A 300 MW added load in Puget Sound Energy's area, January 2024

Each row changes exactly one assumption and keeps the others as set. Only assumptions this case uses are varied. A row whose added load has a different energy is not a like-for-like comparison, so it shows no change.

• Added loadThe added load draws 300 MW in every hour: 72,000 MWh in the window. Peak equals average; no ramp-up, in service for the whole window.An illustrative constant 300 MW chosen for this example; it stands for no actual proposal, customer or forecast.
  300 MW
• EfficiencyPuget Sound Energy Inc's filed 2024 incremental annual energy savings, 258,144.724 MWh (EIA-861 Schedule 6 Part A line 1, the filer's own total row), are taken as one more year of measures of that size in place in the window and spread evenly over the 8,784 hours of 2024: 29.388 MWh less zone demand in every hour. The filed incremental peak reduction, 43.279 MW at the annual system peak hour, is shown beside it and never used as energy. Measure life does not enter; no share of sales or of demand is formed. Reported Puget Sound Energy Inc, 2024: 258,144.724 MWh incremental annual savings; 43.279 MW incremental peak reduction, shown beside the savings; never used as energy.customer_programme; utility_id_eia=15500; state=WA; ba_code=PSEI; year=2024; programme=energy_efficiency; customer_class=total; metric=incremental_energy_savings_mwh pudl-eia861-energy-efficiency
  hours in year 8,784 h
• Demand shiftingIn each Pacific day, 50% of the added load in the day's 8 hours of highest reported PSEI demand moves evenly into the day's other hours; the day's energy is unchanged. The rule knows each day's demand in advance (perfect foresight), so it is an upper bound on what a schedule could do. Existing customers do not shift. pudl-930-operations
  hours 8 hshare 0.5 fraction
• WindWind shaped as PSEI's reported hourly wind, scaled so its 2023 energy equals the added load's over the same hours: k = 300 MW × 8,760 h ÷ 1,188,772 MWh = 2.2107 MWh of wind per reported MWh. Same place and weather as PSEI's existing wind, with its reported curtailment and outages. The series is energy: no nameplate MW or capacity factor is asserted, and it is not a project, site or interconnection. Reported PSEI wind in 2023: 1,188,772 MWh over 8,760 reported hours.ba_generation_monthly_930; ba_code=PSEI; year=2023; energy_source = wind; sum of net_generation_mwh and hours over the months listed pudl-930-generation
  k 2.2107 MWh/MWh
• Storage300 MW, 1,200 MWh usable (4 hours), round trip 0.82, starting empty. It charges only from the choices' own surplus, never from the grid, and discharges whenever they fall short, hour by hour, with no foresight. Losses are taken on charging. No degradation, auxiliary load or reserve; state of charge stays between 0 and 1,200 MWh. Round trip: EIA's Today in Energy, from 2019 EIA-923 data: the US utility-scale battery fleet's average monthly round-trip efficiency was 82% (pumped storage 79%); the weighted average battery duration was 1.5 hours. U.S. Energy Information Administration, Utility-scale batteries and pumped storage return about 80% of the electricity they store ↗ (2021-02-12, read 2026-09-28)
  duration 4 henergy 1,200 MWhpower 300 MWround trip 0.82 fractionstart 0 MWh
• Everything elseEverything else stays as reported: existing generation, imports and every other customer's demand. No network, price, unit commitment or solver.

1. For each case and hour, in window order, every quantity is MWh in the hour-ending interval. The added load (after shifting, if on) less efficiency and wind (if on) is the net need.
2. Storage (if on): where the need is positive it discharges the least of the need, its power and its stored energy; where it is negative it charges the least of the surplus, its power and its free space divided by the round trip. Never both in one hour; losses are taken on charging.
3. Not met by these choices is the need left after discharge, and beyond the added load the surplus left after charging; at most one is above 0 in an hour.
4. Zone demand left to existing generation and imports is the zone's reported demand plus not met minus beyond.
5. A null input hour makes that hour's outputs null with the reason, and a storage state does not continue past it: later hours are null too. With shifting on, a null load or demand hour leaves its whole local day unranked, so every hour of that day is null. Nothing is zero-filled.
6. Sums run in ascending order over unrounded values; every value is published to 0.001 MWh. Replays are exact.

