[USA] While the recent Paris summit helped move global leaders onto the same page on climate change, the next step is figuring out exactly how to cut down on greenhouse gas emissions.
The federal government has spent millions of dollars to fund research and technology to create algae-based biofuel and scientists are starting to make headway toward making it competitive when it comes to cost.
Delaware Public Media’s Eli Chen recently spoke to a UD researcher whose work shows a lot of promise in paving the way to low-cost algal biofuels.
In a laboratory, a dark green liquid bubbled up in a bioreactor, illuminated by bright fluorescent bulbs. Jennifer Stewart, a researcher at University of Delaware, picked up a flask full of the green liquid, which contains algae. She remarked that the species that they’re using in this particular experiment, called Scenedesmus, isn’t very mobile, “so the bubbling keeps it mixed, so they can all get light evenly and it helps them grow.”
Stewart wants to see how much the algae grow because being able to grow large quantities of them will be important for biofuel production.
Algae biomass is a promising source for alternative fuel. It can be cultivated anywhere, in a desert, in fresh, salty or brackish water. It can produce about 12 times more biodiesel per acre than plants like corn or sugarcane. And it can absorb carbon dioxide, which makes it a powerful tool for reducing carbon pollution.
Algae’s potential to help mitigate the impacts of climate change is why the Department of Energy spends millions of dollars to fund algae biofuel research projects that’s seeking to produce algae biofuel at $3 a gallon by 2030.
But right now, algal biofuels are expensive to produce.
“You have harvesting, extracting, and refining them, and in all of that the bulk cost is growing the algae,” said Stewart.
She added that farming the algae actually makes up 74 percent of the production costs because you need to feed algae a steady amount of carbon dioxide. That can be done with bottled carbon dioxide, but Stewart says that proves too costly.
“We can’t afford to buy all of this purchased CO2 because that just reflects in your final fuel costs. And no one is going to pay 8 to 13 dollars a gallon for an algal biofuel,” she said.
So the thought among scientists is to grow algae at power plants, where they can essentially feed on a free and abundant source of carbon dioxide.
But exposing algae to the flue gases, the combustion exhaust gases at power plants, can cause other problems.
“The problem is that the algae couldn’t survive a lot of the other toxins found in flue gases and one of those toxins was nitric oxide gas,” said Stewart.
About four years ago, when Stewart was a graduate student and hadn’t even started to think about algal biofuels, she was studying an algae species called heterosigma akashiwo. She found that unlike other species, this one contained a special enzyme that allows it to metabolize nitric oxide gas.
Her professor at the time, Kathryn Coyne, remembers discovering this enzyme years earlier.
“I thought it was an artifact, that it wasn’t real,” said Coyne.
They eventually confirmed that it was. But Stewart says finding a species tough enough to deal with the gas, like the scenedesmus we started this story with, is just the beginning.
“They’re very hearty and they can survive the nitric oxide gas, but they don’t use it, as far as we know,” said Stewart, “and so the difference between surviving and actually using is a benefit as far as cost factor because you still have to add nitrogen in the form of fertilizer when you’re growing these things at the power plant. ”
So Coyne and Stewart worked to identify the gene in heterosigma askashiwo that was responsible for this nitric oxide-consuming enzyme. In 2013, they acquired a patent for it. Now, they’re looking to clone that gene for use in other algae species.
Stewart realizes to be successful she has to think about the economics as much as the science when it comes to farming algae. And though it may take time for the cost of algal biofuel to fall below $3 a gallon, she’s optimistic new climate policies, like the recent Paris agreement, will give scientists a much needed boost to put alternative fuels on the market.
“I really think that once policies hit home and once we see how bad climate change is getting, for example, if I’m in a tanktop and it’s Christmastime, it hits the point home that we’ll be ready to supply the answer,” she says, provided that the scientists can figure out how to get the algae to cooperate.
View original article at: A researcher’s effort to make low-cost algae-based biofuels