Course 02 of 20 · Natural Gas Desk Academy

Units, Heating Value & Quantities

Stage A, Gas literacy and measurement. Level 1 of 10.

Conversion between volume, energy and mass, heating value and calorific conventions, and how metered quantity is actually established.

124 chapters · 11 modules · every chapter one 8 to 10 minute explainer · builds on: Course 01

Enrol or enquire See the 124 chapters
How a chapter is sized

One chapter is one idea taken to the point of use

Each chapter is a single self-contained explainer of 8 to 10 narrated minutes, covering one idea to the point where you can use it.

Chapters run in order. Each one assumes only what the chapters before it taught, and capability belonging to a later course is named and deferred rather than half-covered.

Curriculum

11 modules · 124 chapters

Open any module for its full chapter list, in teaching order.

M0 Quantity as a Determined Figure Ch 1-10
  1. Why Gas Trades on Energy and Not on Volume
  2. The Three Bases a Gas Figure Can Carry
  3. The Measurement Chain from Instrument to Invoice Line
  4. Custody Transfer and Why the Point Matters
  5. Standards, Codes and Incorporation by Reference
  6. Accuracy, Precision and Bias Distinguished
  7. Significant Figures, Rounding and Where It Bites
  8. Who Measures, Who Checks and Who Signs
  9. Measured, Determined and Allocated Are Different Words
  10. What This Subject Settles and What It Hands On
M1 Volume Units and Reference Conditions Ch 11-20
  1. The Cubic Metre and the Standard Cubic Foot
  2. Normal and Standard: Two Reference Bases, Not One
  3. Reference Temperature Conventions Across Regions
  4. Line Volume Against Reference Volume
  5. Pressure Units and the Absolute Against Gauge Trap
  6. Temperature Scales and the Absolute Requirement
  7. The Ideal Gas Law as the Backbone of Correction
  8. Compressibility and Why Real Gas Departs from Ideal
  9. Supercompressibility and the Correction Applied in the Field
  10. A Volume Conversion Worked Twice, Right and Wrong
M2 Energy Units and the Conversion Grid Ch 21-32
  1. The Therm, the Decatherm and British Practice
  2. The British Thermal Unit and the MMBtu
  3. The Joule, the Gigajoule and Metric Energy Practice
  4. The Megawatt Hour as a Gas Unit
  5. Building the Conversion Grid You Can Work From
  6. Rate Against Quantity: Per Day, Per Hour, Per Month
  7. Daily, Monthly and Annual Totals Reconciled
  8. The Gas Day and Why the Clock Defines a Quantity
  9. Energy Rounding and Auditable Arithmetic
  10. Unit Errors That Reach a Confirmation
  11. Reading the Units Definition in an Agreement
  12. Unit Conversion Under Time Pressure
M3 Calorific Value and Its Conventions Ch 33-44
  1. What Calorific Value Actually Measures
  2. Gross and Net: The Water of Combustion
  3. Which Calorific Value an Agreement Bills On
  4. Volumetric and Mass-Based Calorific Value
  5. Combustion Reference Against Metering Reference
  6. Calorific Value Calculated from Composition
  7. The Calorimeter and Direct Measurement
  8. Specification Bands Rather Than Point Values
  9. Rich and Lean Gas: One Pipeline, Different Heat
  10. Averaging Calorific Value Over a Billing Period
  11. Calorific Value Zones on a Network
  12. A Heating Value Error Traced to Cash
M4 Composition, Wobbe and Interchangeability Ch 45-56
  1. Reading a Gas Composition Report
  2. Mole, Volume and Mass Fractions Distinguished
  3. Methane and the Heavier Hydrocarbons
  4. Inerts: Nitrogen, Carbon Dioxide and Dilution
  5. The Wobbe Index and What It Captures
  6. Interchangeability as a Commercial Constraint
  7. Blending to a Wobbe Target
  8. Nitrogen Ballasting and Enrichment Arithmetic
  9. Biomethane, Hydrogen and Composition Drift
  10. Dew Point, Water Content and the Meter
  11. Off-Specification Gas and the Quantity Question
  12. Composition Arithmetic Worked End to End
