This entry is the latest in a series on innovations in the climate and energy world.
Ethanol from corn and sugar cane? Beyond passé at this point, with major environmental, land use, and food security concerns.
Second-generation biofuels, made from non-food crops and wastes? So 2008.
The next big thing in biofuels? Algae.
So-called third-generation biofuels have begun to receive serious attention. Biofuels can technically be made from just about any plant material, and some of the advantages of algae are obvious: it wouldn’t compete for arable land, for example, as it is grown in water, and it grows like, well, a weed, allowing for incredible yields.
The two avenues of third-generation development being considered so far are microalgae (pond scum, etc) and macroalgae (seaweed). Research is going into both harvesting algae from its natural environment and creating artificial growing environments.
Various algae have been discussed academically as a potential fuel since 1955. The U.S. Department of Energy has looked into fuels from microalgae since 1978, although the Aquatic Species Program, as it was called, was discontinued in 1996. Since then, various government bodies, including the Department of Defense, National Science Foundation, and Department of Agriculture, have continued to look into algal biofuels.
Private investment has sprung up as well, now far exceeding public funding. ExxonMobil alone has pledged US$600 million. Other countries, including South Korea, the United Kingdom, Italy, Japan, and the Philippines, have also announced plans to invest heavily in research and development on algae-based biofuels.
Does it pass the laugh test?
Over the past few years, we’ve gotten used to discussing the biofuel potential of previously “unknown” plants like jatropha, canarygrass, and short-rotation coppice—so considering the merits of seaweed doesn’t seem so odd. And the Aquatic Species Program long ago demonstrated the technical feasibility of producing oil from algae.
Does it have that WOW factor?
The parade of “shiny object” biofuels may have left us ready to accept seemingly unlikely candidates like pond scum, but it also leaves us somewhat jaded. I could read tomorrow that scientists think four-leaf clover is the long-term solution to moving away from oil and I’d be willing to believe it.
What does it bring to the table?
A lack of competition for resources.
Algal biofuels are grown in either natural or created aquatic environments and therefore don’t compete for land with food crops. They offer a yield, in terms of fuel per acre per year, roughly 30(!) times that of conventional feedstocks. Replacing all of U.S. oil consumption with algae fuel would require 15,000 square miles of production, slightly larger than the state of Maryland. By comparison, 35,000 square miles of corn production is currently used to meet just 10 percent of U.S. fuel needs in the form of ethanol.
Algae’s hunger for carbon dioxide, its ability to handle nitrogen inputs, and its existence in aquatic environments means that the microorganism is an ideal candidate for recycling carbon from stationary emissions sources such as power plants and industrial facilities. Algae have already proven able to absorb 90 percent of CO2 when the gas is piped through algae ponds. Using power-plant exhaust to produce fuel would be a robust combination for lowering greenhouse gas emissions.
Moreover, algae do not require fresh water, as they can grow in marine environments or utilize waste water, produced water, and saltwater in artificial environments. They also require no pre-treatment before processing, since they do not contain lignin, and wouldn’t require any engine modifications for use in vehicles.
In short, many of the physical objections to first- and second-generation biofuels—land use, water use, food security—do not apply to algae.
How close is it to commercialization?
Getting closer every day (with a positive second derivative, for the mathematically inclined among us).
The U.S. Defense Advanced Research Projects Agency (DARPA) thinks it has found a way to produce algal fuel at a cost of $2 per gallon, part of the military’s effort to wean itself off oil. But this is still a world of pilot projects and demonstration facilities. No one expects commercialization in less than a couple of years, as costs will need to come down and production successfully scaled up.
How scalable is it?
One outlandish plan for creating mobile seaweed plantations along ocean surface currents claims that seaweed could become “the largest renewable energy source of the 21st century.” Setting that aside, the inputs for algae are readily available—in the case of CO2, too readily available—and they can be grown on marginal land or in aquatic environments.
What is the biggest obstacle to success?
The recent explosion of interest and funding in the algal biofuel sector has led to increased academic scrutiny, and researchers have begun to raise red flags. Initial studies show that the energy consumption, greenhouse gas emissions, and water use associated with producing microalgal fuel is higher than that of conventional biofuels. These are mostly upstream impacts, however. Using wastewater as an input, for example, would reduce not only freshwater usage but also greenhouse gas emissions and energy use, as wastewater contains nitrogen and phosphorus that algae need to grow and that would otherwise need to be produced from petroleum.
The final word(s):
Get your pond skimmers ready, or at least a few of them.
With all of its advantages over other biofuels, algal fuel seems destined for a role in our energy future. But the environmental backlash against first- and second-generation biofuels is now being replicated with the ascendance of algae. If the energy needs and greenhouse gas emissions of algal fuel production cannot be lowered, algal fuels may be limited to areas in which they can feed off of wastewater and power plant effluents. But with significant funds just beginning to enter the sector, the economics of algal fuels at least seem destined to improve. When the world decides that it is time to move on from oil, algae very well may be the best option.