Electricity customers depend on a complicated system of generating resources and power lines to produce and deliver electricity. A constant balance of supply and demand is needed to maintain the flow of electricity. Extreme hot or extreme cold temperatures can lead to unusually high customer demand. When this balance is at risk for any reason—such as more customer demand than available supply—steps must be taken to avoid a more serious emergency.
Supply and demand on electric grids must be balanced constantly, and in Michigan that task falls to grid operators. When there is unanticipated high customer demand on the grid or an unexpected loss of electric output from a power plant or other significant generation source, Michigan’s grid operators work through several emergency action steps to increase electric generation output or reduce demand to balance the grid before asking the public to conserve energy.
You may be asked to conserve electricity.
When customers are asked to conserve electricity, it is to avoid or limit the need for rolling blackouts or controlled power outages. Conserving electricity when asked will allow more customers to avoid periodic or possibly even lengthy electricity outages.
When asked to conserve energy, anything you can do to reduce your electricity use will help—but you should never take actions that risk your health or safety. The best ways to conserve energy for extended periods are to adjust your thermostat to reduce heating or cooling, turn off all unnecessary lights and electronics, limit the use of electric appliances such as ovens, stovetops, dishwashers, clothes washers and dryers, and consider delaying charging your electric vehicle.
Grid Operators may begin rolling blackouts.
In worst-case scenarios, grid operators may have to begin rolling blackouts — also known as controlled power outages — to prevent the power grid from collapsing. Rolling blackouts are rare and have not happened in Michigan before. A large-scale power grid collapse could lead to widespread lengthy power outages while repairs are made and the power grid is restored.
Controlled power outages, commonly known as rolling blackouts, are intentional disconnections of customers, often for defined periods of time such as two hours, meant to lower stress on the power grid when demand exceeds supply.
Michigan is most at risk during the hottest days of the summer and the coldest days of the winter, when home heating or cooling places the most demand on the grid. But rolling blackouts or controlled outages could happen anytime if the electricity demand exceeds supply. Rolling blackouts are rare and have not happened in Michigan before.
No. Michigan utilities prepare for and regularly run drills to prevent situations that could lead to rolling blackouts. Controlled outages generally happen when there are unplanned significant power plant or transmission failures and simultaneous high customer demand usually resulting from extreme hot or cold temperatures.
If Michigan’s regional grid operators exhaust all other options to prevent the need for controlled outages, they may direct utilities to reduce demand on the power system. This could apply to parts of Michigan, the entire state, or, if part of a wider grid problem, affect the entire region. Grid operators will notify utilities how much demand needs to be reduced and the affected utilities take action to reduce demand by implementing rolling blackouts or controlled power outages. Each utility, such as DTE Electric or Consumers Energy, handles this task in accordance with their own policies and procedures. They hold regular exercises to practice what to do during these types of emergencies.
The Midcontinent Independent System Operater (MISO) is the regional grid operator for most of the Lower Peninsula and all of the Upper Peninsula of Michigan. The PJM Interconnection is the regional power grid operator for a small portion of southwest Michigan. The regional power grid operators’ job is to keep the power grid up and running.
Rotated outages may take place to keep as many people connected as possible. The utilities will try to make sure there is service to parts of the grid that serve critical care facilities such as hospitals. In the most extreme of emergencies, even hospitals and other critical facilities may be impacted.
If your power is still on, reduce your electric use by turning off lights and not using household appliances or charging electric vehicles. Placing phones on battery saver mode will help extend the amount of time before charging is necessary. Conserving energy can help reduce the need for and length of rolling blackouts. If your power goes out during a rolling blackout, unplug appliances and electronics and turn off light switches. These steps can help prevent a power surge, which can damage electronics and appliances, once the power comes back on.
Without controlled outages during emergencies, the grid could fail and cause widespread outage, leading to damage that could take days or weeks to repair.
