feedstock

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.

The use of plant biomass for energy has existed since humans mastered the use of fire, although utilization beyond the open fire has evolved. The concept of using recent biomass as a major energy feedstock is being revisited, driven by high consumer demand (growing population), declining domestic oil supplies, increasing cost of fossil fuels, and a desire to curb the emission of greenhouse gases (Johnson et al., 2007b). In general terms, agriculture and forestry are the economic sectors commercially producing a wide array of bioenergy feedstocks (e.g., grains, herbaceous annuals, herbaceous perennials, and woody perennials). For this review, biomass feedstock is any nongrain, plant-derived feedstock. These commodities can serve as feedstock for cellulosic ethanol or other thermochemical platforms such as gasification or pyrolysis.

The type of bioenergy feedstock produced and the desired energy product can alter the management implications, which likely will vary by region. It is also likely that a given farm operation may produce multiple feedstocks, including corn and soybean grain, perennial grasses, and crop residues. The potential risks and benefits of growing and using feedstocks vary considerably (Johnson et al., 2007b). The challenge of establishing a perennial biomass system depends on prior management. Conversion of highly diverse grassland systems to low-diversity or monoculture perennial systems could reduce the environmental benefits of these lands. Conversely, converting from high-input, annual crop species to perennial species could reduce input requirements (fertilizer, fuel, pesticides) and reduce erosion risks, and thus have positive environmental impacts (Mann and Tolbert, 2000). Agronomic, environmental, and economic issues need to be addressed for the wide range of feedstocks and feedstock combinations to assure sustainability.

The Regional Feedstock Partnership (the Partnership) has published a report to summarize its accomplishments from 2008–2014. DOE’s Bioenergy Technologies Office (BETO) partnered with the Sun Grant Initiative and Idaho National Laboratory to co-author this report.

The report, entitled Regional Feedstock Partnership Summary Report: Enabling the Billion-Ton Vision, includes appendices describing study findings for nine different energy crops and containing a list of the more than 400 scientific presentations and publications produced by the Partnership.

A wide range of stakeholders will benefit from the Partnership’s work—farmers can gain further knowledge about energy crops, companies building biorefineries that rely on corn stover now have more yield-specific information, and students trained through the Partnership have the knowledge to become a ready workforce for biomass production, logistics, and conversion.

The Partnership has engaged the nation’s leading researchers to populate the Bioenergy Knowledge Discovery Framework (KDF) with new data on energy crop yields. Modeling crop yields reduces risks associated with the commercial planting of dedicated energy crops, and can be useful for farmers nationwide as they plan their crops in future years. Because of the information gained through the Partnership, many of the projections set forth in the Billion-Ton Study that were once thought by some to be optimistic have been proven reasonably realistic.

The 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy is the third in a series of Energy Department national assessments that have calculated the potential supply of biomass in the United States. The report concludes that the United States has the future potential to produce at least one billion dry tons of biomass resources (composed of agricultural, forestry, waste, and algal materials) on an annual basis without adversely affecting the environment. This amount of biomass could be used to produce enough biofuel, biopower, and bioproducts to displace approximately 30% of 2005 U.S. petroleum consumption and would not negatively affect the production of food or other agricultural products.

Water sustainability is an integral part of the environmental sustainability. Water use, water quality, and the demand on water resource for bioenergy production can have potential impacts to food, feed, and fiber production and to our social well-being. With the support from United State Department of Energy, Argonne National Laboratory is developing a life cycle water use assessment tool for biofuels production at the national scale with multiple spatial resolutions. This open-access web-based model – WATER (Water Assessment Tool for Energy Resources) – ties hydrologic cycle to energy production supply chain with a focus on feedstock production and biorefinery conversion stages. The model employs water footprint accounting to quantify the consumption of blue water, green water, and grey water in the fuel production at regional, state, and county resolution for the entire United States. Direct and indirect water uses are considered, which includes electricity generation and petroleum fuel and natural gas production. It is capable of simulating future climate scenarios. Currently, WATER includes biofuel produced from corn grain, corn stover, switchgrass, miscanthus, and soybean. The model is designed to allow for evaluation of production pathways at the region where the specific feedstock grown; for comparison of biorefinery locations based on water sustainability metric, and for analysis of the interplay of policy, feedstock, pathway, and location factors and the trade-offs among environmental, economic, and social impacts.

