Madrid Forum

See European Gas Regulatory Forum.

Major interstate pipeline

In the US, a pipeline company whose combined sales for resale and gas system throughput, transported interstate or stored for a fee, exceeded 50 bcf in the previous year.

Make up

Gas that a buyer under a long-term sales contract may be able to take above its Annual Contract Quantity, at no or reduced charge, to make up for gas it has paid for but not used in earlier years. The opposite of Carry forward.


Document containing a full statement of the ship’s cargo, extracted from the bill of lading.

Manning scales

The minimum number of officers and crew members that can be engaged on a ship to be considered as sufficient hands with practical ability to meet every possible eventuality at sea.

Manufactured gas

Gas produced by certain processes from oil, coal or coke.

Maritime emissions controls

As part of global efforts to reduce atmospheric pollution, stricter controls on emissions of sulphur dioxide (SOx), nitrogen dioxide (NOx) and carbon dioxide from shipping have been introduced or are planned. Most of the US and Canadian coasts have been designated low SOx and NOx zones, while the North Sea and Baltic Sea are low SOx zones. The EU plans to implement more sweeping restrictions in coming years. The International Maritime Organisation is coordinating efforts to reach wider international agreements on reductions, though progress has been slow. International shipping accounts for around 3% of global carbon dioxide emissions at present, but the IMO has estimated this could rise to 18% by 2050 without adequate regulation. Tighter emissions limits should lead to the use of more efficient engines and other technology on ships including LNG carriers. See also Dual fuel.

Markets centre

An interchange where multiple pipelines or electric transmission lines interconnect and form a hub. See Hub.

Market clearing price

The price at which supply equals demand.

Market-area storage

Storage or hub facilities located near natural gas users (markets).

Market-based price

The price for natural gas as determined by the decisions of many buyers and sellers in a market.

Marketing affiliate

A marketer who is owned or controlled by a pipeline company. See FERC Order 497.

Master (Captain)

Highest officer aboard ship who oversees all ship operations; has general charge of the vessel, overall responsibility. Handles all ship’s records and communications, and receives and implements instructions from home office; takes command of vessel in inclement weather and in crowded or narrow waters. See Crew

Maximum allowable operating pressure (MAOP)

The maximum gas pressure at which a pipeline system or process facility is allowed to operate.

Maximum capacity of pipeline

The maximum amount of natural gas a segment of pipeline can contain at a given time.

Maximum daily quantity (MDQ)

The maximum daily quantity of natural gas that can be nominated for delivery to a customer’s premises.

Maximum demand

The greatest of all demands of the load that has occurred within a specified period of time.

mcf, MCF, Mcf

A measurement of volume denoting one thousand cubic feet of natural gas. 1,000 cf of gas = 1.03 mmBtu (also, 1 kWh = 3,412 Btu). See note under cubic foot for alternative terminology

Megajoule (MJ or MMJ)

Equivalent to one million joules, or 3.6 MJ = 1kWh.

Megawatt (MW)

A unit of electricity equal to 1m watts, or 1,000 kilowatts.

Memorandum of Understanding (MoU)

Normally a brief document setting out the framework for a full contract to be signed in the future and a planned date for its completion. Also known as a Heads of Agreement or Memorandum of Intent. 


A mechanical device for automatically measuring and recording quantities of gas.


The simplest hydrocarbon (CH4) and the main constituent of natural gas, it is also known as C1 in the carbon complexity chain. See Natural gas

Midstream activities

The activities that lie between the Upstream and Downstream sections of the gas supply chain. The term is not well defined and may be used include elements that also fall into the other two categories, such as natural gas processing.

Mid-term gas contract

A supply contract in the physical market covering gas deliveries up to 18 months, although most mid-term contracts are for one year or less. These contracts can be characterized by 1) variable prices, where the cost of the commodity is indexed over time to the futures price of some published spot price; 2) fixed reservation fee and service fee; and 3) mainly fixed volumes per day or per month with modest variation. These contracts are of long enough term to hedge price risk with financial instruments. These contracts are important for local distribution companies (LDCs) because they can extend over a heating season. See Physical gas contract


The molar composition of a sample of natural gas expressed as a percentage of the whole.

Most-favoured nation clause

A contract clause that recognises a status accorded by one nation to another in international trade. Typically this means that the receiving nation will be granted all trade advantages, such as low tariffs, that any other nation receives. They will, therefore, always be treated at least as well as other nations.

Multilateral institutions

A major source of LNG financing for developing countries; includes Asian Development Bank (ADB), European Bank for Reconstruction and Development (EBRD), International Bank for Reconstruction and Development (IBRD) and the International Finance Corporation (IFC). See Export-credit agencies (ECAs)

Must-take gas

Natural gas supplies committed to a purchaser under terms such as drainage protection or reservoir protection clauses or other provisions that absolutely obligate a purchaser to take natural gas from a supplier.


One million British thermal units.

mt/y, Mtpa

Million tonnes a year/per annum.