In the opinion of some analysts, world oil production peaked in 2006 and is now on a downhill run. If this is correct, we can expect a continuing trend towards higher petrol prices at the bowser. Sources of oil are now being tapped that were previously too energy-intensive to extract economically, and one of these is the vast tar sands reserves of Northern Alberta, Canada.
Energy return on energy invested (EROEI)
Many environmentalists see this is the last great fix for our oil-addicted culture. To process tar sands, the total energy input has been calculated at approximately two barrels for every three recovered, yielding a mediocre energy return on energy invested (EROEI) of around 1.5. (In other words, it yields 50% more energy than is required for all the production steps.)
Industrialised countries are increasingly aware of how dependent they have become on a handful of major oil exporters, and are taking steps to reduce their degree of reliance on imported fuel. Smaller, more efficient, cars are in, and even the US has finally raised its minimum fuel efficiency standards.
Rick Wagoner, CEO of the American giant General Motors, attracted attention early this year when he said that a switch towards fossil fuel alternatives is now inevitable. These include electric cars, and renewable fuels such as biodiesel and ethanol. The world’s ethanol industry is growing quickly, often aided by government incentives. But is it a genuinely green option?
The same substance as drinking alcohol, ethanol can be derived from a range of feedstocks including corn (especially in the US, which recently overtook Brazil as the world’s largest producer) and sugarcane (Brazil and Australia), while wheat and sugar beet are used to a lesser extent. Production plants are large, and unlike biodiesel, ethanol is not a candidate for a backyard cottage industry.
Until a few years ago, ethanol-fuelled cars were synonymous with Brazil, which since the 1970’s has taken advantage of its tropical climate to allocate large swathes of land to sugar cane destined for ethanol facilities. Today, ethanol represents about 30% of all automotive fuel sold in Brazil, while the remaining organic matter from sugar cane (known as bagasse) is burned in biomass power stations to generate renewable electricity.
The food versus fuel dilemma
One objection commonly levelled at ethanol is that diverting large acreages of farmland into fuel production, as has occurred in the US, puts a squeeze on the amount of land available for food as the world’s population continues to climb and weather conditions become less predictable.
Increased demand for corn, coupled with the diversion of land away from other key agricultural commodities in favour of corn cultivation, has resulted in sharp commodity price increases. In the 12 months up to July, 2007, the world price of corn shot up by 60%, wheat rose by 53%, and soya increased by 40%.
Unfortunately, such price rises hit the poor hardest, and they have perhaps been felt the strongest in Mexico, where the country’s staple food (and an important source of protein) is the tortilla. Last year, when the cost of Mexican corn doubled within the space of a few months, there were angry protests on the streets. The corn was being sent north, to ethanol production plants in the US, attracted by a higher buying price.
In the US, the prices of meat and dairy products have risen as a result of increasingly costly stock feed, while the same has happened to processed foods that depend heavily on corn and soya ingredients. In a circular knock-on effect, corn price rises have also hit ethanol refineries, and without the multi-billion dollar corn cultivation and ethanol production subsidies provided by the US government, it is doubtful whether the industry would remain economically viable.
Ethanol from corn – an energy comparison
Any credible environmental appraisal of corn ethanol needs to include a lifecycle analysis. When produced from agricultural crops, the major energy-intensive input is nitrogen fertiliser, while others include farm equipment, pesticides, fuel used on farms, and the production process. Ethanol has the undesirable habit of absorbing water when transported by pipeline. Consequently it has to be carried by road, which is a far more energy-intensive option.
According to the US Department of Agriculture (USDA), ethanol made from corn has an EROEI of 1.34. However, there is a wide range of estimates concerning energy return, and some analysts have concluded that it ultimately requires more energy to produce than it eventually yields. This is however a minority view.
From a climate change perspective, a 2006 meta-analysis of numerous corn ethanol studies carried out at Berkeley University came up with a smaller 7.4% reduction in greenhouse emissions, while a 2007 feature in National Geographic estimated a 22% reduction in CO2 emissions.
Other environmental impacts
A third element that further complicates the fuel versus food tug-of-war is the protection of natural assets. The EMPA Research Institute in Switzerland has developed a method that extends beyond a simply energy analysis to take into account a broader range of ecological factors. These include ecosystem destruction, pollution, impacts on streams and rivers, and human health effects. Using these criteria, ethanol from US corn and Brazilian sugarcane were both found to have a greater environmental impact than regular automotive fuel.
As the acreage under ethanol expands, both forests and wetlands may come under greater threat. Although the EROEI for sugarcane ethanol is estimated to be around eight, and the National Geographic article estimates a CO2 emissions reduction of 56%, there are other factors to consider. In January, Jörn Scharlemann and William Laurance of the Smithsonian Tropical Research Institute pointed out in the journal Science that any environmental benefit would be quickly negated if tropical forests are destroyed to make way for sugar cane plantations.
This process is already occurring via a more indirect mechanism highlighted by Scharlemann and Laurance: one negative side-effect of climbing soya prices has been an acceleration of forest and savanna destruction in southern Brazil to make way for more soya plantations.
Less obvious is the boost that ethanol has already given to the GE industry. While many consumers have major reservations about eating GE food, it is unlikely that they will extend these concerns to the fuel pump. Syngenta’s GE alpha-amylase corn is already being grown in the US to meet the demands of the ethanol market. Last year, Australia became the first country to approve it for human consumption after South Africa had earlier voiced health concerns.
