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Oil From Algae
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As we inch closer towards a post-carbon economy, the future mix of energy sources is slowly bubbling to the top. One potential addition to this mix is the large-scale production of oil-containing algae. Jamais brought GreenFuel to our attention last year, but, as with most things in the sustainability realm, the momentum behind algae has grown tremendously since then. New companies, new methods, and a changing landscape indicate that biofuel from algae is poised to play a larger role.

Unlike crops that are currently being using for oil production such as soy, palm, corn and jatropha, some strains of algae contain as much as 50% oil. Once algae is grown, harvested and pressed to extract the oil, the remaining residue can be processed into ethanol, or burned directly in a power plant. The oil can then be processed into biodiesel using the ethanol (or methanol from another source). The National Renewable Energy Lab also believes jet fuel from certain strains of algae is possible.

Algae needs just a few simple things to kick-start a happy, oil-bearing life: water, sunlight and nutrients. While these might seem abundant and easy to come by, scientists and engineers who have been working in this area wish it were only that easy. The Aquatic Species Program, funded by the U.S. Department of Energy, tried for 20 years to find the optimal species for algal oil production. The program was unfortunately cut short when diesel prices bottomed out in the mid-1990's.

The July 1998 close out report from the program concluded that even with the most optimistic lipid yields the production of bio-diesel from algae would only become cost effective if petro-diesel prices rose to twice the 1998 levels. (October 2006 oil prices are three times higher than the average 1998 price in constant dollars).
The program’s database of algae species and their characteristics have proven very useful for companies in the private sector who have realized the potential that algae has as a fuel source. Commercial algae production, however, is still in a nascent stage with only a handful of companies deploying their respective technologies on a large scale. There are two main types of technologies for mass-producing algae for conversion to biodiesel.

Photo Bioreactors:
This type of technology implements a closed system that introduces carbon dioxide to the algae to enhance its growth in the presence of light, water and nutrients. GreenFuel's Emissions-to-Biofuels technologym (previously featured here) is a system where CO2-rich flue emissions feed into tubes filled with water and nutrients where the algae are suspended. The rapidly growing algae is continuously removed from the system. The technology first rolled-out at the MIT power plant, and in the next 18-24 months several pre-commercial pilot projects will follow around the world. CEO Cary Bullock hopes this next phase of implementation will lead to the installation of hundreds and perhaps thousands of acres of algae systems.

The GreenShift CleanTech system, born out of the work of David Bayless of Ohio University, uses solar collectors to concentrate sunlight.  The system then pipes the light into a closed chamber and distributes it over glow plates with a large surface area enriched with CO2 from a nearby power plant. Between the glow plates are growth media, over which water and a nutrient solution flow, and algae grow. When the algae are ready to harvest, an increase in water pressure separates them from the growth media for collection. A very neat animation and description of their technology is available here.

Solix Biofuel in Fort Collins, Colorado has partnered with Colorado State University to develop an alternative bioreactor. While most of the other set-ups take CO2 from power plants, the Solix demonstration site sits adjacent to a brewery where the fermentation process yields enough CO2 to feed the algae. Long, narrow tanks sealed with plastic sheeting contain algae, water, nutrients, and CO2 that are pumped in from the nearby brewery. In order to ensure that the algae have sufficient light, a roller passes back and forth over the tank to mix the contents.

Open Pond:
The other common method to cultivate algae uses an open pond design. Open ponds, such as Aquaflow Bionomic's in New Zealand, use carbon and nutrient rich effluent streams from waste water treatment plants to grow their algae. Unlike the closed photo bioreactor, enough carbon is present in the effluent stream that additional CO2 doesn't need to be added. While currently under development, Aquaflow hopes that the process will sufficiently filter the wastewater for re-use in other applications like irrigation. To demonstrate the potential of their technology, the company drove the energy minister of New Zealand around using a B5 blend of their algae-based biodiesel.

