Technological and scientific advances are providing researchers with new ways to efficiently create new biofuels from algae-based feedstocks.
A major part of the support for biofuel research, production and testing arises from the federal government’s Energy Policy Act (EPAct) of 2005 and the Energy Independence and Security Act (EISA) of 2007. These Acts established requirements for the volume of renewable fuels that must be blended into transportation fuels, which is currently targeted at 36 billion gallons by 2022 (nearly three times the current volume). The laws and subsidies surrounding biofuels are complex with links to various types of biofuels (diesel, gasoline), various base materials (cellulosics), various feedstocks (corn, soybean, biomass) and even links to how much green house gases (GHGs) they generate.
Research and testing of potential feedstocks for creating biofuels continues to evolve with testing equipment and testing protocols (standards) evolving as well from established petroleum-based methodologies (ASTM and EPA in the U.S and EN/ISO in Europe). The feedstocks, or biomass, for creating renewable biofuels can come from 1) forestry and agricultural waste products (i.e., wood chips, corn stalks, dairy farm biosolids, etc.), 2) food crops (currently the largest source) and by-products (i.e., corn, soybeans, grape stems), 3) municipal and industrial liquid and solid wastes (municipal refuse, sewage sludge, etc.) and 4) dedicated energy crops (i.e., switchgrass, algae). These feedstocks can be used to produce ethanol, biodiesel, pyrolysis oils and chars.
One of the most encompassing biofuel testing methods is ASTM D 6751 – The Standard Specification for Biodiesel Blend Stock for Distillate Fuels. This standard includes tests for measuring biofuel properties that include flash point, moisture (water) content, viscosity, cetane number, cloud point, acid number, glycerin content, sulfur content, phosphorous content, visual appearance and more. Some of these measurements are supported by dedicated instruments, such as flash point testers. Others are supported by conventional laboratory equipment that includes centrifuges (for moisture and sediment content), titration (for precise moisture content and acid number), furnaces (for metal and sulfur content), scales and balances, gas chromatographs (glycerin content), freezers (cloud point), ion chromatographs (oxidative stability) and IR spectrometry (level of biofuel in petroleum-based fuels). Multispectral imaging systems (primarily IR-based) are also now used in the field in combination with satellite and unmanned aerial vehicles platforms to collect data for determining the quality of possible energy crops.
When biofuels were first considered on a major scale as a renewable substitute for petroleum-based transportation fuels, the first feedstocks considered were food crops and in particular corn. The technologies for efficiently producing ethanol from corn has existed for hundreds of years and in some cases, even large-scale production facilities existed. But as the knowledge base grew, it became quickly and readily apparent that there wasn’t enough agricultural land in the U.S. or elsewhere to grow sufficient crops of corn, palm and similar alternatives to feed both people and provide large quantities of transportation fuels. Also, the processes for creating these feedstock-based biofuels were both water-use intensive and far from carbon neutral. Add to this scenario, the now large availability of increasingly cheaper natural gas from fracking fields throughout the U.S. and the high-cost and inefficient of food-crop biofuels becomes unsustainable.
Algae-based biofuels offers a potentially viable alternative to the food crop biofuel scenario. U.S. Dept. of Energy studies reveal that algae is a highly efficient lipid growth medium, producing up to 100 times more potential fuel per unit area than could be obtained f rom non-food waste crops. And roughly 15,000 square miles of dedicated growth production (about 14% of the current area dedicated to corn) could produce enough algae-based biofuel to completely replace all of the U.S.’s current petroleum usage.
So while the massive EPAct and EISA biofuel requirements are based on the safe and sure food-based biofuel crops (and artificially raising food costs in the process), researchers are increasingly looking to algae as a possible ultimate biofuel alternative. As a result, a number of research centers focusing on the development of algae-based biofuels. One of these is the Arizona Center for Algae Technology and Innovation (AZCATI) located at Arizona State Univ. (ASU), Tempe. A few of the 20 Partners with AZCATI include Intel, Thermo Fisher Scientific and the Univ. of Arizona.
