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 Environment Index
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Emissions
Atmospheric emissions are an unavoidable by-product of our activities;
any process requiring fuel will generate emissions through the process of
combustion. The principal gas that raises concern is CO2 to which climate
change has been attributed. Emissions produced by the oil and gas industry
can be grouped into onshore and offshore origin.
Offshore emissions sources include gas, fuel and diesel consumption, flaring
and venting, and fugitive emissions. By far the largest amount of CO2
offshore comes from gas, fuel and diesel consumption; that is, from the
processes involved in running an offshore installation.
Gas flaring also accounts for a relatively high amount of emissions from an
installation. The principal purpose of flaring offshore is for safety –
flare stacks are used for burning off unusable waste or flammable gases that
are released by pressure relief valves during unplanned over-pressuring of
plant equipment. A much smaller contribution to overall emissions comes from
fugitive emissions, which are those not caught by emissions capture
processes.
Realising the importance of reducing the amount of potentially harmful gases
from emissions, the EU has set up an Emissions Trading Scheme. The offshore
sector is accounted for in the scheme, and the industry worked hard to
ensure that its emissions allocations allow continuity of business along the
sector. The offshore sector is represented by Oil & Gas UK’s National
Allocation Plan (NAP) Workgroup.
Significant work has been undertaken to assess the feasibility of schemes
such as carbon capture and storage (CCS) which could effectively store away
carbon in depleted oil and gas reservoirs and subsea aquifers. CCS offers
great potential for significant reduction in CO2 emissions. The British
Geological Survey (BGS) estimates potential capacity under the North Sea at
around 20 billion tonnes of CO2 in oil and gas fields, with an additional
20–70 billion tonnes in confined aquifers which compares with the UK’s
current emissions of CO2 of some 580 million tonnes per year. In 2006, Oil &
Gas UK responded to the UK Government’s Energy Review, and Treasury Review,
on the topic of CCS.
Such technologies will require significant development, funding, changes to
legislative regimes and environmental assessments before they can be used,
but they may form part of our solution base for the future challenges that
industry may face. |
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Environment Index
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