M5 Mass, Density and Cross-Phase Conversion Ch 57-66
  1. Molar Mass of a Gas Mixture
  2. Density, Relative Density and Specific Gravity
  3. Converting a Volume into Tonnes
  4. The Tonne of Liquefied Gas and Its Energy Content
  5. Compressed Gas: Mass Held in a Fixed Volume
  6. Energy Density Compared Across Phases
  7. Boil-Off and Phase-Change Quantity Effects
  8. Mass Balance as a Quantity Check
  9. Energy Balance Against Mass Balance
  10. Cross-Phase Conversion Errors Worth Money
M6 Metering Technology and What Each Establishes Ch 67-78
  1. What a Gas Meter Can and Cannot Establish
  2. Diaphragm Meters and Domestic Measurement
  3. Rotary and Turbine Meters in Commercial Service
  4. Orifice Plates and Differential Pressure Measurement
  5. Installation Effects and Why Geometry Is Contractual
  6. Ultrasonic Meters and Transit-Time Measurement
  7. Coriolis Meters and Direct Mass Measurement
  8. Thermal Mass and Vortex Meters in Niche Service
  9. Meter Sizing, Turndown and the Low-Flow Problem
  10. The Volume Corrector and the Flow Computer
  11. Check Meters, Redundancy and Dual Streams
  12. Choosing a Meter for a Custody Point
M7 Correction, Chromatography and Energy Determination Ch 79-90
  1. The Correction Calculation in Full
  2. Fixed-Factor Correction and Where It Is Permitted
  3. Live Pressure and Temperature Measurement
  4. Compressibility Inputs and the Composition Assumption
  5. Gas Chromatography: How Separation Yields a Composition
  6. Chromatograph Calibration and Reference Gas
  7. Sampling Systems and the Representative Sample
  8. Spot, Composite and Continuous Sampling Compared
  9. Putting Volume and Heating Value Together
  10. Time Alignment of Volume and Heating Value
  11. Deemed and Declared Values When Analysis Fails
  12. One Station, One Day, Determined End to End
M8 Meter Error, Proving and Uncertainty Ch 91-101
  1. Where Meter Error Comes From
  2. Calibration, Traceability and the Certificate
  3. Proving a Meter While It Stays in Service
  4. The Error Curve and Flow-Weighted Correction
  5. Expressing Uncertainty as a Range
  6. Combining Uncertainty Through the Chain
  7. Uncertainty Targets Written into an Agreement
  8. Detecting a Failing Instrument from the Data
  9. Retrospective Correction and the Error Period
  10. Estimation When Measurement Is Absent
  11. An Uncertainty Statement a Counterparty Will Accept
M9 Allocation of Measured Quantity Ch 102-111
  1. Why Allocation Exists at All
  2. The Allocation Point and the Metered Boundary
  3. Nomination-Based Allocation
  4. Pro-Rata and Ranked Allocation Methods
  5. Operational Balancing and Allocation Agreements
  6. Metered and Allocated Quantity Reconciled
  7. Allocation at a Wellhead and in a Gathering System
  8. Allocation Across a Processing Plant
  9. Provisional and Final Allocated Quantities
  10. Allocation Statements and the Data Behind Them
M10 Shrinkage, Losses and the Closing Case Ch 112-124
  1. Shrinkage as a Quantity Someone Must Account For
  2. Fuel Gas: Compression and Process Consumption
  3. Line Loss, Leakage and Venting
  4. Line Pack and the Quantity Held in the Pipe
  5. Unaccounted-For Gas and How It Is Analysed
  6. Theft, Tampering and Unmetered Consumption
  7. The System Balance Statement
  8. Shrinkage Shared Among Shippers
  9. Measurement Governance and the Audit Trail
  10. A Full Month Determined End to End, Part One
  11. A Full Month Determined End to End, Part Two
  12. Where Quantity Determination Stops Being Decisive
  13. The Quantity Skills Carried Into Every Later Course

The brochure gives each of these 124 chapters a paragraph on what it covers and what you can do once you have worked through it.

This is course 2 of twenty

It stands alone, and it is also the entry point to the Natural Gas Desk Academy pathway.

Enrol or enquire See the whole pathway