Atmospheric Emissions - Process Venting and VOC Emissions from Offshore Loading

• 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

Revised Annex VI as implemented in the UK through the 2010 Regulations, introduces a new mandatory requirement for all crude oil tankers to have on board and implement a VOC Management Plan approved by the administration.

• EC Directive 2001/81/EC on National Emission Ceilings for Certain Atmospheric Pollutants
• National Emission Ceilings Regulations 2002

These Regulations set national ceilings and a requirement for the development of a reduction programme for sulphur dioxide, nitrogen oxides and volatile organic compounds in the UK. These Regulations apply to emissions from land, territorial sea and the UKCS.

At present, the UK government believes that it can meet targets through existing targets onshore. However, this does not preclude future targets for offshore operations. 

• Climate Change Act 2008

The Act sets up a framework for the UK to achieve its long-term goals of reducing greenhouse gas emissions and to ensure steps are taken towards adapting to the impact of climate change. The Act enables a number of elements (see EU ETS - Pending Legislation).

• Council Directive 2003/87/EC establishing a scheme for greenhouse gas emission allowance trading with the community

Offshore installations come within the scope of the mandatory EU Emissions Trading Scheme. The mandatory EU ETS currently only includes carbon dioxide and does not apply to venting.

DECC Guidance Notes for the Completion of Flare and Vent Applications

MIN 395 - Revised Annex VI of MARPOL: Prevention of Air
Pollution from Ships (pdf file)

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 Performance Standards).

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 DECC and operators must exercise a high level of technical and operational dilligence 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 Renewal). Less detailed (minimum) information may be provided on the application form for these venting levels.

See Performance Standards for options for multiple fields producing across the same facility.

Crude Oil Tankers

From 1st July 2010 all crude oil tankers must have on board a VOC Management Plan approved by the MCA.

In writing by letter to DECC. The DECC 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; and
• Onshore facilities.

DECC Contacts for Consent to Vent are as follows:

Northern and Central North Sea

Carol Campbell

Tel: 01224 254052

Email: carol.campbell@decc.gsi.gov.uk

Southern North Sea and Onshore

Ivor Newman

Tel: 020 7215 5163

Email: ivor.newman@decc.gsi.gov.uk

Consent will specify the vent volume that must not be exceeded over a specified period.

DECC 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 onboard the installation for the purpose of providing an inert blanket for onboard oil storage tanks.

Vents may contain nitrogen, carbond dioxide, water vapour, hydrocarbons and possibly traces of sulphur compounds etc. Operators should give an estaimted annual average composition of vented stream(s) in the notes section of the vent application.

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 fileds have different operators and licensees, usually separate consents will 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.

Daily vent and cumulative vent volumes.

There are two types of reporting required for venting. The first is statutory reporting to DECC 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 DECC 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.

Vent Consent

DECC’s Petroleum Production Reporting according to terms of consent.

EEMS Reporting

Completed forms should submitted electronically to the EEMS website.

Vent Consent

As specified in consent.

EEMS Reporting

Annually before 7th February.

This is reported through the routine vent consent reporting.

Applications can be made for vent consents on an annual basis or for a 3-year period (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 DECC Guidance on the Completion of Flare and Vent Applications)

This is considered a venting activity, and controlled under the venting consent. It should not be reported as flaring, or counted against the flaring consent.