Not met by these choices

Not met by these choices: energy the added load needed in an hour that the chosen efficiency, wind and storage did not supply, so the existing system would have had to supply it. It is not load shed, an outage or a shortfall, and the calculation cannot say whether the existing system could have supplied it.

Beyond the added load

Beyond the added load: energy the choices supplied in an hour beyond what the added load needed, after storage charged. It reads as lower imports only where it is at most the hour's reported import; an hour where it is more is counted and labelled, never credited as an export.

Zone demand left to existing generation and imports

Zone demand left to existing generation and imports: the zone's reported demand plus not met minus beyond. Because the zone's own reports balance in every hour, its reported demand equals its reported net generation minus interchange.

The zone's reported net generation minus demand minus total interchange is 0 MWh (at 0.001 MWh) in every window hour where all three are reported. Otherwise the scenario is not available, because the demand left would no longer equal reported supply.

• AdequacyOne historical window, not a probabilistic study. Not met by these choices is energy the existing system would have had to supply; the calculation cannot say whether it could have. No statement that the utility, the zone or the Northwest could or could not serve such a load.
• Line headroomNo network, path limit or transfer capability. Reported imports only bound what beyond the added load is credited as; they are not a claim that more imports were available.
• DispatchExisting generation and imports stay as reported. No unit commitment, price or market. The storage schedule is a stated rule, not an optimum, and the shifting rule uses foresight a real schedule lacks.
• EcologyNo hydro, river or fish effects. The episode's river section is context and never an input.
• Cost, emissions and forecastsNo cost, price, bill or emission. Not a forecast, a plan or the utility's position. The added wind is not a project and has no nameplate.

• U.S. EIA Form 930 Hourly and Daily Balancing Authority Operations Report: demand, net generation, total interchange, day-ahead demand forecast per balancing authority and UTC hourreported · direct · balancing authority x UTC hour (hour-ending)episode january-2024-cold-spell authorities[ba_code=PSEI] (ba_hourly_930, EIA-replaced hours left out); ba_monthly_930 ba_code=PSEI for a demand-shaped load
  PUDL v2026.9.0 (embedded 2026.8.1.dev50)retrieved 2026-09-29Publisher ↗
• U.S. EIA Form 930: net generation by energy source per balancing authority and UTC hourreported · direct · balancing authority x energy source x UTC hour (hour-ending)core_eia930__hourly_net_generation_by_energy_source.parquet; generation_energy_source=wind; the window of episode january-2024-cold-spell; and ba_generation_monthly_930 for the reference years
  PUDL v2026.9.0 (embedded 2026.8.1.dev50)retrieved 2026-09-29Publisher ↗
• U.S. EIA Form 861 Schedule 6 Part A, energy efficiency programs: reporting-year incremental and incremental life-cycle savings and costs and the portfolio's weighted average life, by customer sector, as each utility (or its nonutility DSM administrator) files them (utility x state x BA x customer class x year)reported · direct · utility x state x balancing authority x customer class (residential, commercial, industrial, transportation, and the filer's own total) x report yearcustomer_programme; utility_id_eia=15500; state=WA; ba_code=PSEI; year=2024; customer_class=total
  PUDL v2026.9.0 (embedded 2026.8.1.dev50)retrieved 2026-09-29Publisher ↗

Checks in this release: scenarios.balance_holds passed · scenarios.generation_scale_reproduces passed · scenarios.outputs_labelled passed · scenarios.report passed. Every value on this page: scenarios/psei-january-2024-added-load.json (JSON).