Algae fuel

Algae fuel


Algae fuel, also called algal fuel, algaeoleum or second-generation biofuel,[1] is a biofuel which is derived from algae. During photosynthesis, algae and other photosynthetic organisms capture carbon dioxide and sunlight and convert it into oxygen and biomass. Up to 99% of the carbon dioxide in solution can be converted, which was shown by Weissman and Tillett (1992) in large-scale open-pond systems. Several companies and government agencies are funding efforts to reduce capital and operating costs and make algae fuel production commercially viable.[2] The production of biofuels from algae does not reduce atmospheric carbon dioxide (CO2), because any CO2 taken out of the atmosphere by the algae is returned when the biofuels are burned. They do however eliminate the introduction of new CO2[citation needed] by displacing fossil hydrocarbon fuels.



High oil prices, competing demands between foods and other biofuel sources, and the world food crisis, have ignited interest in algaculture (farming algae) for making vegetable oil, biodiesel, bioethanol, biogasoline, biomethanol, biobutanol and other biofuels, using land that is not suitable for agriculture. Among algal fuels' attractive characteristics: they do not affect fresh water resources,[3] can be produced using ocean and wastewater, and are biodegradable and relatively harmless to the environment if spilled.[4][5][6] Algae cost more per unit mass (as of 2010, food grade algae costs ~$5000/tonne), due to high capital and operating costs[7], yet can theoretically yield between 10 and 100 times more energy per unit area than other, second-generation biofuel crops.[8] One biofuels company has claimed that algae can produce more oil in an area the size of a two car garage than a football field of soybeans, because almost the entire algal organism can use sunlight to produce lipids, or oil.[9] The United States Department of Energy estimates that if algae fuel replaced all the petroleum fuel in the United States, it would require 15,000 square miles (40,000 km2).[10] This is less than 1⁄7 the area of corn harvested in the United States in 2000.[11] However, these claims remain unrealized, commercially.

Factors


Dry mass factor is the percentage of dry biomass in relation to the fresh biomass; e.g. if the dry mass factor is 5%, one would need 20 kg of wet algae (algae in the media) to get 1 kg of dry algae cells.[12]



Lipid content is the percentage of oil in relation to the dry biomass needed to get it, i.e. if the algae lipid content is 40%, one would need 2.5 kg of dry algae to get 1 kg of oil.[13]



 Fuels

The vegoil algae product can then be harvested and converted into biodiesel; the algae’s carbohydrate content can be fermented into bioethanol and biobutanol.[14]



Biodiesel

Currently most research into efficient algal-oil production is being done in the private sector, but predictions from small scale production experiments bear out that using algae to produce biodiesel may be the only viable method by which to produce enough automotive fuel to replace current world diesel usage.[15]



Microalgae have much faster growth rates than terrestrial crops. The per unit area yield of oil from algae is estimated to be from between 5,000 to 20,000 US gallons per acre per year (4,700 to 18,000 m3/km2·a);[citation needed] this is 7 to 30 times greater than the next best crop, Chinese tallow (700 US gal/acre·a or 650 m3/km2·a).[16]



Studies[17] show that some species of algae can produce up to 60% of their dry weight in the form of oil. Because the cells grow in aqueous suspension, where they have more efficient access to water, CO2 and dissolved nutrients, microalgae are capable of producing large amounts of biomass and usable oil in either high rate algal ponds or photobioreactors. This oil can then be turned into biodiesel which could be sold for use in automobiles. Regional production of microalgae and processing into biofuels will provide economic benefits to rural communities.[18]


 Biobutanol

Main article: Butanol fuel

Butanol can be made from algae or diatoms using only a solar powered biorefinery. This fuel has an energy density 10% less than gasoline, and greater than that of either ethanol or methanol. In most gasoline engines, butanol can be used in place of gasoline with no modifications. In several tests, butanol consumption is similar to that of gasoline, and when blended with gasoline, provides better performance and corrosion resistance than that of ethanol or E85[19].



The green waste left over from the algae oil extraction can be used to produce butanol.



