Atmospheric Emissions – Process Venting and VOC Emissions from Offshore Loading

Note – VOC emissions from offshore loading are covered by the Vent Consent requirements under the Energy Act 1976.

For information on the impact of Brexit on oil and gas environmental legislation, please refer to the pdf document downloadable from the Home Page.

Key Legislation:	Energy Act 1976 MARPOL 73/78 Annex VI – Prevention of Air Pollution from Ships Annex VI entered into force on 19 May 2005 and a revised Annex VI was adopted in October 2008 which entered into force on 1 July 2010. The Merchant Shipping (Prevention of Air Pollution from Ships) (Amendment) Regulations 2010 For more detail on the Legislation relevant to this page, please use the following links: Main UK Legislation Atmospherics Legislation
Supporting Legislation:	EC Directive 2016/2284 on the reduction of national emissions of certain atmospheric pollutants, implemented by the National Emission Ceilings Regulations 2018 in England, Wales, Scotland and Northern Ireland.
Emission Trading Schemes:	Climate Change Act 2008 Climate Change (Scotland) Act 2009, amended by The Climate Change (Emissions Reduction Targets) (Scotland) Bill which sets revised targets for the reduction of greenhouse gases emissions. Council Directive 2003/87/EC establishing a scheme for greenhouse gas emission allowance trading with the community
Guidance Notes:	Clean Air Strategy 2019: This document sets out a new air quality policy through which the government aims to tackle atmospheric emissions from activities such as emissions from small industrial sites and the use of certain products which release air pollutants Technical Guidance Note on Monitoring of stack gas emissions from medium combustion plants and specified generators: A guidance for organisations that service and maintain medium combustion plants and other specified generators to monitor stack gas emissions. North Sea Transition Authority is responsible for venting consent. They have issued guidance on the review of flare and vent applications during commissioning and production operations, available here. Specific guidance is also listed below. Field Consents Guidance NSTA flaring and venting guidance OGA Guidance on Flaring and Venting: The Oil and Gas Authority has issued, in June 2021, an updated guidance on flaring and venting, which sets out a tougher approach to driving atmospheric emissions reductions. NSTA Stewardship Expectation 11 – Net Zero: This publication gives operators and licensees clarity on expectations and good practices regarding greenhouse gases emissions reduction within the UK continental shelf. OEUK Emissions Reduction Action Plan (ERAP) guidance: OEUK published the Emissions Reduction Action Plan (ERAP) guidance in July 2024, available here. OEUK: Offshore Flare and Vent Systems – Identified Issues and Associated Good Practice, Issue 2: OEUK published new guidance on the design, operation and maintenance of offshore flare vent systems. This guidance is a vital resource for operators to minimise hazards, ensure compliance and manage risks. OGA Plan: The OGA Plan was published in 2024 under the OGA Strategy. The OGA Strategy incorporates a range of net zero obligations for the UK oil and gas industry, including a requirement for relevant persons to, in securing that the maximum value of economically recoverable petroleum is recovered, and take appropriate steps to assist the Secretary of State in meeting the net zero target. This includes reducing greenhouse gas emissions from sources such as flaring, power generation and venting, aligning with the NSTA Stewardship Expectation 11 (Net Zero). The OGA Plan outlines the steps to be taken by relevant persons to help achieve the OGA Strategy, where relevant persons refer to holders of petroleum licences; operators under petroleum licences; owners of upstream petroleum infrastructure; persons planning and carrying out the commissioning of upstream petroleum infrastructure; and owners of relevant offshore installations. The OGA Plan includes requirements for relevant persons to reduce emissions via four broad headings: investment and efficiency, platform electrification and low carbon power, inventory and flaring and venting. The OGA Plan requires relevant persons to produce an Emissions Reduction Action Plan (‘ERAP’) for each asset. They also place low carbon requirements for upcoming developments (with first oil and gas 1^st January 2030) (e.g. assets to be partly or fully electrified or run on low carbon power). OGUK: Methane Action Plan 2021. This document highlights the actions the oil & gas industry will take to cut methane emissions on the UK Continental Shelf.

