The secret to better solar panels just might be in a big magnet.
The industrial-strength magnet is inside a roomful of experimental work on New Haven’s Hillhouse Avenue, where it makes ultra-tiny “nanowires” all stand up in one direction.
For Yale engineering professor Chinedum Osuji and his colleagues, this is a breakthrough: It allows energy to travel through channels in a polymer matrix, rather than meandering about. The end result is more energy produced, since less is lost in the chaos of disorganization.
Think about the Mason Lab activities this way: Osuji’s efforts look like a multi-lane highway, while the older scenarios resemble a Plinko board from the television game show “The Price Is Right.”
“We’re overcoming the bottlenecks,” Osuji said.
That’s a promising development for people looking to solar panels and other renewable energy sources to help solve our dependence on foreign oil. It’s also a rare ray of hope. Despite the promise of everything from Osuji’s nanowires to flexible “power plastic” solar panels, nano-enabled energy isn’t ready to provide a full alternative to our thirst for fossil fuels.
Osuji (pictured) and his colleagues recently published their work, which took more than a year to complete. It could make a big contribution to overcoming a challenge that’s a constant source of vexation for developers looking to expand the world’s capacity to generate and store solar energy: Efficiency.
Big, heavy, hard panels made of silicon are the standard in solar power. But they’re expensive and need to be carefully installed to maximize their ability to produce energy, making them impractical for many people and uses. That’s why scientists and manufacturers are looking to nanotechnology for solutions for solar and other energy applications, seeking answers in the often-unique properties of ultra-tiny materials.
But interviews with leading nanotechnology researchers and corporate leaders suggest that, at least for now, nano-based applications are niche-fillers at best.
So if nano-energy isn’t heralding the transformative advent of “green energy” that’s being sought—and subsidized—by governments around the world, what can it do?
Solar Hype, Or Reality?
The question is more pointed now, in the wake of the controversial federal loans to the now-failed solar company Solyndra. That debacle has highlighted the difficulties of funding innovation in a field that’s still really in its infancy.
Ian Illuminato, a health and environmental campaigner for the advocacy group Friends of the Earth, worked on a scathing report that questioned the practical value of nano-based energy efforts. The report found more hype than reality.
Some examples, according to the report: Nano-based solar panels are less efficient than their bigger, silicon-based cousins. Super-light carbon nanotubes may make wind turbines more durable, but the energy needed to produce them nullifies some of the energy they generate. And the end of the useful life for these products may create new disposal problems.
“Through my research, it was hard for me to pinpoint factual details that led me to believe this is something that’s actually going to have a big impact,” Illuminato said.
Then there are the potential effects of some nanomaterials on people, animals and the environment. While the small size of these particles—a nanometer is a billionth of a meter—makes them exciting, it can also create problems. Carbon nanotubes, which add strength with almost no weight to composite materials, circuits and other products, are insulating and conducting, but may be hazardous when inhaled.
The U.S. government finds itself in a strange spot with this and other emerging technologies: Funding its development while scrambling to research the possible downsides. In the interim, few laws specifically govern nano-enabled products.
“I think that’s the biggest issue—we’re kind of walking blindly here,” Illuminato said. “There’s no laws, and nobody wants to enforce this.”
For now, though, the focus is mostly on what these new materials can do to help wean the human race off fossil fuels, even as we use more and more energy.
Emphasis On “Mini”
When a customer comes to Ken McCauley, senior vice president of sales, marketing and business development at Konarka Technologies, Inc., looking for megawatts of power, he tells them they’ve got the wrong company. Konarka, based in Lowell, Mass., makes flexible, customizable solar panels in an old Polaroid film factory. The panels, which the company calls “power plastic,” can be incorporated into a wide array of objects, from window glass to laptop cases, making mundane surfaces mini-generators.
But the emphasis is on the “mini.”
“That’s not our business,” McCauley said of the capacity to generate bigger amounts of electricity. “We’re more about putting renewable energy into small spaces, and kind of the overarching view that I have is I think renewable energy will become so ubiquitous at some point in the not too distant future that we’ll tend to not think of it at all.”
The company’s technology is simple, McCauley said: “Basically, it’s a plastic that makes electricity when the sun hits it.”
