National Energy Options for Reducing Carbon Dioxide Emissions. Volume One

National Energy Options for Reducing Carbon Dioxide Emissions. Volume One

One point four point two The MARKAL Model

Characteristics of MARKAL

MARKAL is a demand-driven model. Its structure can be described as follows.

Energy is extracted from primary resources, then transformed by supply technologies into a variety of energy carriers such as fuels, electricity, and low temperature heat (for district heating systems); these energy carriers are finally used by a vast array of end-use technologies in order to satisfy various socioeconomic needs expressed as useful demand. Useful demand is a direct expression of a demand for a particular service. for example, steel, newsprint, train passengers-kilometres, automobile passenger-kilometres, houses to heat, etc. Useful demands are usually disaggregated into five sectors: industrial, transportation, residential, commercial, and nonenergy uses, each of which may be further divided into several subsectors.

Thus, MARKAL is driven by the specification of useful demands in each sector and subsector of the economic system. This implies in particular that the so-called final energy consumption of the various subsectors is not exogenously specified, but is rather determined by the model as a result of competition among the many demand technologies to satisfy the useful demands. The competition will usually result in some substitution among fuels. Where a choice among end-use technologies is not sought, a single hypothetical demand device can represent energy use in that subsector.

MARKAL is a dynamic model that is usually used to represent the energy system for up to nine time periods of five years each. It accepts a set of initial values for the installed capacities of all technologies and for their residual lives. From period to period, capacity of a technology is automatically conserved up to end of its service life. New technologies are allowed to become available at specified future dates.

MARKAL is a techno-economic model since its data base is composed mainly of technical coefficients describing the energy inputs and outputs of a very large set of technologies, their efficiencies, their costs (investment and operation, fixed and variable), their lifetime, their dates of availability, etc.

MARKAL can capture the most important features of energy systems, namely:

the necessity to satisfy final demands the limited availability of primary resources the obligation to balance supply and demand for intermediate resources the necessity to install sufficient capacity to be able to operate at a desired level the capacity accumulation process, through investment, retention, and then phasing out of residual capacity the input-output interaction between a set of activities other types of constraints, such as upper bounds on market penetration and allowable emissions.