For example, the availability of power plants may increase at first as initial problems are overcome, and later decline due to more outages as parts wear out. By vintaging installations, their technical characteristics depend upon the year of installation and the age structure of the stock. The model accepts technology-specific discount rates as well as a general discount rate. This is used for discounting the yearly payments of investment costs over the economic life of a technology. The model can represent sunk costs of materials and energy carriers, that is, those embedded in a technology at its inception.
Examples are the uranium core of a nuclear reactor, or the steel embedded in an automobile.
Unless these are represented in the RES, their cost should be included in the investment cost. The investment in new technology may not occur in a single year, but can be represented as a series of annual increments. Fixed and variable operating and maintenance costs. Decommissioning or dismantling costs are accepted, with an optional time lag that, for example, may be required for radioactive material to cool down. The recuperation of sunk materials can be credited when a facility is decommissioned.