The big difference from silicon-based photovoltaic, or PV, panels is that it doesn’t use metal. Instead, polymers conduct the electricity. That’s why Konarka’s products can be small and flexible.
Konarka’s panels are being used on the roofs of bus shelters in San Francisco, deriving enough energy from the sun to power not just the LED nighttime lights, but WiFi connections as well, McCauley said. Adding the company’s film-like solar panels to window glass can reduce the load on air-conditioning systems while generating some of the power needed to run them.
“About 40 percent of the energy used in this country is by buildings,” McCauley said. “The more we can reduce that, the better off we’ll be.”
MIT professor Gang Chen, who is also the director of a U.S. Department of Energy-funded research center on solar-thermal energy conversion, is bullish on the nano-energy field. Even small gains are important, he said, and nanotechnology is transforming the field of batteries and other products that use small circuits.
“People don’t quite appreciate that energy is a very difficult field,” he said. “Your competition is from coal, which is very cheap.”
Chen also said that thinking just in terms of “nano” gives an incomplete picture of what’s going on. Lots of batteries and other products might have a nano-sized component, but if it’s not marketed as “nanotechnology,” it’s discounted, he said.
“Nobody knows what’s inside—it’s nano, but actually at the end, your interface is at the macro level,” he said. “So normally, people would not pay attention.”
Chen praised the Obama administration, and in particular Energy Secretary Steven Chu. Chen said the administration has been open and positive on all kinds of alternative energy ideas, and research money is flowing in ways that reflect a real commitment. But much more needs to be done before the U.S. is competitive on a global level, Chen said.
“In general, if you compare what the U.S. is doing to other countries—Germany is a good example—we are far behind in terms of the government trying to really push and stimulate,” he said.
But Illuminato argues that some of that support may be going to the wrong places.
“What we found is a lot of governments … were supporting nanotechnology research to find and extract more oil and gas,” Illuminato said. “That’s not really a green application.”
In addition, Illuminato said, the process of engineering nanomaterials—mostly for other applications—is often energy-intensive. Carbon nanotubes, for example, are made in a giant furnace, and require lots of water to process. Purifying other substances, like nanogold, for medical uses can also eat up precious resources. And nano-enabled energy products aren’t making up the difference.
“What we’re really seeing on the market is nano-strengthened golf clubs,” Illuminato said. “These products aren’t offering any environmental savings, and these products are the ones that really outnumber the products that really could offer energy savings.”
Illuminato said he does think that nano-enabled energy will eventually make a difference in concert with a number of other developments—and efforts by people to simply change their behavior. He hopes companies, and the U.S. government, will stop making claims and open up the process, so everyone can see what’s possible, what’s not and what is going into these newfangled products.
“When it comes down to it, we just need to acknowledge these issues and we just need to be honest,” he said.
That honesty includes expecting breakthroughs from “nanotechnology,” when the actual chemistry isn’t that different from what’s been happening in laboratories for decades. Both Osuji and Yale professor Hur Koser said they often marvel at the expectations engendered by the term.
“Nanotechnology really has been worked on for more than a century—it really is chemistry,” Koser said.
It was a hot topic, especially when it came to grant funding, when the government wanted a “decade of energy,” fueled by innovations using super-small materials.
“There was an era in the early 2000s when you just could not get funded without ‘nano’ in the title,” he said.
Such trends aren’t unusual, Osuji said.
“I think nanotechnology’s like everything else—it suffers from hype or marketing,” he said.
“The truth is, it’s been ages that people have been studying small particles,” Osuji added. The trick now is converting those particles into applications that can go beyond the lab—where his group’s work is—and into commercial production. He’s confident the process of getting the nanowires to go vertical and stay there, using the magnet, is a “scalable” development, meaning it can be reproduced easily in a large capacity.
As those scale-ups happen, will the science of safety keep up? Illuminato said the answer to that question should come from a society that’s grappling with the tradeoffs associated with its deep hunger for energy.
“I think nanotechnology, and the root of where it’s coming from … is going to have an impact on the world, and I think it’s up to us to choose what kind of impact it’s going to have,” he said. “I think the positive elements of this technology are going to come out of transparency, and making sure the money, especially that taxpayers are putting into this, is not just another way to make another buck.”