Glossary of Terms
Activity at the IBP
For every Sell Nomination at the IBP, there is a matching Buy Nomination.
Adjusted Weighted Degree-Days (AWDD)
Adjusted Weighted Degree-Days (AWDD) is the weighted degree day value adjusted to take account of all variations in demand (e.g. weekend/weekday).
Allocation means the quantity of gas attributed to a network user by a TSO as an input or an off-take expressed in kWh for the purpose of determining the daily imbalance quantity.
Available Capacity means the part of the technical capacity that is not allocated and is still available to the system at that moment.
Balancing relates to the matching of gas deliveries (inputs) with actual consumption (outputs) over the Gas Day.
Balancing Action means an action undertaken by the TSO to change the gas flows onto or off the transmission network, excluding those actions related to gas unaccounted for as off-taken from the system and gas used by the TSO for the operation of the system.
Calorific Value (CV)
Calorific Value (CV) is a measure of the energy contained in gas. The CV depends on the composition of the gas. The CV refers to the amount of energy released when a known volume of gas is completely combusted under specified conditions. The CV of natural gas is measured continually using process gas chromatographs.
Capacity means the maximum flow, expressed in energy unit per time unit (i.e. in kWh), to which the network user is entitled in accordance with the provisions of the transport contract.
Confirmed Quantity (CQ)
Confirmed Quantity (CQ) means the quantity of gas confirmed by a TSO to be scheduled or re-scheduled to flow on Gas Day D.
Daily Metered (DM)
Where the Annual Quantity is > 5,500,000 and < 57,500,000 kWh.
Delivered Quantity means the quantity of gas that, according to the measurement equipment from the TSO, has physically flowed at an Entry/ Exit Point per time period.
End of Day (EOD) Aggregate Shipper Imbalance Position
End of Day (EOD) Aggregate Shipper Imbalance Position is an aggregate figure based on allocations.
Entry Points include Bellanaboy, Inch, Moffat, and Gormanston. Entry Point Allocations to Isle of Man and Northern Ireland are also reported.
Exit Points from the ROI gas system are via the following aggregate Market Sectors: NDM, DM, and LDM (including the Power Generator sub-sector).
FIRM Capacity means gas transmission capacity contractually guaranteed as uninterruptible by the TSO.
First Tier Imbalance Price
First Tier Imbalance Price shall be payable by or credited to the Shipper in respect of the portion of the Final Daily Imbalance Quantity that is equal to the Shipper Portfolio Tolerance.
Forecast EOD Aggregate Shipper Imbalance Position
Forecast EOD Aggregate Shipper Imbalance Position is an aggregate figure based on nominations.
Gas Day means the period from 05:00 to 05:00 UTC the following day for winter time and from 04:00 to 04:00 UTC the following day when daylight saving is applied.
Interruptible Capacity means gas transmission capacity that may be interrupted by the TSO in accordance with the conditions stipulated in the transport contract.
- VRF is the only interruptible product on the ROI network at present.
- While an interruption, or a number of interruptions to the VRF product may occur on a day during individual hourly matching cycles, Shippers can continue to re-nominate in subsequent hours as more Moffat Entry Nominations are received later in the day. The available VRF Quantity is published hourly to the Shipper Nominations Summary Screen in GTMS (GNI’s Gas Transmission Management System).
Imbalance Prices are the buy and sell prices that the TSO pays for shippers’ long and short daily imbalance positions respectively.
Large Daily Metered (LDM)
Where the Annual Quantity on the first day of the Capacity Booking Period of a LDM Capacity Booking is > 57,500,000 kWh.
Nomination means the prior reporting by the network user to the TSO of the actual flow that the network user wishes to inject into or withdraw from the system (i.e. an instruction to flow at Entry/ Exit Points on their behalf).
Non-Daily Metered (NDM)
Where the Annual Quantity is < 5,500,000 kWh.
Power Generator is a sub-sector of the ROI Large Daily Metered (LDM) Sector.
Processed Quantity (PQ)
Processed Quantity (PQ) means the quantity of gas determined by the initiating TSO and by the matching TSO, which takes into account the network user's nomination or re-nomination and contractual provisions as defined under the relevant transport contract and which is used as the basis for the matching process.
- ROI PQ and CQ values are reported for entry nominations at Interconnection Points (i.e. Moffat and Gormanston), while only CQ values are reported for domestic Entry Points (i.e. Bellanaboy and Inch).
- In terms of VRF Nominations, the ROI PQ is the Nominated VRF Processed Quantity (PQ) on GTMS, whereas the CSO PQ is the Nominated VRF Processed Quantity (PQ) on Gemini (National Grid).
Renomination means the subsequent reporting of an amended nomination.
ROI LDM Market
ROI LDM Market excludes gas consumption by Northern Ireland and Isle of Man LDM Sites.
Second Tier Imbalance Price
Second Tier Imbalance Price shall be payable by or credited to the Shipper in respect of the portion of the Final Daily Imbalance Quantity that is the Second Tier Imbalance Quantity.
Second Tier Imbalance Buy Price
Second Tier Imbalance Buy Price is the higher of (System Marginal Buy Price - Balancing Transportation Cost) and (Applicable Second Tier Negative Imbalance for this Month of the First Tier Buy price - Balancing Transportation Cost).
Second Tier Imbalance Sell Price
Second Tier Imbalance Sell Price is the lower of (System Marginal Sell Price - Balancing Transportation Cost) and (Applicable Second Tier Positive Imbalance for this Month of the First Tier Sell price - Balancing Transportation Cost).
Secondary Capacity Trading
Secondary Capacity Trading means trading of capacity on the Secondary Capacity Market between Shippers.
Services Contract means a service provided to the TSO via a contract for gas required to meet short term fluctuations in gas demand or supply, which is not a short term standardised product.
Shrinkage Gas includes Own Use Gas used by the TSO for the operation of the transportation system; and/or, natural gas required to replace Unaccounted For Gas lost or otherwise unaccounted for from the Transportation System.
Supply means the sale, including resale of natural gas, to customers.
System means any transmission networks, distribution networks, and / or storage facilities owned and / or operated by a natural gas undertaking, including linepack and its facilities supplying ancillary services and those of related undertakings necessary for providing access to transmission and distribution.
System Average Price (SAP)
System Average Price (SAP) equals First Tier Buy/Sell Price.
Technical Capacity means the maximum FIRM capacity that the TSO can offer to the network users, taking account of system integrity and the operational requirements of the transmission network.
Total LDM Market
Total LDM Market includes gas consumption by Northern Ireland and Isle of Man LDM Sites.
Trading Platform means an electronic platform provided and operated by a trading platform operator by means of which trading participants may post and accept, including the right to revise and withdraw, bids and offers for gas required to meet short term fluctuations in gas demand or supply, in accordance with the terms and conditions applicable on the trading platform and at which the TSO trades for the purpose of undertaking balancing actions.
Transmission System Operator (TSO)
Transmission System Operator (TSO) means a natural or legal person who carries out the function of transmission and is responsible for operating, ensuring the maintenance of, and, if necessary, developing the transmission system in a given area and, where applicable, its interconnections with other systems, and for ensuring the long-term ability of the system to meet reasonable demands for the transport of gas. The TSO for the ROI gas market is Gas Networks Ireland.
Virtual Reverse Flow (VRF)
Virtual Reverse Flow (VRF) (Backhaul) is a ‘reverse flow’ service offered on a virtual basis, at the Moffat Interconnection Point, to enable shippers to virtually flow gas from ROI to Moffat.
Wind Speed is the Actual mean Wind Speed supplied by Met Éireann.