Background of the Solar Bio-Fuels Consortium
Climate Change and the Need to Replace Fossil Fuels
The extensive Intergovernmental Panel on Climate Change (IPCC)
and Stern report
most comprehensive analyses of the effects of climate change
, its economic
impacts, and the importance of developing clean fuels for the future.
The Focus of the Solar Bio-Fuels Consortium: Clean Fuels for the Future
Rapid implementation of clean energy systems is needed to facilitate CO2
stabilization: In order to
levels between 450 and 550 ppm it is predicted that we are faced with the
challenge of installing systems capable of producing energy free of CO2
emissions, at a level almost
equivalent to ~50-75% current global energy demand in 2005 (15 TW), in 20 years time (Hoffert et al. 1998
Green algae and advanced bioreactor systems have significant practical and economic advantages for
bio-fuel production over traditional crop plants. To facilitate the efficient
development of algal bio-fuels processes, such as
the production of bio-hydrogen, bio-diesel, biomass
for BTL and biomass for bio-methane, Ben
Hankamer and Olaf Kruse established the Solar Bio-Fuels Consortium through the
commercialization wing of the Institute for Molecular Bioscience
(IMB) - IMBcom. This consortium now includes 8 groups: Ben
Hankamer (The University of Queensland),
Olaf Kruse (Universität Bielefeld, Germany), Clemens
Posten (Universität Karlsruhe, Germany), Peer
Schenk (The University of Queensland), Ute Marx (The University
of Queensland), Michael Hippler (Universität Münster), Tony
Larkum (The University of Sydney) and Peter Nixon (Imperial
College London), and continued expansion is planned. Collectively, we conduct
bio-discovery, structural biology, molecular biology, microbiology, genomics,
transcriptomics, proteomics, metabonomics, culture optimization and bioreactor
scale-up within a coordinated research program. The consortium therefore provides
an extensive set of skills and facilities and a single point
of contact for industry as well as a network of international links.
M. Hoffert, K. Caldeira, A. Jain, E. Haites, L. Harvey, S. Potter, M. Schlesinger, S. Schneider, R. Watts, T. Wigley, D. Wuebbles, Energy implications of future stabilization of atmospheric CO2 content, NATURE 395 (1998) 881-884.
Photosynthesis is Central to All Bio-Fuel Production
Photosynthesis plays an absolutely central role in all bio-fuel production processes as it
is the first step in the conversion of solar energy (light) to chemical energy and therefore ultimately responsible for driving
the production of the feed stocks required for fuel synthesis (Fig.1
): protons & electrons (for bio-H2
sugars & starch (for bio-ethanol
), oils (for bio-diesel
) and biomass
(for BTL & bio-methane
Consequently, any increase in photosynthetic efficiency will enhance the competitiveness of bio-fuel production in general.
In higher plants and green algae, light is captured by specialised Light Harvesting Complex proteins,
referred to here as LHCI and LHCII, (Fig.1) which confer the ability to adapt to changing light levels. The
excitation energy is then funnelled to the photosynthetic reaction centres of photosystem I (PSI) and photosystem
II (PSII). PSII uses this energy to drive the photosynthetic water splitting reaction, which converts water into
protons, electrons and oxygen. The electrons are passed along the photosynthetic electron transport chain (Fig.1,
thin solid black arrows) via plastoquinone (PQ), cytochrome b6f (Cyt b6f), photosystem I (PSI), and ferredoxin (Fd)
and on to NADPH. Simultaneously, protons are released into the thylakoid lumen by PSII and the PQ/PQH2 cycle (Fig.1; proton flow
indicated by thin black dashed arrows). This generates a proton gradient, which drives ATP production via
ATP synthase. The protons and electrons are recombined by ferredoxin-NADP+ oxidoreductase (FNR) to produce NADPH.
NADPH and ATP are used in the Calvin cycle and other biochemical pathways to produce the sugars, starch, oils and
other bio-molecules (which collectively form biomass) that are required to produce bio-ethanol, bio-diesel,
bio-methane- and BTL-based bio-fuels. Alternatively in some photosynthetic micro-organisms like the green alga
Chlamydomonas reinhardtii the protons and electrons extracted from water (or starch) can be fed to the
hydrogenase (HydA) via the electron transport chain to drive the direct production of bio-H2 (Fig.1).
Figure 1: The central role of photosynthesis in bio-fuel production.
