THE LOWDOWN ON GAS
COMPRESSOR BLOWDOWN: THE DIRTY TRUTH OF UNREPORTABLE EMISSIONS
Compressors must periodically be taken off-line
for maintenance, operational stand-by, or emergency
shut down testing,
and as a result, methane
may be released to the atmosphere from a number of sources. When compressor units are shut down, typically the high pressure
gas remaining within
the compressors and associated piping between
isolation valves
is vented to the atmosphere (‘blowdown’) or to a flare.
In addition to blowdown emissions, a depressurized system may continue
to leak gas from faulty or improperly sealed unit isolation valves.
The recent notice of
violation and proposed civil penalty from the US Department of Transportation
against Maritimes and Northeast Pipeline, LLC (Spectra Energy) is
a reminder of what has been going on for many years in the gas compression
business as far as emissions from the gas compressors. We attach in its entirety the Notice of
Violation (NOV) letter sent to Spectra Energy from DOT just to see the
magnitude of the methane emissions associated with compressor blowdown: one of the dirtiest aspect of these
operations, along with pigging, pipe leaks, spills and so on. These pipelines have been protected by the
feds under the authority of the Natural Gas Act that has allowed them to
operate under the radar of pretty much every environmental law. As these stations have become closer to the
public (or the public coming closer to them by building homes near the
pipelines) more attention has been paid on their operations, and noises and blowdown
emissions.
Here are some facts regarding
methane losses from compressor stations at natural gas pipelines.
Methane Losses from Compressor Stations
There are currently
about 1,650 compressor stations in the U.S. transmission sector;
1.
There
are approximately 9,000 compressors inside these stations;
2.
About 50
billion cubic feet (Bcf) per year is lost from compressor fugitives (does not
include the lube oil being emitted – and it is sizable);
3.
7.0 Bcf
per year is lost from compressor venting
It should be noted that
these are the transmission line compressor emission; there are an addition 40,000
compressors in the oil and gas production and processing phase that precedes
the transmission/storage state.
The problem we are
facing is that the gas compressors are cycled on- and offline to match the
fluctuating gas demand. We have both
peak and base load compressors. The
standard practice is to blow down (depressurize) off-line compressors. On average, one blowdown vents 15 Mcf gas to
the atmosphere. Just to give you a
perspective as to why the DOT decided to fine Spectra Energy is that the
blowdown at the Maine station provided in the letter below was calculated by
Spectra itself to be 70 Mcf – and they refused to reported it, claiming it was
a maintenance issue.
We have found that simple changes
in operating practices
and in the design of blowdown systems
can save money and significantly reduce methane emissions
by keeping systems fully or partially
pressurized during shutdown. Though pressurized systems may also leak from the closed blowdown valve and from reciprocating compressor rod packing, total
emissions can be significantly reduced. Four
options for reducing
emissions when taking
compressors off-line are available. These include:
1.
Keeping compressors pressurized when off-line.
2.
Connecting blowdown vent lines to the fuel gas system
and recovering all, or a portion, of the vented gas
to the fuel gas system.
3.
Installing static seals on compressor rod packing.
4.
Installing ejectors on compressor blowdown
vent lines.
Keeping compressors fully pressurized when off-line achieves
immediate payback—there are no capital
costs and emissions
are avoided by reducing the net leakage
rate. Routing blowdown
vent lines to the fuel gas system
or to a lower pressure
gas line reduces
fuel costs for the compressor or other facility equipment, in addition to avoiding
blowdown emissions. Static seals installed on compression rods eliminate gas leaking back through the rod packing while a compressor is shutdown under pressure. An ejector uses the discharge
of an adjacent compressor as motive to pump blowdown
or leaked gas from a shut down compressor into the suction
of an operating compressor or a fuel gas system. Benefits
of these practices include fewer bulk gas releases, lower leak rates, and lower most cases of
less than a year.
