Siting Issues for Offshore LNG Facilities

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Siting Issues for Offshore LNG Facilities
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Presentation

• Background LNG and its transport, agency
  responsibilities
• Siting issues EIS (environmental and safety)
  risk analysis, consequence modeling
• Preliminary LNGMAP modeling results
• Summary

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What is LNG?

• Liquefied Natural Gas (LNG) is natural gas that
  has been cooled to -260F at atmospheric
  pressure
• Colorless, odorless, non-toxic and non-corrosive
• Less dense than water
• Liquid occupies 600 times less volume than gas
• Vapor is more dense than air until 162F when it
  becomes buoyant appears as white cloud since its
  cold temperature causes humidity in air to
  condense
• Flammable at concentrations between approximately
  5 and 15 by volume
• Non explosive in unconfined areas
• Composed mainly of
• methane and small amounts
• of heavier hydrocarbons
• such as ethane, propane,
• butane, and inerts such as
• nitrogen and carbon dioxide

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How does LNG get to us?

• Most sources are located in Trinidad and Tobago,
  Qatar, Algeria, Nigeria, Australia and Indonesia.
• Transported in large, specially built tankers to
  one of five U.S. import terminals.
• Most LNG is regasified and sent out via pipelines
  as ordinary natural gas some LNG is delivered to
  consumers as liquid.
• There are 113 LNG production, transport and
  storage facilities across the country.

Dominion Cove Point LNG, LP is located on the
Chesapeake Bay in Cove Point, Maryland, south of
Baltimore
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How is LNG transported?

• 175 specially designed ships with approximately
  140,000 m3 capacity
• LNG is stored in either double membrane
  containment systems or Moss spherical tanks with
  heavy insulation unpressurized but not freely
  vented
• Emergency systems identify potential safety
  problems and shut down operations
• 33,000 carrier voyages covering 60 million miles
  around the globe without a major accident over a
  45-year history
• In 16 marine incidents (9 with spillage) only
  minor hull damage occurred
• No explosions, cargo fire, or fatalities have
  ever occurred in the marine incidents

Moss
Membrane
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Federal Agency Oversight - Onshore -

• Federal Energy and Regulatory Commission
• Authorizes siting and construction of LNG import
  terminals
• Lead federal agency under National Environmental
  Policy Act analyzing environmental, safety,
  security and cryogenic design of proposed
  facilities
• Pipeline and Hazardous Materials Safety
  Administration of the DOT
• Authority over safety regulations and standards
  of onshore LNG facilities beginning at last valve
  before storage tanks

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Federal Agency Oversight - Offshore -

• United States Coast Guard (USCG)
• Responsible for the safety of marine operations
  at LNG terminals and of tankers in U.S. coastal
  waters
• Regulates the design, construction, manning, and
  operation of vessels and the duties of crew
• Inspects all LNG vessels to ensure they comply
  with safety regulations
• Ensures policies and procedures conform to
  required standards
• Assists in conducting emergency response drills
  to test response plans
• Ensures there are adequate safety and
  environmental protection equipment and procedures
  to respond to an incident
• Determines suitability of a waterway to transport
  LNG safely
• Creates safety rules for specific ports, such as
  port safety zones for each tanker
• USDOT Maritime Administration (MARAD)
• Issues license to operate deepwater port facility
• Works jointly with USCG to process applications
  to construct, own and operate deepwater ports

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Environmental Impact Statement (EIS) Process for
Offshore Facilities

• Necessary to satisfy requirements of National
  Environmental Policy Act (NEPA)
• Integrated with FERC requirements for onshore
  components and USCG requirements for offshore
  operations
• Prepared for the USCG by a 3rd party contractor
  paid for by the applicant and based on USCG
  specifications

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Project Components Requiring EIS

• Deepwater Port
• Offshore Pipeline
• Onshore Pipeline
• Graving Dock (if required)

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EIS Organization

• Description of proposed action and alternatives
  for each project component
• Description of affected environment for each
  component
• Environmental consequences of each alternative /
  component
• Cumulative impacts of multiple activities
• Risk management for terminal, marine operations
  and pipeline

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EIS Environmental Concerns

• Water Resources
• Water quality
• Circulation
• Turbidity
• Wildlife and Fisheries Resources
• Marine mammals
• Seabirds and migratory birds
• Aquatic habitats
• Benthos
• Plankton
• Fisheries
• Threatened and Endangered Species
• Marine mammals
• Sea turtles
• Birds
• Fisheries
• Essential Fish Habitat (EFH)
• Geological Resources
• Geologic setting

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EIS Environmental Concerns

• Cultural Resources
• Existing conditions
• LNG terminal archaeological survey
• Offshore pipeline archaeological survey
• Land Use, Recreation, and Visual Resources
• Principal uses of area in vicinity
• Near and off shore recreation
• General aesthetic appeal
• Socioeconomic Resources
• Population
• Employment
• Housing
• Commercial fisheries
• Recreational fisheries
• Environmental justice
• Transportation Resources
• Movement of marine vessels and helicopters
• Air Quality
• Pollutant levels

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EIS Safety and Security Concerns

• Major hazards
• Flammable vapor clouds that form if spill is not
  immediately ignited
• LNG pool fires that could occur on surface of
  water
• Rapid phase transition (RPT) from rapid mixing of
  LNG and water (less likely)
• Minor hazards
• Asphyxiation by concentrated vapors
• Exposure to low temperature LNG sufficient to
  cause rapid frostbite, severe tissue damage or
  death
• Thermal stress can cause brittleness and fracture
  in common construction materials like steel

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Risk Management Planning

• Risk management is designed to ensure
• Terminal safety
• Vessel safety
• Pipeline safety
• Port security and maritime safety
• Hazards Identification (HAZID) analysis is
  conducted to identify, rank and establish
  probability of occurrence of potential accidents
  for
• LNG carrier approach berthing
• Offloading of LNG
• LNG carrier unberthing
• Regasification of LNG
• Pipeline operations
• General facility assessment

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Risk Analysis

• Risk is potential for suffering harm or loss from
  an event
• Risk can be quantified as product of
• Probability of an event occurring
• Probability of preventive or mitigating measures
  failing
• Consequences of event
• LNG spills are considered low probability, high
  consequence risks
• Possible events
• Accidental LNG ship collision with another ship
  or a stationary object
• Intentional attack on LNG ship by terrorist group
• Understanding potential risks ahead of time
  allows for preparation and planning to mitigate
  the risks.

