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PNNL study finds algal oil could replace 17% of US petroleum oil imports

A new Pacific Northwest National Laboratory (PNNL) study shows finds that oil from algae grown in outdoor raceway ponds located in the Gulf Coast, the Southeastern Seaboard and the Great Lakes could replace 17% of the United States’ imported oil for transportation.

The study also found that shows that water use for algae cultivation is much less if algae are grown in the US regions that have the sunniest and most humid climates: the Gulf Coast, the Southeastern Seaboard and the Great Lakes. The paper is published in the journal Water Resources Research.

Algae has been a hot topic of biofuel discussions recently, but no one has taken such a detailed look at how much America could make—and how much water and land it would require—until now. This research provides the groundwork and initial estimates needed to better inform renewable energy decisions.

—Mark Wigmosta, lead author and a PNNL hydrologist

Wigmosta and his co-authors provide the first in-depth assessment of America’s algal biofuel potential given available land and water. The study also estimated how much water would need to be replaced due to evaporation over 30 years. The team analyzed previously published data to determine how much algae can be grown in open, outdoor ponds of fresh water while using current technologies. Although algae can also be grown in salt water and covered ponds, the authors focused on open, freshwater ponds as a benchmark for this study; much of today's commercial algae production is done in open ponds.

First, the team developed a comprehensive national geographic information system database that evaluated topography, population, land use and other information about the contiguous United States. That database contained information spaced every 100 feet throughout the US—a much more detailed view than previous research. This data allowed them to identify available areas that are better suited for algae growth, such as those with flat land that isn’t used for farming and isn’t near cities or environmentally sensitive areas like wetlands or national parks.

Next, the researchers gathered 30 years of meteorological information. That helped them determine the amount of sunlight that algae could realistically photosynthesize and how warm the ponds would become. Combined with a mathematical model on how much typical algae could grow under those specific conditions, the weather data allowed Wigmosta and team to calculate the amount of algae that could realistically be produced hourly at each specific site.

The researchers found that 21 billion gallons of algal oil, equal to the 2022 advanced biofuels goal set out by the Energy Independence and Security Act, can be produced with American-grown algae. That’s 17% of the petroleum that the U.S. imported in 2008 for transportation fuels, and it could be grown on land roughly the size of South Carolina. But the authors also found that 350 gallons of water per gallon of oil—or a quarter of what the country currently uses for irrigated agriculture—would be needed.

The study also showed that up to 48% of the current transportation oil imports could be replaced with algae, though that higher production level would require significantly more water and land. So the authors focused their research on the US regions that would use less water to grow algae, those with the nation’s sunniest and most humid climates.

The authors also found that algae’s water use isn’t that different from most other biofuel sources. While considering the gas efficiency of a standard light-utility vehicle, they estimated growing algae uses anywhere between 8.6 and 50.2 gallons of water per mile driven on algal biofuel. In comparison, data from previously published research indicated that corn ethanol can be made with less water, but showed a larger usage range: between 0.6 and 61.9 gallons of water per mile driven. Several factors—including the differing water needs of specific growing regions and the different assumptions and methods used by various researchers—cause the estimates to range greatly, they found.

Because conventional petroleum gas doesn’t need to be grown like algae or corn, it doesn’t need as much water. Previously published data indicated conventional gas uses between about 0.09 and 0.3 gallons of water per mile.

Looking beyond freshwater, the authors noted algae has several advantages over other biofuel sources. For example, algae can produce more than 80 times more oil than corn per hectare a year. And unlike corn and soybeans, algae aren’t a widespread food source that many people depend on for nutrition. As carbon dioxide-consuming organisms, algae are considered a carbon-neutral energy source. Algae can feed off carbon emissions from power plants, delaying the emissions’ entry into the atmosphere. Algae also digest nitrogen and phosphorous, which are common water pollutants. That means algae can also grow in—and clean— municipal waste water.

Next up for Wigmosta and his colleagues is to examine non-freshwater sources like salt water and waste water. They are also researching greenhouse ponds for use in colder climates, as well as economic considerations for algal biofuel production.

The research was funded by DOE’s Office of Energy Efficiency and Renewable Energy.


  • Mark S. Wigmosta, Andre M. Coleman, Richard J. Skaggs, Michael H. Huesemann, Leonard J. Lane (2011) National Microalgae Biofuel Production Potential and Resource Demand. Water Resources Research. doi: 10.1029/2010WR009966



It is the capital investment required versus return on investment that will make the difference. If investors can see a sure thing to make money, they will probably be there. That is no guarantee, they will go where ever the best return and the lowest risk is, but it could happen.


A replacement for only 17% of the petroleum that the U.S. imported in 2008 grown on land roughly the size of South Carolina?

South Carolina has an area of 32,020 square miles.
I think it's already been calculated that if all the cars in America were BEVs you could charge them with a PV array of only 10,000 square miles. Using these numbers, that makes solar BEVs about 19 times more land efficient than algae powered cars and 1,520 times more than corn powered ones. And PV arrays don't need any water.