Biogasoline

Biogasoline is gasoline produced from biomass such as algae. Like traditionally produced gasoline, it contains between 6 (hexane) and 12 (dodecane) carbon atoms per molecule and can be used in internal-combustion engines.



Methane

Through the use of algaculture grown organisms and cultures, various polymeric materials can be broken down into methane.[20]

 SVO

The algal-oil feedstock that is used to produce biodiesel can also be used for fuel directly as "Straight Vegetable Oil", (SVO). The benefit of using the oil in this manner is that it doesn't require the additional energy needed for transesterification, (processing the oil with an alcohol and a catalyst to produce biodiesel). The drawback is that it does require modifications to a normal diesel engine. Transesterified biodiesel can be run in an unmodified modern diesel engine, provided the engine is designed to use ultra-low sulfur diesel, which, as of 2006, is the new diesel fuel standard in the United States.



 Hydrocracking to traditional transport fuels

Main articles: Vegetable oil refining and Green crude

Vegetable oil can be used as feedstock for an oil refinery where methods like hydrocracking or hydrogenation can be used to transform the vegetable oil into standard fuels like gasoline and diesel.[21]



 Jet fuel

Main article: Aviation biofuel

Rising jet fuel prices are putting severe pressure on airline companies,[22] creating an incentive for algal jet fuel research. The International Air Transport Association, for example, supports research, development and deployment of algal fuels. IATA’s goal is for its members to be using 10% alternative fuels by 2017.[1]



Trials have been carried with aviation biofuel by Air New Zealand[23], Continental Airlines[citation needed] and Virgin Airlines[24].

In February 2010, the Defense Advanced Research Projects Agency announced that the U.S. military was about to begin large-scale production oil from algal ponds into jet fuel. After extraction at a cost of $2 per gallon, the oil will be refined at less than $3 a gallon. A larger-scale refining operation, producing 50 million gallons a year, is expected to go into production in 2013, with the possibility of lower per gallon costs so that algae-based fuel would be competitive with fossil fuels. The projects, run by the companies SAIC and General Atomics, are expected to produce 1,000 gallons of oil per acre per year from algal ponds.[25]

Algae cultivation

Algae can produce up to 300 times more oil per acre than conventional crops, such as rapeseed, palms, soybeans, or jatropha. As Algae has a harvesting cycle of 1–10 days, it permits several harvests in a very short time frame, a differing strategy to yearly crops (Chisti 2007). Algae can also be grown on land that is not suitable for other established crops, for instance, arid land, land with excessively saline soil, and drought-stricken land. This minimizes the issue of taking away pieces of land from the cultivation of food crops (Schenk et al. 2008). Algae can grow 20 to 30 times faster than food crops.[26]

Photobioreactors

Most companies pursuing algae as a source of biofuels are pumping nutrient-laden water through plastic tubes (called "bioreactors" ) that are exposed to sunlight (and so called photobioreactors or PBR).


Running a PBR is more difficult than an open pond, and more costly.


Algae can also grow on marginal lands, such as in desert areas where the groundwater is saline, rather than utilize fresh water.[27]



Because algae strains with lower lipid content may grow as much as 30 times faster than those with high lipid content,[28] the difficulties in efficient biodiesel production from algae lie in finding an algal strain with a combination of high lipid content and fast growth rate, that isn't too difficult to harvest; and a cost-effective cultivation system (i.e., type of photobioreactor) that is best suited to that strain. There is also a need to provide concentrated CO2 to increase the rate of production.



[edit] Closed loop system

Another obstacle preventing widespread mass production of algae for biofuel production has been the equipment and structures needed to begin growing algae in large quantities. Maximum use of existing agriculture processes and hardware is the goal.[29]



In a closed system (not exposed to open air) there is not the problem of contamination by other organisms blown in by the air. The problem for a closed system is finding a cheap source of sterile CO2. Several experimenters have found the CO2 from a smokestack works well for growing algae.[30][31] To be economical, some experts think that algae farming for biofuels will have to be done as part of cogeneration, where it can make use of waste heat, and help soak up pollution.[27][32]



