, latest observed month
EIA STEO OPEC surplus capacity
OPEC Spare Capacity Chart
The oil market’s emergency production buffer: OPEC surplus crude capacity, with Saudi Arabia isolated as the group’s most important swing producer. Monthly EIA STEO data in million barrels per day.
SPARE Jun 2026
0.00 million b/dDISRUPTIONS Jun 2026
12.42 million b/d Fragile supply resilience · observed data only.million b/d of unplanned crude outages
million b/d of unplanned liquid-fuels outages
Low spare capacity / high disruptions
World supply 99.41
World demand 102.05
Implied draw 2.63
Uncovered shortfall 2.63 million b/d
EIA forecast · not observed
Spare-capacity scenario, kept separate
Short-Term Energy Outlook, released Sep 9, 2026
Forecast only. It is excluded from every chart and from the observed supply-resilience signal.
View EIA forecast values and limitations
OPEC surplus crude capacity; Saudi Arabia 0.00 million b/d.
OPEC surplus crude capacity; Saudi Arabia country detail is not published for this month.
The latest measured OPEC buffer, for comparison.
These are EIA projections, not available barrels guaranteed to enter the market. Capacity estimates can change with outages, sanctions, maintenance, investment, and EIA's assessment of what can be reached within 90 days and sustained. The chart below plots observed months only; projected months remain in this labelled outlook so they cannot be mistaken for measured capacity.
Observed capacity only
OPEC spare capacity and the Saudi-controlled share
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Source: U.S. Energy Information Administration (Sep 2026). Published Sep 9, 2026.
How this series is sourced
View recent monthly values
| Month | OPEC spare | Saudi spare | Saudi share | OPEC outages | Non-OPEC outages |
|---|---|---|---|---|---|
| June 2026 | 0.00 | 0.00 | — | 9.21 | 3.21 |
| May 2026 | 0.04 | 0.00 | 0.0% | 11.73 | 4.46 |
| April 2026 | 0.00 | 0.00 | — | 11.15 | 4.53 |
| March 2026 | 0.00 | 0.00 | — | 8.98 | 4.50 |
| February 2026 | 2.20 | 1.10 | 50.1% | 0.94 | 1.19 |
| January 2026 | 2.92 | 1.75 | 60.0% | 1.03 | 1.93 |
| December 2025 | 2.97 | 1.80 | 60.7% | 0.89 | 1.02 |
| November 2025 | 3.05 | 1.90 | 62.4% | 0.93 | 0.75 |
| October 2025 | 2.94 | 1.85 | 63.0% | 0.87 | 0.76 |
| September 2025 | 2.52 | 1.60 | 63.5% | 0.92 | 0.89 |
| August 2025 | 3.50 | 2.50 | 71.5% | 1.02 | 1.05 |
| July 2025 | 3.41 | 2.40 | 70.3% | 1.05 | 1.19 |
| Month | OPEC | Saudi Arabia |
|---|---|---|
| July 2026 | 0.00 | 0.00 |
| August 2026 | 0.00 | 0.00 |
| September 2026 | 0.00 | — |
| October 2026 | 0.00 | — |
| November 2026 | 0.00 | — |
| December 2026 | 0.00 | — |
| January 2027 | 0.00 | — |
| February 2027 | 0.00 | — |
| March 2027 | 0.00 | — |
| April 2027 | 2.35 | — |
| May 2027 | 2.35 | — |
| June 2027 | 2.35 | — |
About this series
The barrels that can answer a disruption.
Capacity minus production
Spare capacity is supply that is not producing today but can be brought online quickly and sustained. EIA defines effective capacity as output reachable within 90 days and sustainable; surplus capacity is that effective capacity minus actual production. It is therefore a flow buffer, not oil already sitting in storage.
Saudi concentration is the second signal
Saudi Arabia matters because spare capacity is concentrated. A large OPEC total is less reassuring when only one producer controls most of it, and Saudi policy can determine whether that buffer remains available or enters the market. The Saudi line and share make that concentration visible rather than burying it inside the aggregate.
