The words pipelines use in their notices, and the words Enercast uses on this site, in plain English. Each term has its own link (for example #force-majeure) you can share.
B
- Basis (basis differential)
- The price difference between natural gas at a regional trading point (for example Transco Zone 6 New York or Waha) and Henry Hub. Pipeline outages move basis first: a constraint that traps supply upstream weakens basis there and strengthens it downstream.
- Bcf/d (billion cubic feet per day)
- The unit Enercast uses for capacity and flows. U.S. dry gas production is roughly 100+ Bcf/d; a single compressor outage is often 0.05–0.5 Bcf/d. Pipelines usually post in Dth/d or MMBtu/d; Enercast converts at 1,000,000 Dth/d ≈ 1 Bcf/d.
C
- Ceiling (posted capacity cap)
- A notice that says how much a point or segment can move (“capacity through Station 50 is limited to 2.27 Bcf/d”) rather than how much was cut. Enercast shows ceilings but never adds them into a capacity-offline total, because a ceiling is not a loss.
- Citygate (LDC citygate)
- The meter where an interstate pipeline hands gas to a local distribution company (LDC) for delivery to homes and businesses. One of Enercast’s eight supply & demand categories.
- Compressor station (CS, Sta.)
- A facility every 50–100 miles along a pipeline that re-pressurizes gas to keep it moving. A unit or station outage reduces how much gas the segment downstream can carry — the most common cause of capacity going offline.
- Critical notice
- A bulletin a pipeline must post on its website when an event affects service — a force majeure, an outage, a capacity restriction, an OFO. Interstate pipelines post them under FERC and NAESB standards. Enercast reads every one and scores it 1–5. How notices are scored.
- Curtailment
- When a pipeline cannot move every scheduled nomination and cuts some of them, lowest priority first: interruptible service, then secondary firm, then primary firm. A notice that warns of primary-firm curtailment is a strong signal.
D
- Dekatherm (Dth, MMBtu)
- The energy unit pipelines schedule in. 1 Dth = 1 MMBtu = 10 therms, about 1,000 cubic feet of gas. 1,000,000 Dth/d is roughly 1 Bcf/d.
- Derived reduction
- A capacity cut Enercast calculates from what the pipeline posted: the posted new ceiling subtracted from the posted prior or design capacity (for example 800,000 Dth/d design reduced to 700,000 Dth/d = 0.100 Bcf/d). Labeled “derived” wherever it appears.
- Design capacity
- The maximum a point or segment is built to move. Compare operating capacity, what it can move today.
E
- Electronic bulletin board (EBB, informational postings)
- Each interstate pipeline’s public website where it posts notices, operationally available capacity, scheduled quantities and its tariff. Enercast monitors 192 of them around the clock.
- Event (outage event)
- Enercast’s unit for capacity offline: one outage from declaration to lift, however many notices the pipeline posts along the way. The calendar draws one bar per event, not per notice.
F
- Firm service (primary firm, secondary firm)
- Transportation a shipper has reserved and pays for whether used or not. Primary firm (between its contracted receipt and delivery points) is the last service cut; secondary firm (using other points) is cut before it.
- Force majeure (FM, FMJ)
- A declaration that an unforeseeable event — a leak, a mechanical failure, a storm — prevents the pipeline from providing service. Force majeure events are usually unplanned and often scored severity 4–5.
G
- Gas day
- The 24-hour day gas is scheduled and measured on: 9:00 AM to 9:00 AM Central Clock Time. A notice “effective Gas Day October 20” starts at 9:00 AM CT on October 20. The gas day and nomination cycles.
H
- Henry Hub
- The Louisiana pipeline interconnect that is the delivery point for NYMEX natural gas futures and the U.S. benchmark price. “Bullish” and “bearish” on Enercast are read against Henry Hub.
I
- Interconnect
- A meter where two pipelines exchange gas. Interconnect restrictions matter because they decide whether gas can reroute around an outage.
- Interruptible service (IT)
- Transportation offered only when capacity is available, and the first to be cut in a constraint.
- Interstate pipeline
- A pipeline that crosses state lines and is regulated by FERC, which requires public posting of notices and scheduled quantities. Enercast covers interstate pipelines; most Texas intrastate systems do not post.
L
- LDC (local distribution company)
- The utility that delivers gas to homes and businesses from the citygate.
- Lift (return to service, restoration)
- The notice that ends an outage: the pipeline says the restriction is over. Enercast closes the event on the day the lift posts and counts the capacity as back.