[edit] Open pond

Open-pond systems for the most part have been given up for the cultivation of algae with high-oil content.[33] Many believe that a major flaw of the Aquatic Species Program was the decision to focus their efforts exclusively on open-ponds; this makes the entire effort dependent upon the hardiness of the strain chosen, requiring it to be unnecessarily resilient in order to withstand wide swings in temperature and pH, and competition from invasive algae and bacteria. Open systems using a monoculture are also vulnerable to viral infection. The energy that a high-oil strain invests into the production of oil is energy that is not invested into the production of proteins or carbohydrates, usually resulting in the species being less hardy, or having a slower growth rate. Algal species with a lower oil content, not having to divert their energies away from growth, have an easier time in the harsher conditions of an open system.



Some open sewage ponds trial production has been done in Marlborough, New Zealand.[34]



[edit] Algae types

Main article: SERI microalgae culture collection

Research into algae for the mass-production of oil is mainly focused on microalgae; organisms capable of photosynthesis that are less than 0.4 mm in diameter, including the diatoms and cyanobacteria; as opposed to macroalgae, such as seaweed. The preference towards microalgae is due largely to its less complex structure, fast growth rate, and high oil content (for some species). However, some research is being done into using seaweeds for biofuels, probably due to the high availability of this resource.[35][36]



The following species listed are currently being studied for their suitability as a mass-oil producing crop, across various locations worldwide[37][38][39]:



Botryococcus braunii

Chlorella

Dunaliella tertiolecta

Gracilaria

Pleurochrysis carterae (also called CCMP647)[40] .

Sargassum, with 10 times the output volume of Gracilaria.[41]

In addition, due to its high growth rate, Ulva[42] has been investigated as a fuel for use in the SOFT cycle, (SOFT stands for Solar Oxygen Fuel Turbine), a closed-cycle power generation system suitable for use in arid, subtropical regions.[43]



[edit] Specific research

Some commercial interests into large scale algal-cultivation systems are looking to tie in to existing infrastructures, such as cement factories,[32] coal power plants, or sewage treatment facilities. This approach changes wastes into resources to provide the raw materials, CO2 and nutrients, for the system.[44]



Aquaflow Bionomic Corporation of New Zealand announced that it has produced its first sample of homegrown bio-diesel fuel with algae sourced from local sewerage ponds. A small quantity of laboratory produced oil was mixed with 95% regular diesel.



A feasibility study using marine microalgae in a photobioreactor is being done by The International Research Consortium on Continental Margins at the International University Bremen.[45]



The Department of Environmental Science at Ateneo de Manila University in the Philippines, is working on producing biofuel from a local species of algae.[46]



NBB’s Feedstock Development program is addressing production of algae on the horizon to expand available material for biodiesel in a sustainable manner[47].



[edit] Nutrients

Main article: Algal nutrient solutions

Nutrients like nitrogen (N), phosphorus (P), and potassium (K), are important for plant growth and are essential parts of fertilizer. Silica and iron, as well as several trace elements, may also be considered important marine nutrients as the lack of one can limit the growth of, or productivity in, an area.[48]



One company, Green Star Products, announced their development of a micronutrient formula to increase the growth rate of algae. According to the company, its formula can increase the daily growth rate by 34% and can double the amount of algae produced in one growth cycle.[49]


Wastewater

Wastewater treatment facility

A possible nutrient source is waste water from the treatment of sewage, agricultural, or flood plain run-off, all currently major pollutants and health risks. However, this waste water cannot feed algae directly and must first be processed by bacteria, through anaerobic digestion. If waste water is not processed before it reaches the algae, it will contaminate the algae in the reactor, and at the very least, kill much of the desired algae strain. In biogas facilities, organic waste is often converted to a mixture of carbon dioxide, methane, and organic fertilizer. Organic fertilizer that comes out of the digester is liquid, and nearly suitable for algae growth, but it must first be cleaned and sterilized.



