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Could Peak Phosphate be Algal Diesel’s Achilles’ Heel?
BIOFUEL FROM ALGAE: SALVATION FROM PEAK OIL?
population has risen to its present number of 6.7 billion in consequence of cheap
fertilizers, pesticides, and energy sources, particularly oil. Almost all modern farming has been engineered to depend on phosphate fertilizers, and those made from
natural gas, e.g., ammonium nitrate, and on oil to run tractors, etc. and to distribute the final produce. Worldwide production of phosphate has now peaked (in the
USA, the peak came in the late 1980s), which lends fears as to how much food the
world will be able to grow in the future, against a rising number of mouths to feed
(Phillpott, 2008). Consensus of analytical opinion is that we are close to the peak
in world oil production too.
The algae route sounds almost too good to be true. Having set up these ponds,
albeit on a large scale, i.e., they would need an area of 3,200 km2 to produce 40
million tons of diesel, which is enough to match the UK’s transportation demand
for fuel, if all vehicles were run on diesel engines (the latter are more efficient in
terms of tank-to-wheels miles by about 40% than petrol-fuelled spark-ignition
engines), one could ideally leave them to absorb CO2 from the atmosphere (thus
simultaneously solving another little problem) by photosynthesis, driven only by
the flux of natural sunlight. The premise is basically true; however, for algae to
grow, vital nutrients are also required, as a simple elemental analysis of dried algae
will confirm. Phosphorus, though present in under 1% of that total mass, is one
such vital ingredient, without which algal growth is negligible. Two different methods of calculation have been used here to estimate how much phosphate would be
needed to grow enough algae, first to fuel the UK and then to fuel the world:
1. The analysis of dried Chlorella (Wikipedia, 2009b) has been taken as an
illustration, which contains 895 mg of elemental phosphorus per 100 g of algae.
UK Case: To make 40 million tons of diesel, 80 million tons of algae would
be required (assuming that 50% of it is oil and this can be converted 100% to
The amount of “phosphate” in the algae is 0.895 × (95/31) = 2.74 %. (MW
PO43− is 95, that of P = 31).
Hence this amount algae would contain: 80 million × 0.0274 = 2.19 million
tons of phosphate.
World case: The world gets through 30 billion barrels of oil a year, of which
70% is used for transportation (assumed). Since 1 t of oil is contained in 7.3 barrels,
this equals 30 × 109/7.3 = 4.1 × 109 t and 70% of that = 2.88 × 109 t of oil for transportation.
So, this would need twice that mass of algae = 5.76 × 109 t of it, containing:
5.76 × 109 × 0.0274 = 158 million tons of phosphate.
2. To provide an independent estimate of these figures, it has been noted that
growth of this algae is efficient in a medium containing a concentration of 0.03–
0.06% phosphorus; the lower part of the range, i.e., 0.03% P is used here. “Ponds”
for growing algae vary in depth from around 0.6 to 1.5 m and so a depth of 1 m
could be assumed for simplicity.
UK case: Previously, the author has worked out (Rhodes, 2009) that producing
40 million tons of oil (assumed equal to the final amount of diesel, to simplify the
CHRISTOPHER J. RHODES
illustration) would need a pond/tank area of 3,200 km2. An area of 3,200 km2 is
equal to 320,000 ha, and at a depth of 1 m, this amounts to a volume of: 320,000 ×
(1 × 104 m2/ha) × 1 m = 3.2 × 109 m3.
A concentration of 0.03 % P = 0.092% phosphate, and so each cubic meter
(1 m3 weighs 1 t) of volume contains 0.092/100 = 9.2 × 10–4 t (920 g) of phosphate.
Therefore, we need:
3.2 × 109 × 9.2 × 10–4 = 2.94 million tons of phosphate, which is in reasonable accord with the amount of phosphate taken up by the algae (2.19 million
tons), as deduced earlier.
World case: The whole world needs 2.88 × 109 t of oil, which would take an
area of 2.88 × 109/125 t/ha = 2.30 × 107 ha of land to produce it.
2.3 × 107 ha × (104 m2/ha) = 2.3 × 1011 m2 and at a pond depth of 1 m they
would occupy a volume = 2.30 × 1011 m3. Assuming a density of 1 t = 1 m3, and
a concentration of PO43− = 0.092%, we need:
2.30 × 1011 × 0.092/100 = 2.13 × 108 t of phosphate, i.e., 213 million tons.
This is also in reasonable accordance with the figure deduced from the mass
of algae accepting that not all of the P would be withdrawn from solution during
the algal growth. Indeed, the ratio of algal phosphate to that present originally in
the culture medium (i.e., 158/213) suggests that 74% of it is absorbed by the algae.
