Study: Algae Biofuel Production Guzzles Water & Energy

By Smriti Rao | January 27, 2010 3:42 pm

algaeWhen algae is discussed as an alternative source of biofuel, it’s often in tones of breathless excitement; many green tech boosters believe that the slimy goo can be turned into fuel superior to that made from corn, canola, or switch grass.

You don’t need vast tracts of land to cultivate algae for biofuel, the thinking goes, all you need is the right strain of algae, water, sunlight, and carbon dioxide. Even Exxon and Dow Chemical recently joined the biofuel brigade, and are now investing millions in algae operations.

But a new study suggests that while algae might produce good fuel, the environmental costs involved in the production would be heavy. A life-cycle assessment published in the journal Environmental Science and Technology argues that algae production consumes more water and energy than other biofuel sources like corn, canola, and switch grass, and also has higher greenhouse gas emissions. While the study’s results are sobering, they’re also being met with harsh criticism from alage-based biofuel companies and their trade group, the Algal Biomass Association.

The culprit, the researchers say, is fertilizer. Growing algae in open ponds is akin to producing them in a shallow swimming pool, [lead researcher Andres] Clarens said, so all of the nutrients — nitrogen and phosphorus — needed to keep them alive and boost their production come from outside sources [Scientific American]. The researchers point out that corn can draw at least some of its nutrients naturally from the soil, and that process can be amplified by rotating crops, whereas algae production draws all of its fertilizer from external sources. Since the fertilizers dumped into the algae pools usually come from petroleum-based feedstocks, the cultivation process has a large carbon footprint. However, Clarens offers one solution to the fertilizer problem: The algae ponds could be placed near wastewater sources, which the algae could use for nutrients.

There’s another issue, according to the study. Algae use sunlight and water to convert carbon dioxide into materials that can be easily converted into fuel [Scientific American]. But researchers say that even that CO2 presently comes from external petroleum-based sources, since we don’t yet have a cheap way to trap and transport the CO2 emissions from power plants and factories.

The research, unsurprisingly, has drawn the ire of biofuel companies who allege the researchers used old and outdated data for the study. In response, Andres Clarens the lead author of the study said he used the most recent data that he could, which was about 10 years old. Algae biofuel companies keep their research a closely guarded secret, he said. He invited companies to share any more recent and relevant data they had with him [The New York Times]. There is now speculation that Clarens may do a follow-up study if the biofuel companies provide him with more recent data.

Related Content:
80beats: Could Exxon Go Green? Oil Giant Invests in Algae Biofuel Research
80beats: Algae Tech’s Latest Goal: Make Ethanol for Bioplastics
80beats: Forget Biofuel. Is Bioelectricity the Next Big Thing?
80beats: Algae-Filled Greenhouses Aim to Take in CO2 and Turn out Biofuel
80beats: Super-Green, Algae-Derived Jet Fuel Passes Tests With Flying Colors
DISCOVER: The Second Coming of Biofuels

Image: flickr / Lee Nachtigal

CATEGORIZED UNDER: Environment, Living World, Technology
  • Dave

    Hydrogen combustion sounds more promising. It’s just a matter of developing a practical system that can seperate hydrogen from deionized water fast enough to feed it into an engine. That way you don’t have to keep tons of hydrogen under pressure in a tank/bomb. It’s nice to think too that pretty much all current combustion engines can me modified to run off of hydrogen.

  • Mark

    Why not grow the algae in rivers where fertilizer runoff from agriculture has been a problem.

  • Mark

    Why not grow the algae in rivers where fertilizer runoff has been a problem?


    It would be nice if hydrogen could be the solution as Dave describes –perhaps we should look into those vaults of the major automotive companies that contain the solutions but were purchased and shelved immediately in the “corporate interest” of the automotive and petroleum producing companies. On a different note, way back in the dawn of time in the 70s, there was a book published by organic gardening in Emmaus Pennsylvania which gave a simple method for growing algae for a variety of purposes. While I know that algae is just not algae this could serve as a basis of research. It boiled down to adding dried and processed cow manure (a common garden fertilizer-organic of course)– add sunlight and voila!!–there you are-algae! Now granted this was to create algae and upon to feed catfish etc. but it certainly did work especially in any one acre pond. Cheap, effective, why not?


