N2O Release from Agro-biofuel Production Negates Global Warming Reduction by Replacing Fossil Fuels

Abstract. The relationship, on a global basis, between the amount of N fixed by chemical, biological or atmospheric processes entering the terrestrial biosphere, and the total emission of nitrous oxide (N2O), has been re-examined, using known global atmospheric removal rates and concentration growth of N2O as a proxy for overall emissions. The relationship, in both the pre-industrial period and in recent times, after taking into account the large-scale changes in synthetic N fertiliser production and deforestation, is consistent, showing an overall conversion factor of 3–5%. This factor is covered only in part by the ~1% of "direct" emissions from agricultural crop lands estimated by IPCC (2006), or the "indirect" emissions cited therein. This means that the extra N2O entering the atmosphere as a result of using N to produce crops for biofuels will also be correspondingly greater than that estimated just on the basis of IPCC (2006). When the extra N2O emission from biofuel production is calculated in "CO2-equivalent" global warming terms, and compared with the quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the outcome is that the production of commonly used biofuels, such as biodiesel from rapeseed and bioethanol from corn (maize), can contribute as much or more to global warming by N2O emissions than cooling by fossil fuel savings. Crops with less N demand, such as grasses and woody coppice species have more favourable climate impacts. This analysis only considers the conversion of biomass to biofuel. It does not take into account the use of fossil fuel on the farms and for fertilizer and pesticide production, but it also neglects the production of useful co-products. Both factors partially compensate each other. This needs to be analyzed in a full life cycle assessment.

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N<sub>2</sub>O release from agro-biofuel production negates global warming reduction by replacing fossil fuels

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-389-2008 ◽

2008 ◽

Vol 8 (2) ◽

pp. 389-395 ◽

Cited By ~ 619

Author(s):

P. J. Crutzen ◽

A. R. Mosier ◽

K. A. Smith ◽

W. Winiwarter

Keyword(s):

Global Warming ◽

Large Scale ◽

Fossil Fuels ◽

Fossil Fuel ◽

Conversion Factor ◽

Production Systems ◽

Climate Impacts ◽

Biofuel Production ◽

N2o Emissions ◽

Agricultural Crop

Abstract. The relationship, on a global basis, between the amount of N fixed by chemical, biological or atmospheric processes entering the terrestrial biosphere, and the total emission of nitrous oxide (N2O), has been re-examined, using known global atmospheric removal rates and concentration growth of N2O as a proxy for overall emissions. For both the pre-industrial period and in recent times, after taking into account the large-scale changes in synthetic N fertiliser production, we find an overall conversion factor of 3–5% from newly fixed N to N2O-N. We assume the same factor to be valid for biofuel production systems. It is covered only in part by the default conversion factor for "direct" emissions from agricultural crop lands (1%) estimated by IPCC (2006), and the default factors for the "indirect" emissions (following volatilization/deposition and leaching/runoff of N: 0.35–0.45%) cited therein. However, as we show in the paper, when additional emissions included in the IPCC methodology, e.g. those from livestock production, are included, the total may not be inconsistent with that given by our "top-down" method. When the extra N2O emission from biofuel production is calculated in "CO2-equivalent" global warming terms, and compared with the quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the outcome is that the production of commonly used biofuels, such as biodiesel from rapeseed and bioethanol from corn (maize), depending on N fertilizer uptake efficiency by the plants, can contribute as much or more to global warming by N2O emissions than cooling by fossil fuel savings. Crops with less N demand, such as grasses and woody coppice species, have more favourable climate impacts. This analysis only considers the conversion of biomass to biofuel. It does not take into account the use of fossil fuel on the farms and for fertilizer and pesticide production, but it also neglects the production of useful co-products. Both factors partially compensate each other. This needs to be analyzed in a full life cycle assessment.

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Polyhydroxyalkanoates (PHAs): Biopolymers for Biofuel and Biorefineries

Polymers ◽

10.3390/polym13020253 ◽

2021 ◽

Vol 13 (2) ◽

pp. 253

Author(s):

Shahina Riaz ◽

Kyong Yop Rhee ◽

Soo Jin Park

Keyword(s):

Global Warming ◽

Oxygen Content ◽

Fossil Fuels ◽

Environmentally Friendly ◽

Structural Diversity ◽

Biofuel Production ◽

Energy Requirements ◽

Manufacturing Processes ◽

High Oxygen Content ◽

Future Work

Fossil fuels are energy recourses that fulfill most of the world’s energy requirements. However, their production and use cause severe health and environmental problems including global warming and pollution. Consequently, plant and animal-based fuels (also termed as biofuels), such as biogas, biodiesel, and many others, have been introduced as alternatives to fossil fuels. Despite the advantages of biofuels, such as being renewable, environmentally friendly, easy to source, and reducing the dependency on foreign oil, there are several drawbacks of using biofuels including high cost, and other factors discussed in the fuel vs. food debate. Therefore, it is imperative to produce novel biofuels while also developing suitable manufacturing processes that ease the aforementioned problems. Polyhydroxyalkanoates (PHAs) are structurally diverse microbial polyesters synthesized by numerous bacteria. Moreover, this structural diversity allows PHAs to readily undergo methyl esterification and to be used as biofuels, which further extends the application value of PHAs. PHA-based biofuels are similar to biodiesel except for having a high oxygen content and no nitrogen or sulfur. In this article, we review the microbial production of PHAs, biofuel production from PHAs, parameters affecting the production of fuel from PHAs, and PHAs biorefineries. In addition, future work on the production of biofuels from PHAs is also discussed.

