Green Energy

A new kind of solar panel, developed at the University of Michigan, has achieved 9% efficiency in converting water into hydrogen and oxygen—mimicking a crucial step in natural photosynthesis. Outdoors, it represents a major leap in the technology, nearly 10 times more efficient than solar water-splitting experiments of its kind. But the biggest benefit is driving down the cost of sustainable hydrogen. This is enabled by shrinking the semiconductor, typically the most expensive part of the device. The team’s self-healing semiconductor withstands concentrated light equivalent to 160 suns. Currently, humans produce hydrogen from the fossil fuel methane, using a great deal of fossil energy in the process. However, plants harvest hydrogen atoms from water using sunlight. As humanity tries to reduce its carbon emissions, hydrogen is attractive as both a standalone fuel and as a component in sustainable fuels made with recycled carbon dioxide. Likewise, it is needed for many chemical processes, producing fertilizers for instance. “In the end, we believe that artificial photosynthesis devices will be much more efficient than natural photosynthesis, which will provide a path toward carbon neutrality,” said Zetian Mi, U-M professor of electrical and computer engineering who led the study reported in Nature. The outstanding result comes from two advances. The first is the ability to concentrate the sunlight without destroying the semiconductor that harnesses the light. “We reduced the size of the semiconductor by more than 100 times compared to some semiconductors only working at low light intensity,” said Peng Zhou, U-M research fellow in electrical and computer engineering and first author of the study. “Hydrogen produced by our technology could be very cheap.” And the second is using both the higher energy part of the solar spectrum to split water and the lower part of the spectrum to provide heat that encourages the reaction. The magic is enabled by a semiconductor catalyst that improves itself with use, resisting the degradation that such catalysts usually experience when they harness sunlight to drive chemical reactions. In addition to handling high light intensities, it can thrive in high temperatures that are punishing to computer semiconductors. Higher temperatures speed up the water splitting process, and the extra heat also encourages the hydrogen and oxygen to remain separate rather than renewing their bonds and forming water once more. Both of these helped the team to harvest more hydrogen. For the outdoor experiment, Zhou set up a lens about the size of a house window to focus sunlight onto an experimental panel just a few inches across. Within that panel, the semiconductor catalyst was covered in a layer of water, bubbling with the hydrogen and oxygen gasses it separated. The catalyst is made of indium gallium nitride nanostructures, grown onto a silicon surface. That semiconductor wafer captures the light, converting it into free electrons and holes—positively charged gaps left behind when electrons are liberated by the light. The nanostructures are peppered with nanoscale balls of metal, 1/2000th of a millimeter across, that use those electrons and holes to help direct the reaction. A simple insulating layer atop the panel keeps the temperature at a toasty 75 degrees Celsius, or 167 degrees Fahrenheit, warm enough to help encourage the reaction while also being cool enough for the semiconductor catalyst to perform well. The outdoor version of the experiment, with less reliable sunlight and temperature, achieved 6.1% efficiency at turning the energy from the sun into hydrogen fuel. However, indoors, the system achieved 9% efficiency. The next challenges the team intends to tackle are to further improve the efficiency and to achieve ultrahigh purity hydrogen that can be directly fed into fuel cells. Some of the intellectual property related to this work has been licensed to NS Nanotech Inc. and NX Fuels Inc., which were co-founded by Mi.

In January 2023, the Caltech Space Solar Power Project (SSPP) is poised to launch into orbit a prototype, dubbed the Space Solar Power Demonstrator (SSPD), which will test several key components of an ambitious plan to harvest solar power in space and beam the energy back to Earth.

Space solar power provides a way to tap into the practically unlimited supply of solar energy in outer space, where the energy is constantly available without being subjected to the cycles of day and night, seasons and cloud cover.

The launch, currently slated for early January, represents a major milestone in the project and promises to make what was once science fiction a reality. When fully realized, SSPP will deploy a constellation of modular spacecraft that collect sunlight, transform it into electricity, then wirelessly transmit that electricity over long distances wherever it is needed—including to places that currently have no access to reliable power.