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LNG Consequence Analysis
Depends on
Modeled by
Release rate from vessel tank

• Quantity released
• Duration of release

Transport and spreading of pool
Pool spreading dynamics
Plume fate and transport

• Evaporation from spill to atmosphere (heat
  transfer from water and fire)
• Dense gas vapor dispersion

Ignition of LNG
Thermal radiation from pool fire
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Gaps in LNG Spill Modeling

• Over-simplified assumptions on release rate
  (ignores pressure effects varying head,
  glug-glug effect, hole shape)
• Effect of environmental conditions (currents,
  waves, wind) on pool development and vaporization
  not explicitly taken into account
• Simplified assumptions of vaporization and
  burning for large pool fires (evaporation rate
  poorly quantified, empirical models based on
  small scale experiments, effect of flamelets)

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LNGMAP

• ASA has extensive experience in spill modeling of
  oil and other hazardous materials in aquatic
  environments
• ASA is developing LNGMAP, a PC-based computer
  model based on ASAs proven integrated GIS and
  modeling approach
• Model components include release (orifice) model,
  pool fate and transport model, vapor dispersion
  model, thermal effects model, environmental
  conditions (hydrodynamics model)
• Model output provides geographical context for
  pool size and shape and vapor and thermal hazard
  zones

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LNGMAP Model Overview

• Intended for instantaneous or continuous moving
  LNG spills on water
• LNG is represented by spillets with unique mass,
  surface area and location
• LNG moves in response to winds and currents
• LNG vapor may either burn or disperse
• If LNG burns, thermal intensity levels are
  calculated
• If LNG disperses, the vapor plume is tracked and
  concentrations calculated

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LNG Release

• Stationary or moving, instantaneous or continuous
  source
• Orifice model release rate depends on
• Size (larger hole allows more flow)
• Shape (jagged hole lowers flow)
• Location (higher elevation above water surface
  lowers flow)
• Level of LNG in tank (lower level lowers flow)
• Tank venting (partial vacuum lowers flow)
• Simulated as a series of particles (spillets)
  having mass and size that undergo transport and
  fate processes

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Pool Spreading

• Upper limit on pool size depends on the duration
  of the release
• Pool will spread to the point where evaporation
  rate (or burning rate in case of a fire) equals
  the release rate into the pool
• Spreading is governed by fluid inertia, gravity
  forces and friction effects
• Pool shape is affected by waves, currents, and
  wind

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Vapor Dispersion

• Dispersion and transport is governed by local
  environmental conditions
• Vapor cloud initially hugs the ground when the
  vapors are cold (-260F to - 162F)
• When vapor warms above 162F the cloud becomes
  lighter than air and quickly disperses

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Burning

• Flammable with right proportions of air
  (approximately 5 to 15 methane by volume)
• Easily ignited by machinery, cigarettes or static
  electricity
• Will burn back to the vapor source
• Does not explode in unconfined spaces

Threshold Effect
1,600 BTU/hr/ft2 (5 kW/m2) Sufficient to cause pain in 20 seconds, 2nd degree burns are possible but non fatal. Typical value for injury threshold.
3,800 BTU/hr/ft2 (12 kW/m2) Minimum energy required for piloted ignition of wood and melting of plastic tubing. Typical value used for fatality.
7,900 BTU/hr/ft2 (25 kW/m2) Minimum energy required to ignite wood at indefinitely long exposure
12,000 BTU/hr/ft2 (38 kW/m2) Sufficient to cause damage to process equipment
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Preliminary LNGMAP Results in Boston Harbor

• Two scenarios in Boston Harbor
• Release via a 1 m diameter hole
• Release occurs during ebb tide after high slack
• Ship traveling at 10 kt in outer harbor and 5 kt
  in inner harbor
• SW wind at 5 mph
• Volume of LNG spilled 12,500 m3
• Release duration of 33.2 minutes

Assumed ship routes
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Outer Ship Path and Surface Spillets with Burning
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Thermal Radiation - Outer Ship Path
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Outer Ship Path and Surface Spillets with
Evaporation
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Vapor Plume - Outer Ship Path
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Inner Ship Path and Surface Spillets with Burning
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Thermal Radiation - Inner Ship Path
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Inner Ship Path and Surface Spillets with
Evaporation
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Vapor Plume - Inner Ship Path
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Summary

• LNG is an important energy source for the U.S.
• Ship borne transport of LNG is required because
  of distant sources
• Siting based on access to shipping and delivery
  options
• LNG risk analysis expanded from accidents to
  attacks since 9/11
• Both environmental and safety issues determine
  project acceptance or rejection
• Offshore siting presents less public safety risk
  (onshore presents more delivery options and lower
  costs)
• Models now under development to address analysis
  gaps in assessing consequences of LNG spills
• Future model systems will provide more accurate
  estimate of consequences resulting in better
  analysis of risk

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(Globe Staff Photo / David L. Ryan)