Electric Boats Could Be Floating Batteries for Island Microgrids

Electric Boats Could Be Floating Batteries for Island Microgrids

Trending Technologies   August 17, 2019

Researchers in Australia have developed a control algorithm that allows electric boats equipped with solar panels to sell power to a microgrid

In developed countries, lights roar to life with the flick of a switch and televisions hum quietly with the touch of a button—given you still have one of those. But on most of Indonesia’s remote islands, accessing electricity is neither simple nor convenient. 

For example—prior to 2018, diesel generators provided residents of East Kalimantan’s Berau district with electricity for just four hours a day. That June, a government-backed organization installed new hybrid microgrids, enabling residents to have electricity all day long, PV magazine reported. These hybrid microgrids were composed of photovoltaic solar panels (PVs) to collect energy and lithium-ion batteries to store it. 

But there may be another way to power remote islands, especially in the aftermath of natural disasters: boats. Yes, boats.

Researchers at the University of New South Wales in Sydney, Australia created an algorithm that can theoretically turn electric boats into small renewable power plants. They tested the algorithm with a microgrid in their lab, using four 6-volt gel batteries connected in a 24-V series as a stand-in for a boat. 

In their experiment, they found that the algorithm could manage power flows reliably enough to allow electric boats to provide peak load support to a grid directly after a trip.  

To implement this approach, they’d need an electric boat with its own PV system, which would charge the boat’s batteries when the boat was adrift. Then when the boat is docked, it could act as a small power plant, providing electricity to homes on the island. 

With the algorithm in place, boat owners could decide when to sell electricity—and how much they wanted to sell. They might, for example, set their system to automatically sell 10 per cent of its stored energy, and only if the batteries are at least halfway charged. 

Boats are uniquely positioned to provide this kind of service, the researchers point out. Electric cars don’t generally have their own PV system. So instead of adding power to the grid-like, a boat could, electric cars draw from it. 

The proposed technology works pretty similarly to the microgrids that are gradually rolling out in Indonesia—those microgrids also contain PVs to collect energy and lithium-ion batteries to store it. But there’s one key difference: portability. 

If Indonesia were hit with a natural disaster, those microgrids could be destroyed. Even Indonesia’s widely electrified islands may be impacted. With the new approach, the Indonesian government could use the boats it sent with food and supplies to also provide power. 

The concept is still in its infancy, but the University of New South Wales team expects to get its algorithm out of the lab and into the ocean by testing it with an actual electric boat in the near future.

Content Credits :IEEE Spectrum

Technique identifies electricity-producing bacteria

Technique identifies electricity-producing bacteria

Research   January 13, 2019

Microbes screened with a new microfluidic process might be used in power generation or environmental cleanup.

Living in extreme conditions requires creative adaptations. For certain species of bacteria that exist in oxygen-deprived environments, this means finding a way to breathe that doesn’t involve oxygen. These hardy microbes, which can be found deep within mines, at the bottom of lakes, and even in the human gut, have evolved a unique form of breathing that involves excreting and pumping out electrons. In other words, these microbes can actually produce electricity.

Scientists and engineers are exploring ways to harness these microbial power plants to run fuel cells and purify sewage water, among other uses. But pinning down a microbe’s electrical properties has been a challenge: The cells are much smaller than mammalian cells and extremely difficult to grow in laboratory conditions.

Now MIT engineers have developed a microfluidic technique that can quickly process small samples of bacteria and gauge a specific property that’s highly correlated with bacteria’s ability to produce electricity. They say that this property, known as polarizability, can be used to assess a bacteria’s electrochemical activity in a safer, more efficient manner compared to current techniques.

“The vision is to pick out those strongest candidates to do the desirable tasks that humans want the cells to do,” says Qianru Wang, a postdoc in MIT’s Department of Mechanical Engineering.

“There is recent work suggesting there might be a much broader range of bacteria that have [electricity-producing] properties,” adds Cullen Buie, associate professor of mechanical engineering at MIT. “Thus, a tool that allows you to probe those organisms could be much more important than we thought. It’s not just a small handful of microbes that can do this.”

Buie and Wang have published their results today in Science Advances.

Just between frogs

Bacteria that produce electricity do so by generating electrons within their cells, then transferring those electrons across their cell membranes via tiny channels formed by surface proteins, in a process known as extracellular electron transfer, or EET.

Existing techniques for probing bacteria’s electrochemical activity involve growing large batches of cells and measuring the activity of EET proteins — a meticulous, time-consuming process. Other techniques require rupturing a cell in order to purify and probe the proteins. Buie looked for a faster, less destructive method to assess bacteria’s electrical function.