    Hydrogen would be the perfect answer and perhaps (since the automotive companies are owned by the American people) we should dig in their vaults and bring forth some of those secret devices that were privately developed and bought up by GM and others and immediately sequestered in their deepest, darkest closets to avoid impact on the automotive and petroleum industries. A publication called Organic Gardening originating in Emmaus, Pennsylvania that highly recommended adding dried and processed cow manure (a common, organic garden fertilizer) in substantial ratios to poems large and small in order to facilitate the growth of algae to feed catfish and other pond denizens-just add sunlight–voila!!–algae in abundance. Mad be the right type of algae but it certainly could be a starting poin using water sludge from sewage reclamation plants. Wake up people!

  • Mike

    I’m ignorant on the subject, but like all technologies…it needs to get going, then can be tweeked and perfected. We can’t expect the perfect solution right from the start. Or grow them near large factory farms…like pig and chicken farms??? Using the waste for food. I think to make this work, they might have to marry some of these industries together, or at least give it a try.
    I think it will be a while before we find the right solution to our energy needs…perhaps a little bit of all of them might be best, depending on the area and climate…corn, algae, wind, solar, natural gas, wave energy….

  • Spironis

    An advocate makes virtue of failure. The worse the cure the better the treatment – and the more that is required. Dow Chemical looked at growing algae in nuclear power plant cooling streams in the 1970s. The heat was free and algae growth was already a problem. It couldn’t even begin to pull a profit, not even in the spreadsheets of professional financial liars. Therefore.. how large are the Federal subsidies?.

    A petroleum refinery is off the grid. It makes its own electricity and steam from the cheapest fuels around – its own wastes and outputs. Athabasca, Canada is the largest natural gas consumer in Canada. If its tar sands’ petroleum output is much more expensive/joule than natural gas, why is it producing any at all? NO fuel ethanol plant runs on fuel ethanol. They run on Federal subsidies.

    “Dr John Benemann, the scientist who literally wrote the book on biodiesel from algae, has called some of the claims being made for the technology and yields ‘bizarre’ and ‘totally absurd’.”

    “A biodiesel-from-algae plant using the much-hyped industrial photobioreactor approach and operating at maximum efficiency is not economically feasible at fuel prices below US$800 per barrel.”

    Agri-giant maize pimp Archer-Daniels-Midland’ corn produces 172 litersl/ha biodiesel. Oil palm produces 5950 liters/ha biodiesel. Replanted Lousiana could have a (lawful) multi-$billion/year crop, no Federal subsidies required, with every man a king. But who wants that?

  • Russ

    I’m sorry Dave, I’m afraid you can’t do that.

    Combining oxygen and hydrogen to create usable energy is like releasing a wound spring. Someone has to wind the spring first. Liberating hydrogen from oxygen is the process of winding that spring. So in that sense it is a zero sum game. Even worse though, just like in a real spring, the spring heats up a little each time you bend a release it, thus losing energy, you also can’t have a 100% efficiency process from h2o -> h+o2 ->h2o.

  • Greg

    I am part of a team that produced the bio-oil from an industrial bioreactor with natural sunlight, very limited CO2 enrichment to the air that was introduced to sweep the algae-produced oxygen out and “stir” the reactor contents at just under $0.50/gal of oil – oil still has to be transesterfied but that processing cost (including transportation to trans facility) is under $0.60/gal. So Dr John Benemann is looking at the hype not the reality and he is absolutely correct most of the supposed Algae leaders do have remarkably expensive production facilities – one company’s system has an expected capital cost of just over 419 per gal of oil, right at Dr Benemann’s $800/bbl, another company’s giant Ziplock bag design is an expected installed cost of just over $30,000,000 per hectare and a debt service cost of just over $12/gal of annual production.

    Most of these leaders are stock price plays/scams – lots of razmataz but little substance. Three of the leaders are primarily managed by good scientists with no commercial background – this shows in company’s like GreenFuel who burned through over $70MM in research but is gone today. One of the supposed leaders is artifically pricing their “production system” installed cost to capture as much of the stimulus money as possible – very tough for any governement or owner’s engineers to detect the funny business when there is no history on facility costs.

    A well-deigned system should have about 10% of the energy requirements of corn farming on the same farmland area – that is the result of my team’s pre-commercial facility – my corn data came from the adjacent 200 acre field that we had contract farmed and collected all of the energy input data including fertilizer use (and back-caled the natural gas use to produce the fertilizer that was used with the manufacturer’s data), the direct farming fuel use and the transportation/ethanol production energy use at the ethanol plant that the corn went to. And yep, the corn energy balance was negative – produced less useful fuel than the nat gas and liquid fuel it took to produce the crop and transform it.

