A working paper review of current approaches to accounting for indirect land-use changes in green house gas balances of biofuels. This report reviews the current effort made worldwide to address this issue. A
description of land-use concepts is first provided (Section 2) followed by a classification of
ILUC sources (Section 3). Then, a discussion on the implications of including ILUC
emissions in the GHG balance of biofuel pathways (Section 4) and a review of methodologies
being developed to quantify indirect land-use change (Section 5) are presented. Section 6
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A series of life cycle assessments (LCA) have been conducted on biomass, coal, and natural gas systems in order to quantify the environmental benefits and drawbacks of each. The power generation options that were studied are: (1) a biomass-fired integrated gasification combined cycle (IGCC) system using a biomass energy crop, (2) a direct-fired biomass power plant using biomass residue, (3) a pulverized coal (PC) boiler representing an average U.S. coal-fired power plant, (4) a system cofiring biomass residue with coal, and (5) a natural gas combined cycle power plant.
An analysis was performed at NREL to examine the global warming potential and energy balance of power generation from fossil and biomass systems including CO2 sequestration. To get the true environmental picture, a life cycle approach, which takes into account upstream process steps, was applied. Each system maintained the same constant generating capacity and any lost capacity due to CO2 sequestration was accounted for by adding power generation from a natural gas combined-cycle system. This paper discusses the systems examined and gives the net energy and GWP for each system.
The generation of electricity, and the consumption of energy in general, often result in adverse effects on the environment. Coal-fired power plants generate over half of the electricity used in the U.S., and therefore play a significant role in any discussion of energy and the environment. By cofiring biomass, currently-operating coal plants have an opportunity to reduce the impact they have, but to what degree, and with what trade-offs? A life cycle assessment (LCA) has been conducted on a coal-fired power system that cofires wood residue.
It is technically feasible to capture CO2 from the flue gas of a coal-fired power plant and various researchers are working to understand the fate of sequestered CO2 and its long term environmental effects. Sequestering CO2 significantly reduces the CO2 emissions from the power plant itself, but this is not the total picture.
This report discusses the development of greenhouse gas (GHG) emissions estimates for the production of Fischer-Tropsch (FT) derived fuels (in particular, FT diesel), makes comparisons of these estimates to reported literature values for petroleum-derived diesel, and outlines strategies for substantially reducing these emissions.
Coal has the largest share of utility power generation in the U.S., accounting for approximately 56% of all utility-produced electricity (U.S. DOE, 1998). Therefore, understanding the environmental implications of producing electricity from coal is an important component of any plan to reduce total emissions and resource consumption.
It has become widely accepted that biomass power offers opportunities for reduced environmental impacts compared to fossil fuel-based systems. Intuitively obvious are the facts that per kilowatt-hour of energy produced, biomass systems will emit less CO2 and consume less non-renewable energy.
A life cycle assessment (LCA) of different coal-fired boiler systems was performed at NREL in collaboration with the Federal Energy Technology Center. Three designs were examined to evaluate the environmental aspects of current and future coal systems.
Biodiesel is a renewable diesel fuel substitute. It can be made from a variety of natural oils and fats. Biodiesel is made by chemically combining any natural oil or fat with an alcohol such as methanol or ethanol. Methanol has been the most commonly used alcohol in the commercial production of biodiesel. In Europe, biodiesel is widely available in both its neat form (100% biodiesel, also know as B100) and in blends with petroleum diesel. European biodiesel is made predominantly from rapeseed oil (a cousin of canola oil).
Biodiesel is a renewable diesel fuel substitute that can be made by chemically combining any natural oil or fat with an alcohol such as methanol or ethanol. Methanol has been the most commonly used alcohol in the commercial production of biodiesel. In Europe, biodiesel is widely available in both its neat form (100% biodiesel, also known as B100) and in blends with petroleum diesel. Most European biodiesel is made from rapeseed oil (a cousin of canola oil).
A life cycle assessment (LCA) on coal-fired power systems has been conducted to assess the environmental effects on a cradle-to-grave basis. Three different designs were studied: (1) a plant that represents the average emissions from coal-fired power plants in the U.S. today, (2) a plant that meets the New Source Performance Standards (NSPS), and (3) an advanced plant incorporating a low emission boiler system (LEBS).
Electric power production from biomass has the potential to make significant contributions to the power mix in the U.S., and to do so with substantially fewer environmental impacts than current technologies. Using dedicated energy crops for power production will significantly close the carbon cycle, reduce and stabilize feedstock costs, increase the feasible size of biomass power plants, and provide economic benefits to agricultural communities.
EXECUTIVE SUMMARY: Life cycle assessment (LCA) is a powerful tool that may be used to quantify the environmental impacts of products and services. It includes all processes, from cradle-to-grave, along the supply chain of the product. When analysing energy systems, greenhouse gas (GHG) emissions (primarily CO2, CH4 and N2O) are the impact of primary concern. In using LCA to determine the climate change mitigation benefits of bioenergy, the life cycle emissions of the bioenergy system are compared with the emissions for a reference energy system.
The IPCC SRREN report addresses information needs of policymakers, the private sector and civil society on the potential of renewable energy sources for the mitigation of climate change, providing a comprehensive assessment of renewable energy technologies and related policy and financial instruments. The IPCC report was a multinational collaboration and synthesis of peer reviewed information: Reviewed, analyzed, coordinated, and integrated current high quality information.
This study focuses on the simulation of a complete process for producing butanol via
acetone, butanol, and ethanol corn fermentation.
We assessed the life-cycle energy and greenhouse gas (GHG) emission impacts of the following three soybean-derived fuels by expanding, updating, and using Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model: (1) biodiesel produced from soy oil transesterification, (2) renewable diesel produced from hydrogenation of soy oil by using two processes (renewable diesel I and II), and (3) renewable gasoline produced from catalytic cracking of soy oil.
The aim of this study is to show the impact of different assumptions and methodological choices on the life-cycle greenhouse gas (GHG) performance of biofuels by providing the results for different key parameters on a consistent basis. These include co-products allocation or system expansion, N2O emissions from crop cultivation, conversion systems and co-product applications and direct land-use change emissions. The results show that the GHG performance of biofuels varies depending on the method applied and the system boundaries selected.
Governments worldwide are promoting the development of biofuels in order to mitigate the climate impact of using fuels. In this article, I discuss the impacts of biofuels on climate change, water use, and land use. I discuss the overall metric by which these impacts have been measured and then present and discuss estimates of the impacts. In spite of the complexities of the environmental and technological systems that affect climate change, land use, and water use, and the difficulties of constructing useful metrics, it is possible to make some qualitative overall assessments.
Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more.