Now, world phosphate production amounts to around 140 million tons (noting
that we need 213 million tons to grow all the algae), and food production is already
being thought to be compromised by phosphate resource depletion. The USA produces less than 40 million tons of phosphate annually, but would require enough to
produce around 25% of the world’s total algal diesel, in accord with its current
“share” of world petroleum-based fuel, or 53 million tons of phosphate. Hence, for
the USA, security of fuel supply could not be met by algae-to-diesel production
using even all its indigenous phosphate rock output, and imports (of phosphate) are
still needed. The world total of phosphate is reckoned at 8,000 million tons and that
in the USA at 2,850 million tons (by a Hubbert Linearization analysis). However, as
is true of all resources, what matters is the rate at which they can be produced.
Some aspects of the practicalities of algae-to-fuel conversion, including field
trials, have been discussed previously (Gao and McKinley, 1994; Miyamoto, 1997;
Christi, 2007; Sheehan et al., 1998). The author remains optimistic over algal diesel, but clearly if it is to be implemented on a serious scale, its phosphorus has to
come from elsewhere than phosphate rock mineral. There are regions of the sea
that are relatively high in phosphates and could in principle be concentrated to the
desired amount to grow algae, especially as salinity is not necessarily a problem.
Recycling phosphorus from manure and other kinds of plant and animal waste
appears to be the only means to maintain agriculture at its present level, and certainly if its activities will be increased to include growing algae. In principle too, the
BIOFUEL FROM ALGAE: SALVATION FROM PEAK OIL?
phosphorus content of the algal waste left after the oil-extraction process could
be recycled into growing the next batch of algae. These are all likely to be energyintensive processes, however, requiring “fuel” of some kind, in their own right.
It is salutary that there remains a competition between growing crops (algae)
for fuel and those for food, even if not directly in terms of land, for the fertilizers
that both depend on. This illustrates for me the complex and interconnected nature
of, indeed Nature, and that like any stressed chain, will ultimately converge its
forces onto the weakest link in the “it takes energy to extract energy” sequence.
A Hubbert analysis of human population growth indicates that rather than
rising to the putative “9 billion by 2050” scenario quoted from WHO figures, it will
instead peak around the year 2025 at 7.3 billion, and then fall (Phillpott, 2008). It is
probably significant too that that population growth curve fits very closely both
with that for world phosphate production and another for world oil production
(Phillpott, 2008). It seems to be highly indicative that it is the decline in resources
that will underpin our demise in numbers as is true of any species: from a colony
of human beings growing on the Earth, to a colony of bacteria growing on agar
nutrient in a petri dish.
Becker, E.W. (1994) In: J. Baddiley et al. (eds.) Microalgae: Biotechnology and Microbiology. Cambridge University Press, Cambridge/New York, p. 178.
Christi, Y. (2007) Biodiesel from microalgae. Biotechnol. Adv. 25: 294–306.
Deffeyes, K.S. (2005) Beyond Oil. Hill & Wang, New York.
Duffield, J.A., Shapouri, H. and Wang, M. (2006) Assessment of biofuels, In: J. Dewulf and H. Van
Langenhove (eds.) Renewables-Based Technology. Wiley, Chichester.
Elgood, G. and Eastham, T. (2008) Biofuels blamed for food price crisis, http://uk.reuters.com/article/
Fraser, J. (2008). http://thefraserdomain.typepad.com/energy/2008/03/fyi-petrosun-to.html.
Gao, K. and Mckinley, K.R. (1994) Use of macroalgae for marine biomass production and CO2 remediation – a review. J. Appl. Phycol. 6: 45–60.
Global Green Solutions (2006). http://www.globalgreensolutionsinc.com/s/VertigroFAQ.asp.
Hubbert, M.K. (1956) Nuclear energy and the fossil fuels. Presented before the Spring meeting of
the Southern District, American Petroleum Institute, Plaza Hotel, San Antonio, TX, March
Hubbert, M.K. (1982) Techniques of production as applied to oil and gas, In: Glass SI (ed.) Oil and
Gas Supply Modelling, Special Publication 631. National Bureau of Standards, Washington
DC, pp. 16–141.
Low, D. (2007) ASPO conference confirms a peak in global oil production by 2012. http://www.energybulletin.net/35127.html
Maio, X. and Wu, Q. (2006) Biodiesel production from heterotropic microalgal oil. Bioresour. Technol. 97: 841–847.
Miyamoto, K. (ed.) (1997). Renewable biological systems for alternative sustainable energy production
(FAO Agricultural Services Bulletin – 128).
Phillpott T. (2008) Biofuels and the fertilizer problem. http://www.energybulletin.net/print.
Rhodes, C.J. (2005) Energy Balance: http://firstname.lastname@example.org.
CHRISTOPHER J. RHODES
Rhodes, C.J. (2008) Oil calculator. Chemistry and Industry, July 7, p. 12.
Rhodes, C.J. (2009) Oil from algae; salvation from peak oil? Sci. Prog. 92: 39–90.
