Model Development
Model development constitutes one of the core activities of work within the GTSP. The modeling framework must evolve and develop to keep pace with the changing nature of technology strategy questions and integrated assessment issues. Our model development efforts are focused on two important areas: improving the resolution and level of detail in the economic-energy system modules of our model set and extending our understanding of agricultural and land use systems and their relationships with technology choices and climate impacts.
The Third-Generation Model (TGM)
The PNNL modeling team has begun the development of a new framework to better address the ever-changing nature of the climate change problem. With time, the climate problem has become increasingly complex. This complexity is a direct reflection of the evolving science, technology, and policy. For example, the role of technology has been increasingly recognized as a crucial determinant of future anthropogenic greenhouse gas emissions and of the cost of any response to limit emissions. Yet, one of the most difficult tasks for scientists participating in the IPCC third assessment report was the reconciliation of chapters that examined technology options with reduced net emissions of greenhouse gases, "bottom-up" studies, and chapters that reported cost estimates from economic "top-down" studies.
Much of the difficulty stems from the fact that neither approach as yet encompasses the other. Bottom-up studies take advantage of greater technological detail, but lack the aggregate economic context in which technologies compete and penetrate the market. Top-down studies represent the larger economic context, but lack technological detail. To address the role of technology requires a modeling system that can bridge the gap between "bottom-up," that is the engineering detail of technologies, and "top-down," that is aggregation of technologies within the context of a macro-energy-agriculture-land use-economy-climate system to create a complete picture of the wide array of important interactions.
New model framework for electricity generation facilitates analysis at much finer level of technological detail. Full-Size (.gif, 24Kb)
It is this increasing complexity that requires the team to invest in the development of new tools. Tool development has already begun. A prototype model has been developed and is already being tested. These tools, which will be the third generation in modeling tools built at PNNL, will be based on a modular approach to model development. The new approach will facilitate more rapid examination of technology-related developments, including the assessment of new markets. The new modeling environment will build on the algorithms and frameworks of the MiniCAM and SGM models. Improvements will include the development of modular technology representations, databases to support an expanded set of technology representations (e.g., alternative transportation systems or combined heat and power), an expanded set of market representations (e.g., hydrogen markets), and increased specificity in technological descriptions (e.g., distributed versus central fuel cell systems and alternative transportation systems).
The modular structure is well suited to increase the productivity of collaborations between the PNNL team and other regional and technical teams around the world. This is particularly important to the continually expanding network of international collaborations. Discrete, well-documented modules will enable more rapid development of new regional TGM components as well as upgrades for existing modules.