Observed resilience, not a forecast model
The resilience state combines two observed ranks since 2019: OPEC spare capacity and reported unplanned disruptions. It is descriptive, not predictive. The chart switches between the capacity buffer and disruption history, while forecast months stay above the chart and never enter the signal.
See spare capacity beside global oil supply How this series is sourced
- Source
- EIA Short-Term Energy Outlook
- OPEC series
- COPS_OPEC_R02, R05, R06
- Saudi series
- COPS_SA
- Disruption series
- PADI_OPEC, PADI_NONOPEC
- Production series
- COPR_AG, COPR_IZ, COPR_KU, COPR_SA
- Target source
- OPEC monthly required-production tables
- Measure
- Effective capacity minus production
- Unit
- Million barrels per day
- Cadence
- Monthly, revised each STEO
Compare across the balance
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Source: U.S. Energy Information Administration (Sep 2026).
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OPEC spare production capacity FAQ
How EIA defines the buffer, why Saudi Arabia matters, and how to read the observed and projected series.
What is OPEC spare production capacity?
It is crude oil production capacity that EIA estimates can be reached within 90 days and sustained, minus actual crude production. It measures potential flow that is currently idle, not barrels already held in inventory.
Which EIA series build the OPEC capacity line?
StorageCurve sums EIA STEO regional surplus-capacity series COPS_OPEC_R02, COPS_OPEC_R05, and COPS_OPEC_R06 month by month. EIA can omit a component containing only zeroes; a published regional component anchors the aggregate for that month.
How is Saudi Arabia shown separately?
The Saudi line uses EIA STEO series COPS_SA. Its share is calculated as Saudi spare capacity divided by the OPEC regional aggregate for the same observed month, and is left unavailable when the aggregate is zero.
Why is Saudi Arabia called a swing producer?
Saudi Arabia has historically held a large share of readily available OPEC capacity and can adjust output materially relative to most producers. That makes both the size of its unused buffer and its willingness to use it important to the global balance.
Why does low spare capacity matter to oil markets?
A thin buffer leaves less production headroom to replace disrupted supply or meet an unexpected demand increase. All else equal, that can make the physical market more sensitive to outages, but it does not by itself determine price.
How is the supply-resilience state calculated?
StorageCurve ranks the latest observed OPEC spare capacity and total reported disruptions against their own observed monthly distributions since 2019. Low spare capacity and high disruptions is labelled Fragile; a thin buffer alone is Exposed; high disruptions with a larger buffer is Buffered stress; otherwise it is Resilient. It is a compact historical classification, not a forecast or price signal.
Which disruption estimates are shown?
The Disruptions chart mode uses EIA STEO series PADI_OPEC for unplanned OPEC crude-oil production disruptions and PADI_NONOPEC for unplanned non-OPEC liquid-fuels disruptions. They are kept separate because their scopes differ, and neither is treated as production guaranteed to return.
How is OPEC actual production compared with its target?
StorageCurve sums observed EIA crude production for Algeria, Iraq, Kuwait, and Saudi Arabia, then compares it with the required levels for those same four countries in OPEC’s matching monthly adjustment table. UAE is not treated as zero when a matching current EIA crude series is unavailable. The result is labelled a target gap rather than official conformity because OPEC’s assessment can also include compensation schedules and other adjustments.
Why show the last non-zero Saudi share?
When the current OPEC spare-capacity aggregate is zero, a current Saudi share is mathematically unavailable and would hide the concentration history. The page therefore shows the most recent month with a positive OPEC buffer, Saudi Arabia’s share in that month, and the OPEC buffer one year earlier.
Does the chart include the STEO forecast?
No. The chart plots observed months only. EIA projection months appear in a separately labelled outlook above the chart and in a separate table, so projected capacity cannot be mistaken for a measurement.
How should spare capacity be read with inventories?
Inventories are the accumulated stock left by past supply and demand; spare capacity is a possible future supply response. Tight stocks with little spare capacity describe a more fragile physical system than the same stocks backed by a large production buffer.
Can EIA revise spare-capacity history?
Yes. Effective capacity is an estimate that changes with operating conditions, outages, sanctions, maintenance, and new information. Each updater run re-fetches the published history so revisions replace older values rather than being appended as new observations.