Energy Citations Database (ECD) - - Document #6588442
We have many times made reference to, and report of, the potentials for utilizing biological agents for the large-scale recycling of industrial effluent Carbon Dioxide.
Although we are personally and preferentially drawn to more straightforward chemical processes for CO2 recycling, such as those technologies based on the Sabatier process, and on CO2 reforming with Methane and/or Steam, we have documented that Algae can be employed to harvest industrial exhaust gas Carbon Dioxide, and to transform it into a wider variety of products, including "lipids", which can then rather easily be refined into Diesel fuel.
Herein, from the US Department of Energy, is further exposition of those potentials; an exposition with a somewhat unusual twist:
They weren't, as it happens, looking for, or trying to engineer, better bugs for converting CO2 into Diesel fuel.
They already, it seems, have those in hand.
The USDOE-funded scientists herein were assessing the best places to grow those bugs.
Comment, with another twist, concerning Coal, follows excerpts from the initial and following links to:
View Document or Access Individual Pages; DOI:10.2172/6588442
"Title: CO2 Sources for Microalgae-based Liquid Fuel Production
Date: August, 1990
Authors: D. Feinberg and M. Karpuk
OSTI ID: 6588442; Legacy ID: DE90000367; Report: SERI/TP-232-3820; Contract: AC02-83CH10093
Organization: Solar Energy Research Inst., Golden, CO; Sponsor: USDOE
Abstract: Researchers in the Aquatic Species Program at the Solar Energy Research Institute are developing species of microalgae that have high percentages of lipids, or oils. These lipids can be extracted and converted to diesel fuel substitutes. Because microalgae need carbon dioxide (CO2) as a nutrient, optimal microalgae growth occurs in CO2-saturated solutions. For this reason, the authors of this study sought to identify possible large-scale sources of CO2 for microalgae-based liquid fuels production. The authors concluded that several such promising sources exist.
The Solar Energy Research Institute's (SERI) Aquatic Species Program is developing microalgal species and culture technologies that result in microalgal cells with a high percentage of lipids. The lipids can be extracted and converted to a diesel fuel substitute.
Optimal microalgae growth occurs in carbon dioxide (CO2) saturated solutions. If these research efforts are successful, large quantities of low-cost CO2 will be needed.
(How much more "low-cost" can it get, if we're willing to pay to collect it and ship it all to West Texas, to be stuffed down a leaky geologic sequestration rat hole?)
The purpose of this study is to identify possible CO2 sources for microalgae based fuel production and to quantify the amounts available and possible costs. Because of the early stage of development of the fuel synthesis technology, and the current plentiful supplies of gaseous and liquid fossil fuels, we chose the year 2010 as the earliest date that CO2 for fuel synthesis would be needed.
We analyzed four sources of CO2:
Natural Reservoirs. Large natural reservoirs of CO2 in the southwestern United States are currently being utilized for enhanced oil recovery (EOR). These reservoirs are expected to be depleted by the year 2010 and consequently unavailable for micro algae production. However, the CO2 used for EOR will remain in the depleted oil fields. and could be recovered for micro algae production. Some natural gas fields contain significant quantities of CO2• which are not currently being produced because of high separation costs. If the economics of these fields improve, this CO2 could become available.
(Note, as above, as we earlier documented for you: Oil companies are already pumping natural CO2 out of the ground, so they can pump it back for "Enhanced Oil Recovery". How much leakage of CO2, into the atmosphere, do you suppose is caused by such operations?)
Fossil Fuel Combustion. The United States has very large coal reserves, and coal is expected to remain a primary energy source in 2010 and beyond. Coal combustion in power, synthetic fuels, and chemical process plants will produce large quantities of CO2.
(Wait a second! Did they just mention "Coal" and "synthetic fuels", together, in the same statement?)
Clean coal technologies under investigation by the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE) have the potential to produce large quantities of concentrated CO2 at low cost. Concern about possible regulation of global warming caused by the release of CO2 into the atmosphere may make CO2 available from these sources at low or even negative costs.
(CO2 could, in other words, be better than free, especially if Cap & Trade taxation becomes law.)