Consent Needed:	Consent to Vent is required under the Energy Act 1976. For Vent Consents both the inert gas and the hydrocarbon faction obtained from the licensed area must be included in the consent application, and the combined rate for both will be the consent basis. Consents to vent are required for all Category 4 (Unignited Vents) including venting of gases from onboard crude oil storage tanks including FPSOs during crude oil filling operations (see the Performances Standards tab). Where a field is venting > 5 tonnes per day the vent level will be reviewed and a vent consent issued annually. These applications will be subject to detailed review by OGA and operators must exercise a high level of technical and operational diligence in estimating quantities. This level of vent is considered to represent a potential opportunity for further reduction in levels. These applications will need full supporting details with medium and long term plans for reduction of venting. Where a field is venting < 5 tonnes per day, a longer term vent consent may be applied for/issued (see the Renewal and Variation tab). Less detailed (minimum) information may be provided on the application form for these venting levels.See the Performance Standards tab for options on multiple fields producing across the same facility. Crude Oil Tankers From 1 July 2010 all crude oil tankers must have on board a VOC Management Plan approved by the MCA.
How to Apply:	Application should be submitted via the UK Oil Portal. The OGA Guidance Notes for the Completion of Flare and Vent Applications provide further information.Venting consent applications should contain the following: A summary of the main points of the application A summary of the main venting assumptions A detailed description of the plant start-up procedures and philosophy; the procedure for filling the gas export line should also be described The commissioning schedule Venting calculations – to include venting on a daily basis and total quantities. The quantities of gas should be presented on the same basis as the hydrocarbon gas in the Flaring Consent application Sketches and figures should also be supplied for: Overall commissioning programme Fuel gas system Gas dehydration system Gas compression system Gas export system and pipeline Onshore facilities
Who to Apply to:	Applications to be submitted to the UK Oil Portal
When to Apply:	Consent(s) should be submitted at least two months before ‘First Oil’ and towards the expiry of the existing consent for operations. However, it is advised by BEIS and OGA that the operator is in contact with the regulator at all stages, from design through construction to commissioning planning, and demonstrate that all reasonable steps have been taken to keep venting to a minimum.

Limits Placed on Vent Volumes:	Consent will specify the vent volume that must not be exceeded over a specified period.
Definition of Unignited Vents:	OGA has provided definitions for four categories of flare and vent activities, of which, Category 4 applies to venting.Category 4 – Unignited Vents This covers inert gases and hydrocarbon gases which may be discharged to an atmospheric vent. The Energy Act requires both the inert and hydrocarbon gases obtained from the licensed area that are vented to be covered by the consent. This should also include venting of gases from onboard crude oil storage tanks, e.g. for FPSOs during crude oil filling operations. However, this excludes inert gases that are generated on board the installation for the purpose of providing an inert blanket for on board oil storage tanks.Vents may contain nitrogen, carbon dioxide, water vapour, hydrocarbons and possibly traces of sulphur compounds, etc. Operators should give an estimated annual average composition of vented stream(s) in the notes section of the vent application.
Multiple Field Tie-ins to Single Facility:	Where several fields tie-in to common facilities and venting is < 5 tonnes per day, and the fields have the same operator and licensees, the operator may apply for a single composite consent and the level of venting permitted in this consent will be based on the sum of the individual field contributions to the total vent level.Where the fields have different operators and licensees, separate consents will usually continue to be issued. However, if all parties agree to apply for a single vent consent covering all the fields going into the facilities and the total vent level is < 5 tonnes per day then a combined 3-year vent consent will be considered.

Vent Volumes:

Daily vent and cumulative vent volumes.

