Outages - Power Supply

Electricity use can increase rapidly during extreme weather, especially:

• The coldest winter days, when heating systems run continuously
• The hottest summer days, when air conditioners are working hardest
• Extended periods of extreme temperatures lasting several days

During these times, electricity demand across the region can reach very high levels in a short period of time.

The electric system in Southside Virginia is part of the Eastern Interconnection, 1 of the largest interconnected power grids in North America.

Within the Eastern Interconnection, day-to-day regional grid operations are coordinated by PJM Interconnection, which balances electricity supply and demand across 13 states and Washington, D.C., including Virginia.

PJM works to:

• Ensure electricity supply and demand remain balanced
• Maintain grid stability during extreme conditions
• Reduce the risk of widespread, uncontrolled outages

A loss of power supply occurs when available electricity across the region is limited or when demand increases faster than supply can respond.

This may happen when:

• Extreme heat or cold drives unusually high electricity use
• Power generation resources unexpectedly go offline
• Transmission constraints limit the flow of electricity
• Fuel supply issues affect power generation

These events are not caused by damage to local power lines or equipment.

Demand response is a tool used by PJM to reduce strain on the electric grid during periods of extreme demand.

Because electricity supply and demand must stay in balance at all times, demand response is used when electricity use increases quickly, and there is limited additional power available across the regional grid.

During these periods, PJM may direct utilities to:

• Implement rolling outages, which are controlled power interruptions used only when necessary to protect the regional grid
• Temporarily reduce electricity use across the system
• Issue conservation directives for a limited period of time

These actions are temporary and are used to help maintain grid stability and prevent larger, uncontrolled outages during extreme conditions.

Rolling outages are:

• Controlled power interruptions
• Rotated among different areas, so not everyone is affected at once
• Used only when necessary to protect the overall grid

Power is restored automatically once the scheduled outage period ends.

During power supply or demand response events, members may notice:

• Power interruptions without visible storm damage
• Controlled outages during extreme heat or cold
• Conservation directives issued for limited periods of time
• Outages that are regional in nature rather than localized

Not all members will be affected at the same time

Periods of extreme weather place added stress on the electric system, especially when demand increases quickly across the region. At the same time, electricity use continues to grow as communities, businesses, and technology evolve.

Several factors contribute to higher regional demand:

• More frequent extreme heat and cold, which increase heating and cooling use
• Population and economic growth, leading to higher overall electricity needs
• Large electricity users, such as data centers and industrial facilities, that operate around the clock
• Greater reliance on electricity for daily life, work, and essential services

Managing demand during these conditions helps:

• Maintain grid stability
• Protect essential services like hospitals and emergency responders
• Reduce the risk of long-lasting, uncontrolled outages

When conservation directives are issued, members can help by:

• Reducing use of non-essential electrical equipment
• Delaying discretionary electricity use when possible
• Staying informed through official communications

Even small, temporary reductions across many homes and businesses make a meaningful difference.

Key things to remember

• These events are regional, not caused by local damage
• Crews may not be able to restore power immediately because there may be no physical damage to repair
• Rolling outages are used only as a last resort
• Demand response helps protect the grid during extreme conditions