Whatever method or methods ultimately prove most efficient, Narsi Santhanam of believes that the key to a successful algae industry lies in finding optimal algae strains, proper technologies for growth/culturing, and efficient oil extraction. Cary Bullock of GreenFuel understands the necessity to lower current production costs to be competitive in the larger market, and sees bountiful opportunities to cut costs by harnessing carbon and heat from manufacturing facilities and power plants. 

Similarly, our colleague Matt Johnston believes that technological hurdles are hampering algae from breaking through to become a substantive force in the renewable energy generation portfolio. He points to companies like Earthrise that specialize in producing spirulina algae in large, open raceway tracks for sale in the natural food market at many times the price of algal biofuels. While the production methods are a bit different for spirulina as industrial exhaust or effluent can't be used for consumer products, existing technologies already show promise for closing the gap between algal biodiesel and dino-diesel.

If algae biofuels become economically competitive, they an advantage over more radical options like hydrogen fuel cells by fitting into the existing transportation infrastructure. And unlike food crops like corn or canola that at most yield several hundred gallons of biodiesel per acre, potential algal yields of 15,000 gallons per acre mitigate worries that algae will compete for land we currently use to grow food.

Michael Briggs of the University of New Hampshire estimates that the entire transportation needs of the United States could hypothetically be met with just 9.5 million acres of algae farms--about 15% of the urban land area in the US and a little more than all urban land added during the 1990's. This is a fathomable area to be sure, and an amount dwarfed by agriculture, but it's also enough so that we should be mindful of potential land-use consequences.

The land devoted to algae farms would require a reliable stream of nutrients, water, and carbon. Jamais calculated that 1600 giga-watt power plants converted to algae production could manufacture enough ethanol and biodiesel to replace the US annual consumption of 146 billion gallons of gasoline. Replacing convention diesel too would increase this requirement to over 2000 giga-watt sized power plants—or twice the number of suitably located major plants. Smaller facilities or other industries might conceivably close the gap. 

Although recycling carbon from power generation for transportation would be a huge advance, Jamais cautioned that it could slow the transition to a truly sustainable economy by prolonging dependence on fossil fuels. A 50% emission reduction would no doubt be a great victory, and one we would likely accept from anything less uncharismatic than coal. Any net carbon emissions to the atmosphere, however, are unsustainable in the long run.

Whether or not an algae-economy would ultimately slow the transition to zero-emissions could depend on the legal and economic mechanisms used to allocate emission reductions. If, for example, we enact a carbon tax or cap and trade system, who will pay the tax or get the credits, the people driving cars or the ones running power plants? And how will these shifts in green power play out politically under Kyoto or some other legislation? If, for instance, new legislation assigns the benefits of emission reductions to algae biofuels instead of power plants, cheaper biofuels might pose a barrier to fuel cells or advanced battery vehicles. By contrast, if those same benefits instead go to power plants, they could conceivable undercut the price of wind power or emerging sources of renewable energy.

These non-technical questions are in some ways the most difficult ones, and although they might not have as clear of an answer as the kinds of questions we can ask about R&D, they are every bit as important to ensuring that algal biofuels, or any potential technology for that matter, contribute to a sustainable future.

Algae's dearest contribution might not be just in reducing carbon emissions but rather in offering a viable holistic approach to integrating waste and resources. How brilliant is it to turn the industrial waste products from brewing beer, making concrete produce CO2, or burning fossil fuels into clean, green energy? And on top of that, some systems promise turning dirty, nutrient filled sewage into fresh water. This is the kind of industrial ecology that we need to think harder about that nests cycles within cycles to optimize across a slew of difficult problems at once. Better ways to turn waste into a revenue stream and low-carbon energy, while at the same time mitigating air and water pollution, is a win-win situation for producer, consumer, and the environment.

(Thanks Matt, Vicki, Marc, Cary and Narsi!)