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Global Warming and Its Multiple Causes

Journal of Atmospheric Science Research ◽

10.30564/jasr.v3i2.2013 ◽

2020 ◽

Vol 3 (2) ◽

Author(s):

Romdhane Ben Slama

Keyword(s):

Global Warming ◽

Greenhouse Gases ◽

Greenhouse Effect ◽

Infrared Radiation ◽

Fossil Fuels ◽

Ambient Air ◽

The Earth ◽

The One ◽

Heat Released ◽

Emission Of Greenhouse Gases

The global warming which preoccupies humanity, is still considered to be linked to a single cause which is the emission of greenhouse gases, CO2 in particular. In this article, we try to show that, on the one hand, the greenhouse effect (the radiative imprisonment to use the scientific term) took place in conjunction with the infrared radiation emitted by the earth. The surplus of CO2 due to the combustion of fossil fuels, but also the surplus of infrared emissions from artificialized soils contribute together or each separately, to the imbalance of the natural greenhouse effect and the trend of global warming. In addition, another actor acting directly and instantaneously on the warming of the ambient air is the heat released by fossil fuels estimated at 17415.1010 kWh / year inducing a rise in temperature of 0.122 ° C, or 12.2 ° C / century.

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Conversion of biomass to biofuels and life cycle assessment: a review

Environmental Chemistry Letters ◽

10.1007/s10311-021-01273-0 ◽

2021 ◽

Author(s):

Ahmed I. Osman ◽

Neha Mehta ◽

Ahmed M. Elgarahy ◽

Amer Al-Hinai ◽

Ala’a H. Al-Muhtaseb ◽

...

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Energy Demand ◽

Fossil Fuels ◽

Biomass Conversion ◽

Biofuel Production ◽

Process Efficiency ◽

Liquid Fuels ◽

Thermochemical Processes ◽

Lower Temperature

AbstractThe global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.

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Effect of Co, Cu, and Zn on FeAlK catalyst in CO2 hydrogenation to C5+ hydrocarbons

Catalysis Science & Technology ◽

10.1039/d1cy01980e ◽

2022 ◽

Author(s):

Khasan Nasriddinov ◽

Ji-Eun Min ◽

Hae-Gu Park ◽

Seung Ju Han ◽

Jingyu Chen ◽

...

Keyword(s):

Global Warming ◽

Catalytic Activity ◽

Fossil Fuels ◽

Co2 Hydrogenation ◽

High Catalytic Activity ◽

Long Chain ◽

Cu And Zn

Direct CO2 hydrogenation to long-chain hydrocarbons can mitigate global warming by extensively replacing fossil fuels. However, designing a suitable catalyst with high catalytic activity and C5+ hydrocarbon selectivity continues to...

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The Race of Mankind: Global Warming In the 21rst Century

Business and Management Horizons ◽

10.5296/bmh.v4i2.9677 ◽

2016 ◽

Vol 4 (2) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Jan Erik Lane

Keyword(s):

Climate Change ◽

Global Warming ◽

Policy Implementation ◽

Third World ◽

Fossil Fuels ◽

Implementation Process ◽

Financial Assistance ◽

The Third ◽

The Third World ◽

First World

The implementation process of the global accord on climate change has to start now in order to be implementable. The decentralized process if implementation should take the lessons from the theory of policy implementation into account (Pressman & Wildavsky, 1984; Wildavsky, 1987). The dependency upon various forms of coal (wood, stone) and fossil fuels is so large in the Third World that only massive financial assistance from the First World can mean a difference for the COP21 objectives. And many advanced countries (except Uruguay) also need to make great changes to comply with COP21.

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The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana

Plants ◽

10.3390/plants9040463 ◽

2020 ◽

Vol 9 (4) ◽

pp. 463 ◽

Cited By ~ 1

Author(s):

Ali Nawaz Kumbhar ◽

Meilin He ◽

Abdul Razzaque Rajper ◽

Khalil Ahmed Memon ◽

Muhammad Rizwan ◽

...

Keyword(s):

Lipid Content ◽

Fossil Fuels ◽

Fossil Fuel ◽

Lipid Production ◽

Total Lipid Content ◽

Biomass Productivity ◽

Chlorella Sorokiniana ◽

Biofuel Production ◽

Promising Strategy ◽

Waste Extract

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.

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An Assessment Of Microalgal Biodiesel With Acetone, Butanol and Ethanol Using LIfe Cycle Assessment (LCA) Methodology

10.32920/ryerson.14668032.v1 ◽

2021 ◽

Author(s):

Cherilyn Dignan

Keyword(s):

Fossil Fuels ◽

Ghg Emissions ◽

Primary Energy ◽

Biofuel Production ◽

Production Model ◽

Lca Methodology ◽

Fuel Production ◽

Renewable Fuel ◽

Production Processes ◽

Microalgal Biodiesel

Canada, as one of the largest producers and consumers of fossil fuels per capita on the planet, is attempting to reduce greenhouse gas (GHG) emissions. In order to accomplish this, fuel alternatives, such as biofuel, are required. Accordingly, this study uses LCA methodology to quantify the GHG impact of a unique biofuel production model. This unique model produces biodiesel (BD), acetone, butanol and ethanol (ABE) from microalgae and assesses the process GHG impact against other microalgal BD production processes. This study’s microalgal BD and ABE production process produces 76 kgCO2e per functional unit, whereas other comparable microalgal BD production processes produce between 3.7 and 85 kgCO2e. Overall, this study clarifies that without the development of versatile infrastructure to accommodate biofuel production, LCA studies will continue to find renewable fuel production processes net GHG positive for the simple reason that fossil resources are still the primary energy source.

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