Before asking customers to conserve energy or calling for rolling blackouts, the grid operator takes several steps to balance the electricity system. Lean more about these steps in the table below.
| Status | What This Means | Grid Operator Actions | What the Public Should Do |
| Conservative Operations | Grid operator indicates there could be a reliability issue for a certain area. | Grid operator directs utilities to ensure all transmission resources be made available by cancelling maintenance and bringing all lines back to full operation. | Nothing. |
| Hot/Cold/Severe Weather Alert | Forecasted weather could lead to increases in customer usage resulting in tight energy supplies. | Grid operator directs utilities to review outage plans and attempt to defer or cancel planned outages to ensure maximum resources are available. | Nothing. Consider charging all electronic devices and electric vehicles prior to the arrival of the extreme weather. If a severe storm is coming, consider plans for dealing with an electricity outage. |
| Capacity Advisory | A shortage of resources to meet the electrical needs of customers is forecasted in the next 2-3 days. | Grid operator directs utilities to update all data on load forecast and available resources in the system. | Nothing. Consider plans to deal with an electricity outage. |
| Maximum Generation Alert | A shortage of resources to meet the electrical needs of customers is forecasted in the next day or two. | If Conservative Operations has not already been declared, grid operator calls for Conservative Operations. Grid operator prepares for a possible emergency event and implements Emergency Pricing to attempt to bring emergency resources online. | Nothing. Consider plans to deal with an electricity outage. |
| Maximum Generation Warning | Prepare for a possible emergency on the electric grid in the very near term due to a lack of supply to meet customer needs. | The grid operator limits exports to neighboring regions and attempts to obtain all available imports from neighbors into our area. Emergency Pricing is increased to attempt to bring emergency resources online. The increased pricing could initiate the activation of economic demand response resources. | Nothing. Consider plans to deal with an electricity outage. |
| Maximum Generation Event Step 1 | Normal procedures to bring economic resources online have not been successful. Grid operator begins emergency actions to avoid a shortage. | The grid operator brings all emergency resources online (Step 1a) and activates emergency operating ranges for all generation units (Step 1b). | Nothing. Consider plans to deal with an electricity outage. |
| Maximum Generation Event Step 2 | The likelihood of a shortage increases because a shortage of resources is still projected after all emergency supply resources have been deployed. | The grid operator activates load modifying resources and increases emergency pricing (Step 2a). If a shortage is still projected, Emergency Demand Response is activated (Step 2b). If a shortage is still projected, the grid operator issues a public appeal requesting the public to reduce electricity usage to avoid rolling blackouts. | Consider plans to deal with an electricity outage. Place phones on battery saver mode. Reduce the use of electric appliances, devices and lights that are not needed for health and safety. |
| Maximum Generation Event Step 3 | Shortage conditions being experienced. The operating reserves have been used and operator attempts to keep minimum contingency reserves to avoid a widespread blackout. | Grid operator utilizes operating reserves to meet customer demand. Environmental waivers are sought (Step 3a). Demand reductions may take place from additional load management actions. (Step 3b). | The public is encouraged to reduce the use of non-essential electric appliances, devices, and lights. |
| Maximum Generation Event Step 4 | All available emergency resources in MISO are in use, the public appeal is in effect, and shortage conditions continue. Emergency actions take place to avoid a potential cascading widespread blackout. | The grid operator seeks and purchases emergency resources from external regions. | The public is encouraged to reduce the use of non-essential electric appliances, devices, and lights. Consider plans for dealing with an electricity outage. |
| Maximum Generation Event Step 5 | All avenues to avoid rolling blackouts have been put into place and shortage conditions still exist. Rolling blackouts are initiated. | The grid operator directs the amount and location of involuntary load reductions (rolling blackouts) to avoid a potential widespread cascading blackout. | The public is encouraged to reduce the use of non-essential electric appliances, devices, and lights. Consider plans for dealing with an electricity outage. |
| Maximum Generation Event Termination | System has returned to normal conditions. | Grid operator returns to normal operating conditions and standard pricing. | Nothing |