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I guess the key is to develop an algae that will grow fast enough and in great enough density to make extraction from the growing medium efficient. I think that one of the processes you mention, (Green fuel's )may need the algae to be conditioned to increasing levels of carbon dioxide. I'd be interested in hearing whether this is a problem or not, and if it is what they're planning to do about it...I've written a bit about algae on the Big Biofuels Blog

Posted by: Biofuelsimon on 8 Feb 07

Something to follow

Posted by: A3K on 8 Feb 07

Great timing - I just was just sent information about a proposal to use accelerated microalgae propogation to soak up carbon from the atmosphere. Algae grows amazingly fast and is 50% carbon.

Although the site is a bit rudimentary the idea looks to be worthy of study. I have a paper written by the founder, Harry Hart, that explains the concept. Would love to network him with resources that could move this forward. Using microalgae to emulate nature's carbon cycle sounds like an elegant solution to remove excess CO2 while producing all sorts of benefits (fuel, food, fertilizer, etc.)

Posted by: Hal Brill on 8 Feb 07

One aspect of this that I think has been ignored, by those that pay attention to it in the first place that is, is that while Greenfuel Technologies has demonstrated a 40% reduction in CO2 levels over the course of 24 hours, they've achieved 85% during daylight hours. Eventually if this becomes viable and scalable, the thing that will make it the clear winner (and allow for a dramatic reduction in fossil carbon use) is the adoption of temporary CO2 storage in the same manner that natural gas is temporarily stored in geological formations.

Down the road there should be no reason to pump flue gases through bioreactors during nighttime hours or on cloudy days. Storing the gases for use only when production is optimized would require larger farms, but would also produce more fuel per ton of CO2. With increased efficiency, the amount of coal or natural gas required for primary generation could be reduced so that a larger percentage of primary generation could be sourced from biomass.

And as has been demonstrated elsewhere, biomass sources such as tall grasses and fast growing trees, a significant portion of the CO2 taken up from the atmosphere is locked into the soil with the roots. No-till growing of biomass could make the process carbon negative as up to half of the CO2 taken up by plants would be sequestered in the soil with the other half used in a current carbon energy cycle.

This would mean that biomass could be burned with the carbon used twice, first to make electricity, second to make transportation fuels. Since none of the carbon in this scenario is fossil carbon and since the roots would sink carbon into the soil, the process would clearly have a reducing effect on atmospheric CO2.

The goal should not be an end to the "carbon economy" but a rapid replacement of the fossil carbon economy with a current carbon economy. Competition with wind and solar need not be a concern as they should be seen as complementary rather than competing sources of energy. There is too much energy demand to assume that any alternative energy form could supplant any other in anything resembling the near term.

The true scope of what needs to happen is that "transitional technologies" are in reality the technologies we'll probably use for centuries to come with the only transition being a change from fossil fuel to biomass fuel.

"Clean coal" or IGCC technology will be the same technology to increase the energy return from biomass including MSW. And industrial scale CO2 recycling through algae bioreactors will further increase the energy return on terrestrial biomass.

Posted by: A3K on 8 Feb 07

A few policy changes that could put us on the road to a sustainable energy portfolio include placement of an immediate tariff on imported energy. Such a tariff should be structured so that there is a minimum tariff-adjusted price of something more than $50/bbl petroleum equivalent. The minimum tariff could be set at $5/bbl initially with a schedule of increases with the goal of ending the importation of energy within 15 years.

To skew the economy's response away from simply liquifying coal and mining oil shale, a hard cap and trade scheme should accompany this with a cap that drops slowly at first but then drops faster over the course of the next two decades.

Such a scheme would incent companies that develop carbon neutral or carbon consuming energy processes.