Advantages of Algal Bioreactors
Economic Viability: The potential of solar bio-fuel production is highlighted by the fact that even using current technology,
Brazilian sugar-cane-based and US corn-based bio-ethanol production are cost competitive at oil prices of
US $40 and US $60 per barrel, while the equivalent for biodiesel is US $80 (The Economist, 2006). Thus, even modest increases in
photosynthetic efficiency are expected to yield significant increases in economic competitiveness. Algae have various
advantages over classical crop plants for the production of biofuels and can be engineered to increase photosynthetic
Reducing arable land use for bio-fuel production: A common concern related to bio-fuels is that as their
production capacities increase, so will the competition with agriculture for arable land. Similarly rainforest
regions are being cleared to make room for the palm plantations required for the production of oil for bio-fuels.
In contrast algal bioreactors are designed to be sited on non-arable land, eliminating this competition and opening
up new economic opportunities for arid regions.
Short life cycles increase yield: In contrast to conventional crop plants, which yield a harvest once or twice a year, the micro-algae have a life cycle (~1-10 days depending on the process), with the result that multiple or continuous harvests with increased yield are be produced.
Reducing H2O use in agriculture: Conventional crops used for bio-fuel production require substantial amounts
of fresh water. Due to the increased photosynthetic efficiency of engineered algae and the use of closed
bioreactors, considerable savings in net water use can be achieved.
Coupling clean fuel production to desalination: Marine and salt tolerant algae can extract hydrogen
(as protons and electrons) and oxygen from water. Upon combustion of hydrogen and oxygen fresh water is produced.
Consequently by using stationary fuel cells that use hydrogen and oxygen to feed electricity into the national
grid, energy generation can be coupled with desalination.
Environmentally sensitive waste disposal: The algal biomass generated in algal bioreactors can be
gasified to produce a range of bio-fuels. The CO2 released during gasification is no more than that
previously absorbed, making this type of process CO2 neutral. In this way biological GMO waste can
also be effectively disposed of in an environmentally sensitive way.
The Economist (2006) Steady as she goes, in The Economist: London. p.65-67.
Climate Change - The Environmental Impact
The Intergovernmental Panel on Climate Change (IPCC)
has provided probably the most authoritative reviews of the effects of climate change. The IPCC provides the following explanation of its work (http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_FrontMatter.pdf
"The Intergovernmental Panel on Climate Change (IPCC) was set up jointly
by the World Meteorological Organization and the United Nations Environment Programme
to provide an authoritative international statement of scientific understanding
of climate change. The IPCC’s periodic assessments of the causes, impacts and
possible response strategies to climate change are the most comprehensive and
up-to-date reports available on the subject, and form the standard reference
for all concerned with climate change in academia, government and industry worldwide.
Through three working groups, many hundreds of international experts assess climate
change in this Fourth Assessment Report."
This report can be obtained from http://ipcc-wg1.ucar.edu/wg1/wg1-report.html.
An 18 page summary for policy makers can be obtained from http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf.
The importance of the IPCC work for the Solar Bio-fuels Consortium, is that it highlights the environmental
importance for the development of clean fuels for the future. However it took the
Stern report (2006)
to convincingly demonstrate that acting to combat climate change not only makes environmental but also economic sense.
The Economics of Climate Change - Stern Report
In October 2006 Sir Nicholas Stern (Chief Economist and Senior Vice President
of the World Bank from 2000-2003) released the extensively reported Stern
Review on the Economics of Climate Change
This extensive review is widely accepted to be the most authoritative summary
available on the "economic
effects of climate change" and is based on the rigorous scientific evaluation
of its predicted effects provided by the
Intergovernmental Panel on Climate Change
and other sources.
The predicted effect of climate change include melting of the polar ice caps (by ~2100), sea level rises, disruption of ocean
currents (e.g. Gulf Stream), extreme weather patterns (e.g. droughts, flooding and hurricanes) and large scale
species extinction. Figure 2 shows an adaptation of the data presented in the Stern review, with the effects
predicted to occur at atmospheric CO2 levels of 450 ppm and 550 ppm CO2 being highlighted.
These suggest that it would be far safer to stabilize at 450 ppm than 550 ppm. Many scientists however think that
unless very strong environmental policies are put in place quickly, we will only be able to stabilize at the
550 ppm level.
The importance of the Stern review lies in the fact that it defines the scale
of the climate change problem, presents a path of action to prevent the worst
of these effects and helps to establish a timetable within which to do so.
Stern states "Taking strong action to reduce emissions - must be viewed
as an investment [~1% GDP vs. 20% loss of GDP for inaction], a cost incurred
now and in the coming few decades to avoid the risks of very severe consequences
in the future." "This investment" [represents] "the
pro-growth strategy for the longer term" and should enable a "policy
to support innovation and deployment of low carbon technologies".
Figure 2: Adapted from Figure 2 of the Stern report-Executive summary.