The greenest of energy: inedible biofuels
Summary: Using bioengineered enzymes to convert grasses growing on marginal land is the next big thing in biofuels — biofuels that do not reduce food production. Here is a brief and current summary. Great promise, potentially a valuable component to replace conventional oil. But (as usual) nothing like promised by the more euphoric promoters.
Cellulosic ethanol is a biofuel produced from wood, grasses, or the non-edible parts of plants.
It is a type of biofuel produced from lignocellulose, a structural material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus and woodchips are some of the more popular cellulosic materials for ethanol production. Production of ethanol from lignocellulose has the advantage of abundant and diverse raw material compared to sources like corn and cane sugars, but requires a greater amount of processing to make the sugar monomers available to the microorganisms that are typically used to produce ethanol by fermentation.
Switchgrass and Miscanthus are the major biomass materials being studied today, due to high levels of cellulose. Cellulose, however, is contained in nearly every natural, free-growing plant, tree, and bush, in meadows, forests, and fields all over the world without agricultural effort or cost needed to make it grow.
Like so many alternative energy sources, it is touted as ready to go — commercially feasible real soon on a large scale. As usual, the truth is somewhat different. Much more R&D is needed, then the years-long process of moving from pilot plant to development project to first commercial to mass rollout. Here is a current status report from one of the premier sources of information about food: “Cellulosic conversion spurs debate at biotech conference“, Peter Meyer, Milling and Baking News, 26 August 2008 – Emphasis added. Excerpt:
The Bio International Conventionwas held June 17-20 at the San Diego Convention Center. There were 20,108 attendees from 70 countries and from 48 states in the United States, including 4,270 attendees and exhibitors from California, the worldwide home of the biotech industry.
… The area of cellulosic conversion raised the two key issues facing the industry.
First, the timing to reach a process that will be commercially viable. There are a few pilot systems that produce product, but these are not cost competitive with either RBOB gasoline or corn-based ethanol. The solution to the cellulosic ethanol cost conundrum seems to lie in a combination or cocktail of enzymes that convert, not only cellulose to dextrose, but also may handle the more problematic conversion of hemi cellulose. This second conversion adds the most cost or leaves the input cellulose only partially used. Either alternative leaves the costs of production stubbornly high.
The second key issue is the collection of the biomass.The switch grass alternative allows four to five harvests a year but is relatively less energy intense than other crops and each harvest requires going over the ground again with the commensurate energy spent in collection and space required for storage. Corn stover may be collected along with the corn harvest, but again requires a massive storage facility for a commercial-size ethanol plant. Wood waste from a mill and bagasse from sugar cane are candidates, but much of those products already make their way into the energy mix in a more direct way. Some of the wood waste is burned to fire boilers, and a very small amount is being used in experimental ethanol plants. For bagasse, the byproduct of sugar production from cane sugar, the vast majority is burned to fire the boilers in the sugar mills around the world. Where the boilers are efficient, a sugar mill will co-generate electricity to be sold into the electrical grid.
A solution to cellulosic ethanol’s cost problems continues to slip into the future. Much effort and money, including government funds, are being spent. The consistent cost advantages of corn-based ethanol are the utility and value of the feed being created as a byproduct of corn ethanol production. Hope for cellulose continues.
Please share your comments by posting below — brief, civil, and relevant, please — or email me at fabmaximus at hotmail dot com (note the spam-protected spelling).
For more information about biofuels
- On the cutting edge there is always another perspective: “Cellulose Ethanol Renders Peak Oil Irrelevent (for us, at least)“, Dan Tdaxp, 3 September 2008
- On the FM site: A snapshot of our engines of innovation, as they develop new energy sources, 12 May 2008 — About other promising biofuel sources.
Studies about biofuels
- “A Look Back at the U.S. Department of Energy’s Aquatic Species Program: Biodiesel from Algae“, DOE’s National Renewable Energy Laboratory, July 1998 (PDF, 328 pages)
- “Brief on Biomass and Cellulosic Ethanol“, California Research Bureau, March 2005 — PDF 37 pages
- “Cellulosic Ethanol: Where are we now, where are we going?“, DOE’s National Renewable Energy Laboratory, 6 October 2006 – PDF of 30 slides
- “Research Advances Cellulosic Ethanol, NREL Leads the Way“, National Renewable Energy Laboratory, March 2007, PDF, 8 slides
- “Energy Department Selects Three Bioenergy Research Centers for $375 Million in Federal Funding“, Dept of Energy, 26 June 2007 — “Basic Genomics Research Furthers President Bush’s Plan to Reduce Gasoline Usage 20 Percent in Ten Years and making cellulosic ethanol cost-competitive with gasoline by 2012.”
- “Roadmap for bioenergy & biobased products in the US“, Biomass Research and Development Technical Advisory Committee, October 2007
- “Roadmap for bioenergy & biobased products in the US“, Biomass Research and Development Technical Advisory Committee, 1 March 2008 (32 pages)
- “Gut Reactions“, The Atlantic, September 2008 — “Could the same properties that make the termite such a costly pest help us solve global warming?”
For more information see the website for the DOE Biomass Program and DOE’s National Renewable Energy Laboratory Biomass Research program.
News reports about new biofuels
- “Are Backyard Ethanol Brewers an Answer to High-Priced Gas?“, Scientific American, 9 May 2008
- “Corvallis Cellulosic Ethanol Start-Up Receives Energy Grant“, Daily Journal of Commerce, 8 May 2008
- “Swiss yeast developer Butalco gets financial boost” Ethanol Producer Magazine, 6 May 2008
- “G.M. Invests in Second Ethanol Process“, New York Times, 1 May 2008
- “BlueFire to Break Ground“, GreenTech Media, 8 May 2008
- “Sweet New Fuel“, Forbes, 23 April 2008
- “Scientists find bugs that eat waste and excrete petrol“, The Times, 14 June 2008
- “Japanese Sake Brewer Produces Bioethanol from Nonfood Plant Materials“, Japan for Sustainability,18 August 2008
- “Jet fuel from algae passes first test“, Scientific American, 9 September 2008
- “Aquaflow Strikes Oil with ‘Green Crude’ from Algae“, Adam Shake, posted as gas2.0, 16 September 2008
For more studies about alternative energy, see the FM Reference Page: Peak Oil – Other Resources.
Some other posts on the FM site about unconventional and alternative energy sources
- Links to articles and presentations of some A-team energy experts , 11 November 2007
- Let us light a candle while we walk, lest we fear what lies ahead , 10 February 2008
- Fears of flying into the future , 25 February 2008
- Fusion energy, too risky a bet for America (we prefer to rely on war) , 4 May 2008
- Peak Oil Doomsters debunked, end of civilization called off , 8 May 2008
- A snapshot of our engines of innovation, as they develop new energy sources, 12 May 2008 — A look at 6 new forms of biofuel.
- Good news about oil, but for our grandkids – not us , 14 July 2008
- How does the long-term trend of peak oil affect us, in terms of short-term events?, 30 August 2008
- An urban legend to comfort America: crash programs will solve Peak Oil, 5 September 2008
- An urban legend to comfort America: oil is oil, even if it is not oil, 10 September 2008
- An urban legend to comfort America: alternative energy will save us, 16 September 2008
Here is an archive of all my articles about Peak Oil and energy.