Arizonans have cleaned algae from cattle tanks, swimming pools and fish tanks for decades.

Now, Arizona researchers are developing algae as a promising 21st-century alternative fuel to power cars, trucks and planes and propel the state's economy into the future.

With its ideal climate and abundance of available land, Arizona is poised to become a major center of a multibillion-dollar, algae-based, biofuel industry.

Scientists at Arizona State University's Polytechnic campus say major innovations in research in recent years have put them on the brink of boosting production capabilities from thousands of gallons to millions - the difference between powering a few vehicles and fueling millions of cars and fleets of airliners.

ASU researchers say they are three to five years from large-scale production, a breakthrough that could eventually reduce U.S. dependence on foreign oil.

As a further sign of Arizona's prominence as an algae fuel-research hub, about 800 of the world's leading energy scientists and industry representatives will gather in the Valley for an "algae summit" next month.

ASU's effort and similar work at the University of Arizona are among a growing number of projects around the country that are developing algae as a cost-efficient, renewable, environmentally-responsible energy source.

Scientists have long known that algae, one of the most primitive forms of plant life, create lipids or oils in their cells that can be extracted and converted into fuel. ASU scientists have discovered particularly "oil rich" algae strains and have designed increasingly efficient "bioreactors" - large Plexiglas containers filled with water and nutrients that, when exposed to the sun, accelerate algae growth.

They are also at the forefront of developing new methods to extract the oil and turn it into biodiesel and aviation fuel.

Unlike hydrogen power or electric vehicles, algae fuel won't require new engines to burn it or new infrastructure to deliver it. It will be remarkably similar to the diesel fuel that trucks and cars use and the JP-8 jet fuel that aircraft burn.

Another bonus is that algae is considered carbon-neutral. It produces oxygen and absorbs carbon dioxide as it grows and then releases the same amount of CO{-2} when it burns. Carbon dioxide in the atmosphere is considered one of the key causes of global warming.

On the cusp

In the past year, about $1 billion of public and private funding has been invested in algae research for fuel production, according to the Minneapolis-based Algal Biomass Organization, which is hosting the September summit.

ASU's Laboratory for Algae Research and Biotechnology, based at the Polytechnic campus in Mesa, has received millions in grants, including $3 million from Science Foundation Arizona and a local company, Heliae Development, to develop jet fuel from algae. The laboratory also recently was awarded a $6 million U.S. Department of Energy grant.

ASU and the laboratory have also partnered with a local company to develop equipment for large-scale production of algae fuel as they seek to establish it as a credible alternative. Algae fuel has already proved it is not just science fiction - a Boeing helicopter recently made a test flight in Europe using an algae-based fuel.

"We're right at the cusp of commercializing and making fuel from algae," said Mary Rosenthal, executive director of the Algal Biomass Organization. "There are companies making thousands of gallons of fuel now, but in several years - maybe by 2015 - we should be at millions of gallons."

ASU Senior Vice President Rick Shangraw said that although solar energy and hydrogen power hold great promise, algae will "deliver soon" because, in the past few years, "most of the hard science problems regarding algae have been solved."

"Now," he said, "it's largely an engineering problem."

Shangraw said algae fuel meets practical demands around the globe.

"The reason we keep trying to get fuel out of algae and ethanol from corn is that we've put trillions of dollars into a liquid-fuel infrastructure around the world," Shangraw said. "We know how to transport the stuff, and we have hundreds of millions of vehicles and boilers that burn it. For us to move to a hydrogen-based economy, or to go electric, would mean huge costs redoing the infrastructure."

Ethanol, however, "has turned out to be inefficient; growing corn and producing energy from it doesn't pencil out because you have to expend too much energy to get energy," Shangraw said, particularly in cultivating and harvesting corn.

Shangraw said that, unlike with ethanol, growing and harvesting algae results in an energy gain "because you get more energy out at the end of the process than you put in." In addition, the byproducts from algae can be turned into fertilizer or feedstock for animals.

