Designing Cost Accounting Models for Woody Biomass Systems and Direct Applications of Geothermal Energy

摘要

A framework for determining the characteristics of cost accounting models most appropriate to evaluating energy technologies at different stages in their development is outlined. This analytical perspective is used to evaluate existing models for wood energy plantations and for direct (non-electric) applications of geothermal energy. The concern is with micro-economic cost estimation systems based on a simulation of the technology's physical plant and the projected cash flow resulting from the investment. For discussion purposes three general stages of technology evaluation are described. The level of detail in the engineering simulation should increase as the evaluation progresses through the three stages. Too much detail in the preliminary stage restricts applicability of model outputs to specific system designs, some of which may be inappropriate for other potentially attractive applications. The economic analysis should gradually shift from a general economic perspective on all costs and benefits of system operation to a more specific depiction of cash flows as seen by project developers. Unfortunately, developers of cost models for both woody biomass plantations and direct applications of geothermal energy appear to build all the engineering and financial detail available into their models. They then apply them to any stage in the evaluation process to inaccurate assessments. (ERA citation 07:021171)