Solar Energy

War is speeding Ukraine’s green energy shift: CEO

Published

1 week ago

January 26, 2025

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War is speeding Ukraine’s green energy shift: CEO

By Sophie ESTIENNE

Davos, Switzerland (AFP) Jan 23, 2025

Russia’s invasion is forcing Ukraine to speed up its green energy transition as a way to secure its electricity supply and infrastructure against attacks, the head of Ukraine’s biggest private electricity provider said.

“Building wind farms or solar farms is not only about decarbonisation. It’s about also energy security and resilience,” Maxim Timchenko, chief executive of DTEK, told AFP at the World Economic Forum on Wednesday.

“It’s much harder to hit and switch off these power stations than thermal or hydro,” he said.

Russia has repeatedly targeted Ukraine’s energy system as part of its nearly three-year war waged on its neighbour.

Timchenko announced at the Davos gathering what he called the biggest private investment in Ukraine since Moscow launched its invasion in 2022: A 450 million euro ($468 million) deal to buy 64 wind turbines from Denmark’s Vestas.

The turbines will expand DTEK’s Tyligulska wind farm on the Black Sea coast.

Turbines also offer the advantage of coming online rapidly and progressively as they are installed, with some of the new ones from Vestas churning out power as soon as this year.

“I hope that by, before next winter we will add already 60 megawatts of capacity with this program,” with full capacity of 500 megawatts at Tyligulska reached by the end of 2026.

That would be enough to supply around 900,000 homes, he said.

– ‘More resilient’ –

The project underscores Ukraine’s push to reduce its reliance on fossil fuels or nuclear energy to operate huge power plants for an extensive grid, which are both particularly exposed to Russian airstrikes.

The country’s infrastructure has often been targeted and crippled, leading to blackouts or emergency voltage reductions — so-called “brownouts” — that are especially painful during the winter.

“This transition from… a highly centralised, highly vulnerable energy system to clean, decentralised, more resilient, and new in terms of technology system… this transition is accelerated by the war,” Timchenko said.

DTEK also announced two weeks ago a deal with a German-American group Fluence to build what Timchenko called the first industrial-scale battery storage project in Ukraine.

That project is targeted for October, and the company is in talks with potential partners for two other wind parks.

The hope is that smaller renewable energy sites spread across the country will reduce the system’s vulnerability as well as emissions.

And an attack would have to destroy all of a wind farm’s turbines to completely shut it down.

Wind and solar currently generate 10 percent of Ukraine’s needs and coal or gas-fired plants produce 20 percent, with nuclear plants the main provider at 55 percent.

“These investments make us more resilient. We feel much more confident that the Russians will not destroy this new power station in such extent that they can do it withe thermals,” Timchenko said of the Tyligulska expansion.

“Basically all our power stations were attacked for several times during 2024,” he noted, with substations and transmission lines also targeted.

Nonetheless he said DTEK had managed to recover much of the lost capacity, and currently 50 to 60 percent is operational.

“Taking into account that we have a drop of consumption since the beginning of the war, this capacity together with support of imports of power is enough to avoid any blackouts,” Timchenko said.

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VESTAS WIND SYSTEMS

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Solar Energy

Advancing safer lithium energy storage

Published

1 day ago

February 4, 2025

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Advancing safer lithium energy storage

by Erica Marchand

Paris, France (SPX) Feb 04, 2025

Charging our phones has become so routine that we rarely reflect on the breakthrough that made it possible. Rechargeable lithium-ion batteries, introduced commercially in the 1990s, propelled a technological revolution that earned their creators the 2019 Nobel Prize in Chemistry. This key innovation underpins the functionality of today’s smartphones, wireless headphones, and electric vehicles, making them both financially and environmentally practical.

As our devices grow more advanced, the demand for batteries that pack more power while remaining safe continues to rise. Yet engineering such power sources is far from simple. One promising design is the lithium metal battery, which could deliver more stored energy than standard battery types. Unfortunately, its potential is curtailed by a persistent issue: the emergence of tiny threads, or dendrites, that accumulate with each charge. When dendrites build up, they can form metallic connections that degrade battery functionality and pose a serious fire hazard. Until recently, researchers had limited approaches to probe and understand dendrite formation. In a new study led by Dr. Ayan Maity in the lab of Prof. Michal Leskes at the Weizmann Institute of Science’s Molecular Chemistry and Materials Science Department, scientists developed a novel method to identify the factors that spark dendrite growth, as well as to rapidly evaluate various battery components for improved safety and performance.