For the past 10 years, his group has been building microfluidic chips etched with small channels, through which they flow microliter-samples of bacteria. Each channel is pinched in the middle to form an hourglass configuration. When a voltage is applied across a channel, the pinched section — about 100 times smaller than the rest of the channel — puts a squeeze on the electric field, making it 100 times stronger than the surrounding field. The gradient of the electric field creates a phenomenon known as dielectrophoresis, or a force that pushes the cell against its motion induced by the electric field. As a result, dielectrophoresis can repel a particle or stop it in its tracks at different applied voltages, depending on that particle’s surface properties.

Researchers including Buie have used dielectrophoresis to quickly sort bacteria according to general properties, such as size and species. This time around, Buie wondered whether the technique could suss out bacteria’s electrochemical activity — a far more subtle property.

“Basically, people were using dielectrophoresis to separate bacteria that were as different as, say, a frog from a bird, whereas we’re trying to distinguish between frog siblings — tinier differences,” Wang says.

An electric correlation

In their new study, the researchers used their microfluidic setup to compare various strains of bacteria, each with a different, known electrochemical activity. The strains included a “wild-type” or natural strain of bacteria that actively produces electricity in microbial fuel cells, and several strains that the researchers had genetically engineered. In general, the team aimed to see whether there was a correlation between a bacteria’s electrical ability and how it behaves in a microfluidic device under a dielectrophoretic force.

The team flowed very small, microliter samples of each bacterial strain through the hourglass-shaped microfluidic channel and slowly amped up the voltage across the channel, one volt per second, from 0 to 80 volts. Through an imaging technique known as particle image velocimetry, they observed that the resulting electric field propelled bacterial cells through the channel until they approached the pinched section, where the much stronger field acted to push back on the bacteria via dielectrophoresis and trap them in place.

Some bacteria were trapped at lower applied voltages, and others at higher voltages. Wang took note of the “trapping voltage” for each bacterial cell, measured their cell sizes, and then used a computer simulation to calculate a cell’s polarizability — how easy it is for a cell to form electric dipoles in response to an external electric field.  

From her calculations, Wang discovered that bacteria that were more electrochemically active tended to have a higher polarizability. She observed this correlation across all species of bacteria that the group tested.

“We have the necessary evidence to see that there’s a strong correlation between polarizability and electrochemical activity,” Wang says. “In fact, polarizability might be something we could use as a proxy to select microorganisms with high electrochemical activity.”

Wang says that, at least for the strains they measured, researchers can gauge their electricity production by measuring their polarizability — something that the group can easily, efficiently, and nondestructively track using their microfluidic technique.

Collaborators on the team are currently using the method to test new strains of bacteria that have recently been identified as potential electricity producers.

“If the same trend of correlation stands for those newer strains, then this technique can have a broader application, in clean energy generation, bioremediation, and biofuels production,” Wang says. 

This research was supported in part by the National Science Foundation, and the Institute for Collaborative Biotechnologies, through a grant from the U.S. Army.

Explaining the plummeting cost of solar power

Explaining the plummeting cost of solar power

Research   November 20, 2018

Researchers uncover the factors that have caused photovoltaic module costs to drop by 99 percent.

Photos show a solar installation from 1988 (left) and a present-day version. Though the basic underlying technology is the same, a variety of factors have contributed to a hundredfold decline in costs. Now, researchers have identified the relative importance of these different factors.

The dramatic drop in the cost of solar photovoltaic (PV) modules, which has fallen by 99 percent over the last four decades, is often touted as a major success story for renewable energy technology. But one question has never been fully addressed: What exactly accounts for that stunning drop?

A new analysis by MIT researchers has pinpointed what caused the savings, including the policies and technology changes that mattered most. For example, they found that government policy to help grow markets around the world played a critical role in reducing this technology’s costs. At the device level, the dominant factor was an increase in “conversion efficiency,” or the amount of power generated from a given amount of sunlight.

The insights can help to inform future policies and evaluate whether similar improvements can be achieved in other technologies. The findings are being reported today in the journal Energy Policy, in a paper by MIT Associate Professor Jessika Trancik, postdoc Goksin Kavlak, and research scientist James McNerney.

The team looked at the technology-level (“low-level”) factors that have affected cost by changing the modules and manufacturing process. Solar cell technology has improved greatly; for example, the cells have become much more efficient at converting sunlight to electricity. Factors like this, Trancik explains, fall in a category of low-level mechanisms that deal with the physical products themselves.