It could be that the first impact of cap and trade scheme is that CO2 output increases in the short term as another greenhouse gas, methane, is reduced to CO2 for energy production. Converting anthropogenic methane to energy has a huge impact in reducing GHG build-up since the first impact is that the GHG potential of the carbon atom drops by nearly 96%. But it's actually bigger than that, because if the methane burned replaces coal that would have been burned (and given the constraints on the natural gas supplies, coal is the likely source of additional energy) and since natural gas/methane produces 1/4th as much GHG per kWh as coal, the reduction is even larger, bringing the total closer a 99% reduction.

Since the big three sources of anthropogenic methane are landfills, feedlots and coal mines, a cap and trade scheme would incent large CO2 emitters to invest the capital in anaerobic digesters, landfill gas-to-energy projects and coal mine methane to energy projects. Many of these projects would pay for themselves if the decision-makers were willing to risk the capital and invest the time and energy into tapping these energy sources.

But since it's unlikely that a majority of feedlot, coalmine and landfill owners will undertake these projects, allowing the transfer to carbon credits under a cap and trade scheme would encourage third parties to put their capital at risk and manage these projects professionally.

Posted by: A3K on 8 Feb 07

Sorry for the poorly written screed above. The "few policies" I intended to mention were: applying a tariff on imported energy, adopting a cap and trade scheme for GHGs, and though I didn't discuss it at all, eliminating the practice of landfilling calorific materials.

Posted by: A3K on 8 Feb 07

I would be less optimistic.

1. The yields of algae in open ponds are far below those of ordinary energy crops. (Algae: 35MT/ha, energy crops: 70MT/ha). So that option is not economically viable.

2. What is the energy balance fuels made in closed photobioreactors? These things are made from steel, glass, rubber, etc...

Plants make their own photobioreactors (cellulose keeps them strong).

Moreover, it takes a lot of energy to transport the algae through the system; during the Aquatic Species Program, merely moving the algae through shallow open ponds used up more energy than the energy contained in their biomass! Pumping algae 2 metres up, vertically, as in the photobioreactors, will probably make the energy balance even worse.

I don't think the technology will ever be implemented on a large scale. Photobioreactors were dismissed long ago as being far too expensive, and open ponds result in very low yields and unstable cultures.

Posted by: Gio on 9 Feb 07


1. The only "open pond" approach I've read about recently is where they're harvesting algae from sewage ponds in New Zealand.

2. You assume the energy balance is negative without providing any data.

Your comments about "pumping algae 2 meters up" don't seem to be responsive of anything. Have you read anywhere that algae will be pumped 2 meters up? The Greenfuel bioreactors, at least the ones they've described publicly, use the fluid dynamics caused by rising gases (gas in liquids rise with no energy input required) to stir the algae and facilitate even distribution of light among the algae in the bioreactors. And harvest would seem to be accomplished with simple plumbing using gravity to deliver algae-rich medium to a central location for dewatering.

None of the companies working on this have demonstrated industrial scale production yet, but that's largely because the push to commercialize algae for fuel has only come on in the past few years.

I'd follow the money on this. There are several companies putting millions in investor money at risk to develop these technologies. Investor money doesn't fund basic research, it funds practical research based on a business plan.

Posted by: A3K on 9 Feb 07

A3K, the data on biomass yields come from the Aquatic Species Program.

Posted by: Gio on 10 Feb 07


You're conflating. The ASP doesn't provide any data on closed photobioreactors since the ones in testing were all developed after the program was shuttered.

And as I said before, see where the money is going. I would presume that investors willing to front a company like Greenfuel tens of millions of dollars will have seen some data to justify the investment.

Posted by: A3K on 10 Feb 07

You're conflating. The ASP doesn't provide any data on closed photobioreactors since the ones in testing were all developed after the program was shuttered.

A3K, that's not correct. The ASP's close-out report clearly dismissed closed photobioreactors:

[page 5]: "The Japanese, French and German governments have invested significant R&D dollars on novel closed bioreactor designs for algae production. The main advantage of such closed systems is that they are not as subject to contamination with whatever organism happens to be carried in the wind. The Japanese have, for example, developed optical fiber-based reactor systems that could dramatically reduce the amount of surface area required for algae production. While breakthroughs in these types of systems may well occur, their costs are, for now, prohibitive—especially for production of fuels. DOE’s program focused primarily on open pond raceway systems because of their relative low cost."