Dave R

I'm with ai_vin. And EVs don't have any of the tailpipe emissions of millions of cars running around, either - even if they are powered by biofuels.


And how could you justify using 350 gallons of water for every gallon of bio-oil produced?

That's a lot of bloody water.


@Ai vin and DaveR,
From a land use efficiency point of view, you're right that photovoltaic and solar thermal kick biofuels' greasy behind. Assuming each driver travels about 40 miles/day, and .25 Kwh/mile that's about 10 Kwh/driver/day, which 15 to 25 panels should produce most places. That's far less than the 1-2 acres of pond per car in a warm place required by algae.

However, given that it will take decades to convert the automotive fleet over to electricity, biofuel is apt to have a place for a long time. Also, algae fed by smokestack emissions reduces CO2 and NOx emissions considerably. There will hopefully be a big market for electric, and inevitably be a big market for biofuel for some time.


Fully electrified vehicles are the only logical way to go for the longer term or when batteries have evolved enough, whichever comes first.

For the short and mid-terms, we will have to do with improved ICEV, HEV and PHEV and liquid fuels. Progressive introduction of those vehicles and a few BEVs will eventually stabilize and reduce liquid fuel consumption. By 2020 the effect should be noticeable.

The world should be able to produce the liquid fuels required for the next 4 or 5 decades with crude oil, converted NG, SG, coal and multiple wastes. Edible feed stocks, such as corn and sugar, should not be used to produce liquid fuels for our very low efficiency gas guzzlers.

Energy efficiency programs, Solar and Wind can produce enough e-energy for all future electrified vehicles.


Like many here, I am not very positive on these algae for biofuel, the cultivation of it is too complex, and I don't think you can easily cover big areas with ponds that need to be enclosed and fed with CO2 to work efficiently. Open pond can be used but their yield is dramatically lower.

The main source of energy in the decade to come is energy efficiency, once you have the energy efficiency everything become simpler. If you look at evolution the winner or the fittest is always the one who use energy more efficiently. A salmon can swim rivers up stream thousands of miles without eating at all. Some birds can fly over tens of thousands miles with very little food, bottom line they are extremely efficient.


Considering the practicality of liquid fuels and the superior efficiency of fotovoltaics, I am sure heterotrophic organisms may be the perfect synergy. Use fotovoltaics or thermal electric to produce H2 from water, and feed it to heterotrophic algae, together with concentrated CO2. Coskata-like organisms already exist. Then you can grow the algae extremely efficiently in dark containers, while producing liquid fuels with solar energy even 10 times more effciently than the best autotrophic algae. Also no risk of contamination and almost zero water use. It's also easy to use the electricity directly when you need the electricity and only use the spare-capacity to produce H2.


We'll likely see the market for algal oils driven by heavy lift needs in ground and air transport. Algal oil and alcohols are at least sustainable alternatives to petroleum and algae grown in salt water address the water issue.

Trucking and aircraft are the two sectors that will be hard to convert to non-liquid fuels. Without going exotic.


That depends, do you consider electrified rail as exotic?


They are attacking imported oil on all fronts. Biomass, algae, synthetic fuels and other methods will all help. It is not just ONE thing but everything that helps.

Roger Pham

Hi ai vin,

That's right. With PV panels on every roof top for charging BEV's and producing H2 from excess electricity, we can produce enough electricity and H2 to replace ALL imported petroleum. Many cars and light trucks will have to run on either batteries, H2-FC or H2-ICE-HEV, while saving the domestic petroleum for airplanes and conventional autos and large trucks.

We will create tens of millions of new jobs to the tax role and will be able to avoid gov. budget deficits, pay off the national debts, avoid the partisan bickering between the Reps and the Dems regarding deep deep budget cuts that will sabotage America's future...etc
Oh, most importantly, secure our energy future, reduce environmental pollution, and reduce global warming.

Stan Peterson

Dream On, Dream On.

Placing PV cells over an area the size of South Carolina would alter the local Albedo from 71% to almost 100% over an area of some 32,000 square miles. What would you propose to do with the waste thermal pollution?

It would likely be enough at better than 100+ W/M**2 to sterilize an area the size of SC and its neighboring states. Think beyond the Sahara to the drier Aticama Desert, only hotter, with pools of liquid glass accumulating in the depressions. Certainly, enough to create an eco-catastrophe. Might even produce the CAGW that y'all seem to desire.

The EIS would take a century to write and approve, even with eco-political protection. I'm certain that you will find a million snail darters or their equivalents, whose habitat would be destroyed with such crazy schemes and eco-lawyers to monkey wrench the projects a thousand times over.

As for the algal pools of that size, can you imagine the the hydraulic and damning necessary, and the simple plumbing problems? You can't get an EIS through for a simple single damn now, never mind a network of damns, canals, and channels to distribute the water.

Eco-chondriacs Unite! Dream On. Dream On.

