lca

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. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels.

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
addresses the question of methodological choices in LCA to account for ILUC. The
approaches to account for this effect in carbon reporting initiatives are discussed in Section 7.
Finally, recommendations and further research work are described.

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.

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.

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). In the United States, initial interest in producing and using biodiesel has focused on the use of soybean oil as the primary feedstock, mainly because this country is the world's largest producer of soybean oil.

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.

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.

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).

The model is a vehicle fuel-cycle model for transportation systems. The model provides a set of outcomes that would involve feedstock production, biorefinery production, storage and consumer demand as the complete fuel-cycle. The data is internal to the model, but might be adaptive to different biofuels specifications. This model was developed by the Energy Systems Division at Argonne National Laboratory.

Fertilizers used to increase the yield of crops used for food or bio-based products can migrate through the environment and potentially cause adverse environmental impacts. Nitrogen fertilizers have a complex biogeochemical cycle. Through their transformations and partitioning among environmental compartments, they can contribute to eutrophication of surface waters at local and regional scales, groundwater degradation, acid rain, and climate change. Phosphate fertilizers have a simpler fate in the environment, although leaching of soluble and bound phosphorus is an important contributor to eutrophication.