[page 161] "Another biophotolysis project tested an optical fiber system for diffusing solar light into algal cultures, thereby overcoming the light saturation limitation to photosynthetic efficiencies. This was shown to be impractical and was abandoned after only some very initial work."

The technical addenda also clearly talk about photobioreactors and dismiss them as way too expensive.

This is why the ASP focused on open ponds from the very beginning of the project, right until the end of it.

And I quoted biomass yields from these open pond systems. They're very low compared to ordinary energy crops.

The fundamental point is that the energy balance of photobioreactors isn't that great. Plants build their own reactors as they grow (with lignocellulose).

About following the money as a criterion to assess the technical and environmental value of a business: you can't be serious.

As long as these algae companies who keep issueing press releases, don't issue some sort of energy balance sheet, I don't think the concept makes sense.

Posted by: Gio on 10 Feb 07

I have been watching oil from algae initiative for some time.
I have a feeling an intensely marine & robust microalgae is a better bet for producing algal biodiesel in an open pond system. Intense & harsh marine environment would prevent/limit contamination by bacteria etc thereby making it worthy of open pond cultivation of microalgae for biodiesel production.
Further as sunlight is to be used - all other things remaining same a flat open surface as you encounter in open pond situation offers maximum exposed surface area compared to the surface area of a photo bioreactor 'tube' assembly.Presumably initial capital investment would also likely to be quite less compared to a closed PBR system. Immediate vicinity plains lying on the coast around the globe - some of which are being used for salt reclaiming - would thus offer an idle fertile ground for cultivating such marine algae cultivation without encroaching on the otherwise cultivable land that had already been ear-marked for agricultural use.
It would be a nice idea if some one can help with the information regarding robust marine algae candidates that would fit the bill for higher lipid growth!

Posted by: Dhirendra Kumar Nath on 10 Feb 07


"About following the money as a criterion to assess the technical and environmental value of a business: you can't be serious."

Actually, I can. When comparing the efficacy of government funded research with open-ended commitment and no demand for a ROI to privately funded research with a real-term demand for ROI, I'll follow the money, the private money, any day.

The ASP abandoned all hope (on photobioreactors) without doing any serious research, relying largely on second-hand reports from Japanese, French and German governments as you pointed out. If governments were building automobiles, that idea would have been abandoned early on as impractical, too.

Feel free to maintain your lack of optimism. I see the injection of private capital into this area as a sign that there are novel technologies that could produce positive returns. And I preface all comments with a huge "IF" because I have yet to see proof that any of the proposed photobioreactors will produce fuel economically. But IF they do, THEN the potential of this is immense.

I remain skeptical not just of the technologies, but of your ability to judge them. Your initial effort on this thread included numerous logical and factual errors, so I'm not optimistic that your opinion is worth further discussion. If you can present some data on which you will base future discussion, that my change my assessment.

Posted by: A3K on 12 Feb 07

check out a great message board on oil from algae...

Posted by: Tom Catino on 15 Feb 07


One of the fundamental mistakes made when examining the value of new technology is to assume that the current state of the art is its end state. This was true when electric vehicles were first being researched. While they certainly haven't been perfected yet, many of the assumptions made by the naysayers (e.g., EVs will never go fast, drive further than 50 miles, or require less than 12 hours to recharge) have been decisively proven false. Given the amazing things that human ingenuity has been able to dream up in the last century, we would be foolish to equate a lack of development with lack of potential.

As an interested neophyte in the area of algae biomass, I lack much of the hard data but would be interested in more. Does anybody have figures on the amount of CO2 absorbed/O2 generated by algae compared to other crops? Would simply having 9.5 million acres of algae help to sponge up the excess CO2 in the atmosphere?


