For all of the hope surrounding algae biofuels, surrounding Craig Venter’s big algae project, and then, surrounding Sapphire – one of the last algae games left in town, we get news that Sapphire Energy’s CEO has been replaced. Some read this as a significant and negative sign.
It would seem that we’ve been putting a lot of false hope into algae as a “sustainable” savior for liquid fuels. The requirements to grow it and to get it to produce oil are not so little as it turns out. Nor can living cells be manipulated to produce a lot without requiring a lot in return.
A new emphasis may be emerging from fledgling algae start-ups, and that is to produce an Omega-3 oil human nutrient product instead of crude oil, something that might actually be a profitable venture.
I’ve had a post on the back burner for a very long time, and this seems like a good time to run it. Captain T. A. “Ike” Kiefer wrote a paper titled “Twenty-First Century Snake Oil: Why the United States Should Reject Biofuels as Part of a Rational National Security Energy Strategy” in January 2013. I liked all of it, but I especially liked the part about algae for biodiesel.
The remainder of this post is the excerpt on algae for biodiesel, written by Kiefer and republished with his permission.
A third option, besides growing a plant for its starches or cellulose, is to grow it directly for oil. Species which yield some biomass as lipids include soy, camelina, rapeseed, oil palm, jatropha, peanut, sunflower, cottonseed, safflower, and microalgae. All of these crops, including a non-poisonous Mexican variant of jatropha, have provided human and animal food over the centuries. The natural lipids in these plants can be broken down by adding methanol (made from natural gas) to convert them into a soup of fatty-acid methyl esters (FAME) commonly known as “biodiesel.”
Lipid fractions of plants are generally small compared to starch fractions, and that is why soy biodiesel yields per acre are much smaller than corn ethanol yields (70 gal/acre v. 500 gal/acre) and consume so much more water per liter of fuel, as will be discussed later. Soy Biodiesel EROI calculated from rigorous, full commercial-scale lifecycle studies is slightly better than corn ethanol at 1.9:1, but still nowhere close the 6:1 threshold for minimal utility. The well- known oil fraction limitation of terrestrial plants is why there has been 80 years of research on fast-growing, higher lipid fraction micro-algae as a way to get a high- yield biodiesel crop.
Algae is the only biodiesel crop with high enough potential yields to replace US petroleum without consuming all US territory as cropland, so it is worth a detailed look. All plants, including algae, stubbornly want to produce carbohydrate structural biomass instead of lipids because that is how they grow and reproduce. Lipids are an intermediate synthesis product that are only accumulated in larger amounts when the plant is starved of some essential nutrient such as nitrogen or silicon essential to complete biosynthesis of new structural biomass.
Lipid yield in g/m2 of pond or bioreactor surface area is a function of the number of algae cells and their individual lipid fractions. Absolute yield is limited because one can either starve the algae to produce more oil or feed them to foster reproduction, but not both—another catch-22. In addition, lipid fraction controls buoyancy for algae. It cannot be increased beyond the point where the algae float to the surface, crowd out the sunlight, dry out, and die. These are physical and biological limits known from previous research under the Aquatic Species Program. It is not possible to change basic physical laws such as Archimedes’ principle of buoyancy with even the most sophisticated genetic engineering.
Additionally, attempts to move algae from the lab bench to commercialization continue to be crushed by poor EROI. A literature survey of reported algae EROIs performed by the National Research Council found values from 0.13:1 to 7:1, but in the higher cases, energy credits from co-products dwarfed the energy delivered as biodiesel—biodiesel was really the co-product and solid biomass the product.
If there is any benefit and profit to be made from algae, it appears to be more in producing soylent green than in producing green fuel. A critical look at the more optimistic studies that predict the higher EROIs reveals that they depend upon a host of unrealistic assumptions—massive supplies of free water and nutrients, a free pass on enormous environmental impact, and market economics that miraculously transform the huge burden of enormous accumulations of soggy byproduct biomass that has per-ton value less than the cost of transportation into a cash commodity crop. Proponents often claim that algae need only sunlight and CO2 to grow.
However, to make the high yields promised, fertilizer energy is typically supplied in the nitrogen, carbon, and hydrogen molecules of a solid form of ammonia called urea. Solazyme Inc., the US Navy’s choice for algae biofuel and recipient of a $21 million DoE biorefinery grant, actually grows their product in dark bioreactors, feeding it carbon and hydrogen energy in the form of sugar. This makes them unique in producing a biofuel 100% dependent upon a food crop and getting 0% of its energy from the sun via direct photosynthesis—a worst case scenario.
The most realistic, full-scale, full commercial lifecycle studies find a break- even 1:1 EROI if the algae biomass is simply sun-dried and shoveled directly into a furnace for heat. Any attempt to convert to liquid fuel results in a large negative energy balance. Hydrotreating further destroys EROI, as can be seen in prices paid by the US Navy for algae biofuels below. The simple but decisive math is that, even at commercial scale, with generous assumptions about cellular reproduction rate and lipid fraction and oil extraction, and ignoring the costs of facilities and water, Argonne National Laboratory calculated that it takes 12 times as much total energy and 2.6 times as much fossil fuel energy to put a gallon of non-hydrotreated biodiesel in a gas station pump instead of a gallon of petroleum diesel.
Under the heading “The Mineral Problem”, Captain T. A. “Ike” Kiefer has some more important comments about algae for biodiesel:
￼Exchanging a fuel dependent upon foreign oil imports for a fuel dependent upon foreign mineral import does not improve national security.
Potash and phosphate are critical plant macro-nutrient minerals which must be provided in large quantities for both food and biofuel cultivation. The United States currently imports 85% of its potash supply. In 2011 the global price of potash doubled, sending fertilizer prices skyrocketing. In 2010 America imported 13% of its phosphate, and 90% of this came from Morocco, an Islamic kingdom of the North African Maghreb region that is a growing stronghold of Al Qaeda. In 2011, phosphate prices jumped $60 per ton.
Replacing US transportation fuel with algae biodiesel would require about 88 million more tons of phosphate rock to be mined a year compared to current US production of 28.4 million tons and total global production of 191 million tons. While there is a loud chorus of pundits preaching doom about the price volatility of oil and US dependence upon unstable Persian Gulf nations (source of 13% of US crude in 2011), few are those who recognize how susceptible US agriculture is to foreign economic influences.
Basing our transportation energy supply on agriculture via biofuels only exacerbates this risk. It is critically important for energy strategists and policy makers to realize that exchanging a fuel dependent on foreign crude oil imports for a fuel dependent on foreign potash and phosphate imports does not improve national security. In fact, it puts both food and fuel in jeopardy of a single embargo.
There is much more of value in the paper…
Source: “Twenty-First Century Snake Oil: Why the United States Should Reject Biofuels as Part of a Rational National Security Energy Strategy” by Captain T. A. “Ike” Kiefer (JAN 2013):