The AZCATI facility provides services for bioprospecting, screening, isolation, selection, identification and characterization of microalgae of commercial interest. Their researchers can develop culture media and maintenance protocols for selected algae strains, along with DNA fingerprinting and phenotypic trait identification. Side-by-side comparisons of culture performance and productivity of customer-provided strains compared to AZCATI’s best-in-class strains can be made under defined environmental or culture conditions. The facility also has a BSL-2 greenhouse and closed photobioreactor available to evaluate genetically modified algae.
“We work with a diversity of algae types, looking for desirable traits such as growth rates, robustness under different growing conditions and product yield,” says Milton Sommerfeld, Professor in the Dept. of Applied Biological Sciences at ASU and co-Director of the Laboratory of Algae Research and Biotechnology (with co-Director Qiang Hu). “Algae can differ greatly in growth rates, the ability to grow under different environmental conditions and metabolism that leads to specific products.
“We’re working with model algae strains that have been partially genetically sequenced to either up or down regulate steps in the metabolism of the algae strains to improve the yield of products,” he says. “The field is advancing rapidly as a result of greater interest in the use of genetics to understand the metabolic pathways to products.”
Researchers at ASU are also participating in the Sustainable Algal Biofuels Consortium (SABC) with researchers from the National Renewable Energy Laboratory, Sandia National Laboratories, Georgia Institute of Technology, the Colorado Renewable Energy Collaboratory, Colorado School of Mines, SRS Energy, Lyondell Chemical Co. and Novozymes. The primary objective of the SABC is to evaluate biochemical (enzymatic) conversion as a potentially viable strategy for converting algal biomass into lipid-based and carbohydrate-based biofuels.
Testing algae biofuels
Biofuels can have different characteristics than conventional petroleum-based transportation fuels, depending upon the quality of the bio-extender that the biofuels use to polymerize with heat. As a result, testing of the bio-extender and finished blends is important. This testing helps to protect the end-use transportation engines and fuel systems from damage caused by poor stability, organic insoluble matter and water/moisture, along with contamination from metals or byproducts from the trans-esterification process.
“We typically perform analyses of the algae feedstock to determine the overall biomass composition with respect to not only the lipid or oil content and fatty acid composition, but also the protein, carbohydrate and elemental content and composition of the feedstock,” says Sommerfeld. “Currently available instrumentation is adequate for our current algae biofuel testing. Some of the standard methods for testing biofuels were very time-consuming and we continue to be interested in more automated processes that can reduce technician or processing time. In some cases, we have worked with the instrumentation industry to revise or improve methods and procedures for instruments that we felt had value to our laboratory. Newly developed instrumentation has typically reduced personnel time and the quantity of reagents used, while at the same time providing more reliable data.”
Instrumentation for testing biofuels has changed over the past few years and continues to change, according to John McFarlane, General Manager at JM Science, Grand Island, N.Y. “We certainly have upgraded our titrators for biofuel testing.”
Some of the tests performed on algae- or other biomass-based biofuels are similar to those performed on conventional petroleum-based fuels, however, algae-based biomass contains a very diverse set of organic and inorganic compounds that must be identified and dealt with, according to Sommerfeld. “We typically determine total lipid/oil yield from the algae biomass on a weight or volume basis, followed by separating lipid/oil fractions into those for use as transportation fuels and for other uses.”
Growing algae feedstocks
Algae “farms” would likely consist of many ponds with water from six to 15 inches deep, according to researchers at Pacific Northwest National Laboratory (PNNL), Richland, Wash. The availability of water has been one of the biggest concerns for producing algae-biofuels. The PNNL researchers estimate that algae would use more water than industrial processes used to harness energy from oil, wind, sunlight or most other forms of raw energy. To produce 25 billion gallons of algae-based biofuel, the processes would require the equivalent of about one-quarter of the amount of water now used each year in agriculture for the entire U.S. While this is a large amount, the PNNL team notes that the water would come from fresh groundwater, salty groundwater and seawater. This water demand would dictate where algae farms might be located, meaning in humid coastal areas rather than dry desert regions.