Cellulosic ethanol – biomass and a possible solution
Genuine waste materials are a better environmental choice of ethanol feedstock, where sufficiently large supplies exist. At the Manildra flour mills near the New South Wales town of Nowra, an ethanol plant makes use of flour waste. The industry group Australian Friends of Ethanol draws attention to other possible agricultural wastes such as rain-damaged grain and fruit crops, while the Australian Cane Growers Council refers to such feedstocks as molasses and lower-grade sugar.
In order to transcend the food versus fuel conflict, the US in particular is looking at what has been dubbed a ‘second generation’ technology involving cellulosic ethanol that can be derived from many different plant materials. Depending on the source and production method, the EROEI for cellulosic ethanol has been estimated to be anywhere between 2 and 36. Various options include bagasse from sugarcane, corn stover (the leaves and stalks), wheat straw, and alfalfa stems. Some critics such as the UK’s Biofuelwatch warn however that excess harvesting of waste biomass is liable to deplete soil fertility levels over time.
Two perennial American prairie grasses known as switchgrass and micanthus (elephant grass) are currently arousing the most interest as sustainable feedstocks. Data released early this year indicates that switchgrass, which can be grown without fertiliser, yields a reasonably good EROEI of 5.4 and has a deep root system that provides the added benefit of carbon sequestration. According to the USDA, it curbs carbon dioxide (CO2) emissions by 94% compared with regular fuel.
While production from corn is relatively straightforward, cellulosic ethanol requires fungi or other organisms to break down the woody parts of plants, and this is not so easy to accomplish at an industrial scale. Nevertheless, pilot-scale plants are up and running in America, and six larger refineries are under construction, to be completed by 2010. Only time will tell whether suitable cellulosic feedstocks can be identified in other countries.
Australia’s growing ethanol industry
A handful of ethanol plants are operational in Australia, of which the majority are located along the Queensland coast and use sugarcane.
Several more are under construction, including a plant in Western Australia that will use wheat, and a pilot cellulosic ethanol plant in the Northern NSW sugar belt near Maclean, which is expected to run on wood residues and bagasse from sugarcane. Inevitably, once plants running on such feedstocks come on stream, further commodity price hikes will diminish the industry’s economic viability in the absence of government subsidies. As in the US, such a trend is certain to push up the price of stock feed, and this is arousing the attention of the Australian Lot Feeders Association.
In vehicles, despite the worries about ethanol-blended fuel that surfaced a few years ago, there is now a broad consensus in Australia that unmodified cars can run on 10% ethanol (E10) without any adverse effects. The ethanol component of petrol sold around Australia currently goes no higher than E10, and servos are required by law to label any ethanol content. Higher blends may attack certain components of a vehicle’s fuel system.
Motorists need to be aware that the energy density of ethanol is 33% lower than for unleaded, and therefore a vehicle driving on pure ethanol would require significantly more fuel to make a particular trip. An E10 blend incurs an approximate 3% drop in fuel economy, but this is largely balanced out by the fact that the Australian Competition and Consumer Commission has found the average selling price of ethanol-blended fuel to be three cents per litre lower than for non-ethanol unleaded.
An additional use for ethanol is as an oxygenate additive that raises the octane level of regular fuel, resulting in increased power. In this role, it has the capacity to substitute various carcinogenic chemicals including MTBE, notorious for water pollution incidents in America. MTBE is banned in some Australian states, and in the others its concentration is limited to only 1%.
The effects of ethanol on vehicle emissions are mixed: carbon dioxide levels remain relatively unchanged and carbon monoxide drops. There is less benzene in the air, but more nitrous oxide and aldehydes, and ozone rises significantly.
To boost the development of a domestic ethanol industry, an excise of around 38 cents per litre is applied to imported ethanol fuel, while domestic production is exempted. Last year, in a move designed to stimulate the state’s rural economy, New South Wales mandated that fuel supplied to petrol stations within the state must contain 2% ethanol. It has further plans to mandate the use of E10 fuel by 2011.
Those vehicles with fuel system modifications that can run on an 85% ethanol blend in addition to regular unleaded are often referred to as ‘flex-fuel’. The Saab BioPower was the first of these to go on sale in Australia late last year, but selling at over $60,000 it has the disadvantage of being fairly pricey. In the major cities, E85 bowsers are expected to be appearing some time this year.
It is obvious that ethanol is not a simple panacea. At the most basic level, if all of the world’s farmland were allocated to producing ethanol feedstocks and we found a way of surviving without food, the resulting production would still not be sufficient to fuel the world’s car fleet. Greenpeace makes the point that as a first step we would be better off investing in more efficient vehicles.
Another factor delaying the widespread introduction of any prospective new automotive energy solution, including ethanol, is the world’s existing vehicle fleet, which will take some time to be replaced.
As time goes on, observers have become increasingly wary of ethanol, and many are only prepared to give it very qualified support. Numerous difficult-to-quantify factors determine whether its environmental benefits are dubious (in the case of corn), or fairly promising (in the case of prairie grasses). We can only lobby for the further development of ethanol to evolve in an environmentally responsible way.
Share this post