NOTICE OF PROBABLE
VIOLATION AND PROPOSED CIVIL PENALTY
OVERNIGHT EXPRESS MAIL
October 27,
2014
Mr.
J. Drake,
VP Operations
& EHS
Maritimes
and Northeast Pipeline, LLC
(Spectra Energy) 5400 Westheimer
Court
Houston,
TX
77056
CPF 1-2014-1011
Dear Mr. Drake:
On January 2, 2014, a representative of the Pipeline and Hazardous
Materials Safety Administration (PHMSA), Office of Pipeline
Safety (OPS), pursuant to Chapter 601 of 49 United States Code contacted Spectra Energy regarding a release of gas at the Maritimes
and Northeast Searsmont
Compressor Station located
in Searsmont, Maine. Maritimes
and Northeast Pipeline,
LLC is a subsidiary of Spectra Energy.
According to information obtained from Spectra
Energy, the gas release
occurred during the evening of December 31, 2013. The release
was caused by the unintentional opening of a station emergency shutdown system (ESD) blow down valve which caused gas from the pipeline to be released through the ESD system.
The total amount of gas loss during this
incident was calculated by Spectra to be 70 million
standard cubic feet (MMSCF).
As a result of PHMSA’s investigation into this release of gas, it appears
that you have committed a probable
violation of the Pipeline
Safety Regulations, Title 49, Code of Federal Regulations. The item inspected
and the probable violation is:
1.
§191.5(a)
Immediate notice of certain
incidents.
(a)
At the earliest practicable moment following discovery, each operator shall give notice in accordance with paragraph (b) of this
section of each incident as
defined in §191.3.
Maritimes and Northeast Pipeline failed to notify the National Response Center (NRC) at the earliest practicable moment following the discovery
of the natural gas release that occurred the evening of December
31, 2013, at the Maritime
Compressor Station located in Searsmont, Maine. In a September
6, 2002, (67 FR 57060) advisory bulletin, “PHMSA advised owners and operators of gas and hazardous liquids
pipeline systems and LNG facilities that, ‘at the earliest
practicable moment,’ usually
means one-
urs after discovery
of the incident.”
urs after discovery
of the incident.”
Section
§191.5 of the code of Federal
Regulation, requires pipeline owners and operators
to notify the
NRC by telephone or electronically
at the earliest practicable moment following
discovery of an incident
as defined in Section
§191.3. Section §191.3
defines incident
as any of the following
events:
2.
An event that involves a release
of gas from a pipeline,
or of liquefied natural gas, liquefied petroleum gas, refrigerant gas, or gas from an LNG facility,
and that results
in one or more of the following
consequences:
(a) A death,
or personal injury
necessitating in-patient hospitalization;
(b)
Estimated property damage of $50,000 or more, including loss to the operator and others, or both, but excluding cost of gas lost;
(c)
Unintentional estimated
gas
loss of three million
cubic feet or more;
The total amount of gas loss for
this incident was calculated
by Spectra to be
70 MMSCF,
which exceeds the reporting criteria of 3 MMSCF for an incident as outlined in 191.3 (1)(iii). Thus, the incident should have been reported
to the NRC at the earliest
practicable moment following discovery. As of January 2, 2014 when PHMSA Eastern
Region staff inquired about the release,
no notification had been made to the NRC
regarding this natural gas
release.
On January
2, 2014, PHMSA Headquarters received an inquiry
from the Editorial Director of the Penobscot
Bay Pilot, a local newspaper
in Maine, regarding
a possible release
of natural gas from the Maritimes
Pipeline near Searsmont during the evening of December 31, 2013.
The PHSMA Eastern
Region office contacted Spectra Energy, the operator
of the Maritimes
and Northeast Pipeline,
and confirmed that a
release of gas did occur due
to the unintended opening of a
station emergency shutdown
(ESD) valve at the Maritimes
and Northeast Searsmont
Compressor Station. PHMSA Eastern Region staff also
confirmed that the
event had not been reported
to the National Response Center.