Rechargeable batteries function by allowing positively charged ions to migrate between the anode (negative electrode) and the cathode (positive electrode) through an electrolyte. Charging forces the ions back into the anode, counter to the usual flow in a typical chemical reaction, thus preparing the battery for another cycle of use. Lithium metal batteries take a different approach by employing a pure lithium metal anode, enabling higher energy storage. However, lithium metal is chemically reactive and quickly forms dendrites when it interacts with the electrolyte. Over time, enough dendrites can short-circuit the battery and raise the likelihood of combustion.

One way to avoid fire risks is to replace the volatile liquid electrolyte with a solid, nonflammable one, often comprising a polymer-ceramic composite. While altering the ratio of polymer to ceramic can influence dendrite growth, finding the ideal formulation remains a challenge for extending battery life.

To investigate, the team employed nuclear magnetic resonance (NMR) spectroscopy, a standard tool for pinpointing chemical structures, and tracked both dendrite formation and the chemical interplay within the electrolyte. “When we examined the dendrites in batteries with differing ratios of polymer and ceramic, we found a kind of ‘golden ratio’: Electrolytes that are composed of 40 percent ceramic had the longest lives,” Leskes explains. “When we went above 40 percent ceramic, we encountered structural and functional problems that impeded battery performance, while less than 40 percent led to reduced battery life.” Intriguingly, batteries with that optimal ratio displayed more dendrites overall, but those dendrites were effectively confined in a way that prevented destructive bridging.

These insights prompted a larger question: what halts the extension of the dendrites? The team hypothesized that a thin covering on the surface of dendrites, called the solid electrolyte interphase (SEI), might be crucial. This layer, formed when dendrites interact with the electrolyte, can affect how lithium ions travel through the battery, and it can also either prevent or accelerate the movement of harmful substances between electrodes. Both of these factors, in turn, can stifle or foster further dendrite development.

Probing the chemical composition of such thin SEI films is inherently difficult, since they measure only a few dozen nanometers thick. The researchers tackled this problem by enhancing the signals in their NMR data using dynamic nuclear polarization. This specialized technique leverages the strong spin of polarized lithium electrons, bolstering signals from the atomic nuclei in the SEI and exposing its chemical makeup. Through this refined lens, the researchers discovered precisely how lithium metal interacts with polymer or ceramic materials, revealing that certain SEI layers can simultaneously improve ion transport and block hazardous substances.

Their findings pave the way to design sturdier, safer, and more powerful batteries that will store greater energy for a longer duration with reduced environmental and economic costs. Such next-generation batteries could power larger devices without having to increase the physical size of the battery itself, while also extending the battery’s life cycle.

“One of the things I love most about this study is that, without a profound scientific understanding of fundamental physics, we would not have been able to understand what happens inside a battery. Our process was very typical of the work here at the Weizmann Institute. We started with a purely scientific question that had nothing to do with dendrites, and this led us to a study with practical applications that could improve everybody’s life,” Leskes says.

Research Report:Tracking dendrites and solid electrolyte interphase formation with dynamic nuclear polarization-NMR spectroscopy

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Solar Energy

Role of barrier films in maintaining the stability of perovskite solar cells

Published

2 days ago

February 3, 2025

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Role of barrier films in maintaining the stability of perovskite solar cells

by Riko Seibo

Tokyo, Japan (SPX) Jan 31, 2025

Perovskite solar cells (PSCs) offer a promising advancement in renewable energy due to their high efficiency, lightweight, and flexible properties. However, their commercial viability is challenged by their vulnerability to environmental conditions, particularly heat and humidity.

To tackle this issue, a research team led by Professor Takashi Minemoto, a Fellow at the Ritsumeikan Advanced Research Academy, alongside Dr. Abdurashid Mavlonov from Ritsumeikan University’s Research Organization of Science and Technology and Dr. Akinobu Hayakawa from Sekisui Chemical Co., Ltd., conducted an in-depth study on the durability of PSC modules under harsh environmental conditions. Their research, published in Volume 286 of *Solar Energy* on January 15, 2025, was first made available online on December 17, 2024.

