More on Biofuels

More on biofuels from the January 27 Science (also see post on net benefits from ethanol): the US, EU, and India expect that 5% of their fuels will be bioderived within 5 years. Up to 30% of (today’s? future?) global fuels can be supplied “in an environmentally responsible manner without affecting food reduction,” according to Steven Koonin (BP). The rest of this post comes from The Path Forward for Biofuels and Biomaterials, same issue.

Currently, about 2% of the US fuel mix comes from ethanol, 0.01% from biodiesel. The US Department of Energy goal is to replace 30% of liquid petroleum transportation fuel with biofuels, and 25% of organic chemicals (dyes, synthetic fibers, solvents, etc) with biomass-derived chemicals, all by 2025.

“More, Bigger, and Better,” the mantra of modern consumerism, also summarizes—ironically—the goals of research aimed at modifying plant species for use in sustainable biomass production. Interrelated plant traits such as higher yield, altered stature, resilience to biotic and abiotic challenge, and biomass composition will increase industrial crop value in terms of biofuels and biomaterials. The challenge is to weave these different strands of research into an integrated production strategy… The grand challenge for biomass production is to develop crops with a suite of desirable physical and chemical traits while increasing biomass yields by a factor of 2 or more.

Transgenic (genetically modified) technology will be crucial in creating plants that capture more of the light energy, increasing photosynthesis. Messing with the nitrogen metabolism can produce taller, more massive trees. Most plants invest heavily in reproduction, but in tweaked plants, more of the plant can be made available for biofuels. Etc.

Currently, biorefineries look like petroleum refineries, producing transportation fuels, co-products and direct energy. But the difficult processes occur at different stages, requiring different solutions. Costs will come down with economies of scale.

Future biorefinery operations will first extract high-value chemicals already present in the biomass, such as fragrances, flavoring agents, food-related products, and high-value nutraceuticals that provide health and medical benefits.

Then there is the still-to-be-perfected step of separating for fuels and bio-derived materials. Even at this stage, though, some are already competitive with petrochemicals and solvents such as toluene, aniline, and acetaldehyde.

Today’s plants depend on fermenting corn (US) or sugar cane (Brazil). The goal is to move toward corn stovers (stalks), trees, and other low-cost agricultural and municipal waste materials. Getting costs down for these materials remains a challenge. Chemical and physical pretreatments have brought part of the costs down by a factor of 5 to 10, and new techniques will likely bring costs down more. Transgenic microorganisms are just one of many techniques being applied to the problem of converting a variety of inputs into a variety of outputs.

Some of the waste left at the end of the process can be use to make syngas, synthetic gasoline often made from coal or natural gas.

This 5.5 page article is full of details for the chemistry-savvy reader. Since energy demand is expected to grow 50% over the next 20 years, fuel resources are finite, and there’s climate change,

future reductions in the ecological footprint of energy generation will reside in a multifaceted approach that includes nuclear, solar, hydrogen, wind, and fossil fuels (from which carbon is sequestered) and biofuels.

One Response to “More on Biofuels”

  1. Bob Seeley says:

    Switching to biofuels might or might not help fill projected energy needs as well as help to prevent global warming. I assume that it would, although my understanding is that the production method favored by the current U.S. Administration is very energy-intensive and would consume quite a large amount of fossil resources and fuel–not a good start toward using less fossil fuel.

    The problem with all of these proposals, from my perspective, is that they assume current and expanding rates of fuel consumption. Economists and scientists have to do this, but policymakers need to be rethinking our dependence on cheap, available energy. In a world where resources are finite and the climate is changing in ways that will make life harder for all of earth’s inhabitants, simply inserting biofuels into a fundamentally flawed system will not do. We need to pay attention to our dysfunctional design.

    My favorite example is the private automobile. We can save on fossil fuels by making cars that run on biofuels–but this doesn’t solve the fundamental problem of our dependence on the private automobile. Manufacturing automobiles uses a lot of fuel and raw materials; building the roads necessary to accommodate them destroys precious environment that we cannot afford to lose. None of this is good for the earth in the long run.

    There is no iron law of Nature or economics that says we must live in widely-scattered houses and depend on private vehicles when we want to visit neighbors or go to the store. Well-designed city neighborhoods can be completely car-free and still remain viable. Well-designed public transit can take people to other neighborhoods more economically and efficiently (and more safely) than the hundreds of private automobiles that each subway would replace. But good social design will not happen without clear thinking.

    I like the idea of biofuels in principle, but simply inserting them into our flawed system might, in the long run, do more harm than good.