In
an email to Eastern Region
staff from Spectra
date January 3, 2014, Spectra
stated:
“The
gas release was caused by
the unintended opening
of a station emergency
shutdown (ESD) blowdown
valve at Maritimes
& Northeast Searsmont
Compressor Station on Dec. 31 around midnight. The ESD System was not activated and a station
isolation valve did not close, resulting
in the pipeline venting through the station
ESD system. The affected
section of pipeline
was isolated by the control room using mainline remote operated valves located
upstream and downstream of the station. The station was then subsequently isolated from the mainline
by Spectra responding personnel and the mainline
was restored to normal operations. We are investigating the cause of the unintended opening of the
ESD blowdown valve and the subsequent non-closure
of
the station isolation
valve.
Since the only gas release
was through the ESD system vent, this was not classified as a reportable incident. Thus no NRC report was required. This event does meet the definition of an Abnormal
Operating Condition (unintended valve operation), and the required
investigation is in progress. Any necessary corrective
actions will be implemented
as determined
by the
investigation.”
During a subsequent meeting with Spectra
on January 15, 2014, attended by PHMSA and Spectra personnel, Spectra again stated that the event at Searsmont was an intentional release of gas and not a reportable incident due to the fact that the gas released
through the ESD vent. Spectra
stated that they consider any release
through a relief device an intentional release because the relief device is designed
and functions to relieve gas pressure in the system. An incident per 191.3 requires an “unintentional estimated gas loss
of
three million cubic feet or more.”
PHMSA Eastern Region views Spectra’s interpretation of the code to be incorrect and views this event
as an unintentional release caused
by equipment failure.
Proposed Civil Penalty
Under 49 United
States Code, § 60122,
you are subject
to a civil penalty not to exceed $200,000 per violation per day the violation persists up to a maximum of $2,000,000 for a related series of violations. For violations occurring prior to January
4, 2012, the maximum
penalty may not exceed $100,000 per violation per day, with a maximum penalty
not to exceed $1,000,000 for a related
series of violations. The Compliance Officer has reviewed the circumstances and supporting documentation involved in the above probable
violation(s) and has recommended that you be preliminarily assessed a civil penalty of
$34,500 as follows:
Item number PENALTY 1 $34,500
Response to this
Notice
Enclosed as part of this Notice
is a document
entitled Response Options for Pipeline Operators in Compliance Proceedings. Please refer to this document and note the response options. All material you submit in response
to this enforcement action
may be made publicly
available. If you believe that any portion of your responsive material qualifies for confidential treatment under 5 U.S.C. 552(b), along with the complete original document you must provide a second copy of the document
with the portions you believe qualify for confidential treatment redacted and an explanation of why you believe the redacted information qualifies for confidential treatment under 5 U.S.C. 552(b).
If you do not respond
within 30 days of receipt
of this Notice,
this constitutes a waiver of your right to contest the allegations in this Notice and authorizes the Associate
Administrator for Pipeline Safety to find facts as alleged in this Notice without further notice
to you and to issue a
Final Order.
Please submit all correspondence
in this matter to Byron Coy, PE, Director,
PHMSA Eastern Region, 820 Bear Tavern Road, Suite 103, W. Trenton, NJ 08628. Please refer to CPF 1-2014-1011 on each document
you submit and please,
whenever possible, provide a signed PDF copy in electronic format. Smaller files may be emailed
to Byron.Coy@dot.gov.
Larger files should be sent on a CD accompanied by the
original paper copy to the Eastern Region
Office.
Additionally, if you choose to respond to this (or any other case), please ensure that any response letter pertains
solely to one CPF case number.
Sincerely,
Byron Coy
Director, Eastern Region
Pipeline
and Hazardous Materials Safety
Administration
Enclosures: Response
Options for Pipeline Operators
in Compliance Proceedings
