Cellulosic ethanol: Clean but value unproven

by Stephen Leahy

30-06-07

With biofuels being blamed for rising food prices and offering limited environmental benefits, diverse luminaries like former US vice-president Al Gore and Microsoft’s Bill Gates are throwing their considerable support behind cellulosic ethanol, a second generation biofuel. The big benefit cellulosic ethanol has is that virtually any plant material -- left-over corn stalks, sawdust, wood chips, native perennials grown on marginal lands -- could be turned into “green gold”, a low-emission fuel for the transportation sector.
"Cellulosic ethanol would reduce carbon emissions 88 % over gasoline," says Bruce Dale, a chemical engineer at the Biomass Conversion Research Laboratory at Michigan State University.

Dale recently published a life cycle analysis comparing various fuels on a carbon emissions per kilometre basis in the prestigious journal Science.
"Any form of ethanol is greatly superior to gasoline in this respect," Dale told. And he calculates that cellulosic couldsupply all of the US's gargantuan appetite -- 200+ bn US gallons -- for liquid fuel without pushing up food prices because it will use non-food crops grown on marginal lands.
But, he cautions, the cellulosic green-gold revolution will have to proceed carefully to avoid mistakes such as palm oil biodiesel production in south-east Asia that has been labelled as “deforestation diesel” by environmental activists.

European subsidies for biodiesel prompted an enormous boom in planting palm oil trees in Indonesia and Malaysia in the past few years. Forests were clear-cut and peat swamps drained to plant hundreds of thousands of hectares. Cutting the forests and draining the swamps emitted far more carbon than could ever be saved from using biodiesel, a number of recent analyses show.
"Biofuels for transport is the wrong approach entirely," says Andrew Boswell of Biofuelwatch, a British environmental NGO. Vast monocultures of oil palm, soya, sugar cane and maize for biofuels results in massive losses of biodiversity and rural livelihoods, serious impacts on water, soil, and food security, Boswell told.

Biofuelwatch and more than 150 civil society organisations have called on the European Union to abandon their targets for biofuel use. A May 2007 UN Energy report concurred stating that biofuels are more effective when used for heat and power rather than in transport. Boswell does not see cellulosic as much of an improvement as a fuel for transport.
Converting biomass into fuel means less biomass for soil which is crucial to maintaining soil fertility. Growing crops and cellulosic processing plants also require huge amounts of water. T

There are also bio safety issues since the cellulosic process uses genetically engineered enzymes and genetically engineered crops as feedstocks, he said.
"Investments in energy-efficiency, plug in hybrid cars and more transit would be cheaper and more effective," said Boswell. "Cellulosic ethanol is just the next big money-maker for the agro-chemical and biotech corporations," he said.

While large companies like Dow Chemical, Monsanto as well as Exxon and Royal Dutch Shell among many others are certainly involved, not a single cellulosic plant has gone into production yet despite 50 years of research.
"It's much more difficult and complex to get ethanol from cellulose," says John Ferrell, co-director of the National Biomass Coordination Office within the US Department of Energy (DOE). A corn kernel is mostly starch and water, which is easy to breakdown into a sugar and start the fermentation process that produces ethanol, Ferrell said.

Cellulose is the structural part of a plant -- what holds a plant up -- and it contains much more than starch and water, lignin for example. Genetically engineered bacteria that produce special enzymes can break down some of the materials but not all of it, so there are several steps in the process, longer fermentation times and more energy inputs.
"It's a more costly process, while corn-ethanol production is a proven andprofitable technology," says Ferrell.

The world's first and only pre-commercial cellulosic demonstration facility has been in operation for several years in Ottawa, Canada. Funded in large part by the Canadian government and Royal Dutch Shell, the Iogen Energy facility uses wheat, oat and barley straw to make a 100,000 litres of ethanol a year.
Iogen has been hard at this for close to 25 years and are about to build a full-scale production facility in Iowa, thanks to $ 80 mm from the DOE as part of a special 385 mm dollar US government programme to kick-start the nascent industry. The goal of this largesse is have four to six small but commercial-scale cellulosic plants up and running by 2010, says Ferrell, Iogen among them.

As oil prices stay high, banks and other investors are eager to finance corn ethanol facilities but will steer clear of cellulosic until it proves itself, hence the need for government subsidies, he says.
"It's hard to grasp the current state of the technology because it's in the hands of private companies," says Elizabeth Marshall, an economist at the World Resources Institute who studies the industry. "There are a lot of smoke and mirrors in the industry with everyone scrambling to get money," Marshall said. And technical challenges remain, she says. The special-enzyme producing bacteria are fussy about what they eat and most operations require a specialised, uniform feedstock such as wheat straw and nothing else.
"However, if it works the energy balance for cellulosic is much better than grain ethanol which uses a lot of energy just to grow crops like corn as feedstocks," Marshall concludes.

Corn prices are at record highs in the US due to the growing demand for ethanol. According to FAO’s latest Food Outlook report, global food import bills are increasing, partly due to soaring demand for biofuels. Whether cellulosic feedstocks will compete with food crops for land and water depends on how the industry evolves. Marshall is investigating the various implications of a possible future with a major cellulosic industry.
Where and how are the high volumes of biomass going to be grown? How will they be transported and stored? How much biomass can be removed without negative impacts on the soil? How will the industry affect food prices?

A holistic examination of the industry is needed to make sure it brings the promised environmental benefits and minimise the impacts on food prices, she says.
"Protective legislation will be needed to guarantee those benefits and impacts," she adds.
 

Source: IPS News