Getting greener: the next generation of biofuels
As concern grows over greenhouse gas emissions and climate change, biofuels are increasingly seen as an alternative to petrol and diesel. Companies like Shell are helping to develop the next generation of biofuels that do not compete with food crops and are better for the environment.
July 13, 2007
by CHRIS LOGAN
On the corn-trading floor of the Chicago Board of Trade, America’s oldest grain futures exchange, prices hit record levels. Farmers in the corn belt of the Midwest, who once faced lacklustre demand, planted more crops to keep up.
This year 90 million acres of prime US arable land will be given over to corn, or maize, the largest acreage dedicated to the crop in more than 60 years. A quarter of the corn produced will go towards making ethanol, a biofuel that can be blended with petrol, or gasoline. Bio-refineries, which ferment and distil the corn to make ethanol, string out across 19 states. New ones are rapidly springing up, creating jobs.
Henry Ford might have enjoyed the irony: back in 1908 his revolutionary Model T was designed to run on petrol, or what he called “the fuel of the future”- ethanol. His view now seems more prescient than ever, as an energy-hungry world increasingly seeks to foster biofuels as a sustainable alternative to fossil fuels to help keep road transport moving.
And not just in the USA. Farmers and plantation growers in other parts of the world have turned their focus to biofuels, too. In Malaysia, Indonesia and Europe, farmers are getting better prices than ever for vegetable oils from rapeseed, soya, sunflower and palm. When chemically processed these oils can be used to produce a biodiesel for blending with conventional diesel.
In many countries government mandates or tax incentives exist to make biofuels part of the transport fuel mix, partly because they are seen as potential energy security – a way to “grow your own fuel” – and partly with the environment in mind, because some biofuels produce less carbon dioxide (CO2) over their life cycle than the fossil fuels they replace. As a result, sales of biofuels are rising. Shell handles over 3.5 billion litres (nearly a billion US gallons) of biofuels a year, 85% of it ethanol, making it one of the world’s largest distributors of biofuels. The International Energy Agency (IEA) believes that, according to one projection, by 2030 biofuels will account for up to 7% of the road transport fuels market, up from 1% today.
Yet first-generation biofuels now on the market provoke criticism through their dependence on food crops and issues over biodiversity, land use and human rights. They also vary enormously in CO2 emissions - depending on methods used to grow, harvest and transport the crops and then convert them to biofuel. Technical challenges exist, too, in blending them effectively with conventional petrol or diesel, except at low concentrations - a typical biofuel blend today is no higher than 5%, for example.
No waste, less CO2
Instead the key to achieving long-term energy security and environmental benefits appears to lie with advanced, second-generation biofuels. Crucially, they do not compete directly with food crops because they are made from biomass: agricultural and forestry waste, or fast-growing grasses and trees, specially grown – so-called energy crops. They can produce around 90% less CO2 than fossil fuels when compared over their life cycles, taking into account that it is the CO2 absorbed by the plant as it grows which is later emitted during conversion and combustion. This is significantly up from as little as 30% less CO2 for the most common first-generation biofuels. Second-generation biofuels can achieve high CO2 savings partly because the plants they derive from have already been cultivated and harvested. Parts of the biomass not used for biofuel production can also be burnt to generate power at the conversion plant.
With technology, sustainability and cost hurdles to overcome, second-generation biofuels are still several years away from commercial viability. But Shell’s research and investment in the technology needed is well advanced.
For a second-generation petrol substitute the cellulose of straw, for example, can be fermented to make ethanol. Lignin from the same source can be used to generate steam and electricity to power the conversion process, doing away with the need for fossil fuels like coal or gas. Shell is working with Canadian firm Iogen to make this process commercially viable. The process uses enzymes, a biological catalyst, to break down the plant’s cellulose into sugars for fermentation.
For second-generation biodiesel, residue from forestry or the paper industry in the form of woodchips or similar matter can be chemically converted, after heating and gasification, into a liquid fuel identical to that produced from the gas-to-liquids (GTL) process. It has the same performance and local environmental qualities as GTL fuel: colourless, odourless and virtually sulphur-free, with a similar reduction in emissions of particulates and hydrocarbons at the exhaust. Again Shell is working with a partner, CHOREN Industries of Germany, to turn this process – known as biomass-to-liquids (BTL) – into a commercial reality.
Green but costly
None of this is cheap, or easy. Paul Ayoub, Biofuels Process Research and Development Co-ordinator for Shell Global Solutions, explained that one major expense lies in collecting the widely-spread raw materials, whether from agriculture or forestry, and transporting it to the conversion plant in enough bulk for commercial-scale fuel production.
“Another high cost element is the conversion processes themselves,” he said. “Biomass has low energy density – it contains a lot of water which we must get rid of. Nature makes biomass difficult to break down. Our research and development work is focused on trying to bring down these costs.”
Fast-growing, high-yield switchgrass, miscanthus, poplar and willow – which also have the environmental benefits of needing little fertiliser and no pesticides - could be part of the solution.
Iris Lewandowski, a Shell biomass sustainability specialist in Amsterdam, said that in Britain, for example, miscanthus is used as biomass for mixing with coal at some coal-fired power stations, while in Sweden willow trees are grown for woodchips for combustion to supply heat to homes.