A Momentus Vigoride spacecraft carried aboard a SpaceX rocket on the Transporter-6 mission will carry the 50-kilogram SSPD to space. It consists of three main experiments, each tasked with testing a different key technology of the project:

• DOLCE (Deployable on-Orbit ultraLight Composite Experiment): A structure measuring 6 feet by 6 feet that demonstrates the architecture, packaging scheme and deployment mechanisms of the modular spacecraft that would eventually make up a kilometer-scale constellation forming a power station;
• ALBA: A collection of 22 different types of photovoltaic (PV) cells, to enable an assessment of the types of cells that are the most effective in the punishing environment of space;
• MAPLE (Microwave Array for Power-transfer Low-orbit Experiment): An array of flexible lightweight microwave power transmitters with precise timing control focusing the power selectively on two different receivers to demonstrate wireless power transmission at distance in space.

An additional fourth component of SSPD is a box of electronics that interfaces with the Vigoride computer and controls the three experiments.

SSPP got its start in 2011 after philanthropist Donald Bren, chairman of Irvine Company and a lifetime member of the Caltech Board of Trustees, learned about the potential for space-based solar energy manufacturing in an article in the magazine Popular Science. Intrigued by the potential for space solar power, Bren approached Caltech’s then-president Jean-Lou Chameau to discuss the creation of a space-based solar power research project.

In 2013, Bren and his wife, Brigitte Bren, a Caltech trustee, agreed to make the donation to fund the project. The first of the donations to Caltech (which will eventually exceed $100 million in support for the project and endowed professorships) was made that year through the Donald Bren Foundation, and the research began.

“For many years, I’ve dreamed about how space-based solar power could solve some of humanity’s most urgent challenges,” Bren says. “Today, I’m thrilled to be supporting Caltech’s brilliant scientists as they race to make that dream a reality.”

The rocket will take approximately 10 minutes to reach its desired altitude. The Momentus spacecraft will then be deployed from the rocket into orbit. The Caltech team on Earth plans to start running their experiments on the SSPD within a few weeks of the launch.

Some elements of the test will be conducted quickly. “We plan to command the deployment of DOLCE within days of getting access to SSPD from Momentus. We should know right away if DOLCE works,” says Sergio Pellegrino, Caltech’s Joyce and Kent Kresa Professor of Aerospace and Professor of Civil Engineering and co-director of SSPP. Pellegrino is also a senior research scientist at JPL, which Caltech manages for NASA.

Other elements will require more time. The collection of photovoltaics will need up to six months of testing to give new insights into what types of photovoltaic technology will be best for this application. MAPLE involves a series of experiments, from an initial function verification to an evaluation of the performance of the system under different environments over time. Meanwhile, two cameras on deployable booms mounted on DOLCE and additional cameras on the electronics box will monitor the experiment’s progress, and stream a feed back down to Earth. The SSPP team hopes that they will have a full assessment of the SSPD’s performance within a few months of the launch.

Numerous challenges remain: nothing about conducting an experiment in space—from the launch to the deployment of the spacecraft to the operation of the SSPD—is guaranteed. But regardless of what happens, the sheer ability to create a space-worthy prototype represents a significant achievement by the SSPP team.

“No matter what happens, this prototype is a major step forward,” says Ali Hajimiri, Caltech’s Bren Professor of Electrical Engineering and Medical Engineering and co-director of SSPP. “It works here on Earth, and has passed the rigorous steps required of anything launched into space. There are still many risks, but having gone through the whole process has taught us valuable lessons. We believe the space experiments will provide us with plenty of additional useful information that will guide the project as we continue to move forward.”

Although solar cells have existed on Earth since the late 1800s and currently generate about 4% of the world’s electricity (in addition to powering the International Space Station), everything about solar power generation and transmission needed to be rethought for use on a large scale in space. Solar panels are bulky and heavy, making them expensive to launch, and they need extensive wiring to transmit power. To overcome these challenges, the SSPP team has had to envision and create new technologies, architectures, materials, and structures for a system that is capable of the practical realization of space solar power, while being light enough to be cost-effective for bulk deployment in space, and strong enough to withstand the punishing space environment.

