Jay Keasling, Professor of Chemical Engineering and Bioengineering at the University of California, Berkeley, Associate Laboratory Director for Biosciences at the Lawrence Berkley National Laboratory and Chief Executive officer of the Joint BioEnergy Institute, said biofuels faced the twin difficulties of high cost and stiff regulation.
“…Petroleum-derived jet fuels are very inexpensive,” Keasling said. “If countries establish regulations requiring the use of carbon-neutral fuels or carbon taxes on petroleum-derived jet fuels, then this should be excellent motivation to develop bio-jet fuels. We know that they can be produced … the challenge is the economics.”
Dmitry Los, Director of the Timiryazev Institute of Plant Physiology of the Russian Academy of Sciences, offered a similar view.
“The cost of such biofuel remains high. Producing biofuel at this time is more a question of political will than an economic phenomenon,” he said. “Aviation fuel is purified with limited fumes compared to, say, coal-fired power stations.”
Meeting tough regulations and technical standards is a problem equally difficult to confront.
“For good reason, jet fuels are highly regulated. Bio-jet fuel has to meet those very highly regulated standards. The fuel must have high energy density so the jets can fly as far on bio-jet fuel as on petroleum-based jet fuel,” Keasling said. “In addition, the bio-jet fuel needs to be liquid at very low temperatures.”
Los said production of biofuels could be further hampered by the fact they are also high in energy consumption.
“It is generally accepted that living plants and microalgae are able to absorb about the same amount of CO2 as is released by the burning of biofuels produced from them. Biofuels are therefore more ‘environmental’,” he said.
“But if you take account the amount of energy spent on producing the biofuel and the amount of CO2 released into the atmosphere in doing so, the effect of the undertaking is dubious at best.”
Biofuel can be produced from a great variety of different sources of biomass. Keasling said the optimal solution might be fuel produced from plant-derived components, like sugars.
“They could be carbon-neutral, that is they will add no new carbon to the atmosphere when burned,” he said.
Los believes a more effective approach would be to produce biofuel from aquatic plants – that would allow for a solution to the problem of shortages of land or irrigation resources were there to be a mass transition to biofuels from fossil fuels.
“There are sufficient resources for such a transition, particularly if aquatic plants are used in production. First-generation biofuel had problems linked to limits to the amount of crop areas and reduction in farmland for producing food. We are now into third generation biofuel (natural micro-organisms) and fourth generation (genetically engineered micro-organisms),” Los said.
“These are closed-cycle technologies which could be repeated over an extremely long time. At least for as long as the sun continues to shine and photosynthesis continues to occur – the absorption of CO2 by the organisms and the synthesis of biomass from light energy. The CO2 created on the planet from human activity and all such organisms can be recovered.”
Keasling said the problem of scarce resources could be solved by using organic waste in production of biofuel.
Los said the development of biofuel production could well advance with less use of land meant for crops by using controlled bioreactors and microalgae instead of plants.
The use of biofuels for aviation has attracted increasing attention. Last week, the U.S. aerospace company Boeing announced that by 2030 it would start producing aircraft capable of flying on 100 % biofuel.