- LNG feedgas
- Gas delivered by pipeline to LNG export terminals (Sabine Pass, Cameron, Freeport, Corpus Christi, Cove Point and others) to be liquefied and shipped. A cut to feedgas keeps gas in the U.S. market and reads bearish for Henry Hub.
- Location ID (loc, meter ID, POI)
- The number a pipeline gives each meter or point (for example Cameron LNG, loc 4246). Notices and scheduled quantities are posted by location ID, which is how Enercast ties a notice to flows.
M
- Mainline valve (MLV)
- A valve on the main pipe. Maintenance is often posted as a stretch between two valves (“MLV 109-3A to MLV 110-3”).
- Market side (bullish, bearish, basis-only)
- Enercast’s read of which way an outage pushes price. Bullish: supply is stranded (a production lateral, a processing plant, an import point). Bearish: demand is cut (LNG feedgas, a citygate, a power plant). Basis-only: the effect is regional rather than national.
N
- Nomination
- A shipper’s request to move a quantity of gas from a receipt point to a delivery point on a gas day. Nominations are submitted and confirmed in fixed nomination cycles.
- Nomination cycle (Timely, Evening, ID1, ID2, ID3)
- The five daily scheduling windows set by NAESB: Timely and Evening (the day before) and three intraday cycles. Each cycle produces a new set of scheduled quantities. Cycle times.
O
- Observed estimate (~est.)
- When a notice gives no volume, Enercast looks at the drop in the location’s posted operating capacity after the notice and shows it as “~0.170 est.” Estimates are labeled and never added into the Bcf/d total.
- Operating capacity (operationally available capacity)
- What a point or segment can move today, as posted by the pipeline. When it falls below design capacity, something is restricting it.
- Operational flow order (OFO)
- An order requiring shippers to keep receipts and deliveries in balance, with penalties for imbalances. Issued when a pipeline’s pressure or linepack is at risk — often in cold weather.
- Outage Impact Report
- A weekly schedule some pipelines (Tennessee Gas Pipeline, Southern Natural Gas and others) post listing planned work and the expected capacity at each station or segment for the coming weeks.
P
- Pig run (pigging)
- Sending an inspection or cleaning tool (a “pig”) through the pipe. Capacity in that stretch is usually reduced for the day.
- Power burn (power generation)
- Gas delivered to power plants. One of Enercast’s eight supply & demand categories, and the most weather-driven.
R
- Receipt point
- Where gas enters a pipeline — from a processing plant, another pipeline or storage. Its opposite is a delivery point, where gas leaves.
- Reroute potential
- Enercast’s read of whether other pipelines can carry the gas an outage displaces: High, Moderate, Limited or None. Limited reroute makes the same Bcf/d cut matter more.
- Revision
- A pipeline update to an existing notice — new dates, a new volume, an extension. Enercast keeps every revision, shows the latest, and only re-alerts when something material changes.
S
- Scheduled quantity
- The volume a pipeline confirmed for a meter on a nomination cycle — the nomination that cleared scheduling. Every Enercast supply & demand figure is a sum of posted scheduled quantities, not a model. Why.
- Segment
- A stretch of pipeline between two stations or valves, often numbered by the pipeline (“Segment 380”). Capacity is posted and restricted by segment.
- Severity score (1–5)
- Enercast’s AI rating of a notice’s market impact, from 1 (routine bulletin) to 5 (major event, for example a large unplanned outage on a bottleneck). Free alerts cover severity 4–5. The full scale.
- Stale event
- An outage with no posted end date that the pipeline has stopped re-listing. It may have ended without a lift notice; Enercast shows it dashed and leaves it out of the total.
- Stated reduction
- A capacity cut the pipeline posted itself (“eastbound capacity reduced by 504 MMcf/d”). The most reliable figure; labeled “stated”.
- Storage injection / withdrawal
- Gas going into (injection) or out of (withdrawal) underground storage. Net storage flow is one of Enercast’s eight supply & demand categories.
T
- Trading note
- The one- or two-sentence market read Enercast attaches to each scored notice: which trading points are affected, in which direction, how many Bcf/d and for how long. Full trading notes come with Pro alerts.
Z
- Zone (rate zone)
- Large pipelines are divided into zones for pricing and capacity (Transco Zones 1–6, Tennessee Gas Zones 0–6, Texas Eastern M-1 to M-3). Regional prices are quoted by zone, for example Transco Zone 6 NY.
Missing a term? Email support@enercast.com. See also How to read a pipeline notice.
More guides: How Enercast works · Critical notices · Capacity offline · Supply & demand · Getting alerts
