Issue 18

Surveys in silicon

Masters of management

Ready for inspection

Conjuring with coal

Going with the wind

Backwards brainwaves

In praise of gearheads

Back to a bio future

BP's recent launch of the Energy Biosciences Institute marks the start of a new quest to bring the latest advances in biology to bear on energy matters, particularly for the production of next-generation transportation fuels. Terry Knott looks at BP's rationale for entering the realm of bioscience and how this might impact energy production methods in the future

When Henry Ford launched his Model T automobile in 1908, he envisioned that ethyl alcohol, derived from the fermentation of crops readily available in the fields of American farmers, would be its primary fuel. In that same era, diesel engines, patented in 1892 by Rudolf Diesel, were establishing themselves as reliable industrial machines, fuelled by vegetable oil. Neither Ford nor Diesel could foresee that petroleum would soon largely sweep aside these 'biofuels' as energy sources. Nor would they have predicted that now, a century later, biofuels would be enjoying a renaissance as governments and energy companies seek alternative solutions for powering transportation.

'There are two main driving forces that are currently pushing biofuels up the business agenda,' explains Steve Koonin, BP's chief scientist. 'One is security of supply. Governments, particularly those in the OECD (Organisation for Economic Co-operation and Development), are striving to become less dependent on imported oil and are seeking diversified sources of supply. The USA for example, the largest consumer of crude oil, imports around 60 per cent of the oil it currently uses. Growing plants to make biofuels locally or in non-oil producing regions could help ensure a more secure supply of transportation energy.

'The other driver is environmental. Currently, around 55 per cent of the world's oil output goes into transportation fuels, with emissions from these fuels accounting for 21 per cent of total global emissions. Biofuels, and particularly the more advanced biofuels BP believes could become economically viable, hold out the promise of helping to reduce emissions of greenhouse gases.

'So when you look at the broader picture of energy supply, biofuels stand out as the option that has the potential to help address both of these concerns, at scale, and in the nearer term.'

Click the link below to view a graphic of the biofuels cycle

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To Koonin it is no coincidence that biofuels are currently in the spotlight in the energy world. He points to the fact that biology is the most rapidly developing of the sciences, citing as just one example that it took a decade to produce the first complete human DNA sequence, while such a task can now be achieved in a month.

'If you consider that all of life as we know it is based on carbon, and so too is 90 per cent of the world's energy, there are bound to be synergies between biology and energy waiting to be discovered,' he asserts. 'Furthermore, the fact that the main pursuit for modern biological research until now has been in the sphere of medicine, with lesser investment in agriculture, materials and chemicals, means the field of energy bioscience is largely open territory. Fostering the intersection of biology with energy is therefore likely to generate disruptive technologies that can benefit the energy industry.'

He emphasises that this 'compelling rationale for energy biotechnology' is viewed by BP to reach far beyond the more immediate goal of developing biofuels. Additional areas where biology could be brought to bear in the energy sector include improving oil recovery from hydrocarbon reservoirs, carbon sequestration whereby plants and other organisms remove carbon dioxide (CO₂) from the atmosphere and transfer it to the soil or ocean, the conversion of heavy oil into clean fuels, the production of methane from coal, bioremediation, and the manufacture of bio-plastics.

'After 3.5 billion years of evolution, nature has already produced an array of micro-organisms that can perform a wide variety of processes involving carbon,' notes Koonin. 'Our intention is to explore ways of applying these to energy production.'

Big science

It is precisely to understand such processes and investigate their potential in relation to producing new and cleaner energy, that BP has launched the Energy Biosciences Institute (EBI). In February 2007, BP announced a 10-year, $500 million research programme to be undertaken in partnership with the University of California at Berkeley, the University of Illinois, and the Lawrence Berkeley National Laboratory in California. The ground-breaking research programme, unique in both business and academic circles, will enable some of the world's leading researchers to explore how bioscience can be used to increase energy production and reduce the impact of energy consumption on the environment.

'BP believes the EBI is one of the largest mission-driven integrated science programmes to be initiated in the last 50 years,' says Jim Breson, BP's project manager who led the setting up of the EBI. 'We conducted a very rigorous selection process involving many of the world's top scientific organisations - 52 institutions in 10 countries in all. The competition was very stiff. One key reason for selecting Berkeley and its partners was because these institutions have excellent track records of delivering "big science" - that is, large, complex developments aimed at making scientific breakthroughs that can subsequently be deployed in the real world as engineering applications.

'The EBI is unique and gives BP a distinctive position in the energy industry. In effect, we will be creating the discipline of energy biosciences.'