“DOLCE demonstrates a new architecture for solar-powered spacecraft and phased antenna arrays. It exploits the latest generation of ultrathin composite materials to achieve unprecedented packaging efficiency and flexibility. With the further advances that we have already started to work on, we anticipate applications to a variety of future space missions,” Pellegrino says.

“The entire flexible MAPLE array, as well as its core wireless power transfer electronic chips and transmitting elements, have been designed from scratch. This wasn’t made from items you can buy because they didn’t even exist. This fundamental rethinking of the system from the ground up is essential to realize scalable solutions for SSPP,” Hajimiri says.

The entire set of three prototypes within the SSPD was envisioned, designed, built, and tested by a team of about 35 individuals. “This was accomplished with a smaller team and significantly fewer resources than what would be available in an industrial, rather than academic, setting. The highly talented team of individuals on our team has made it possible to achieve this,” says Hajimiri.

Those individuals, however—a collection of graduate students, postdocs, and research scientists—now represent the cutting edge in the burgeoning space solar power field. “We’re creating the next generation of space engineers,” says SSPP researcher Harry A. Atwater, Caltech’s Otis Booth Leadership Chair of the Division of Engineering and Applied Science and the Howard Hughes Professor of Applied Physics and Materials Science, and director of the Liquid Sunlight Alliance, a research institute dedicated to using sunlight to make liquid products that could be used for industrial chemicals, fuels, and building materials or products.

Success or failure from the three testbeds will be measured in a variety of ways. The most important test for DOLCE is that the structure completely deploys from its folded-up configuration into its open configuration. For ALBA, a successful test will provide an assessment of which photovoltaic cells operate with maximum efficiency and resiliency. MAPLE’s goal is to demonstrate selective free-space power transmission to different specific targets on demand.

“Many times, we asked colleagues at JPL and in the Southern California space industry for advice about the design and test procedures that are used to develop successful missions. We tried to reduce the risk of failure, even though the development of entirely new technologies is inherently a risky process,” says Pellegrino.

SSPP aims to ultimately produce a global supply of affordable, renewable, clean energy. More about SSPP can be found on the program’s website.

Net zero is the balance between the amount of greenhouse gas produced and the amount removed from the atmosphere.

You can achieve net zero when the amount we add is no more than the amount taken away.

A contractor in Cape Coral has put a house on the market that is completely solar-powered.

The house on SW First Place is unique because if you turn on the lights it isn’t FPL or LCEC powering it up for you.

“Net zero the official definition is you make as much power as you use. And so that zeroes out your energy usage,” Erin Shine, the homeowner said.

Meaning, the home generates as much power as it uses. The home was originally built in 1984, but in 2023, it operates on solar energy.

“If you go through the list, you can save about 10 to 20 maybe 30% on your bill with efficiency first and then you fill in the rest with solar energy,” Shine said.

After renting out the home to several families, Shine felt it was time to put it on the market.

His goal is to find the perfect buyer who can benefit from the overall energy savings.

Peter Davis, of John R. Wood Properties, might be that person, and he is up for the challenge.

“It takes a particular type of buyer who is interested in sustainability, in solar in, you know, cutting their costs, energy costs, and bills. And so, I think there’ll be a market for it, especially if we prove this concept as I think we will,” Davis said.

The three-bedroom, two-bathroom is listed for $439,000.

Davis told WINK News he priced the property at about 20% more than the average nearby home without solar panels.

He explained it’s a good example of where the market could go in the future.

“I think this is a great case study for what can be done. And it’s been you know, it’s been successful. And it can be replicated in Cape Coral, and, and all-around Florida really because of the abundant sunshine,” Davis said.

The house has been on the market for about a week.

Whoever the new owner is could save up to 30% in energy costs just with efficiency alone.