The team also estimated the cost impacts of “high-level” mechanisms, including learning by doing, research and development, and economies of scale. Examples include the way improved production processes have cut the number of defective cells produced and thus improved yields, and the fact that much larger factories have led to significant economies of scale.

The study, which covered the years 1980 to 2012 (during which module costs fell by 97 percent), found that there were six low-level factors that accounted for more than 10 percent each of the overall drop in costs, and four of those factors accounted for at least 15 percent each. The results point to “the importance of having many different ‘knobs’ to turn, to achieve a steady decline in cost,” Trancik says. The more different opportunities there are to reduce costs, the less likely it is that they will be exhausted quickly.

The relative importance of the factors has changed over time, the study shows. In earlier years, research and development was the dominant cost-reducing high-level mechanism, through improvements to the devices themselves and to manufacturing methods. For about the last decade, however, the largest single high-level factor in the continuing cost decline has been economies of scale, as solar-cell and module manufacturing plants have become ever larger.

“This raises the question of which factors can help continue the cost decline,” Trancik says. “What are the limits to the size of the plants?”

In terms of government policy, Trancik says, policies that stimulated market growth accounted for about 60 percent of the overall cost decline, so “that played an important part in reducing costs.” Policies stimulating market growth globally included measures such as renewable portfolio standards, feed-in tariffs, and a variety of subsidies. Government-funded research and development in various nations accounted for the other 40 percent — although public R&D played a larger part in the earlier years, she says.

This is important information, she adds, because “for a long time there has been a debate about whether these policies work — were they really driving technological improvement? Now, we can not only answer that question, we can say by how much.”

This finding, which is based on modeling device-level mechanisms rather than purely correlational analysis, provides strong evidence of a “virtuous cycle” that can be created between technology innovation and policies to reduce emissions, Trancik says. As emissions policies are implemented, low-carbon technology markets grow, technologies improve, and the costs of future emissions reductions can decline. “This analysis helps us understand why this happens, and how strong the feedbacks can be.”

Trancik and her co-workers plan to apply similar methodology to analyzing other technologies, such as nuclear power, as well as the other parts of solar installations — the so-called balance of systems, including the mounting structures and power controllers needed for the solar modules — which were not included in this study. “The method we developed can be used as a tool to assess costs of different technologies, both retrospectively and prospectively,” Kavlak says.

“This opens up a different way of modeling technological change, from the device level all the way up to policy measures, and everything in between,” Trancik says. “We’re opening up the black box of technological innovation.”

“Going forward, we can improve our intuition about what factors in general make technologies improve quickly. The application of this tool to solar PV is just the beginning of what we can do,” McNerney says.

While the study focused on past performance, the factors it identified suggest that “it does look like there are opportunities for further cost improvements with this technology.” The findings also suggest that researchers should continue working on alternative technologies to crystalline silicon, which is the dominant form of solar photovoltaic technology today, but many other varieties are being actively explored with potentially higher efficiencies or lower materials costs.

The study also highlights the importance of continuing the progress in improving the efficiency of the manufacturing systems, whose role in driving down costs has been important. “There are likely more gains to be had in this direction,” Trancik says.

Gregory Nemet, a professor of public affairs at the University of Wisconsin at Madison, who was not involved in the study, says, “This work is important in that it identifies that the growth in demand for solar PV in the past 15 years was the most important driver of the astounding cost reductions over that period. Policies in Japan, Germany, Spain, California, and China drove the growth of the market and created opportunities for automation, scale, and learning by doing.”

Nemet adds, “Their model is simple and general, which could make it useful for designing policies for other technologies that will be needed to address climate change and other energy-related problems.”

The research was supported by the U.S. Department of Energy.

Source MIT News

A novel way to advance a better battery design

A novel way to advance a better battery design

Trending Technologies   November 14, 2018

Led by “Queen of Batteries” Christina Lampe-Onnerud, Cadenza Innovation is licensing its lithium-ion battery cell architecture to manufacturers around the world. Cadenza Innovation Founder and CEO Christina Lampe-Onnerud at the World Economic Forum’s Annual Meeting of the New Champions.

Cadenza Innovation has developed a new design that improves the performance, cost, and safety of large lithium-ion batteries. Now, with an unusual strategy for disseminating that technology, the company is poised to have an impact in industries including energy grid storage, industrial machines, and electric vehicles.

Rather than produce the batteries itself, Cadenza licenses its technology to manufacturers producing batteries for diverse applications. The company also works with licensees to both optimize their manufacturing processes and sell the new batteries to end users. The strategy ensures that the four-year-old company’s technology is deployed more quickly and widely than would otherwise be possible.

