Energy research for a stronger society

Posted on 19. Feb, 2015 by in Academic Departments, Chemical and Biological Engineering, Civil and Environmental Engineering, Electrical and Computer Engineering, Energy Independence, Engineering Physics, Features, Issues, Magazine, Mechanical Engineering, Research

By Scott Gordon

It’s hard to find an energy researcher in the College of Engineering who thinks only about one piece of the energy puzzle. Talk to an engine researcher about fuel efficiency, and pretty soon you’ll be discussing the engine as a bigger system. Ask an electrical engineer about power storage, and the conversation will turn to reinventing the power grid. Bring up hydropower to a civil engineer, and you might learn a surprising amount about the regional politics of dams.

UW-Madison engineers, and their partners across campus, are thinking about how to meet the human race’s rising energy demands, make the best of established and novel energy sources, and confront the pressures of climate change.

Just as importantly, they have developed a research culture in which science converges with economic, social and policy concerns. That culture has manifested itself in internationally recognized research breakthroughs that position UW-Madison to have a huge impact on how the public relates to energy.

A dynamic system
Nurturing this research culture has been a deliberate project for the Wisconsin Energy Institute (WEI), a transdisciplinary research hub. Originating in the College of Engineering, WEI grew out of a desire to address public concerns about energy, and to facilitate cross-disciplinary research. This brings UW-Madison engineers into collaboration with everyone from bacteriologists to policy scholars. It also makes for more interactions across different sectors of the energy field, where proponents of nuclear energy and renewable energy can not only cross paths but also learn from each other.

WEI Director and Wisconsin Distinguished Professor of Engineering Physics Mike Corradini believes this environment sets UW-Madison up for success by acknowledging certain realities. “In energy, people are looking for an easy answer. The problem is, there’s no easy answer,” Corradini says. “You can’t policy it away, you can’t technologically solve it away, you can’t PR it away.”

Grainger Professor of Power Electronics and Electrical Machines Thomas Jahns, who recently collaborated with his WEI colleagues on a white paper (available at energy.wisc.edu) about transforming the electric power grid, uses the example of fuel cells to show why this cross-cutting research mentality is important. “Huge strides have been made in fuel cell efficiency and compactness, so why don’t we all have fuel
cells right now?” Jahns says. “The necessary infrastructure for supplying the hydrogen fuel to large numbers of prospective users would be very expensive to establish using current technology. That is, it isn’t enough to focus on improving the fuel cell by itself. We can only succeed if it is developed as part of a much larger integrated energy system.”

With this approach in mind, Jahns and his collaborators propose creating a dynamic distribution system (DDS) that will link a wide variety of electric power sources, ranging from large nuclear plants to small photovoltaic arrays. Their white paper lays out details of their new DDS architecture, which modifies the electric power grid in ways that will make it attractive for resources such as rooftop solar panels to play a larger role. Yet, the authors say it’s still important to include large centralized power plants that are optimized to supply bulk power to communities at a steady flow. And they make a point of highlighting the fact that implementing their vision depends on a combination of tightly interwoven changes in technology, policy, regulations and economics that must be addressed as an integrated system that affects everyone from the utilities to the consumers who use the electricity. For Jahns and his colleagues, the Wisconsin Energy Institute provides a fertile environment for assembling the team of interdisciplinary experts needed to tackle such a multi-faceted and complicated topic as the future electric grid.

“For all of our lifetimes, the electric grid has been based on an architecture that depends on operating a limited number of very large power plants,” Jahns says. “The evolution of our electric grid to an architecture that can accommodate much higher numbers of small distributed power generators based on clean renewable energy sources presents tremendous challenges that researchers here at UW-Madison are well-positioned to address if we work together.”

Making the new tech feasible

Xongfu Yu (left)

Xongfu Yu (left)

The kinds of changes Jahns is anticipating also hinge on renewable energy technologies becoming more efficient and cost-effective. Here, again, the push for solar energy and bioenergy has made for some new mixes of backgrounds and expertise.

One of the many UW-Madison researchers looking at how to improve photovoltaics (PVs), Electrical and Computer Engineering Assistant Professor Zongfu Yu finds his opportunities at the intersection of optics and materials science. Yu specializes in understanding and controlling the behavior of light at a small scale. Advances in nanotechnology make it possible to create solar cells that wring more energy from the photons in sunlight.

