WESyS: Waste-to-Energy System Simulation Model

The Waste-to-Energy System Simulation (WESyS) model simulates the evolution of the U.S. waste-to-energy (WTE) industry based on industrial, technological, and incentive-related factors to help inform investment and research.

WESyS is an open-source, system dynamics model that simulates the development of the three primary waste resources: landfills, concentrated animal feeding operations, and publicly owned treatment works. It is split geographically between California and the rest of the United States.

WESyS users can explore technically feasible future scenarios of WTE industry development to gain high-level, long-term insights about their national and/or regional investment decisions and research opportunities.

Waste Resource Modules

WESyS includes eight modules: six resource modules that define waste resource dynamics for two regions in the United States and two modules (Global Inputs and Global Outputs) that manage the input and output data. The Global Inputs Module also models learning dynamics for technologies that are not yet commercially mature.

Within each module, the model performs calculations to estimate facility production for each type of waste resource and expected revenue for each technology configuration to ultimately calculate the overall value of each considered WTE technology configuration. These calculations are supported by eight submodules that factor in investments, incentives, and more.

System Dynamics Framework

The WESyS model uses a system dynamics framework to consider the many physical and social components that impact how the WTE industry might evolve over time. The model simulates three types of wet and gaseous waste resources and represents seven WTE technologies, six of which are commercially available.

Decisions by facility operators and investors are simulated so users can analyze future scenarios and explore how individual parts of the system might influence the buildout of the WTE industry. Users can see how the various components interact and respond to a range of regulatory and techno-economic and market conditions.

This approach provides a tool set for representing key physical and decision processes associated with industry evolution; serves as a vehicle for incorporating multiple perspectives, data, and assumptions; and creates a process to gain insight into a little-known industry.

Motivation Behind the Model

Through a collaboration with industry, government, and academia, NREL developed WESyS to help national government agencies, industry trade groups, utilities, state-level decision-makers, and water resource organizations understand the possible evolution of the U.S. WTE industry.

The total annual energy potential of wet and gaseous waste resources in the United States is more than 2.3 quadrillion British thermal units, or about 8% of the energy used by the U.S. transportation sector in 2018. Yet, many WTE technologies have struggled to make it to commercial scale.

WESyS can help national and regional decision-makers navigate the evolving WTE technology landscape to identify bottlenecks in the system that, if resolved, could advance the industry. Although the model is not designed to inform site-specific investment decisions, it is intended to answer broad questions about market growth, resource utilization, and technological learning. These questions could include which combination of incentives might support sustained growth of the WTE industry, or which waste resources might realistically contribute to energy production in different regions of the United States, including how much energy potential they have.

Related Publications

An Overview of the Waste-to-Energy System Simulation Model, NREL Technical Report (2020)