California Daily Peak Electricity Demand (MW)

## What this measures

The highest hourly electricity demand of each day, in megawatts, for the California region: CAISO plus the Los Angeles, Sacramento-area, Imperial and Turlock utilities. Demand is the electricity used within the area in an hour, as its grid operators report it to EIA. Days run midnight to midnight in the area's standard time.

## Why it matters

Peak demand is what grids are built for. Data centers, factories coming back onshore and electrified heating and transport are pushing peaks up after two decades of flat demand, and every new record tightens reserve margins and raises the value of new generation, storage and transmission.

## How to read it

Higher means more power drawn at the busiest hour of the day. Peaks are seasonal: summer afternoons (air conditioning) and winter mornings (heating) set the records, spring and fall are low. Compare a day with the same season in earlier years, or read the monthly demand and its 12-month change (power.demand.monthly_gwh.cal, power.demand.yoy_12m_pct.cal) for the trend.

## What it does not say

It is demand served by the grid, not consumption behind the meter (rooftop solar lowers it). Weather drives most day-to-day moves. EIA-930 is operating data and some hours are revised later. Hourly values are averages over the hour, so they sit a little below the instantaneous peaks grid operators announce.

## How it's built

Palanor sums the hourly demand of each balancing authority in the area from EIA's bulk files, using EIA's adjusted demand where it has filled it. A balancing authority's hours outside half to one and a half times the median of the surrounding day are treated as reporting errors and dropped; short gaps are filled from its neighbouring hours. The day's peak is the largest hourly total, kept only for days with at least 20 known hours. History from 2016.

## Source

U.S. Energy Information Administration, Hourly Electric Grid Monitor (Form EIA-930), six-month bulk files (eia.gov/electricity/gridmonitor). EIA data are U.S. government works in the public domain; EIA asks that it be credited as the source. Refreshed daily by /api/cron/eia-grid-demand-sync.