The utilization of wastewater and ocean water instead of freshwater is strongly advocated due to the continuing depletion of freshwater resources. However, heavy metals, trace metals, and other contaminants in wastewater can decrease the ability of cells to produce lipids biosynthetically and also impact various other workings in the machinery of cells. The same is true for ocean water, but the contaminants are found in different concentrations. Thus, agricultural-grade fertilizer is the preferred source of nutrients, but heavy metals are again a problem, especially for strains of algae that are susceptible to these metals. In open pond systems the use of strains of algae that can deal with high concentrations of heavy metals could prevent other organisms from infesting these systems (Schenk et al. 2008). In some instances it has even been shown that strains of algae can remove over 90% of nickel and zinc from industrial wastewater in relatively short periods of time (Chong, Wong et al. 1998).


Investment and economic viability

There is always uncertainty about the success of new products and investors have to consider carefully the proper energy sources in which to invest. A drop in fossil fuel oil prices might make consumers and therefore investors lose interest in renewable energy. Algal fuel companies are learning that investors have different expectations about returns and length of investments. AlgaePro Systems found in its talks with investors that while one wants at least 5 times the returns on their investment, others would only be willing to invest in a profitable operation over the long term. Every investor has its own unique stipulations that are obstacles to further algae fuel development. Additional concerns consider the potential environmental impact of Algal fuel development, as well as secondary impacts on wildlife such as bears and fish.[citation needed]

Whereas technical problems, such as harvesting, are being addressed successfully by the industry, the high up-front investment of algae-to-biofuels facilities is seen by many as a major obstacle to the success of this technology. Only few studies on the economic viability are publicly available, and must often rely on the little data (often only engineering estimates) available in the public domain. Dmitrov[50] examined the GreenFuels photobioreactor and estimated that algae oil would only be competitive at an oil price of $800 per barrel. A study by Alabi at al.[51] examined raceways, photobioreactors and anaerobic fermenters to make biofuels from algae and found that photobioreactors are too expensive to make biofuels. Raceways might be cost-effective in warm climates with very low labor costs, and fermenters may become cost-effective subsequent to significant process improvements. The group found that capital cost, labor cost and operational costs (fertilizer, electricity, etc.) by themselves are too high for algae biofuels to be cost-competitive with conventional fuels. Similar results were found by others[52][53][54], suggesting that unless new, cheaper ways of harnessing algae for biofuels production are found, their great technical potential may never become economically accessible.

Algae fuel by country

List of algal fuel producers

Europe

Algae fuel in the United Kingdom

Universities in the United Kingdom which are working on producing oil from algae include:University of Glasgow, University of Brighton, Cambridge University, University College London, Imperial College London, Cranfield University.

The Ukraine plans to produce biofuel using a special type of algae[55].

The CSIC´s Instituto de Bioquímica Vegetal y Fotosíntesis (Microalgae Biotechnology Group, in Sevilla, Spain[56] is researching the algal fuels.

United States
Algae fuel in the United States

The Aquatic Species Program, launched in 1978, was a research program funded by the United States Department of Energy (DoE) which was tasked with investigating the use of algae for the production of energy. The program initially focused efforts on the production of hydrogen, shifting primary research to studying oil production in 1982. From 1982 until its end in 1996, the majority of the program research was focused on the production of transportation fuels, notably biodiesel, from algae. In 1995, as part of overall efforts to lower budget demands, the DoE decided to end the program. Research stopped in 1996 and staff began compiling their research for publication.

US universities which are working on producing oil from algae include: University of Texas at Austin,[57] University of Maine, University of Kansas, and Old Dominion University[58].

At the Woods Hole Oceanographic Institution and the Harbor Branch Oceanographic Institution the wastewater from domestic and industrial sources contain rich organic compounds that are being used to accelerate the growth of algae.[14] The Department of Biological and Agricultural Engineering at University of Georgia is exploring microalgal biomass production using industrial wastewater.[59] Algaewheel, based in Indianapolis, Indiana, presented a proposal to build a facility in Cedar Lake, Indiana that uses algae to treat municipal wastewater, using the sludge byproduct to produce biofuel.[60][61]

Sapphire Energy (San Diego) has produced green crude from algae.

Solazyme (South San Francisco, California) has produced a fuel suitable for powering jet aircraft from algae.