While the EBI will be researching into the broader aspects of energy bioscience over time as its staffing levels build up, its first task is to delve deeper into biofuels.

The term biofuels covers a wide range of products, but in essence biofuels are fuels derived from biomass, that is, recently living organisms or their metabolic by-products, and as such biofuels are renewable sources of energy. Traditional forms of biofuels include wood, charcoal or dried animal dung which can be burned to provide heat for cooking or domestic fires. But for transportation, more sophisticated liquid biofuels are required.

'Biomass is a source of carbon,' says Koonin. 'As we know, molecules containing carbon are readily fungible - that is, convertible into other forms. In this case, the carbon available in plant matter can be processed to produce a carbon-based transportation fuel, what we commonly call a biofuel.'

And there we return to the transportation biofuels used by the pioneers Ford and Diesel. But for the advent of widely available petroleum products, those biofuels may have come to dominate globally, but today such biofuels account for only around two per cent of the world's transportation fuels. The most common of these is ethyl alcohol - ethanol - produced by the action of micro-organisms that ferment sugars and starches found in plants such as cereals, potatoes and sugar crops, a process that has been known and used since ancient times. The starches are first converted to sugar by enzymes in a process known as hydrolysis. The sugars are then fermented by micro-organisms that produce a dilute solution of ethanol, which is then distilled and dehydrated to produce near-pure ethanol, a clear liquid.

While 'bioethanol' is produced in more than 30 countries, the USA and Brazil are by far the leading producers and together account for over 90 per cent of world supply. After a decade which saw significant growth in its bioethanol production, the USA produced around 7.4 million tonnes of oil equivalent of bioethanol in 2005, mainly from corn (maize), using around 14 per cent of its domestic corn crop to do this and resulting in the replacement of just over two per cent of the country's gasoline use. 'In the USA, production of fuel ethanol from corn remains economical while crude oil prices are greater than $45 per barrel,' observes Koonin.

In Brazil around half of the country's sugar cane crop goes into bioethanol for domestic use and export. In 2005, the country produced 7.6 million tonnes of oil equivalent, achieving efficiencies which are economic against crude oil prices as low as $22 per barrel - unlike corn-based ethanol, conversion from sugar cane eliminates the hydrolysis stage, and in Brazil the plant residues are burned to generate heat and electricity, making the process more cost effective.

In addition to bioethanol, biodiesel is another biofuel whose production is on the increase, albeit at lower absolute output levels than ethanol. Biodiesel manufacture is based on the extraction of oils from plants such as soybeans, rapeseed, sunflowers and palm oil, or from animal oil and fats, tallow and waste cooking oil, and even algae - the process used to convert these oils to biodiesel is called transesterification.

Production of biodiesel, which is chemically identified as fatty acid methyl ester, is mainly carried out in the European Union (EU) at present, which, with output of biodiesel in the region of three million tonnes in 2005, accounts for around 80 per cent of global output. Biodiesel currently accounts for about 1.5 per cent of the European diesel market, and is principally manufactured from rapeseed oil. In the USA, biodiesel production is also on the rise.

Counting carbon

Bioethanol and biodiesel manufacture look set to grow as governments lay down legislation to increase the proportion of biofuels in the overall transportation fuels mix as part of their wider strategies to promote the use of renewable energy, and also to help support indigenous agriculture and rural economies. For example, earlier this year the European Commission set a target for biofuels to make up at least 10 per cent of the EU's transportation fuels by 2020, pushing up the previous non-binding target for biofuels to be 5.75 per cent of the fuels mix by 2010. Biodiesel is expected to play a major role in trying to reach this goal, requiring biodiesel output to increase to 24-26 million tonnes per year by 2020 - although debate continues on whether the substantial increase in raw materials required to approach these numbers can be grown domestically or will have to be imported.

In the global biofuels market, BP is already a top player, blending and distributing 2.2 billion litres of ethanol and 265 million litres of biodiesel in 2005, and further pushing up its ethanol supply by over 20 per cent in 2006 to 2.7 billion litres of ethanol blended with gasoline. With the blending and marketing of these products, along with other refined products, BP supplies about 10 per cent of the global biofuels market.

But should these particular biofuels be heralded as the best solution to finding an alternative supply of transportation fuel on a much larger scale, as demand increases? Closer inspection reveals that perhaps they should not, says Koonin.

'On three important fronts - namely, energy, emissions and economics of scale - biofuels such as ethanol and biodiesel fall somewhat short of the mark. In BP we believe there is tremendous scope to improve on all of these aspects.' (See panel "Advantaged molecules" at the end of this feature.)