Sheehan, J., Dunahay, T., Benemann, J.R. and Roessler, P. (1998) A Look Back at the U.S. Department
of Energy’s Aquatic Species Program – Biodiesel from Algae, NREL/TP-580-24190.
Valcent (2009) http://www.valcent.net/s/TomorrowGarden.asp.
Wikipedia (2009a) Algaculture, http://en.wikipedia.org/wiki/Algaculture.
Wikipedia (2009b) Chlorella, http://en.wikipedia.org/wiki/Chlorella.
Biodata of Leila Hayashi, Anicia Q. Hurtado, Flower E. Msuya, Genevieve
Bleicher-Lhonneur, and Alan T. Critchley, authors of “A Review of Kappaphycus
Farming: Prospects and Constraints”
Dr. Leila Hayashi is currently a Postdoc of the Universidade Federal de Santa
Catarina, Brazil. She obtained her Ph.D. from Universidade de São Paulo, Brazil,
in 2007, and continues her studies and research at the Universidade Federal de
Santa Catarina. She gives classes to undergraduate and postgraduate students and
has participated in projects regarding the commercial viability of Kappaphycus
alvarezii in Brazil. Her scientific interests are in the areas of seaweed cultivation
and commercial processing, extraction of value-added products, and integrated
Anicia Q. Hurtado is currently a Visiting Scientist of the Aquaculture Department,
Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines.
She has been there since 2006 after serving the Center as Senior Scientist for 20
years. She finished her Doctor of Agriculture at Kyoto University, Kyoto,
Japan. She works mainly on the aquaculture of Kappaphycus as a Consultant
to international and local, nongovernment organizations directly involved with
seaweed farmers. At present, she is developing “new strains” of Kappaphycus
using tissue culture techniques for possible sources of propagules for commercial
Anicia Q. Hurtado
A. Israel et al. (eds.), Seaweeds and their Role in Globally Changing Environments,
Cellular Origin, Life in Extreme Habitats and Astrobiology 15, 251–283
DOI 10.1007/978-90-481-8569-6_15, © Springer Science+Business Media B.V. 2010
LEILA HAYASHI ET AL.
Flower E. Msuya is currently working as a Senior Researcher at the Institute of
Marine Sciences of the University of Dar es Salaam in Zanzibar, Tanzania.
She obtained her Ph.D. from Tel Aviv University, Israel, in 2004 and continued
her research at the Institute of Marine Sciences. Dr. Msuya’s scientific interests
are in seaweed farming, physiology, ecology, and value addition; Integrated
mariculture; and socio-economic studies in marine science and associated fields.
Genevieve Bleicher-Lhonneur is currently working as a senior Strategic Raw Materials
Procurement manager for Cargill. She has spent her entire career in procurement,
putting her expertise at the disposal of the industry. Her contribution to many
seaweed farming projects and fair support to the farmers are widely recognized.
She is still involved in developing new sources and improving farming conditions for
the benefit of the farmers and the whole industry. To reach this objective, Cargill is
financing specific studies related to strain selection or environmental impact on
cultivated seaweed properties in close cooperation with outside scientists.
Flower E. Msuya
A REVIEW OF KAPPAPHYCUS FARMING: PROSPECTS AND CONSTRAINTS
Alan T. Critchley is a reformed academic. He graduated from Portsmouth
Polytechnic, UK, and had a university career in Southern Africa teaching phycology,
marine ecology, and botany (KwaZulu Natal, Wits and Namibia). He moved to
the “dark side” in 2001 and took up a position in a multinational industry with
Degussa Texturant Systems (now Cargill TS), where he was responsible for new
raw materials for the extraction of the commercial colloid carrageenan. It was
here he began a love affair with Kappaphycus and its cultivation. Since 2005,
he has worked as head of research for Acadian Seaplants Limited working on
value addition to seaweed extracts and on-land cultivation of seaweed for food and
bioactive compounds. Not able to turn his back on the academic world entirely, he
is currently adjunct professor at the Nova Scotia Agricultural College. It has been
his absolute priviledge and pleasure to work with such excellent scientists and
friends as Leila, Anne, Flower, and Genevieve on research into the production
and improved quality of carrageenan-producing seaweeds.
A REVIEW OF KAPPAPHYCUS FARMING:
PROSPECTS AND CONSTRAINTS
LEILA HAYASHI1, ANICIA Q. HURTADO2, FLOWER E.
