The CIMS model has been developed by EMRG over the past several decades and is the primary model used by EMRG researchers. Below is a brief description of CIMS from Rivers & Jaccard (2006).
The CIMS hybrid model is an integrated, energy–economy equilibrium model that simulates the interaction of energy supply demand and the macro-economic performance of key sectors of the economy, including trade effects. Unlike most computable general equilibrium models, however, the current version of CIMS does not equilibrate government budgets and the markets for employment and investment. Also, its representation of the economy’s inputs and outputs is skewed towards energy supply, energy-intensive industries, and key energy end-uses in the residential, commercial/institutional, and transportation sectors.
As a technology vintage model, CIMS simulates the evolution of capital stocks over time through retirements, retrofits, and new purchases, in which consumers and businesses make sequential acquisitions with limited foresight. The model calculates energy costs (and emissions) at each energy service demand node in the economy, such as heated commercial floor space or person-kilometres-travelled. In each time period, capital stocks are retired according to an age-dependent function (although retrofit of unretired stocks is possible if warranted by changing economic conditions), and demand for new stocks grows or declines depending on the initial exogenous forecast of economic output, and then the subsequent interplay of energy supply and demand and the macro-economic feedbacks between the energy sector and the rest of the economy. A model simulation iterates between energy supply and energy demand until energy price changes fall below a threshold value, and repeats this convergence procedure in each subsequent 5-year period of a complete run, which usually extends 30–35 years. A similar iterative convergence procedure is followed to equilibrate the markets for goods and services.
CIMS simulates the competition of technologies at each energy service node in the economy based on a comparison of their life cycle cost (LCC) mediated by some technology-specific controls, such as a maximum market share limit in the cases where a technology is constrained by physical, technical, or regulatory means from capturing all of a market. Instead of basing its simulation of technology choices only on financial costs and social discount rates, CIMS applies a formula for LCC that allows for divergence from that of conventional bottom-up analysis by including intangible costs that reflect revealed and stated consumer and business preferences with respect to specific technologies and time.