He points to the fact that the energy density of ethanol on a volume for volume basis is only about two thirds that of gasoline, giving lower transportation efficiency, and thus greater volumes are required - the energy density of biodiesel is roughly the same as that of ordinary diesel. Moreover, from a practical standpoint, it must be understood that biofuels are not direct substitutes for petroleum-derived fuels in conventional automobile engines, and are used commercially by blending them with gasoline or diesel. The volumes of biofuel mixed with conventional fuels are limited by chemical properties or implementation issues connected with their handling - typically, bioethanol and biodiesel are added to conventional fuels at 5-10 per cent by volume. Their use above these levels requires modifications to be made to engines - ethanol can damage components such as gaskets and seals, and it easily absorbs water, giving it corrosive properties which are unwelcome in transportation pipelines, distribution depots and at retail sites. Some automobile manufacturers make vehicles with 'flexible fuel' engines that can either run on blends containing up to 85 per cent ethanol or can be switched to pure gasoline, but these vehicles are relatively few in number.

On the subject of emissions, biofuels should, at least in theory, be rather 'virtuous'. Carbon - in the form of a molecule of CO₂ removed by plants from the atmosphere - is captured by the plant during photosynthesis. It is then converted into biofuel carbon, burned in the vehicle's engine, and then released back into the atmosphere as one molecule of CO₂. In effect, a cycle that is neutral in terms of carbon emissions.

'In reality this is not the case,' says Koonin. 'To cultivate the crops, we use energy in farming them and produce CO₂ from farm vehicles or fertiliser manufacture. Then, converting the starches in the crop to biofuel requires external energy to be put into the conversion process, and transporting and distributing the fuel to market soaks up still more energy before the fuel gets into the automobile. The net effect is that to make one energy unit of corn-based ethanol in the USA requires around 0.9 energy units of external energy. However, the input energy comes mainly from coal in the form of electricity, and natural gas for heating the distillation process. The contribution of oil products is only 0.05 energy units, hence in effect you can get 20 units of liquid ethanol for every one of liquid petroleum. This is a significant benefit from a security of supply perspective.'

But the resulting CO₂ emissions from biofuels deliver limited benefits. On a 'crop to car' basis - that is, the full ethanol life cycle which takes account of the CO₂ taken in by the plant as it is growing - pure ethanol produces around 18 per cent less CO₂ when used as fuel than does pure gasoline, compared on an equivalent energy content. However, as ethanol is mainly used as a blend with gasoline, say at 10 per cent by volume, a tank of blended bioethanol would therefore deliver less than two per cent overall reduction in emissions compared with a tank of gasoline. Given the fact that the world's transportation fuels account overall for only 21 per cent of total global emissions, the potential reduction in global emissions from ethanol blended fuels is limited.

'It is an improvement in emissions, no doubt, but not sensational,' observes Koonin.

Click the link below to view a panel on the need for new carbon sources

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The third aspect, and perhaps the most critical, is that production of conventional biofuels from starches and sugars does not readily scale up to meet the forecast levels of demand - the USA, for example, is forecasting that biofuels could serve 20-30 per cent of the nation's transportation market by 2020.

'The USA consumes around 650 million tonnes of carbon a year in gasoline and diesel,' states Koonin. 'To impact this by supplying carbon from crop-based biofuels, you would need crop production on a massive scale.'

He illustrates this by setting an imagined target of finding from alternative sources 15 per cent of the carbon consumed in gasoline and diesel in the USA, equivalent to around 100 million tonnes per year (see graphs below). This would require that all of the corn currently produced in the USA, the country's most abundant crop, be diverted into biofuel production, leaving no corn for the food market. Even so, the entire corn crop could only displace around 10 per cent of the nation's gasoline consumption, and this is assuming complete efficiency in the conversion of the corn grain to ethanol This scenario is clearly both impractical and undesirable at current levels of corn production.

Looked at on the global scale, large parts of the world's wheat, rice, corn or wood pulp output would need to be diverted to meet 15 per cent of global transportation fuels demand. Again not a feasible solution at present - and this would still leave 85 per cent of transport in the world fuelled by gasoline and diesel.

