ips to Avoid
Common Emissions Spreadsheet Errors
These tips are provided to assist you in avoiding common air quality reporting errors
and thus facilitate the quickest possible review of your plan:
1. The emissions estimates should be based on and reflect the activity
description and schedule required as part of the plan.
2. The emissions calculations are required to be worst-case estimates for the
facility.
3. Actual emission factors and actual equipment horsepower should be used
whenever they are known. If the drilling rig is not known, the maximum horsepower rating
for the type of rig (jack-up, submersible, platform, barge, semi-submersible, or
drillship) must be used. If actual emissions factors are unavailable, average emission
factors may be used. Average emission factors may not be used if it is known that the
equipment involved emits at a rate greater than the average. Default average emission
factors are provided in the spreadsheets.
4. Equipment should be shown as running 24 hours a day, 365 days a year, unless
you provide with the plan documentation certifying an alternative to the maximum activity
for the equipment. You must also provide a quantifiable method of verifying compliance
with this alternative maximum activity limit. For example, verification can be achieved by
maintaining a log of the actual fuel used by a piece of equipment, or by maintaining a log
of the actual hours a piece of equipment was used. These certifications and verifications
will be in writing. The documentation or certifications must be included in the plan. The
verifications will be documented at least monthly and a copy will be maintained at the
facility involved. Additionally, copies of these verifications will be provided to MMS
employees upon request or as directed by the Regional Supervisor.
5. Emissions from all vessels directly related to the proposed activity must be
included for the duration of their activity within 25 miles of the facility. This
typically includes crew boats, supply boats, work boats, tug boats, anchor handling
vessels, lift boats, pile drivers, standby boats, construction barges/vessels, etc.
6. Emissions from the construction of lease term pipelines must be attributed to
the facility from which the product it carries originates. For gas lift pipelines, the
construction emissions for the pipeline are attributed to the well which is produced using
the lift gas, in other words, the well to which the lift gas flows.
7. If the production is first processed at the receiving (terminus) platform of a
lease term pipeline, the incremental increase in emissions at the receiving facility will
also be included in the spreadsheets covering the producing well.
8. Emissions associated with workovers, recompletions, equipment swapouts, etc.
must be included in spreadsheets for DOCDs. For workovers and recompletions, a few weeks
of drilling allotted to future years precludes the need for a revised DOCD each time you
need to work over a well.
9. For any plan involving subsequent activity at an existing facility, emissions
data must be provided for the proposed activity and for the facility total (proposed plus
existing emissions). This should be depicted in two separate and clearly labeled sets of
spreadsheets.
10. If platforms are bridge connected, they are considered to be one facility for
air quality purposes, and development plans must include the emissions from all of the
connected platforms as one facility. Each structure should have its own set of
spreadsheets, but remember it is the total for the facility which is used for determining
exemption or significance.
11. For purposes of calculating the MMS exemption level, the distance to shore
should be expressed in tenths of a statute mile up to 20 miles, and in whole statute miles
for distances beyond 20 miles. The nearest point of any land should be used. This is
defined as the distance from the facility to the mean high water mark of any State,
including barrier islands and shoals.
12. Verification of non-default emission factors: documentation is required for
any emission factor below the defaults included in the spreadsheets. Verification
(typically by stack-testing) of these reduced emission factors will also be required upon
start-up and occasionally therefore to prove that the reduced emission factors are
actually being achieved and maintained.
13. Emission reductions: describe any proposed emission reduction measures,
including a description of the affected source(s), the emission reduction control
technologies or procedures, quantity of reductions to be achieved, and the monitoring
system you propose to use to measure emissions.
14. Include fugitive emissions for DOCDs.
15. If the activity includes a boom for emergency use, be sure to include a
description of its usage in your description of equipment and processes. Indicate whether
it will be used as a vent or flare and the conditions under which it will be used (e.g.,
compressor downtime, equipment upset, accident). Include estimates of flaring or venting
in the spreadsheets.
16. If the activity includes compressor(s), indicate intended action during
compressor downtime (e.g., shut-in, flare, vent).
17. If the activity includes a continuous flare, describe why it is needed (i.e.,
to incinerate harmful levels of H2S).
18. If the activity includes a glycol reboiler that is operated using waste heat
or electricity, indicate this in a statement.
19. If H2S is expected, indicate the expected concentration.