Posted by: Patrick Clough on 16 Feb 07


I've based most of my comments on information provided by Greenfuel Technologies which applies to their approach alone and may not turn out to be feasible, but if so, WOW!

Anyway, they have claimed to be able to reduce CO2 from flue gases at a natural gas cogen plant by 40% over the course of a full day and over 80% during sunny days. 40% of the CO2 generated in the US is due to power plants where it would presumably be relatively easy to capture and redirect that flue gas. If you apply the low end of their demonstrated results (as measured by an independent testing company), then the following calculations demonstrate the potential scale of this:

The US produces 6.4 billion tons of CO2 annually. 40% of that is generated from power plants burning coal or natural gas. If the CO2 from these plants were recycled through bioreactors and converted into liquid fuels, they could completely replace our use of petroleum. Follow along:

6.4 billion tons of total annual CO2 production * 40% (amount at power plants) = 2.56 billion tons of CO2 available for recycling.

Greenfuel Technologies claims it can recycle up to 40% of the CO2 using their existing bioreactor design, so if their bioreactor were attached to each power plant (or the exhaust from each plant piped to remote algae farms) the amount of CO2 consumed by algae would be 1.024 billion tons.

Each ton of CO2 consumed produces 2 tons of algae. So this process would create 2.048 billion tons of algae.

Each ton of algae (if at 50% oil content) could be processed into 3 barrels of biodiesel and 1.5 barrels of ethanol. So that would be 6.144 billion barrels of biodiesel and 3.072 billion barrels of ethanol for a total of 9.216 billion barrels of liquid fuels.

The US consumes just under 7.7 billion barrels of petroleum annually. So use of this process could theoretically eliminate all of the CO2 generated by the burning of petroleum in the US.

To answer your question about the amount of land required, Greenfuel's founder has estimated that the land required for bioreactors capable of recycling the flue gases from a 1000 MW coal power plant would be around 2 square miles, but produce tens of millions of gallons of liquid fuel. No terrestrial crop can match that.

But as I posted earlier, if processes for CO2 storage could be developed with easy and economic retrieval, then the theoretical limit of this process could be much higher than the calculations above. If CO2 could be stored so it is only passed through bioreactors during hours of peak productivity, we'd be able to produce twice as much fuel and begin to replace coal as well as all of our petroleum consumption.

That would put us in a position to start to use biomass for power plants since 80% or more of the carbon would be recycled with only 20% lost to the atmosphere. That's a lot less carbon to make up with fossil fuels, and would move us ever closer to a current carbon or sustainable energy economy.

Posted by: A3K on 19 Feb 07

And the above ignores other sources of CO2 which might also be able to be tapped. Landfill gas, for example is around 50% methane and 50% CO2. Combusting the methane for energy recovery reduces the GHG potential of the combined output by a huge amount, but it may be possible to set up smaller scale algae bioreactors to consume the CO2 from both the gas and from the exhaust from the combustion of the methane fraction. And it's possible that the trace gases in landfill gas (or AD gas from a cattle feedlot) could be consumed by the algae as nutrients.

The industrialization of microbiology could be and probably is the answer to building a sustainable energy economy.

Pairing a landfill bioreactor with a photobioreactor is an example where this harnessing of naturally occuring microbes for our use can mimic the earth's natural approach to dealing with waste products, by making them food for another organism. And for us, it would maximize the amount of methane produced, improve the ROI of a methane recovery system and convert most of the resulting gases into useful fuel, with the carbon in methane used twice.

That and the recirculation of leachate reduces the toxicity of what has been considered a pollutant, but when recirculated is a vital part of the biological process that stabilizes waste materials.

Posted by: A3K on 19 Feb 07

what does a plate photobioreactor look like.

Posted by: j.douglas on 25 Feb 07

very helpfull for developing country & poor people, if there is any technical description

Posted by: yongky on 26 Feb 07



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