  • Greg

    Dr Clarens etal’s paper is also curious – paper reaches back to late 1980’s and early 1990’s DOE/NERL research on algae species assessment for the algae data. While that was a great body of work in sifting thousands of species, the program was de-funded just as theu were getting into real work on algal production – most of the work focused on open ponds with relatively high water consumption rates due to evaporation and “blowdown” due to the quality of the source water – the blowdown resulted in significant nutient loss along with water “consumption. Almost all of the current open pond algae technologies are located near large water source – the great work going on in Hawaii uses ocean water so water consumption has essentially no impact on local water supplies – the current work in the Southwest is focused on brackish water sources so again has only positive impact on local water sources. Dr Claren’s energy statistics are also curious. The paper shows huge energy contribution from “upstream” (not really defined in the paper and not clear where the data actually came from) but is over an order of magnitude of current pre-commercial consumptions – My read between the lines leads me to think his team is using very very high fertilizer rates for algae compared to the terrestrial crops – in my head to head algae vs corn, algae had a lower fertilizer demand per Mg of total dry mass production than corn – we also saw much lower direct energy use in the on-site farming requirements – this will get a lot of press (as I am seeing this morning) and is not good current research – I am surprized that UofVA is doing this – they are a much finer University than what I see here.

  • YouRang

    Surely one can design the system so that most of the fertilizer comes from the solid waste after the carbon compounds are extracted. I.E. reuse the nitrogen and particularly the phosphorus. (They failed to mention that iron is frequently the rate limiting element for algae blooms.)

  • Scott

    One word…feedlots.

    Look at the tremendous amount of rich organic waste emanating from beef, pork and poultry Confined Animal Feeding Operations. Waste management could switch roles from liability to asset if bioreactors could be coupled with CAFOs.

    RE Greg: It sounds like you are involved in a fascinating project. Is there any public source of the data you have collected or other info you have generated?

  • Jack

    This “STUDY” is an obvious pro big oil piece that takes the dumbest way to grow algae, get nutrients etc. Sounds like something Glen Beck would write.

  • Jack

    Imagine what a losing enterprise it would be to manufacture cell phones! My God, you would have to build thousands of cell phone towers all over the country, and you know those cell phones cost $3000 to build! Just 20 years ago, this was the thinking of “experts”.

  • Sue

    Since those big ugly Therma plants still exit, why not build algae farms in their waste stream. CO2, emitted from stacks, could be cooled and piped through the pond, allowing the algae to trap what they need. This is still a carbon-loop, but better than building huge pipe lines needed to let oil companies use the sequestered CO2 (this is currently being done right now, by the way, google “Encana CO2 sequester Weyburn Saskatchewan”). We’re trying all other ideas to clean up therma flue gas…including trucking in thousands of tons of lime thousands of miles to plant, just to reduce the sulfur (SOx)….why not this?

  • marco

    Wow Do any homework or freethinking- Writer. DO you work for exxon? It doesnt have to be fresh drinking water. More fertilizer than corn, Idiot- Corn requires the most fertilization than any crop we grow! ten year old data thats relevant, every change in the industry has come in the past 5! The internet has not truth police or BS meters, which it should- You need to find the truth yourself and not threw some partisan douche, writer- Your job is facts not ads!

  • Connie Servative

    First food to make fuel now water. You’d think people would learn after cutting down the forest to make fire wood to heat homes this type science never works in the long haul.
    Why not take all this science and learn to make Natural Gas our next fuel and drill baby drill.

    It seems the more we drill the more those reserves of Nat Gas keeping going up.

  • branboom

    Uh, salt water alge, build alge farms out at sea.

  • puja jha

    now the emerging scientists & engineers are focussing toward the generation of electricity via using sea-algae as source.
    for doing this the principle involved is photolysis of water molecule involved during photosynthesis process.

  • Sean

    It’s all about the costs. Yes, the cost of producing fuel from algae is at present prohibitive but these costs are coming down rapidly of late. Agree Jack, just takes a few believers.

  • Thomas

    Lets Get it done

  • Jessia Guastella

    great issues altogether, you just received brand new reader. What would you recommend about your publish that you just made a few days in the past? Any sure?


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