By creating a certain roughness on the nanoscale, Yu and his collaborators hope to coax light into hanging around on the surface of a PV cell, possibly resulting in a 5- to 10-percent increase in energy conversion efficiency. Yu points out that this research draws on his optics- and physics-heavy background, but also requires collaborators who understand how to create the best materials for manipulating light at a scale of around 100 nanometers.

And while there is constant debate about just how big solar energy can become on a global scale, Yu says the increasing efficiency of photovoltaics can win out over the economic ups and downs. “I’m very, very positive on solar energy, because if nothing else, if you look at how the efficiency is gradually improving—even though this or that company may or may not be doing well—the technology has never stopped evolving,” he says.

Biofuels researchers at UW-Madison also are striving for efficiency, but on top of that, they’ve been thinking a lot about deriving a diverse suite of products from that process. Chemical and Biological Engineering Associate Professor Jennifer Reed uses computer modeling to understand how different bacteria and yeast metabolize sugars derived from plant material, and how different gene modifications might make that process more efficient. In April 2014, Reed received a Presidential Early Career Award for Scientists and Engineers—the highest honor the U.S. government bestows on science and engineering professionals in the early stages of their independent research careers.

In one recent experiment, Reed looked at how to get microorganisms to metabolize xylose, one of the prominent sugars found in biofuels feedstocks like corn stover and switchgrass that many microbes do not readily convert into biofuels. “The profit margin with biofuels is low,” Reed says. “So it’s really important that you generate as much product as possible, using all the material you have.”

While chemical engineers are already very process-oriented, Reed says organizations like the Great Lakes Bioenergy Research Center at UW-Madison play an important role in reinforcing the bigger picture. “A lot of times in science, you’re focused on the part of the problem you’re trying to tackle, but being part of the center I’m very much aware of what other people are working on in terms of engineering new crops, breaking down plant material, and evaluating sustainability of the whole process,” Reed says.

That bigger picture is so important to UW-Madison biofuels researchers because they’re convinced that diversification is key. In addition to researching possible fuels for cars, they’ve also been looking at fuels for planes and heavy machinery, as well as bio-derived chemicals that can serve as precursors for traditionally petroleum-derived products like plastic.

Chemical and Biological Engineering Professor George Huber’s research on aviation fuel has yielded a techno-economic analysis that looks at the process from the biomass to the finished product. One of his aims was to better envision how an economically viable “bio-refinery” might work on a more holistic level. Huber, along with Steenbock and Michael Boudart Professor of Chemical and Biological Engineering James Dumesic, Chemical and Biological Engineering Professor Christos Maravelias, and Chemical and Biological Engineering Research Professor Bill Banholzer, is part of a recent $3.3 million Department of Energy grant supporting advanced biofuels and bioproducts development. “So many people have been focusing on fuels that are worth $600 or $700 per ton,” Huber says. “We’re making products that are going to
be worth more than $5,000 a ton. It’s a step toward using our biomass resources more efficiently.”

Huber, who like Dumesic has created spinoff companies in the bioenergy sector, says that by keeping the entire process in mind, bioenergy researchers at UW-Madison show a crucial link between basic science and economic progress. “It’s about prototyping and demonstrating our ideas on a larger scale and getting this exciting technology a step closer to being commercially practical,” Huber says.

The traditional tech still matters

Sage Kokjohn and Rolf Reitz

Sage Kokjohn and Rolf Reitz. Photo: Jeff Miller.

For all the excitement over new energy technologies, UW-Madison researchers also haven’t abandoned machinery and principles that, in this light, might seem just plain old. Wisconsin Distinguished Professor of Mechanical Engineering Rolf Reitz, Mechanical Engineering Assistant Professor Sage Kokjohn and their colleagues in the Engine Research Center believe the internal-combustion engine still has staying power after all these years. “It’s really hard to match the energy density of a liquid hydrocarbon, and that’s really what it comes down to,” Kokjohn says. “An internal-combustion engine’s a good way to convert that energy into mechanical work.”

Still, they believe that concept can be more efficient and flexible if they start with an almost entirely new set of principles. Reitz and Kokjohn recently unveiled an engine technology called reactivity controlled compression injection (RCCI), in which the fuel injection system delivers a constantly adjusted mixture of diesel and gasoline for maximum efficiency.

One thing that makes RCCI so powerful, Reitz says, is that it can adapt to different kinds of fuels in different situations around the world. As biofuels become more prevalent, the efficiency and flexibility of RCCI could help developing nations take advantage of internal combustion engines without contributing too much to pollution and global warming. “Having the fuel flexibility is an enabler,” Reitz says.