MSUYA3, GENEVIEVE BLEICHER-LHONNEUR4,
AND ALAN T.CRITCHLEY5
Depto. BEG, Centro de Ciências Biológicas,
Universidade Federal de Santa Catarina, Trindade, 88040-900
Florianópolis, Santa Catarina, Brazil
Aquaculture Department, Southeast Asian Fisheries
Development Center, Tigbauan, Iloilo, 5021, Philippines
Institute of Marine Sciences, University of Dar es Salaam,
P.O. Box 668, Zanzibar, Tanzania
Raw Material Procurement, Cargill
Texturizing Solutions, 50500 Baupte, France
Acadian Seaplants Limited, 30 Brown Ave., Dartmouth, NS,
Canada B3B 1X8
Global warming is of increasing concern worldwide. The question of how to
mitigate the CO2 released into the atmosphere is the most topical issue, and
sustainable solutions are constantly being sought. Aquaculture has been proposed
as one method for the sequestration or immobilization of CO2 through filtration
or mechanical/chemical processes for long-term storage (Carlsson et al., 2007).
However, the development of new sustainable technologies are but in their infancy,
as the aquaculture sector moves to becoming more efficient and sustainable.
In the above context, Chopin (2008) suggested that if limitations to nutrient
emission are to be put in place, extractive species such as seaweeds could be
considered as suitable for nutrient credits (e.g. for the extraction of nitrogen,
phosphorus, etc.), in a similar system to that of carbon credits, which are becoming
increasingly acceptable to be traded in the global economy.
Kappaphycus alvarezii, commercially recognized as “cottoni,” is considered
the main source of kappa carrageenan, while Eucheuma denticulatum, known as
“spinosum,” is the main source of iota carrageenan. Both species are responsible for
approximately 88% of raw material processed for carrageenan production, yielding
about 120,000 dry tons year−1 mainly from the Philippines, Indonesia, and Tanzania
(Zanzibar) (McHugh, 2003). Considered as two of the most commercially successful
species, they could be potential candidates for carbon and nutrient credits, if
research and technology are developed, since the farms have the potential to
LEILA HAYASHI ET AL.
increase the area occupied for seaweed cultivation, thus improving the carbon
dioxide sequestration and acting as a nutrient sink when cocultivated with other
organisms, thereby improving water quality to some extent.
A review of Kappaphycus (broadly including Eucheuma) farming is presented,
including the current possibilities and challenges with the goal of contributing to
sustainable mariculture management practices.
2. Worldwide Trends of Kappaphycus Production
The world’s geographical area for the Kappaphycus farming lies within ±10°
latitude (Fig. 1), notably from the Southeast Asian countries extending to East
Africa and Brazil. However, the Southeast Asian region, primarily the Brunei–
Indonesia–Malaysia–Philippines (East Association of Southeast Asian Nations
(ASEAN) Growth Area – BIMP-EAGA – integrated countries) has by far the
greatest potential for expanded tropical seaweed cultivation, consisting 60% of
the sites in the world. In particular, Indonesia, Malaysia, and the Philippines
provide sheltered areas that are favorable for cultivation (IFC, 2003).
The current and estimated increase in Kappaphycus production in the
BIMP-EAGA region is shown in Fig. 2. Although the production of the southern
Philippines and Sabah combined is about 100,000 t dry weight year−1, with the
potential to increase by approximately 50%, the shared projected capacity of
West, Central, and East Indonesia is huge (approximately 450,000 t) (IFC, 2003).
The high potential of Indonesia can be attributed to its extensive coastline, which
fits 100% within the tenth parallel latitude, where tropical seaweeds grow abundantly and robustly and, most importantly, where typhoons seldom occur. On the
other hand, the single largest area of Kappaphycus production in the Philippines
(Sitangkai, Tawi-Tawi) offers considerable potential for expansion since it has
60,000 ha available for mariculture purposes, even though only an estimated
10,000 ha are presently used for cultivating Kappaphycus (PDAP, 2007). Sabah
(Malaysia) had a total production of 50,000 t fresh weight (around 6,250 t dry
weight), which was grown on 1,000 ha (= 50 t ha−1 year−1) in 2005 (Neish, 2008).
Projection for this area aims an expansion to 12,000 ha in 2010, with a target
production of 250,000 t fresh weight.
Figure 1. The world’s potential geographical area for the Kappaphycus farming.
A REVIEW OF KAPPAPHYCUS FARMING: PROSPECTS AND CONSTRAINTS
Figure 2. Major areas of Kappaphycus cultivation and potential dry weight production in the BIMPEAGA region (IFC, 2003).
Table 1. World production of Kappaphycus (cottonii) in 2006 (Hurtado, 2007).
Volume (ton dry weight)
The Kappaphycus (cottonii) world production for commercial extraction of
kappa carrageenan shows that the BIMP-EAGA region produces 96.5% of the
total production, of which 55% comes from the Philippines, followed by Indonesia
(38%) and Malaysia (2.5%). The rest of the producing areas contribute relatively
very small volumes (Table 1).
3. Cultivation Techniques and Post-harvest Management
Since the first successful farming of Kappaphycus in the Philippines in 1970, the
cultivation technique has undergone many modifications. The main commercial