The Renewable Nations Institute takes a "whole-of-society" approach to stakeholder consultation utilizing systems modeling theory. This systems approach is supported by Threshold 21 (T21) Systems Dynamic (SD) Modeling software developed by the Millennium Institute. MEC 4722 Renewable Energy Capstone Project students are not required to conduct an SD Modeling analysis. However, the "whole-of-society" approach as represented in SD Modeling is emerging among donor agencies as a response to long-term economic recovery from the COVID-19 pandemic. The information provided below is intended as a brief introduction to SD Modeling utilizing T21 software to support life-cycle stakeholder consultation.
SYSTEMS DYNAMIC (SD) MODELING
Systems Dynamic (SD) modeling is a computer-aided approach to policy analysis and design. It applies to the computer-aided modeling of dynamic problems arising in complex social, managerial, economic, or ecological systems. More specifically, it applies to the macro analysis of dynamic systems characterized by interdependence, mutual interaction, information feedback and circular causality. SD modeling is applied in economics, public policy, environmental studies, defense, theory-building in social science, and in other areas, to examine macro-scale dynamics endogenous and exogenous linkages within and across complex systems.
The primary applications of SD modeling at the Institute are for: (1) predictive modeling and decision support for macro-scale (national, state and mega-city) energy policy, planning and investment; and (2) providing a definitive metric for measuring and verifying progress toward the ecological sustainability. SD modeling of coupled natural and human (CNH) systems in the context of energy, climate and the sustainability of human communities is the primary research focus of the Institute.
The Threshold 21 (T21) Systems Dynamic (SD) Model:
T21 simulation software is transparent, collaborative, and interconnected national policy planning tool that includes many critical features that support an inclusive, comprehensive and integrated development planning process. It not only allows policy and planning stakeholders to analyze and understand the interconnectedness between socioeconomic and environmental factors, but also offers the opportunity to customize the underlying model structure based the ever-changing dynamics of human and natural systems, and/or the advocated interests of individual stakeholder groups.
Users can review and modify various elements of the model structure (without deleting core structural assumptions), run a customized simulation based upon a proposed modification of the SD model structure, and analyze and compare core assumptions against proposed structural modifications. (Click on image below to enlarge.)
Users can review and modify various elements of the model structure (without deleting core structural assumptions), run a customized simulation based upon a proposed modification of the SD model structure, and analyze and compare core assumptions against proposed structural modifications. (Click on image below to enlarge.)
The T21 structural framework is organized in three spheres - Economy, Society and Environment - with each comprising of six spheres. (See Sphere and Sector diagrams, below.) The Economy Sphere contains sectors for production, investment, technology, government, households and ROW (Rest-of-World); the Society Sphere contains population, labor, health, education, poverty and infrastructure sectors; and the Environmental Sphere contains land, climate change, water, minerals, sustainability and emissions sectors. The Energy Sphere (shown below) is an overlay to the model as the subject of research.
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T21 Sphere and Sector Structure
with Energy Sphere Overlay 
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Expanded Model Structure:
Illustrating Causal Sphere-to-Sector and Sector-to-Sector Influences 
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Spheres and sectors are comprised, in aggregate, of thousands of Causal Loop Diagrams (CLD) that stem from the identification of specific "causal tracings" that are broadly accepted in conventional economic theory, or that may be the subject of research inquiry and/or structural (policy) reform. These CLDs contain contain "formulas" or "algorithms" that are vetted by peer-to-peer review. In essence, the many thousands of CLDs and their underlying formulas are each a simplified representation of the SD model in that they show casual relationships existing among all variables (CDLs) that impact systems behavior.
Casual relations in the T21 model are represented by lines with directional arrows, each of them coupled with a polarity that indicates a positive (+) or negative (-) relationship. Each variable in the model is characterized by an equation and unit of measure arrow indicating which factors are in the formation of the equation, and at the same time show where the variable is used (tracings). CLDs with directional and or unit of measure arrows, polarity values, and equations consist of the underlying "systems drivers" of the SD model. Note the CDL samples, below, that are key systems drivers impacting the Energy Sphere.
(Click on images to enlarge.)
Casual relations in the T21 model are represented by lines with directional arrows, each of them coupled with a polarity that indicates a positive (+) or negative (-) relationship. Each variable in the model is characterized by an equation and unit of measure arrow indicating which factors are in the formation of the equation, and at the same time show where the variable is used (tracings). CLDs with directional and or unit of measure arrows, polarity values, and equations consist of the underlying "systems drivers" of the SD model. Note the CDL samples, below, that are key systems drivers impacting the Energy Sphere.
(Click on images to enlarge.)
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A detailed example of sector construction with multiple casual loops is shown below:
(Click on image to enlarge.)
(Click on image to enlarge.)
At the level of micro analysis T21 users have access to examine model equations for system transparency, and modify model equations based upon dynamic, real-world conditions and/or research inquires. The model equation below examines the formula for determining "miles per gallon per vehicle" for a simulation on the impact of Combined Average Fleet Efficiency (CAFE) standards used for a policy study for the U.S. Congress.
(Click on image to enlarge.)
(Click on image to enlarge.)
The next two images show the tracking trees for "causes" and "use" of formulas as a determinate within a Casual Loop Diagram within and across Spheres and Sectors of T21 model structure.
(Click in images to enlarge.)
(Click in images to enlarge.)
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MODEL SIMULATION USING THRESHOLD 21
Once T21 model determinants are accepted and/or modified by stakeholders in the analysis of the development process, users can run simulations to determine results in policy changes, planning schedules, investments using a multitude of variable factors, compare the simulations, and save and/or publish the results. The Simulation Setup example below demonstrates how the process works to rum a simulation model. It involves selection policy determinants (left column) and assumptions (including customized assumptions), the running the simulation model. (Click in image below to enlarge.)
This simulation model results are then displayed as seen in the charts and tables below. T21 then allows users to view the model outcomes across the SD model based upon customized model inputs. Selecting from the policy table, shown at right in the image below, multiple display outputs can be viewed in interactive data tables, charts and graphs, as in the examples, below for motor gasoline consumption and energy demand.
(Click on images to enlarge.)
(Click on images to enlarge.)
The Millennium Institute's Threshold 21 (T21) Systems Dynamic (SD) Model will be integrated across the service platforms of the Institute for healthcare facility electrification.
ADDITIONAL SD MODELING RESOURCES
WEBINAR SLIDE - 11 MAY 2021
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