Environmental concerns and increasingly tight regulations on emissions also have pushed engine researchers to think more holistically about how to improve this century-old technology. “The engine is now a system, all the way to the wheels,” Reitz says. “From a research perspective, it’s broadened considerably over the last 20 years or so, from just looking at what happens in the combustion chamber to a much larger question—and that’s where I think a lot of opportunities are going to emerge for improving the overall technology.”

Electrical and Computer Engineering Assistant Professor Dan Ludois also focuses on taking a well-established, ubiquitous technology and questioning how we produce it and how it operates. “About two-thirds of the electricity on earth goes to powering a motor of some kind,” Ludois says.

And, like the engine researchers, Ludois is pretty sure the technology he deals with isn’t going away, because it plays such a basic role in converting one form of energy to another. Motor technology powers everything from HVAC systems to steel mills, and will continue to play a big role in renewable energy technologies, including wind turbines and electric vehicles.

Ludois sees more efficient motors as a way to help conserve energy while meeting the demands of an ever-churning, energy-hungry society. “We’re too addicted to energy to reduce functionality,” Ludois says. “Most of my work is trying to reduce the footprint behind the scenes, transforming established technologies or replacing them using different physical principles, new materials and manufacturing techniques.”

Ludois and his spinoff company C-Motive are interrogating motor technology from two angles: the means of power transfer in motors, and the materials used to make them. In one recent development, C-Motive created a motor that uses electrostatic force rather than magnetic fields to transfer power, thus reducing the need for magnets that are often sourced from rare-earth metals. New motor technology could be relatively easy to implement in many situations, especially because so many motors in the industrial sector essentially just spin along at one speed 24/7. Ludois sees early opportunities in powering industrial machines, including robotic arms, conveyors and presses. “If you can make small changes there, you can have extreme benefits,” he says.

Supply, demand and society
Water is one of the most primal steering forces in human civilization, and UW-Madison’s diverse group of water engineers are focusing on how water will both use and create energy long into the future. Water distribution and wastewater treatment systems are among the largest consumers of energy in the United States, Civil and Environmental Engineering Professor Gregory Harrington points out.

This resonates not only with research, but also in education, as Harrington and his colleagues decide how to best educate future generations of water engineers and oversee a renovation of their water research lab. “The thing we’re hearing from industry is a need to have students better prepared to deal with energy issues in practice,” he says. “It’s not just better ways of generating electricity, it’s thinking about how we can conserve energy.”

Beyond the processes in which water moves through, say, a treatment plant or a dam, water is a huge and often unseen part of the energy equation. “Every energy system that you can think about, except for wind and solar, needs water,” Civil and Environmental Engineering Professor Marc Anderson says. “Nuclear plants need water for cooling. If you have biofuels, you need water to grow those crops.”

And the nature of this “water-energy nexus,” as Anderson calls it, varies wildly from place to place. When it comes to hydropower, the United States is taking down more dams than it’s building, but the developing world is still looking to dams as a major energy source.

The technical problems new dams raise are hard to separate from issues of climate change and regional politics.

This is where Civil and Environmental Engineering Assistant Professor Paul Block comes in. He’s currently using his computer modeling background to analyze the in-the-works Grand Ethiopian Renaissance Dam. When it’s completed, GERD will be the largest in Africa, and its use of the mighty Nile River will have unavoidable impact on Ethiopia’s downstream neighbors. From a technical standpoint, Block is trying to determine the best way to fill the dam’s reservoir, which will divert about 74 billion cubic meters of water from the Blue Nile.

His computer models for this take into account climate change, evaporation and weather, but Block also is working to incorporate the impacts the dam might have on farmers and other stakeholders throughout the region. He is part of an international group of experts ranging from engineers to social scientists—all of whom are striving to produce an empirical context to help inform the debate over the dam. “A
lot of research could be done on a computer behind closed doors, but it really is in a vacuum then,” Block says. “A lot of it still comes back to these priorities. It’s not about pure optimization or the maximum dollar all the time.”

Like many UW-Madison researchers who grapple with energy-related issues, Block believes it’s fundamentally important to be thinking about the tradeoffs society makes as it maps out new energy solutions.
“We want our model to represent the priorities of the people who would use the outcomes from that model,” Block says.

Corradini strikes a similar note in summing up how UW-Madison researchers try to see energy problems and solutions from many angles at once. “All of these things are very much public-good-related, but buried underneath them is a policy discussion, a technology discussion, and a resource discussion,” he says.

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