TAKE 1
GREEN ALGAE

Carolyn Lee-Parsons, associate professor of chemical engineering, chemistry, and chemical biology
Problem: Find a less expensive alternative to ethanol.
Solution: Devise a way to harvest the energy in microalgae, which has the potential to be produced far more efficiently than ethanol.



Lee-Parsons has spent the better part of her career coaxing plant cells to produce critical pharmaceutical compounds in greater volume and devising efficient ways to harvest those compounds.

Over the years, she has developed an arsenal of biochemical and genetic engineering tools that she uses to increase production of pharmaceutical compounds and to understand the mechanisms behind these increases.

Now she is applying this arsenal to a new area: producing energy from microalgae cells. These cells naturally produce a biodiesel precursor called triacylglycerol. Microalgae cells use triacylglycerol molecules to store energy, but it takes several weeks for the cells to accumulate high enough levels.

If we can uncover the nuances of the machinery in microalgae cells, says Lee-Parsons, then we should be able to manipulate it to speed up triacylglycerol production and overcome another tough challenge—“milking” microalgae of triacylglycerol without destroying the cells.

The basic chemistry of biodiesel illustrates what’s at stake in Lee-Parsons’ research. Biodiesel’s main competitor among plant-based energy sources, sugar-derived ethanol, contains a single carbon-to-carbon bond; biodiesel contains more than a dozen. These bonds are where energy is stored, so biodiesel has the potential to outpace ethanol as a fossil-fuel replacement—but only if an efficient means of producing and harvesting the triacylglycerol can be found.

TAKE 2
FUELED

Sanjeev Mukerjee, professor of physical and materials chemistry
Problem: Creating a cost-effective fuel source.
Solution: Experimenting with a less expensive
fuel-cell catalyst and building a less expensive, more efficient lithium battery.



In the race to develop a cost-effective replacement for the automobile’s internal combustion engine, Mukerjee is convinced that fuel cells and superbatteries are the winning technology combo. Both are under development in Northeastern’s Center for Renewable Energy Technology.

Mukerjee’s NUCRET team is committed to solving what he considers the primary stumbling block to a practical fuel-cell system that converts hydrogen to energy: cost. Because fuel cells use platinum as a catalyst, the existing technology applied to electric cars would cost an unsustainable $5,000 per kilowatt.

NUCRET researchers are experimenting with much less expensive catalysts—such as iron and cobalt polymer composites—to reduce the energy price a thousandfold.

But electric vehicles also need an energy storage system. Mukerjee and his team are working on one that is cheaper and more efficient than existing lithium-ion batteries. The lithium air battery, which was invented and patented by NUCRET, takes oxygen from the air for its oxygen reduction reaction. Lithium-ion batteries, conversely, require a metal-oxide electrode that is more expensive and needs more frequent recharging.

Coupled with inexpensive fuel cells, this novel superbattery technology would enable a fully electric car to drive 500 miles—from San Diego to San Francisco—on a single charge.

TAKE 3
RARE ELEMENT

Laura Lewis, Cabot Professor of Chemical
Engineering
Problem: Finding an alternative to expensive rare earth elements used to create supermagnets.
Solution: Replicate the properties of superstrong magnets by rearranging nanoparticles.



From electric motors to wind turbines, every alternative-energy solution needs a super-strong magnet to function. These magnets, in turn, require rare earth elements, and currently more than 95 percent of the world’s production is in China.

This situation gives China the leverage to maintain high prices for these elements, a big reason alternative-energy technologies are so expensive.

Lewis is building her research on another method for producing superstrong magnets—one that requires only iron and nickel, and is inspired by a similar process that meteorites undergo over a few billion years. As a meteorite gradually cools, its nickel and iron atoms arrange themselves into highly ordered structures that have supermagnetic properties.

With a three-year, $3 million grant from ARPA-Energy, Lewis, an expert in nanochemistry, is on the path to re-creating alternative magnets in her laboratory, and in a tiny fraction of the time, using precisely arranged nanoparticles.

Lewis’ success would relieve us of our reliance on rare earth elements—which are present in virtually every modern technological device—and reduce the cost of alternative energy enough to make it competitive with fossil fuels.