What to Report:	There are two types of reporting required for venting. The first is statutory reporting to OGA on vent volumes. The second is additional reporting of environmental emissions due to venting through EEMS for the UK-PRTR and E-PRTR (see Atmospheric Emissions Reporting). Vent Consent: Reporting to OGA with periodicity and details as specified in vent consent. EEMS Reporting: Complete atmospheric emissions inventory EEMS pro forma (Atmospheric) and guidance notes can be obtained from the EEMS website. ERAP Reporting: The NSTA, via Stewardship Expectation 11, outlined that operators should develop, implement and maintain asset and/or infrastructure hubs’ GHG Emission Reduction Action Plans (ERAPs) in order to reduce their GHG emissions and support delivery of the UK’s net zero target. ERAP’s summarise and assess the applicability of available emissions abatement and emissions monitoring opportunities and technologies, and set out planned emissions reduction initiatives. The OGA Plan, published in 2024, provides further guidance in the associated ERAP explanatory note here. Additionally, OEUK have published a guideline that outlines a framework for implementing good practices within an ERAP – Emissions Reduction Action Plan (ERAP) \| Offshore Energies UK (OEUK).
How to Report:	ERAP Reporting: Operators should produce and maintain their own plans / documents to fulfil the ERAP reporting requirements and have relevant documents available on request from the NSTA. This should include proportionate technical and economic assessments. The reporting requirements differ across various themes (e.g. flaring and venting management plans and electrification assessments), as detailed in the OGA Plan and associated ERAP explanatory note here.
Who to Report to:	Vent Consent: OGA Petroleum Production Reporting according to terms of consent. EEMS Reporting: Completed forms should submitted electronically to the EEMS website. ERAP Reporting: As above, generally the ERAP reporting requirements must be made available to the NSTA on request. However, some reporting requirements may be incorporated into existing submissions to the NSTA (e.g. reporting of flaring and venting quantities and associated emissions through the Emissions section of the UKSS).
When to Report:	Vent Consent : As specified in consent. EEMS Reporting: Annually before 7 February. ERAP Reporting: ERAP’s must be submitted to the NSTA on request. The documents and plans produced as part of the reporting requirements must be refreshed at least every 2 years, as detailed in the OGA Plan and associated ERAP explanatory note here.

What to do if in Breach of Consent:	This is reported through the routine vent consent reporting.
Offshore Inspection:	The BEIS (then DECC) Offshore Oil and Gas Environment Unit Enforcement Policy sets out the general principles that Inspectors shall follow in relation to enforcement, including prosecution.

Duration of Consent:

Applications can be made for vent consents on an annual basis or for a 3-year period (e.g. 2010-2012), depending upon the total daily hydrocarbon vent level from a field. Long term vent consents will not be permitted for any field that seek permission to vent at rates in excess of 5 tonnes a day. If a field is venting less than 5 tonnes of hydrocarbon gas a day, and if, for the period 2010 to 2012 the vent application does not request any increase in the levels permitted in the extant vent consent, licensees can apply for a three year vent consent. If this application is approved by the Department, a long term consent will be issued, subject to a number of conditions (see NSTA Guidance on the review of Flare and Vent Applications).

When to Renew Consent/Exemption:

NSTA will invite applications for renewal in September each year, with annual consents being issued in December for the following year.

Cold Flaring:	This is considered a venting activity and is controlled under the venting consent. It should not be reported as flaring or counted against the flaring consent.
Draft Clean Air Strategy 2018	The draft Clean Air Strategy outlines ambitions to reduce overall air pollution and make our air healthier to breath, protect nature and boost the economy. It highlights the importance of effective co-operation with the devolved administrations and sets out actions already underway in Scotland, Wales and Northern Ireland to cut air pollution right across the UK. It is currently under consultation.
Transitional National Plan (TNP): quarterly register	The TNP scheme allows large combustion plants (with a thermal rating equal to or greater than 50 megawatts) first licensed before 27 November 2002 to trade their annual allowances for sulphur dioxide, nitrogen oxide and particulate matter (dust) with other large combustion plants within the TNP scheme.
Updated Energy and Emissions projections: 2015	A report detailing projections of the UK emissions performance against national greenhouse gas targets under existing policies has been released by BEIS. It includes projections of the demand for each type of fuel for different sectors of the economy. The report includes projected energy demand for electricity and indicates what mix of generation will meet it (link here).