For Cadenza founder Christina Lampe-Onnerud, a former MIT postdoc and a battery industry veteran of more than 20 years, the goal is to help advance the industry just as the global demand for batteries reaches an inflection point.

“The crazy idea at the time [of the company’s founding] was to see if there was a different way to engage with the industry and help it accept a new technology in existing applications like cars or computers,” Lampe-Onnerud says. “Our thought was, if we really want to have an impact, we could inspire the industry to use existing capital deployed to get a better technology into the market globally and be a positive part of the climate change arena.”

With that lofty goal in mind, the Connecticut-based company has secured partnerships with organizations at every level of the battery supply chain, including suppliers of industrial minerals, original equipment manufacturers, and end users. Cadenza has demonstrated its proprietary “supercell” battery architecture in Fiat’s 500e car model and is in the process of completing a demonstration energy storage system to be used by the New York Power Authority, the largest state public utility company in the U.S., when energy demand is at its peak.

The company’s most significant partnership to date, however, was announced in September with Shenzen BAK Battery Company, one of the world’s largest lithium-ion battery manufacturers. The companies announced BAK would begin mass producing batteries based on Cadenza’s supercell architecture in the first half of 2019.

The supercell architecture

Lampe-Onnerud’s extensive contacts in the lithium-ion battery space and a world-renown technical team have quickened the pace of Cadenza’s rise, but the underlying driver of the company’s success is simple economics: Its technology has been shown to offer manufacturers increased energy density in battery cells while reducing production costs.

The majority of rechargeable lithium ion batteries are powered by cylindrical sheets of metal known as “jelly rolls.” For use in big batteries, jelly rolls can be made either large, to limit the total cost of the battery assembly, or small, to leverage a more efficient cell design that brings higher energy density. Many electric vehicle (EV) companies use large jelly rolls to avoid the durability and safety concerns that come with tightly packing small jelly rolls into a battery, which can lead to the failure of the entire battery if one jelly roll overheats.

Tesla famously achieves longer vehicle ranges by using small jelly rolls in its batteries, addressing safety issues with cooling tubes, intricate circuitry, and by spacing out each roll. But Cadenza has patented a simpler battery system it calls the “supercell,” that allows small jelly rolls to be tightly packed together into one module.

The key to the supercell is a noncombustible ceramic fiber material that each jelly roll sits in like an egg in a carton. The material helps to control temperature throughout the cell and isolate damage caused by an overheated jelly roll. A metal shunt wrapped around each jelly roll and a flame retardant layer of the supercell wall that relieves pressure in the case of a thermal event add to its safety advantages.

The enhanced safety allows Cadenza to package the jelly rolls tightly for greater energy density, and the supercell’s straightforward design, which leverages many parts that are currently manufactured at low costs and high volumes, keeps production costs down. Finally, each supercell module is designed to click together like LEGO blocks, making it possible for manufacturers to easily scale their battery sizes to fit customer needs.

Cadenza’s safety, cost, and performance features were validated during a grant program with the Advanced Research Projects Agency-Energy (ARPA-E), which gave the company nearly $4 million to test the architecture beginning in 2013.

When the supercell architecture was publicly unveiled in 2016, Lampe-Onnerud made headlines by saying it could be used to boost the range of Tesla’s cars by 70 per cent. Now the goal is to get manufacturers to adopt the architecture.

“There will be many winners using this technology,” Lampe-Onnerud says. “We know we can deliver on the [safety, performance, and cost] claims. It’s going to be up to the licensee to decide how they leverage these advantages.”

At MIT, where “data gets to speak”

Lampe-Onnerud and her husband, Per Onnerud, who serves as Cadenza’s chief technology officer, held postdoctoral appointments at MIT after earning their PhDs at Uppsala University in their home country of Sweden. Lampe-Onnerud did lab work in inorganic chemistry in close collaboration with MIT materials science and mathematics professors, while Onnerud did research in the Department of Materials Science and Engineering. The experience left a strong impression on Lampe-Onnerud.

“MIT was a very formative experience,” she says. “You learn how to argue a point so that the data gets to speak. You just enable the data; there’s no spin. MIT has a special place in my heart.”

Lampe-Onnerud has maintained a strong connection with the Institute ever since, participating in alumni groups, giving guest lectures on campus, and serving as a member of the MIT Corporation visiting committee for the chemistry department — all while finding remarkable success in her career.

