Supply and Demand Graph and Data
Current System Demand is a snapshot of the total system load from the ISO Energy Management System. The figure is updated every 10 minutes. Because it is only a snapshot, figures reflected on this page may not capture actual peak system load.
Today’s Peak Demand reflects the peak load to this point in time of the 10-minute snapshot of the load displayed in the Current System Load. It may not reflect actual Peak Demand for the day.
Today’s Forecast Peak Demand reflects the forecast peak load for the day.
Tomorrow’s Forecast Peak Demand reflects the forecast of peak load contained in the California ISO OASIS web site under the System Load tab. It is adjusted as a new one-day forecast is published.
Supply and Demand graph shows the Current System Demand 10-minute snapshot figures plotted against the forecast demand and available resources. The forecast hourly demand is used to derive the Today’s Peak Demand. Demand is forecast for each hour, the values between the hourly forecasts are interpolated by the graphing routines. Click on the graph to see the data behind the graph and access the Today's Outlook Tutorial for a more detailed explanation of terms.
Automating Access to Today's Outlook data
If you are interested in re-publishing information from this page, access a comma-separated value (CSV) file here.
Renewables Graph
Renewables graph shows the aggregated output from the wind, geothermal, biomass, biogas, small hydro and solar generation connected directly to the California ISO balancing authority. The graph is intended to depict how much renewable energy is produced in the balancing cauthority and the need to track and compensate for the variability in production.
Flex Meter
Presents the current level of conservation requested within the ISO balancing area. As the Alerts, Warnings & Emergency status increases, the need for conservation will rise. The ISO offers a list of Flex Tips to help consumers conserve electricity at home and the office.
Alerts, Warnings and Emergencies
Emergency notices are issued when operating reserves or transmission capacity limitations threaten the ability of the California ISO to safely and reliably operate the grid or energy markets through normal modes of operation. Transmission Emergency notices are issued for events that threaten, harm or limit the capabilities of any element of the transmission grid and threaten reliability.
Restricted Maintenance Operation notices are declared when routine maintenance on transmission lines or power plants could threaten grid reliability.
Alert notices are issued one day before ISO may require extra resources to avoid electrical emergency.
Warning notices are issued hours in advance of when there may be a shortfall. Requests for conservation issued. Voluntary load reduction programs may be triggered at this point.
A Stage 1 Emergency is called when the minimum required Operating Reserve level falls below approximately seven percent. This amount can vary depending on the type of generation that’s running. Under a Stage 1 Emergency, the ISO continues to call for conservation, and will activate a Flex Alert.
A Stage 2 Emergency is called when the minimum Operating Reserve level falls below five percent. Under a Stage 2 Emergency, the ISO can call on “interruptible” programs operated by the utilities. Typically, participants in these programs are commercial and industrial customers who receive a lower electricity rate and in exchange, are required to reduce their energy usage by a predetermined amount when called upon during a Stage 2 Emergency.
One Hour Notification of Probable Load Interruption notices are issued to the utilities, public safety agencies, the media, regulatory agencies and market participants when a Stage 3 Emergency and rotating outages are deemed probable.
A Stage 3 Emergency is called when on-line Reserves fall below the minimum requirements (amount can vary- usually around 3 percent of the minimum Operating Reserve total). Under a stage 3 Emergency, the ISO may call on the utilities to reduce “firm load” by implementing rotating outages. This is a last resort, used only when a climbing demand for energy is close to surpassing the available supply.