Even before Christmas Day attacks on power substations in five states in the Pacific Northwest and Southeast, similar incidents of attacks, vandalism and suspicious activity were on the rise. Federal energy reports through August—the most recent available—show an increase in physical attacks at electrical facilities across the nation this year, continuing a trend seen since 2017. At least 108 human-related events were reported during the first eight months of 2022, compared with 99 in all of 2021 and 97 in 2020. More than a dozen cases of vandalism have been reported since September. The attacks have prompted a flurry of calls to better protect the nation’s power grid, but experts have warned for more than three decades that stepped-up protection was needed. Twice this year, the Department of Homeland Security warned “a heightened threat environment” remains for the nation, including its critical infrastructure. A USA TODAY analysis of reports that utilities provided to the Department of Energy through August show:

• At least 20 actual physical attacks were reported, compared with six in all of 2021.
• Suspicious-activity reports jumped three years ago, nearly doubling in 2020 to 32 events. In the first eight months of this year, 34 suspicious incidents were reported.
• Total human-related incidents—including vandalism, suspicious activity and cyber events—are on track to be the highest since the reports started showing such activity in 2011.

Since September, attacks or potential attacks have been reported on at least 18 additional substations and one power plant in Florida, Oregon, Washington and the Carolinas. Several involved firearms.

• In Florida: Six “intrusion events” occurred at Duke Energy substations in September, resulting in at least one brief power outage, according to the News Nation television network, which cited a report the utility sent to the Energy Department. Duke Energy spokesperson Ana Gibbs confirmed a related arrest, but the company declined to comment further.
• In Oregon and Washington state: Substations were attacked at least six times in November and December, with firearms used in some cases, local news outlets reported. On Christmas Day, four additional substations were vandalized in Washington State, cutting power to more than 14,000 customers.
• In North Carolina: A substation in Maysville was vandalized on Nov. 11. On Dec. 3, shootings that authorities called a “targeted attack” damaged two power substations in Moore County, leaving tens of thousands without power amid freezing temperatures.
• In South Carolina: Days later, gunfire was reported near a hydropower plant, but police said the shooting was a “random act.”

It’s not yet clear whether any of the attacks were coordinated. After the North Carolina attacks, a coordinating council between the electric power industry and the federal government ordered a security evaluation. The FBI is looking into some of the attacks, but it hasn’t said how many it’s investigating or where. Shelley Lynch, a spokesperson for the FBI’s Charlotte field office, confirmed the bureau was investigating the North Carolina attack. The Kershaw County Sheriff’s Office reported the FBI was looking into the South Carolina incident. Utilities in Oregon and Washington told news outlets they were cooperating with the FBI, but spokespeople for the agency’s Seattle and Portland field offices said they couldn’t confirm or deny an investigation. In January, the Department of Homeland Security said domestic extremists had been developing “credible, specific plans” since at least 2020 and would continue to “encourage physical attacks against electrical infrastructure.” In February, three men who ascribed to white supremacy and Neo-Nazism pleaded guilty to federal crimes related to a scheme to attack the grid with rifles. In a news release, Timothy Langan, assistant director of the FBI’s Counterterrorism Division, said the defendants “wanted to attack regional power substations and expected the damage would lead to economic distress and civil unrest.” Industry experts, federal officials and others have warned in one report after another since at least 1990 that the power grid was at risk, said Granger Morgan, an engineering professor at Carnegie Mellon University who chaired three National Academies of Sciences reports. The reports urged state and federal agencies to collaborate to make the system more resilient to attacks and natural disasters such as hurricanes and storms. “The system is inherently vulnerable. It’s spread all across the countryside,” which makes the lines and substations easy targets, Morgan said. The grid includes more than 7,300 power plants, 160,000 miles of high-voltage power lines and 55,000 transmission substations. One challenge is that there’s no single entity whose responsibilities span the entire system, Morgan said. And the risks are only increasing as the grid expands to include renewable energy sources such as solar and wind, he said.

Emerging forms of thin-film device technologies that rely on alternative semiconductor materials, such as printable organics, nanocarbon allotropes and metal oxides, could contribute to a more economically and environmentally sustainable internet of things (IoT), a KAUST-led international team suggests.

Their paper is published in the journal Nature Electronics.

