced through demand response is a megawatt that doesn’t need to come from those high-emission sources. A systematic review of the research literature found that demand response programs achieved emission reductions averaging 17.8%, with a wide range from 0.1% to 93.9% depending on the local energy mix and the amount of flexible demand available. The biggest reductions happen in grids where peak power is especially carbon-intensive and where customers have enough flexibility to shift usage to cleaner hours.
The Regulatory Landscape
Federal policy has been moving to expand who can participate in demand response. FERC Order No. 2222 is the most significant recent change. It requires regional grid operators to allow distributed energy resources, including home batteries, rooftop solar, and smart appliances, to aggregate together and participate directly in wholesale electricity markets. Previously, small resources were often locked out because they couldn’t meet minimum size thresholds on their own. Under Order 2222, aggregations can be as small as 100 kilowatts, meaning a group of homes with smart thermostats and batteries can collectively bid into the same markets as a power plant.
The order also establishes coordination requirements between grid operators, aggregators, local utilities, and state regulators. The intent is to prevent these coordination rules from becoming barriers that keep small participants out while still respecting the role of distribution utilities in maintaining local grid safety. State regulatory authorities are separately encouraging utilities to adopt pay-for-performance incentive designs, which reward customers based on actual measured reductions rather than simply enrolling in a program.