Lampe-Onnerud founded Boston-Power in 2004, which she grew into an internationally recognized manufacturer of batteries for consumer electronics, vehicles, and industrial applications while serving as the CEO until the company moved operations to China in 2012. In the early stages of the company, more than seven years after Lampe-Onnerud had finished her postdoc work, she discovered the enduring nature of support from the MIT community.

“We started looking for some angel investors, and one of the first groups that responded were the angels affiliated with MIT,” Lampe-Onnerud says. “We support each other because we tend to be attracted to intractable problems. It’s very much in the MIT spirit: We know, if we’re trying to solve big problems, it’s going to be difficult. So we like to collaborate.”

The high-profile experience at Boston Power earned her distinctions including the Technology Pioneer Award from the World Economic Forum, and Swedish Woman of the Year from the Swedish Women’s Educational Association. It also led some to deem her the “Queen of Batteries.”

Immediately after leaving Boston-Power, Lampe-Onnerud and her husband went to work on what would be Cadenza’s supercell architecture in their garage. They wanted to create a solution that would help lower the world’s carbon footprint, but they estimated that, at most, they’d be able to build one gigafactory every 18 months if they were to manufacture the batteries themselves. So they decided to license the technology instead.

The strategy has tradeoffs from a business perspective: Cadenza has needed to raise much less capital than Boston-Power but will allow licensees to generate top line and bottom-line growth while it receives a percentage of sales. Lampe-Onnerud is clearly happy to leverage her global network and share the upside to maximize Cadenza’s impact.

“My hope is that we are able to bring people together around this technology to do things that are really important, like taking down our carbon footprint, eliminating NOx [nitrogen oxide] emissions, or improving grid efficiency,” Lampe-Onnerud says. “It’s a different way to work together, so when an element of this ecosystem wins, we all win. It has been an inspiring process.”

Content Credits:  Massachusetts Institute of Technology

Researchers combine 3D-printed hydrogels and origami to create an electric eel-inspired power source

Researchers combine 3D-printed hydrogels and origami to create an electric eel-inspired power source

Trending Technologies   October 30, 2018

Animal-inspired technology has gone electric. These brightly coloured, 3D-printed gels have the potential to create up to 110 volts of electricity in an instant, similar to the electric eel.

Rows of small hydrogel dots are packed with positively and negatively charged ions that combine together to mimic an electric eel’s cellular structure. Printing and stacking these hydrogels produces the highest amount of voltage, while a connection to a larger contact area produces the highest current. Scientists are hoping that this system could potentially lead to a device that generates power from inside of the human body.

“The electric eel is able to create very, very large amounts of power. And we thought that this was remarkable,” said Anirvan Guha, one of the researchers on the project, designed at the University of Fribourg in Switzerland.  “So we started to think about whether or not we could create a system that could generate electricity in the same way.”

An eel’s unique ability comes from a specialized organ housing thousands of cells called electrocytes. The chemical makes up of these cells allows for a positive or negative charge. The surrounding membranes control the charge by allowing ions to pass through, inciting an electric reaction, or by blocking the ions and returning the organ to a neutral, dormant state. 

When an eel is threatened or stalking prey, a neural impulse is sent to the membranes in the electrocytes, and positive ions flood into the cells. In a second, the electric voltage in each cell can go from zero millivolts to 150 millivolts, producing a total of up to 600 volts.

This new power generator works in a similar way.

It uses four different types of hydrogels to mimic the eel’s electrical system. One with a high salt concentration, one with a low salt concentration, and two charged membranes—one negative and one positive.

The first attempt at putting this system together involved using a fluidic autosampler that pushed the gels into a sequence in tubes. The more gels in a sequence, the higher the voltage. But the researchers couldn’t build an array long enough to produce the desired voltage.

So the researchers moved on to 3D printing.  They printed a sequence of about 2,500 gels on two plastic sheets the size of regular printer paper. When they connected two gel papers, they were able to produce 110 volts of charge within seconds.

This was a huge jump in electricity from the previous method, but the current was still too low for most practical applications.

At the suggestion of a colleague, they tried connecting the gels through a Miura-ori fold, a type of origami fold that allows the gels to stack on a folded sheet. The gels connect simultaneously with a large contact area, more closely resembling the geometry of the eel’s cells.  This method increased the current and prevented energy waste by decreasing the time it took for the gels to connect.

Guha says he and his team would love to find a way to make the hydrogels thinner, which would allow for an even higher current. They imagine that one day this system, or one like it, could be used to power internal biological devices such as pacemakers.

“Because the power source is ionic gradients,” Guha says, “our hope is that you could implant one of these devices and the power could be maintained from the ionic gradients within the human body.”

Content Credits: Christina Dabney