The IoT is set to have a major impact on daily life and many industries. It connects and facilitates data exchange between a multitude of smart objects of various shape and size—such as remote-controlled home security systems, self-driving cars equipped with sensors that detect obstacles on the road, and temperature-controlled factory equipment—over the internet and other sensing and communications networks.

This burgeoning hypernetwork is projected to reach trillions of devices by the next decade, boosting the number of sensor nodes deployed in its platforms.

Current approaches used to power sensor nodes rely on battery technology, but batteries need regular replacement, which is costly and environmentally harmful over time. Also, the current global production of lithium for battery materials may not keep up with the increasing energy demand from the swelling number of sensors.

Wirelessly powered sensor nodes could help achieve a sustainable IoT by drawing energy from the environment using so-called energy harvesters, such as photovoltaic cells and radio-frequency (RF) energy harvesters, among other technologies. Large-area electronics could be key in enabling these power sources.

KAUST alumn Kalaivanan Loganathan, with Thomas Anthopoulos and coworkers, assessed the viability of various large-area electronic technologies and their potential to deliver ecofriendly, wirelessly powered IoT sensors.

Large-area electronics have recently emerged as an appealing alternative to conventional silicon-based technologies thanks to significant progress in solution-based processing, which has made devices and circuits easier to print on flexible, large-area substrates. They can be produced at low temperatures and on biodegradable substrates such as paper, which makes them more ecofriendly than their silicon-based counterparts.

Over the years, Anthopoulos’ team has developed a range of RF electronic components, including metal-oxide and organic polymer-based semiconductor devices known as Schottky diodes. “These devices are crucial components in wireless energy harvesters and ultimately dictate the performance and cost of the sensor nodes,” Loganathan says.

Key contributions from the KAUST team include scalable methods for manufacturing RF diodes to harvest energy reaching the 5G/6G frequency range. “Such technologies provide the needed building blocks toward a more sustainable way to power the billions of sensor nodes in the near future,” Anthopoulos says.

The team is investigating the monolithic integration of these low-power devices with antenna and sensors to showcase their true potential, Loganathan adds.

Lithium ion batteries are widely used as energy storage systems for electronic products and electric vehicles. However, they are vulnerable to ignition as they are manufactured mainly with flammable organic liquid electrolytes, and safety issues continue to be raised.

On the other hand, oxide-based solid electrolytes have the advantage of having high thermal stability and physically preventing the growth of lithium dendrites. Among them, the Li7La3Zr2O12 (LLZO) electrolyte is considered as a next-generation electrolyte due to its excellent lithium ion conductivity.

Despite these advantages, the LLZO electrolyte has a problem—lithium carbonate forms on the surface due to reaction with moisture and carbon dioxide when exposed to the atmosphere. Lithium carbonate is formed on the surface and then grows along the grain boundaries, penetrating into the solid electrolyte and disturbing the transfer of lithium ions, which lowers the lithium ion conductivity of the LLZO solid electrolyte.

Professor Lee Jong-won’s team of the Department of Energy Science and Engineering at DGIST, together with Professor Moon Jang-hyeok’s team from the Chung-Ang University, announced the development of solid electrolytes with enhanced atmospheric stability.

The research team improved the atmospheric stability of the LLZO electrolyte through the hetero-elemental doping of gallium and tantalum (i.e., by adding gallium and tantalum to pure LLZO electrolytes). In particular, it was verified that LiGaO2, a third material formed through the addition of gallium, suppresses the surface adsorption of moisture and carbon dioxide, and promotes the growth of particles during thermal treatment, thus preventing growth of lithium carbonate through grain boundaries and maintaining the lithium ion conduction properties of LLZO electrolytes.

As a result, it was empirically verified that lithium ion conductivity is maintained even when stored for a long time in the air, and stable performance was maintained even after repeated lithium electrodeposition/desorption.

DGIST Department of Energy Science and Engineering Professor Jong-Won Lee said, “I expect the solid electrolyte design concept presented by this research team to be helpful in developing high-performance/high-safety all-solid-state batteries incorporating solid electrolytes, which are stable in the atmosphere and have high lithium ion conductivity.”