Air Separation. It is conceivable that CO2 could be recovered directly from the atmosphere, where it is the fourth-largest constituent. However, because the atmospheric CO2 concentration is very low, significant technical breakthroughs are required to make the process viable.
Anaerobic Digestion. Anaerobic digestion of biomass and wastes is currently being investigated as a
source of methane. Methane and CO2 are coproduced in approximately equal molar volumes and are easily separated. Large quantities of CO2 could be available from fuel-scale anaerobic digestion plants.
(The politically-discrete USDOE failed to mention Corn ethanol fermentation and distillation facilities.)
The results of this study indicate that there are several large sources of CO2 that could support micro algae-based fuel production.
We also evaluated the costs of transporting CO2, Supercritical pipelines are the most economical method of transporting CO2 for the flow rates required for fuel synthesis. Transportation costs are typically $0.008/kg per 100 miles for a pipeline capacity of approximately 2.6 x H1 kg/d. Therefore, transportation of CO2 is feasible only from large concentrated sources over relatively short distances.
This implies that microalgae production facilities should be sited near CO2 sources.
(And, it also implies that "transporting CO2" all the way to West Texas, for leaky Geologic Sequestration, with absolutely no return on the investment, should be absolutely out of the question. But, it does also indicate that places where CO2 producers are concentrated, let's say a section of the Ohio Valley, with a series of Coal-fired power plants strung along the river like diamonds on a necklace, might be ideal. But, the following casts gloom on that prospect.)
Microalgae-based liquid fuel production using CO2 may be important in the future when petroleum and natural gas supplies have largely been depleted. Microalgae production facilities will be located in sunny areas with moderate climates. Consequently, we have emphasized CO2 sources in the southern and southwestern United States where solar radiation is the greatest. We have analyzed CO2 sources in the ten sunniest states in the United States: Alabama, Arizona, California, Florida, Georgia, Louisiana. Mississippi, New Mexico, Oklahoma, and Texas.
Sources of CO2: Ethanol plants. The production of ethanol by the fermentation of organic substances such as com, molasses, and potatoes has grown significantly throughout this decade. The increased use of ethanol as a blending agent in automotive gasoline, the result of tax incentives as well as mandated reductions in tetraethyl lead, has opened up the market considerably. In the fermentation process, ethanol and CO2 are produced in approximately equal weights.
(Check that: For every pound of Corn ethanol we make, we'll be emitting a pound of Carbon Dioxide.)
Hydrogen plants. Refmeries produce hydrogen for operations such as hydrocracking and isomerization, using the first two major steps in the production of ammonia ... . The CO2 (thus generated) must be removed to produce a high-purity hydrogen product. The volumetric ratio of CO2 to hydrogen produced by this process is 1 to 4.
(Holy Toledo! Even sweet, pure elemental Hydrogen can have a Carbon "footprint".)
Domestic Coal Resources. It is reasonable to expect that coal will continue to supply larger and larger fractions of this country's primary energy, especially in the area of electric power generation.
(According to the) 1985 Demonstrated Coal Reserve Base (DRB), the total tonnage that is commercially minable (is)enough to meet the total primary energy needs of the United States for 160 years.
Projected Impact of Synthetic Fuels. DOE has developed projections for synthetic fuels production through the year 2010. Synthetic liquid and gaseous fuel production from coal in 2010 is estimated to amount to 5.9 quads, with 2.5 quads for synthetic liquid fuels and 3.4 quads for synthetic methane (U.S. Department of Energy 1983)."
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Okay, so what happened? Where is it? If we could, and, according to the USDOE in 1983, should have been making so much "liquid and gaseous fuel ...from coal in 2010", why aren't we?
Aside from that, the USDOE, in honesty, is pessimistic about the prospects of utilizing algae-based CO2 recycling outside of the sunbelt states.
But, the potential does exist, as herein, to, in one way, treat the Carbon Dioxide by-product of our essential Coal use as a valuable raw material resource, and to convert it into, specifically, "a diesel fuel substitute".
Why, instead of Cap & Trade taxation and mandated Geologic Sequestration, aren't options such as that being openly and publicly addressed and considered?