When we think about sustainable bioenergy feedstocks in the United States, we ask ourselves what we will grow, where we will grow it, and how much we will grow. We also must consider the local as well as the broad-scale implications. From the perspective of landscape ecology, we tend to look at the broader scales. It is one of the big challenges of bioenergy, not just looking at what happens to the local farmer but thinking about broader implications. From a global perspective, we also need to ask the same questinos, how much, what type and where? We also need to understand what drives land-use change to determine how we can address causes of land-use change equitably in order to foster social benefits as well as economic and environmental benefits across the board. A number of reports on the topic of sustainable bioenergy are currently being published, which reflects the increasing number of groups that are working on this issue of land-use change and equity. This topic is an international issue and presents an opportunity for international cooperation.

A Workshop for Oak Ridge National Laboratory (ORNL), the US Environmental Protection Agency (EPA), and their collaborators was held on September 10-11, 2009 at ORNL. The informal workshop focused on “Sustainability of Bioenergy Systems: Cradle to Grave.” The topics covered included sustainability issues associated with feedstock production and transport, production of biofuels and by-products, and delivery and consumption by the end users. The workshop had two overall goals, to share information about their activities in this area and to identify immediate and long-term needs and opportunities for collaboration.  The workshop also created opportunities to present key issues of bioenergy sustainability and discuss work that is ongoing to address these issues; to develop a systems perspective on bioenergy sustainability
and to identify questions that lead toward a workable definition of bioenergy sustainability.

An efficient and sustainable biomass feedstock production system is critical for the success of the biomass based energy sector. An integrated systems analysis framework to coordinate various feedstock production related activities is, therefore, highly desirable. This article presents research conducted towards the creation of such a framework. A breadth level mixed integer linear programming model, named BioFeed, is proposed that simulates different feedstock production operations such as harvesting, packing, storage, handling and transportation, with the objective of determining the optimal system level configuration on a regional basis. The decision variables include the design/planning as well as management level decisions. The model was applied to a case study of switchgrass production as an energy crop in southern Illinois. The results illustrated that the total cost varied between 45 and 49 $ Mg
1 depending on the collection area and the sustainable biorefinery capacity was about 1.4 Gg d
1. The transportation fleet consisted of 66 trucks and the average utilization of the fleet was 86%. On-farm covered storage of biomass was highly beneficial for the system. Lack of on-farm open storage and centralized storage reduced the system profit by 17% and 5%, respectively. Increase in the fraction of larger farms within the system reduced the cost and increased the biorefinery capacity, suggesting that co-operative farming is beneficial. The optimization of the harvesting schedule led to 30% increase in the total profit. Sensitivity analysis showed that the reduction in truck idling time as well as increase in baling throughput and output density significantly increased the profit.

Indicators are needed to assess environmental sustainability of bioenergy systems. Effective indicators
will help in the quantification of benefits and costs of bioenergy options and resource uses. We identify
19 measurable indicators for soil quality, water quality and quantity, greenhouse gases, biodiversity, air
quality, and productivity, building on existing knowledge and on national and international programs
that are seeking ways to assess sustainable bioenergy. Together, this suite of indicators is hypothesized
to reflect major environmental effects of diverse feedstocks, management practices, and post-production
processes. The importance of each indicator is identified. Future research relating to this indicator suite is
discussed, including field testing, target establishment, and application to particular bioenergy systems.
Coupled with such efforts, we envision that this indicator suite can serve as a basis for the practical
evaluation of environmental sustainability in a variety of bioenergy systems.

This paper examines the impact of biofuel expansion on grain utilization and distribution at the state and cropping district level as most of grain producers and handlers are directly influenced by the local changes. We conducted a survey to understand the utilization and flows of corn, ethanol and its co-products, such as dried distillers grains (DDG) in Iowa. Results suggest that the rapidly expanding ethanol industry has a significant impact on corn utilization in Iowa. Comparing to the earlier survey results, ethanol plants drew a considerable amount of corn away from traditional destination markets, such as feeders or export markets. A major portion of corn supplies came from in-state sources, while the sales of Iowa ethanol and DDG were dominated by out-of-state buyers.