biogas

This spreadsheet serves as an Input file to the National Renewable Energy Laboratory's Waste-to-Energy System Simulation (WESyS) model developed in Stella Pro (isee systems, Lebanon, NH). WESyS is a national-level system dynamics model that simulates energy production from three sectors of the U.S. waste-to-energy industry: landfills, confined animal feeding operations (CAFOs), and publically owned treatment works (POTWs).

For our purposes, a scenario is a set of model conditions (i.e. parameter settings) that approximate a specified condition or potential reality. The rate-based development scenario outlined here represents the ability of publically owned treatment works (POTWs) to take advantage of rate of return regulation to recover the cost of capital associated with the development of waste-to-energy facilities (i.e., POTWs can recover costs by increasing the rates that they charge their customers for water treatment). Under rate-based financing, there is a tendency to invest in the most expensive technology. This is a well-recognized drawback of using a rate-based mechanism to cover capital investment. In California, recommendations have been made to limit rate-base increases to finance projects that directly tie into a state goal and increase demand for electricity. As a result, we limited the rate-based option to be available only to California wastewater treatement plants investing in electricity generation.

This spreadsheet serves as an Input file to the National Renewable Energy Laboratory's Waste-to-Energy System Simulation (WESyS) model developed in Stella Pro (isee systems, Lebanon, NH). WESyS is a national-level system dynamics model that simulates energy production from three sectors of the U.S. waste-to-energy industry: landfills, confined animal feeding operations (CAFOs), and publically owned treatment works (POTWs).

For our purposes, a scenario is a set of model conditions (i.e. parameter settings) that approximate a specified condition or potential reality. The non-negative feedstock cost scenario outlined here represents a potential future reality where feedstock costs for waste become positive (i.e., there is a market for wastes). For the three types of facilities represented in WESyS (i.e., wastewater treatment plants, landfills, and concentrated animal feeding operations (CAFOs)), only CAFOs are expected to have positive feedstock costs for manure in the near future. If this were to happen, CAFOs might chose to sell their waste rather than build on-site waste-to-energy (WTE) facilities. For this scenario, we adopted a farmer-owned cooperative model in which farmers may sell their manure to a cooperatively owned and operated WTE facility. For these farmer-owned cooperatives, we have allow for technology development under three pathways (Hydrothermal Liquifaction (HTL), Fischer-Tropsch (FT), and Renewable Natural Gas (RNG)) that are assumed to operate at full commercial scale. For a given technology pathway to become feasible, there must be enough animal units available to supply the commercial throughput requirement of the technology.

This spreadsheet serves as an Input file to the National Renewable Energy Laboratory's Waste-to-Energy System Simulation (WESyS) model developed in Stella Pro (isee systems, Lebanon, NH). WESyS is a national-level system dynamics model that simulates energy production from three sectors of the U.S. waste-to-energy industry: landfills, confined animal feeding operations (CAFOs), and publically owned treatment works (POTWs).

For our purposes, a scenario is a set of model conditions (i.e. parameter settings) that approximate a specified condition or potential reality. For the landfill diversion scenario outlined here, we examined California Senate Bill 1383, which sets forth a timeline for diversion of organic wastes from landfills. This scenario is only applied to the California landfill (CA LF) and California wastewater treatement plant (CA WWTP) modules. For this scenario, we modified the model to perform a set of calculations that reduce the amount of organic waste (in tons per year) based on the SB 1383 timeframe – 50% by 2020, 75% by 2025 and the total amount of waste and organics that went to California landfills in 2014. We also assumed that all waste diverted from landfills would go to wastewater treatment plants.

Waste to Energy System Simulation Model (WESyS) - Scenario Inputs and Supplemental Tableau Workbook
Daniel Inman, Ethan Warner, Anelia Milbrandt, Alberta Carpenter, Ling Tao, Emily Newes, and Steve Peterson (Lexidyne, LLC)

Abstract
Conversion of biogas from organic waste materials to usable energy (electricity, compressed natural gas [CNG], pipeline-quality natural gas [PQNG], and biofuel) has received attention because the U.S. Environmental Protection Agency categorized biogas-derived energy as a cellulosic biofuel in 2014, making it eligible to collect renewable identification number credits under this designation. NREL developed the Waste-to-Energy System Simulation model to help understand the development of the waste-to-energy system. The objective of this study is to identify barriers to energy production from waste materials, provide insights on the role of policy for this market, and identify data/modeling gaps in the existing modeling and data structure. This study is focused on biogas resources derived from landfills and from confined animal feeding operations (CAFOs) at a national level. Our results suggest that collection and conversion of biogas to energy from landfills and CAFOs has the potential to generate as much as 400 million giga joules (GJ) annually, with the largest energy potential from swine CAFOs. This study highlights the impact of system levers: such as the time delay between deciding to invest and having a completed facility and operating costs.

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