I have a hard time believing in fuel from algae, or any renewable hydrocarbon fuel for that matter, because I wonder where the carbon feedstock will come from (barring the long-awaited hydrogen economy)?
Now I recognize that using CO2 as a feedstock from coal power plants (or perhaps natural gas plants) is certainly a better use than emitting it directly to the atmosphere, and could help reduce oil consumption. Nevertheless, it would still result in large overall CO2 emissions, and can therefore be dismissed as a viable long-term solution (unless the carbon is utilized in a closed-loop system, and we run our transportation system with electric cars). We are in the pinch between alternative energy and climate change, and in such a bind the important, long-term coal technology worth developing is carbon capture and sequestration.
Another option, commonly discussed in relation to cellulosic ethanol, is to use “carbon-neutral” agricultural grasses, woody refuse and "waste" debris from forests, waste pulp from wood mills, waste materials from construction, etc. It is worth looking at a report by the USDA in 2005, “Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply” (http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf). A billion tons is the expected amount of biomaterial necessary to displace 30% of U.S. petroleum consumption. The USDA report concludes that such production is realistic, with 368 million dry tons annually produced from forestland. This estimate includes directly harvested fuelwoods, waste residues from wood-processing mills, urban residues including construction and demolition debris, residues from logging and site clearing operations, and fuel treatment operations to reduce fire hazards. To meet the one billion ton mark, the remainder is derived from agriculture and consists of annual crop residues (e.g. corn stalks), perennial crops (e.g. grasses), grains, animal manures, and other miscellaneous and process residues. Notably, these numbers assume a 50% increase in corn and grain yields, among other things.
The USDA paper only mentions in passing (p. 37) the possible consequences of removing this magnitude of residues from the environment for biofuel conversion, and they say this with regard to the agricultural feedstocks only and not forestry products.
Large quantities of “waste” biomass serve several fundamental purposes in the environment, both in agricultural and forest settings. First and foremost, they provide the nutrients and habitat for the complex soil microbiology that ultimately sustains all life on the planet. Removing a billion tons or more of such material annually will diminish soil microbe ecosystems, thereby decreasing soil health, thus reducing the dependent plant health, and by relation diminishing the health of the entire ecological community. For those interested in sustainable agriculture, “waste” residue (think compost) is called “black gold” for a good reason. It is a primary ingredient upon which all life, including humans, are derived.
Of no less importance, biomass residues contribute to the health of a forest or agriculture by preventing soil erosion, retaining water and thereby reducing necessary irrigation and preventing downstream flooding, reducing stream silting and its associated problems with hydropower and aquaculture (e.g. salmon habitat), etc. The list of connections is numerous, just as the health of the forests is intimately related to the health of the entire ecosystem and everything that lives in it.
I do not believe that a PhD in forestry is necessary to recognize these connections; indeed, such education appears to prevent such a basic understanding of forest ecology within the USDA. My concern is that the public will prefer these large-scale environmental effects (without even recognizing them as such) rather than voluntarily limiting their consumption habits, to which most feel they are inherently entitled. The law of unintended consequences is very real, especially when considering a biofuel program on the scale necessary to continue our current car culture. Would we stop at one billion tons if economists told us we needed more to keep our economy growing?
The reason that we do not hear this type of reasoning when discussing biofuels (from the USDA, no less) is because it is politically unfavorable to state them. Nevertheless, the public needs to hear and acknowledge that there are certain limits to growth, and that at times we need to practice restraint. We need to discuss real cultural and ecological solutions instead of searching for economically and politically favorable alternatives that will never really materialize but will make certain companies and people very rich in the meantime (e.g. Archer Daniels Midland Co. and their various political accomplices, including such past honorable as Bob Dole and Tom Daschle).
Biofuels will create many more problems in addition to the ones it purports to solve. Much research will be done in this area to keep fuel in our cars. The fundamental limits of nature still prevail. Rather than trying and failing to skirt them with ingenious engineering concepts and naïve hubris, our society needs to develop a better understanding of what limits exist, and how we can live in harmony and respect with them. Real, meaningful change occurs as our culture acknowledges these facts and responds appropriately.
Efficiency and conservation are the two most important elements needed within all aspects of our society, from agriculture and transportation to building construction and consumer products. To maintain and improve our standard of living, continuous research and development in energy efficiency (driven by constant increases in technology standards) should be coupled with long-term R&D focused on solar, wind, and geothermal energy, the necessary decentralized energy infrastructure and improved batteries. It is likely that biofuels will only succeed sustainably in fulfilling niche applications (e.g. for local transportation of goods to long-distance rail systems, NASCAR, etc).
Considering the importance of such research, and the ease with which Congress has spent ~$450 Billion in Iraq and $180 Billion on a stimulus package, I recommend we declare war on our own inefficiency and dedicate a further trillion dollars to the avenues I enumerated above immediately. This effort would bring immediate attention to the issues, help educate the necessary future manpower, generate needed economic stimulus, reassert U.S. leadership and moral authority globally, and provide real, usable results without hoping for and relying on the hype of biofuels.