Long before such approaches, I for one, would like to assess the annual bio-production of new petroleum by the one third of the biosphere under the seabeds, whose very existence we knew nothing of half a decade ago. They seem to be quite happy living anaerobically in sub-ocean rocks to a depth of six miles, and producing new petroleum as they live their lives.

When you commission tame "scientists" as such at the PNWL, you get less than what you pay for. Ah, the wonders of government funded, politically correct, R&D. GIGO!



To commute for 1 hour each day an EV needs about 20kWh. A solar panel is about 200W/m2 during daytime (8 hours) in favorable locations of the planet. That means you need an area of (24/8)(20k/200) = 300m2 of solar panels just for one car. Not very practical, is it.



I don't consider electrified rail exotic at all. But that only replaces SOME of the heavy shipping needs across the continent. Trucks pulling 18 wheel trailers will not be replaced by fleets of smaller trucks soon. The more immediate solution is to produce various liquid fuels from biomass/waste supplemented by CTL.

And as Roger notes there will be Nocera-type PV->H2 systems coming online. Some of the heavy ground lift can be managed with NG or H2 ICE - until the H2FCs come down in cost.

"exotic" to me is overunity.

Roger Pham

That's right, Stan, dream on, dream on: anaerobic bacteria under the ocean floor producing oil? Using what primary form of energy? What evidence do you have for this?

Albedo? You're partially right. Most houses and asphalt roads now are as dark or even darker than a typical solar PV panel. I suggest a federal regulation mandating the use of light-colored materials for roof tops and road pavement. This would greatly reduce the electricity consumption in the summer and even reduces slightly the heating requirement in the winter, since ligh-colored object radiates less heat. This would also make urban areas cooler in the summer.

However, a solar PV displaces the coal or NG or nuclear-generated heat used for electrical generation. More solar PV's means less combustion or nuclear heat generation by power plants. Look into thermal pollution problems by power plants! At 33% thermal efficiency by a coal or nuclear power plant, every 1kWh of electricity would generate 3 kWh of heat into the environment. Thus, solar PV's generate practically no net heat gain into the earth.

Please re-do the math regarding energy consumption for a daily commute and the size of PV panel required!

This how I'd do the math: A Chevy Volt needs about 8,000 Wh/day for an average round trip commute of 40 miles. Each square meter (m2) of solar panel can produce 200W x 8hrs= 1,600Wh/day. So, 8,000/1,600= 5m2 of solar PV panel. A solar PV of 4x4 meters would have a surface area of ~16m2 and can support over 3 typical Chevy Volts' daily commute. Many cars and/or commutes may consume more than 8kWh/day, but many will consume less. So, the 8,000Wh/day is the average power consumption for daily commutes as calculated by GM when they size the battery pack of the Volt, and this number should be used.



I should have said 20kWh/(200W/m2*8h)=12.5m2. That's better. My mistake. But you can't expect people to need only 40miles per day or 8kWh per day. 20kWh is more like it.

The start thinking about car #2, and that everyone need to feed the 12.5m2 worth of solar power (2.5kW) into the grid and transport it 20 miles to your workplace (which is where the car is during solar hours). And then there is the house itself, which needs some solar panels for it's own energy needs. Pretty soon we need over 30m2 or 6kW of solar panels per house.

Then there are all the people that do not live in sunny California, Arizona and places like that.

I'm not at all against solar energy or electric cars. But what we need right now is for everyone to use hybrid and diesel technology to get from 25MPG to 50MPG immediately and then we have a little breathing room to go to the next level and get it right.

In other words, let us not have future technology getting in the way of doing what needs to be done NOW in the next 5 years.


Average one-way commute time in America is 26 minutes, due to traffic, but with an average distance of just 16 miles the 40 miles per day Volt will due the job just fine;

My one-way commute is 10km.


Painting roofs white might offset some of the heat island effect in cities. I suppose we could model that theoretical 100 mile by 100 mile area covered with PV in the Nevada desert that could power the whole country for its affect on the weather. I do not think that you would find much compared with global warming.


The thing to remember about PV panels is that they are thin, lite structures mounted high off the ground. As such they have little thermal mass and radiate heat as fast as they get it, and because they also have to face the sun to work this radiated heat is directed up into the sky.

The heat island effect is a problem in cities because the thermal mass of buildings keeps the temperature up at night and the vertical walls of those buildings radiate heat sideways which puts other buildings in the way to reabsorb it - over and over again - slowing the escape of the infrared radiation.

Albedo is also more of a problem in the arctic than a PV array because water, in addition to having high thermal mass, is also transparent to light. It absorbs heat at depth, where ocean currents can move the now warmed thermal mass to the rest of the world, turning a local effect in to a global one.



Albedo is one of those topics that people bring up when they run out of anything else to say. Kramer Junction produces 300 megawatts of concentrated solar thermal electric power on several square miles in the Mojave Desert. If there was a problem with disrupting the reflected solar energy, it would have shown up over the last 30 years.


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