But the sustainability of biofuels is about more than an economic supply of raw material. With first-generation biofuels there are concerns over a lack of internationally-recognised standards in the supply chain, allowing for possible abuses such as human rights violations – using child labour is one – and land clearance in protected areas. To try to combat these concerns, Shell already applies its biodiversity safeguards in assessing the suppliers of the biofuels it distributes. It also works with non-governmental organisations, governments, suppliers and industrial consumers on establishing international standards for sustainable energy crops – including CO2 production - such as the Roundtable on Sustainable Biofuels.
Concerns over the sustainability of second-generation biofuels include how much agricultural or forestry residue can be collected for biomass without causing long-term damage to the soil through lack of nutrients or protection against erosion. If dedicated energy crops are grown, land use issues may also arise. Today around 1% of the world’s total arable land – some 14 million hectares - is given over to biofuels production but by 2030 this could more than triple, according to the IEA. Competition between biofuels and food for farmland has already led to some higher food prices.
Lewandowski, a member of an industry working group which reports on sustainability, said that by the end of this year the European Commission (EC) is expected to issue a set of sustainability criteria for biofuels. “These may include the CO2 benefits and the issue of the land used to produce them. Up to now there have been targets and mandates set for blending biofuels with regular fuels, but nothing laid down about the sustainability of the biofuels used.”
Governments mobilising
The momentum is certainly building among governments keen to be seen to be taking action against fossil fuel consumption. The European Union has decided that by 2010 all vehicle fuel sold should contain 5.75% biofuel, although already it recognises that some countries will fail to meet this. The EC has also proposed a legally binding target of 10% biofuels in transport fuel by 2020 – and this includes an incentive scheme to discourage biofuels produced in a non-sustainable way. It is now working on proposals to further cut CO2 emissions from the production, transport and use of road vehicle fuel by 10% from 2011 to 2020. The EC expects a major part of these reductions to come from the use of second-generation biofuels.
President Bush has declared that he wants biofuel production to increase five-fold by 2017 in order to cut projected consumption of petrol by 20%, and he has announced new tax incentives to promote the use of ethanol. The USA and Brazil - where ethanol made from sugar cane has been an essential part of the transport fuel mix for 30 years, replacing some 40% of petrol use - have also formed a new partnership to push the development of biofuels. Energy security is a key part of their vision.
Even before this, ethanol production in the USA had risen more than three-fold since 2000. In 2006 the country produced 4.9 billion US gallons (18.6 billion litres) of ethanol from more than 100 bio-refineries – up more than 25% on the previous year.
Politicians calling for ever-more biofuel use is one thing. Continuing to meet rising demand in a practical way is another. The IEA, for example, cites trade and subsidy policies as “critical factors” in how and where biofuels will be produced in the coming decades. Then there is the question of how to make more concentrated blends effective. Introducing blends beyond 10% in existing engines on a commercial scale is “a major challenge”, according to Lionel Clarke, Technology Manager Strategic Research at the Shell Technology Centre in Thornton, UK, where engines are tested to find the best way of combining biofuels with fossil fuels.
Most manufacturers only warranty cars for up to 10% of biofuel unless they have been specially designed to take larger proportions, such as socalled flex-fuel cars. These number several million in the USA and can run on a petrol blend of up to 85% ethanol. In Brazil around two million flex-fuel cars run on ethanol blends ranging from 20% to virtually 100%. Flex-fuel cars are designed to withstand corrosion and compatibility problems with seals and engine parts linked to ethanol, and have computerised sensors that can adapt engine behaviour to suit conditions. But they cost more to make than conventional modern cars. Ethanol also has 30% less energy than petrol: most motorists tend to opt for the more economic petrol on the forecourt than an 85% blend. “Shell believes it is better to sell low-concentration blends that can be used in almost all cars, making better use of the current retail network,” said Clarke.
The road ahead
“Clearly, not all biofuels are good biofuels,” said Piotr Tulej, head of the energy and environment unit in the EC’s Environment Directorate-General, and former head of the IEA’s renewable energy unit. “The impact on soils, land use, water and biodiversity can be significant, and the life-cycle greenhouse gas balance of certain biofuels is potentially worsened by deforestation and the use of fertilisers.
“We have to look to those new technologies that do not put us into conflict with food production. But we also have to consider the reality. A 7% share of the global fuels market for biofuels by 2030 is not going to make anyone totally independent of importing oil from foreign parts. Second-generation biofuels may be an improvement on what we now have, but let’s see first how quickly they can be brought to market successfully.”
Darran Messem, Shell Vice President Fuel Development, believes biofuels production needs to be managed responsibly to succeed: “That means having very tight quality controls and having the appropriate measures and assurance systems for sustainability, land use and CO2 production.”
A framework for rewarding companies for reducing CO2 emissions – getting a price for CO2 - would encourage the development of second generation biofuels technologies, he argues. “Our challenge is to make them cost-competitive. Biofuels are the most viable route we have for renewable, sustainable transportation energy. But, realistically, fossil fuel will still provide the bulk of our transport fuel for many years to come because of its high energy density, production cost and relative convenience. You can’t easily replicate that with biomass.”
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