Shangraw said Arizona is uniquely situated to cash in on the development of algal-based fuels. "We have lots of sunshine, plenty of land," he said. "We have lots of agricultural sites from which we can get what otherwise would be wastewater but because of its high nutrient and saline content is perfect for growing algae."

The payoff

Milton Sommerfeld, 69, has been working for more than 30 years at ASU to make the promise of biofuel pay off. Now, in Polytechnic campus labs and greenhouses, his longtime dream is happening.

Qiang Hu, Sommerfeld's fellow scientist and colleague in algae production, is a specialist in designing the algal bioreactors in which the plants grow. At ASU's Laboratory for Algae Research, a large greenhouse complex contains vertical Plexiglas panels within long banks of Hu's newly designed and fabricated bioreactors. These bubble with green, algae-laden liquid, rich in lipids.

When Sommerfeld started his research, the strains of algae being studied had low quantities of fat, or lipids, and the methods for extracting the oil were primitive.

He played a major part in solving the No. 1 problem: finding strains of algae with a high yield of oil. Aided by a U.S. Department of Energy grant, "our job was to find and isolate and characterize algae in the Southwest," Sommerfeld said. "Graduate and undergraduate students sampled about 250 sites. They went to ponds, streams, lakes, particularly looking for water that was brackish or saline, and they found some very oil-rich algae like we hadn't tested before."

In fact, the algae they found changed everything.

"The DOE's target was 40 percent lipid," Sommerfeld said. "We met that goal and have kept finding even better algae. Now, we have organisms that will grow algae with a biomass that's 55 percent oil . . . (so) now, we have algae that can produce an abundance of oil."

Sommerfeld said that the sort of saline water algae thrives in can be found in aquifers in Arizona, New Mexico and Texas, and that "because it's brackish, or saline, we can't drink it. Now, we can use this otherwise unusable water."

Once it became clear that significant oil could be taken from algae, it became more of a mechanical problem to solve, Sommerfeld said. "We needed to create efficient places for the algae to grow - bioreactors - and from which we could extract the biomass which we would turn into oil."

The standard extraction method is to dry the algae biomass and use a solvent to chemically extract the oil. "You dissolve the oil out of the cell, heat the liquid mixture and the solvent boils off. You collect the solvent as it boils off to use again, but when it boils off, the oil is left," Sommerfeld said.

He said one reason large bioreactors are needed is because it takes a significant mass of dried algae to make a significant amount of oil. One pound of dried algae that is 50 percent lipid will yield a half-pound of oil. It would take about 16 pounds of dried biomass to make 1 gallon of oil.

ASU and other research centers have experimented with artificial ponds to grow algae, but Sommerfeld said the answer likely lies in using large, vertical panels or tubes that require less space.

Hu said creating larger and better bioreactors is just a matter of time, money and design. "We will make better and better bioreactors, and we'll keep cutting the cost of producing fuel," he said.

A green future

As researchers converge on the Valley next month to talk about the future of biofuel, there is a growing consensus among scientists and government officials that the time for establishing alternatives to fossil fuels has come and that biofuels are the most likely alternative.

ASU researcher Bruce Rittman, whose work in creating genetically modified bacteria rich in lipids parallels the work of Sommerfeld, said, "There is a growing realization in this country and around the world of the importance of sustainability.

"We have to shift away from fossil fuels, especially petroleum. There are skeptics who say biofuels are too expensive, but when you factor in things like climate change and the eventual cost of that, we don't look expensive at all."

Shangraw said that as research-and-development advances reduce the price of algae fuel from its current cost of about $20 a gallon to more like $3 or $4 a gallon, we need to look carefully at the "true costs" of fossil fuels vs. biofuels. The military and human cost of keeping oil flowing from the Middle East, for example.

"Or what about the cost of the BP oil spill in the Gulf?" Shangraw said. "Economists call these other costs 'externalities.' The factors should figure into the price of something.

"If we had all those factors, the cost of oil would be a lot higher, and the cost of some other fuels, like fuel from algae, would look a lot more reasonable."