Discussing the study’s motivation, Prof. Minemoto stated, “Perovskite solar cells stand out as particularly promising due to their low-temperature wet-coating process and compatibility with flexible substrates, offering unique opportunities for the solar industry. However, the stability of perovskite is weak compared with conventional material, which can be improved by fabrication processes such as encapsulation with barrier films.”

For this research, the team analyzed the durability of flexible PSC modules made from methylammonium lead iodide (MAPbI3) and encapsulated them using polyethylene terephthalate (PET) substrates with barrier films of varying water vapor transmission rates (WVTR). These modules were subjected to a damp heat test at 85 C and 85% relative humidity to replicate long-term outdoor conditions.

After 2,000 hours of exposure, researchers measured photovoltaic (PV) performance and assessed module degradation using current-voltage characteristics, spectral reflectance, and electroluminescence imaging. The findings confirmed that high humidity caused the MAPbI3 layer to break down into lead iodide, obstructing charge transport and significantly reducing the efficiency of the PSC modules.

Moreover, the study demonstrated the critical role of barrier films in maintaining module stability. Notably, the module with the lowest WVTR barrier retained 84% of its initial power conversion efficiency, whereas modules with higher WVTR deteriorated rapidly, ceasing to function after just 1,000 hours.

“Our study is the first to report the durability of encapsulated flexible MAPbI3-based PSC modules. When considering solar energy applications for walls and rooftops with weight limits or for mobile platforms, flexible PSCs are a great alternative to the traditional silicon panels. Insights from our study could help industries optimize these modules for highly stable and durable constructs,” explained Prof. Minemoto.

This research underscores the essential role of barrier films in ensuring the long-term viability of flexible PSC modules, which could reshape the photovoltaic industry. By enabling energy generation in a variety of locations, these advancements help alleviate pressure on power grids. Additionally, enhancing the durability of PSCs expands their usability across different environments, further accelerating the global transition to cleaner and more sustainable energy solutions.

Research Report:Perovskite solar cell modules: Understanding the device degradation via damp heat testing

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Solar Energy

Enhancing Durability and Efficiency in Tin-based Perovskite Solar Cells

Published

2 days ago

February 3, 2025

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Enhancing Durability and Efficiency in Tin-based Perovskite Solar Cells

by Riko Seibo

Tokyo, Japan (SPX) Jan 30, 2025

Tin-based perovskite solar cells are being hailed as a promising alternative for next-generation solar energy solutions due to their high efficiency, flexibility, and the potential for low-cost printing. However, replacing lead with tin to avoid environmental issues linked to lead toxicity presents its own challenges. Tin’s propensity to oxidize quickly results in reduced performance and durability compared to lead-based counterparts.

Researchers have developed a method to enhance the stability of tin-based perovskite by incorporating large organic cations into the perovskite structure. This results in a unique two-dimensional layered configuration known as Ruddlesden-Popper (RP) tin-based perovskites. Despite its potential, the precise internal structure and the mechanism through which this configuration improves performance have remained unclear.

In this study, researchers employed electron spin resonance (ESR) to analyze the internal behavior of the RP perovskite solar cell during operation at a microscopic level. Their findings revealed two key insights about the interaction of the materials under different conditions.

First, when the RP perovskite solar cell was not exposed to light, the holes in the hole transport layer diffused into the RP perovskite. This movement created an energy barrier at the interface between the hole transport layer and the RP tin perovskite, preventing electron backflow and leading to better performance.

Second, when exposed to sunlight, the high-energy electrons produced by short-wavelength light (such as ultraviolet rays) moved from the RP tin perovskite to the hole transport layer. This transfer further elevated the energy barrier, thereby enhancing the device’s efficiency.

Understanding the mechanisms behind these performance improvements is crucial for developing tin-based perovskite solar cells with greater efficiency and longer lifespans. These findings could provide important insights for future advancements in the field of solar energy.

Research Report:Operando spin observation elucidating performance-improvement mechanisms during operation of Ruddlesden-Popper Sn-based perovskite solar cells