Renewable Hydrocarbon Fuels

By James Pfeilschifter

An overview of the technical and economic feasibility for the large-scale production of basic and advanced biofuels, their efficiency of production, compatibility with existing infrastructure, and competition with fossil fuels and lithium-ion battery storage.

• Language: English
• Publisher: James Pfeilschifter
• Release date: Aug 15, 2023
• ISBN: 9798223012801

Book preview

Preface

If we take in our hands any volume[...] let us ask: ‘Does it contain any abstract reasoning concerning quantity or number?’ No. ‘Does it contain any experimental reasoning concerning matter of fact and existence?’ No. Commit it then to the flames, for it can contain nothing but sophistry and illusion.

—David Hume

This work is undoubtedly premature, but certain circumstances have placed time restraints on its development. Considering my position as an incarcerated adolescent, it is hardly necessary to say that this was written and published with the bare minimum quantity and quality of resources possible to create a research essay of any scientific rigor. Though such limitations must also come with a warning of the potential inaccuracies and/or gaps which may be contained in the information provided here, I have confidence in the legitimacy of the general ideas presented and their value in renewable energy development.

To give an idea as to what the resources used in making this were and how its development progressed, I will provide some details: the ideas for this originated from a general interest in alternative energy and agriculture, specifically solar thermal design and the possibility of cost-effective and sustainable hydroponic/aquaponic systems. The two key questions concerning the latter were the possibility of the substantial production of quantifiable and water-soluble organic fertilizers (hydroponics), and the possibility of an effective but energy efficient pumping system which can operate independently and with as few mechanical and electrical components as possible (aquaponics). This inevitably led to research on composting; the first epiphany of sorts came from a picture which displayed steam rising from an industrial-scale compost pile being hosed down, indicating a surprisingly high amount of heat being released. Further reading gave an explanation for this, being that during the middle thermophilic phase of composting the internal temperatures of a large compost pile can reach up to 160°F.

In my mind, it seemed that two birds had been hit with one stone: the same process which could be used to produce organic fertilizer could also be used as a source of thermal energy. I thought of the possibility of combining this source of thermal energy with solar thermal and geothermal power, created a basic design for a pump which could be driven by low-grade heat and uses convection as its basis of operation, and termed the general system concept as ecothermal design. As it turned out, the compost-energy idea was by no means new, in fact being termed biothermal energy and having been pioneered by a French farmer fifty years ago. This individual had proven that he could use a 10ft high compost pile to supply all of his household energy needs in the form of both thermal energy and methane, used to generate hot water and stove fuel/electricity respectively. I soon realized that these basic biothermal designs would either be inadequate or require an unrealistically large compost pile to power an aquaponics system as I had originally imagined, and that in general aquaponics could not be a feasible means to food production unless its energy costs were almost entirely eliminated.

The factor of methane in biothermal energy brought the second epiphany: I became familiar with anaerobic digestion—the oxygen-deprived bacterial decomposition of organic materials into methane and carbon dioxide, or biogas—and it occurred to me how significant of an energy source this could be when I observed the abundance of organic waste. I remembered a PSA from years ago which stated that nearly 40% of food in the US is wasted (presumably not counting inedible byproduct material, such as nut shells or banana peels). Assuming that the average food consumption per person per day in the US is 3lbs, then about 2lbs per person per day would be wasted; this turned out to be a fairly accurate assumption. By using glucose as a basic model for the anaerobic digestion of food materials, I assumed a possibility of 5ft³ of methane to be possibly derived from one dry pound of food material—with a water content of 75% (another fairly accurate assumption)—for a result of a potential annual methane generation of ≈304 billion cubic feet. This would equate to a total energy content of ≈304 trillion BTU (British Thermal Units), or 44.5TWh if the gas were burned in an electric-generating turbine with a 50% thermal efficiency. The total energy would only account for ~0.31% of 2021 US primary energy consumption (~98 quadrillion BTU, EIA), but the electricity could provide the annual electric consumption for >4.2 million households (with an average US household electric consumption of 10,557kWh, Bureau of Labor Statistics).

I soon discovered the Department of Energy’s 2016 Billion-Ton Report, which became a critical resource for the quantitative analysis contained here, as well as a few other scientific articles concerning research on biofuel production, which helped more with the qualitative analysis. These research materials—along with data tables published by the EIA (Energy Information Administration) and other US government entities—supported the significant developments of the ideas described, making this into what it has become. I had originally written a draft which revolved around waste resources and correctable inefficiencies, but by limiting the analysis in such a way the full spectrum of possibilities was being neglected, and so I broadened the original message. Wasted food is only one small portion of potential biomass resources (as are general waste resources), let alone the fact that it wouldn’t be a true source of energy due to the large amounts of energy expended in its production and transportation and its status as unnecessary wastage to begin with. However, wasted resources are wasted resources, the first step would be to capture these readily available sources of biomass, and then work out the inefficiencies from there. I applied the general quantities of potentially available biomass—as sourced from the 2016 Billion-Ton Report—alongside the rates of conversion for various biofuel production processes, with promising results.

As one will see from reading the actual text, the quantities of biofuel which are estimated as possible to produce given projected biomass availability make the current production of ethanol and biodiesel look as impractical as they really are. The main issue is the amount of energy which must be inputted into the most promising biofuel production applications, such as hydrothermal liquification, which existing data indicates as exceeding those for equal energy yields from ethanol and biodiesel. Remembering the ecothermal system concept, and also the controversy surrounding renewable electric because of the costs and limitations of lithium-ion batteries, I had my third and final epiphany: the output of renewable electric sources should be maximized to the greatest extent possible—without regard for the rate of electric consumption or availability of battery storage—and all surplus electricity would be consumed in various processes which would convert biomass into renewable substitutes for