Enter cellulose

'The fundamental problem here is that conventional crop yields are too low,' explains Koonin. 'In the USA, growing corn produces about four tonnes of grain per acre, which in turn could be converted into around 1650 litres of ethanol, or 1100 litres of gasoline fuel equivalent taking into account the lower energy density of ethanol. Even higher yield crops such as sugar cane and sugar beet only produce 1500-1900 litres of ethanol per acre, or 1000-1275 litres of conventional fuel equivalent. Rapeseed oil gives less than 600 litres of biodiesel per acre, or 540 litres of diesel fuel equivalent, while soybeans yield around 250 litres of biodiesel. Although there is variability in crop yields depending on regions, farming methods and biofuel conversion efficiency, the figures illustrate that to impact conventional fuel consumption with biofuels, you need a much greater supply of carbon.'

BP believes that the pathway to that increased biomass lies not only in being able to use the starches and sugars used to make today's conventional biofuels, but also by accessing other substances in plants which are present in greater proportions than sugars and starches.

When plants convert the sun's energy for their growth through photosynthesis, most of the energy is converted not into sugars and starches, but into cellulose (a polymer of glucose, a sugar containing six carbon atoms), plus hemicellulose (other sugar polymers mainly composed of sugars with five carbon atoms) and to lignin (a refractory substance of aromatic carbon compounds). These substances - collectively referred to as lignocellulosic biomass - essentially form the cell walls, the structure and protective armour of the plant.

In more familiar agricultural crops such as corn and wheat, this type of biomass is contained in the corn stover and the wheat straw. But there are many known plant species which produce higher proportions of lignocellulosic biomass, and - not having been selectively bred over centuries to maximise food production rather than biomass - do so with remarkable effectiveness, frequently delivering more than 10 tonnes of dry biomass per acre. Miscanthus, a species of tall grass, can quickly grow to over 3m in height in densely packed fields, and switchgrass, another tall, woody-stemmed grass, exhibits similar growth. Both of these can yield over 10 tonnes of dry biomass per acre in a year, and record-breaking harvests have produced up to 26 tonnes of dry biomass from miscanthus and up to 15 tonnes from switchgrass.

Such plant species produce biomass rapidly with the potential to provide thousands of litres of biofuel per acre. For example, using an efficient conversion process some 420 litres of ethanol could be obtained per tonne of biomass. Taking a yield of 10 tonnes of biomass per acre would give 4200 litres of ethanol, or 2800 litres of fuel equivalent - some experts believe the dry biomass yields could be pushed up by perhaps another 40 per cent on top of these volumes under ideal growing conditions. Furthermore, these perennial grass species can grow well without the need for intensive inputs such as agrichemicals and fertiliser, and thrive on marginal land where more conventional crops would not. In this regard, their mass cultivation would not pose a threat to prime agricultural land and food production.

Lignocellulose biomass could be obtained on a large scale from fast-growing plants, such as miscanthus (left) and switchgrass

'Such factors result in a far more favourable energy balance for lignocellulosic biomass,' Koonin explains. 'We think that it should be possible in time to get more than five times the energy out of the biomass than we have to put in during growing it and converting it to fuel. And seen from a life cycle "crop to car" emissions perspective, efficient conversion of a greater portion of the biomass into fuel, plus its subsequent use for transportation, could result in an overall drop in CO₂ emissions of 90 per cent compared with those arising from petroleum products.

'On top of these benefits, it appears to be plausible to achieve the scale required. For example, 36 million acres of land in the USA are set aside in the Conservation Reserve Programme (CRP). If it were possible to produce just five tonnes of biomass per acre, and generate 420 litres of ethanol per tonne using improved conversion technologies, this many acres could deliver around 75 billion litres of bioethanol per year from lignocellulose, equivalent to around 50 billion litres of gasoline. This is almost 10 per cent of current gasoline use in the USA.

'And there is much more land available than just that in the CRP. A recent study by the US government estimated that lignocellulosic biomass could produce up to 265 billion litres of fuel equivalent per year on other land, without impacting food production.'

Koonin also makes the point that while food crop production has benefited from centuries of breeding and, more recently, genetic engineering, such techniques have not been applied to the fast growing plants involved in lignocellulosic biomass, and hence yields could become even more attractive.

Click the link below to view a panel on producing ethanol from cellulose

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BP refers to the fuels which could arise from lignocellulose as 'next-generation' or 'advanced' biofuels. The approach sounds like an all-round winner, but there is a snag at present, adds Koonin, acknowledging that lignocellulose is tough for enzymes to break down into starch and sugar molecules for fermentation. To make this feasible, chemical and physical treatments of the biomass are currently required to break down the cellulose into fibres, which enzymes can decompose into component sugars, before the fermentation microbes can get to work in producing ethanol, adding a cost factor.

To reduce costs, researchers must find a way to make these enzymes more cheaply than is possible at present, and also to seek micro-organisms capable of fermenting the five-carbon atom sugar molecules found in hemicellulose. At the moment, conversion of lignocellulose to biofuels is not economic at current oil prices, but technology advances should dramatically reduce costs.

Building the best

'Questions like these and many others are among those we will be studying at the EBI in our efforts to optimise the bioenergy value chain,' adds Breson. 'We have road-mapped where we want to go and identified the areas where we need the breakthroughs for making next-generation biofuels technically and economically viable.

'For biofuels, the research will range from the fundamentals of germplasm, through cultivation, harvesting and transportation, processing, and delivery of advanced biofuels. There will also be full-scale field trials on farmland near to the University of Illinois at Urbana-Champaign - you can only take biological theory so far, then you have to test it out.'

In addition to studying next-generation biofuels manufactured from plants, research will also be undertaken into biofuels production from other carbon sources, such as the organic part of municipal solid waste. And a little further down the road there are the wider energy bioscience avenues to explore, including improved oil recovery, carbon conversion and carbon sequestration.

Dedicated facilities on the campuses of the University of California at Berkeley and the University of Illinois will house EBI research laboratories and staff, while the Lawrence Berkeley National Laboratory will carry out supporting research. Over the next two years, the EBI team will ramp up to around 150 people, alongside which up to 50 BP staff - specialists in areas such as refining and fuels processing - will work in partnership with university researchers on the two campuses. The unique nature of the EBI is expected to attract the best minds in the relevant scientific and engineering disciplines.

BP and its academic partners will share governance of the EBI and guidance of its research programmes.

'The research will fall into two main categories,' says Breson. 'One which is freely accessible to the world's technical communities, and the other which covers proprietary projects for commercial bioscience applications. The EBI will also facilitate cross-training of a new generation of researchers, focused on bringing together biotechnology and energy production. We believe cross-fertilisation of disciplines will help drive energy bioscience forward rapidly.'

Henry Ford and Rudolf Diesel may not recognise the modern terminology, nor indeed the advances already made in biology and fuel technology, but their vision of capturing and using nature's clean and renewable energy supplies looks to be coming full circle.

Panel: Advantaged molecules

While bioethanol and biodiesel will remain the leading commercial biofuels for some time to come and will continue to be the subjects of intense research, BP is also investigating other products that could serve as the next generation of biofuels. Underpinning these efforts are what are referred to as 'advantaged molecules' - those exhibiting the potential to produce fuels with properties that can help overcome the limitations of existing biofuels, thereby delivering some of the improvements BP believes to be attainable for a more effective biofuels industry.

Notable among the advantaged molecules is butyl alcohol, or butanol, an organic alcohol based on four carbon atoms - ethanol has two carbon atoms. Butanol, a colourless liquid which has four different isomers, is currently produced from petroleum for use as an industrial solvent. However, for the past four years BP has been working closely with DuPont, a recognised leader in biotechnology, on the production of biobutanol as a fuel for gasoline engines (Frontiers, August 2006).

Biobutanol has several advantageous properties as a fuel when compared with ethanol. It can be easily added to conventional gasoline due to its lower vapour pressure, and has energy content closer to that of gasoline, creating less of a compromise on fuel economy - an important factor as the amount of biofuel in the fuel blend increases. Compared with ethanol, it could be feasible to use butanol at higher blend concentrations without modifying existing vehicle engines.

Biobutanol is also much less miscible with water, which should allow it to be used in existing distribution infrastructure -- in pipelines, storage tanks and pumps at retail stations. It may also be co-blended with ethanol in gasoline, to help reduce overall vapour pressure of the fuel blend. Vehicle emissions research shows that pollutants which can affect air quality, including hydrocarbons, carbon monoxide and oxides of nitrogen, are not adversely impacted by the presence of biobutanol.

BP and DuPont are currently carrying out detailed calculations of biobutanol's life cycle greenhouse gas emissions performance. Initial indications are that, on the same feedstock basis, biobutanol delivers emissions reductions that are at least comparable to those from bioethanol.

Biobutanol can be produced from the same agricultural feedstocks as ethanol, for example, corn, wheat, sugar beet, sorghum, cassava and sugar cane, by employing the bacterium Clostridium acetobutylicum to convert sugars derived from these crops into butanol.

Future biobutanol manufacturing facilities could potentially use any locally grown crops, and development work is planned for a new biotechnology process to produce biobutanol from lignocellulosic biomass, such as fast-growing grasses, straw and corn stalks.

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Back to a bio future

Big science

Counting carbon

Enter cellulose

Building the best

Panel: Advantaged molecules

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