Solar Energy

Floating solar farms could help reduce impacts of climate change on lakes and reservoirs

Published

4 years ago

March 29, 2021

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Floating solar farms could help reduce impacts of climate change on lakes and reservoirs

Floating solar farms could help to protect lakes and reservoirs from some of the harms of climate change, a new study suggests.

However, given the complex nature of water bodies and differing designs of solar technologies, there could also be detrimental ecosystem impacts of deploying floating solar arrays.

Conventional solar farms are controversial due to the amount of land they take up. This is leading to increasing interest in floating solar farms – making use of the additional space that bodies of water provide.

So far, there are three commercial-size floating solar arrays in the UK, and hundreds more across the world. The number of installations is likely to grow significantly in coming decades as demand rises for renewable energy sources with more countries committing to net zero carbon targets.

However, little is known about the impacts – both positive and negative – these floating solar farms are having on the lakes and reservoirs they are installed on – until now.

Scientists from Lancaster University and the University of Stirling have completed the first detailed modelling of the environmental effects of floating solar installations on bodies of water.

“As demand for land increases, water bodies are increasingly being targeted for renewable energy. Deployment of solar on water increases electricity production, but it is critical to know if there will be any positive or negative environmental consequences,” said Mr Giles Exley, PhD researcher and lead author from Lancaster University.

“Given the relative immaturity of floating solar farms, it is important to further scientific evidence of the impacts. Our results provide initial insight of the key effects that will help inform water body manager and policy maker decisions.”

The research team undertook computer modelling using the MyLake simulation programme and data collected by the UK’s Centre for Ecology and Hydrology from England’s largest lake, Windermere. Although the researchers believe it is unlikely floating solar farms will be deployed on Windermere, it presents a rich data-set as it is one of the most comprehensively studied lakes in the world.

Their results show that floating solar arrays can cool water temperatures by shading the water from the sun. At scale, this could help to mitigate against harmful effects caused by global warming, such as blooms of toxic blue green algae, and increased water evaporation, which could threaten water supply in some regions.

The scientists found that floating solar installations also reduce the duration of ‘stratification’ – this is where the sun heats the water, forming distinct layers of water at different temperatures. This tends to happen more in the warmer summer months and can result in the bottom layer of water becoming deoxygenated, which deteriorates water quality – an obvious issue for supplies of drinking water. However, the picture is complex and there are also conditions under which stratification, and therefore detrimental water quality impacts, could increase if floating solar farms are deployed.

Mr Exley said: “The effects of floating solar on the temperature of the water body and stratification, both of which are major drivers of biological and chemical processes, could be comparable in magnitude to the changes lakes will experience with climate change. Floating solar could help to mitigate against the negative effects global warming will have on these bodies of water.”

“However, there are also real risks of detrimental impacts, such as deoxygenation causing undesirable increases in nutrient concentrations and killing fish. We need to do more research to understand the likelihood of both positive and negative impacts.”

The effects on water temperature increased the larger the solar installation, with small arrays of less than ten per cent of the lake surface generally having minimal impacts. However, this model concentrated on one lake. Further studies will be needed to determine the optimum size array, and design, and their effects for individual lakes and reservoirs – all of which have unique characteristics. Different designs of solar installations also have different shading and sheltering effects for the sun and wind.

Arrays covering more than 90 per cent of a lake could increase the chances of the lake freezing over in winter, the study found – though these effects would also be specific to the body of water and design of the installation and require further studying.

Field studies and further modelling work to build on these initial findings is ongoing.

Research Report: “Floating photovoltaics could mitigate climate change impacts on water body temperature and stratification'”

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Solar Energy

Scientists Probe Declining Earbud Battery Longevity

Published

2 days ago

February 5, 2025

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Scientists Probe Declining Earbud Battery Longevity

by Clarence Oxford

Los Angeles CA (SPX) Feb 05, 2025

Have you ever noticed how electronic devices, including wireless earbuds, seem to lose battery capacity faster the longer you use them? An international research team from The University of Texas at Austin set out to examine this familiar issue, known as battery degradation, by focusing on the earbuds that many people rely on daily. Through a series of x-ray, infrared, and other imaging approaches, the researchers investigated the hidden complexities behind these tiny devices and revealed why their battery life declines over time.

“This started with my personal headphones; I only wear the right one, and I found that after two years, the left earbud had a much longer battery life,” said Yijin Liu, an associate professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, who led the new research published in Advanced Materials. “So, we decided to look into it and see what we could find.”

Their analysis showed that crucial earbud features – like the Bluetooth antenna, microphones, and circuits – compete with the battery in a very confined space, producing a microenvironment that is less than ideal. This situation results in a temperature gradient that damages the battery over time, with different sections of the cell experiencing variable temperatures.

Real-world factors also complicate matters. Frequent changes in climate, shifts in air quality, and a host of other environmental variables challenge the battery’s resilience. While cells are generally designed to endure harsh conditions, constant fluctuations can take their toll.

These discoveries highlight the importance of considering how batteries interact with devices such as phones, laptops, and even electric vehicles. Packaging solutions, strategic design decisions, and adaptations for user habits may all play a role in extending battery performance.

“Using devices differently changes how the battery behaves and performs,” said Guannan Qian, the first author of this paper and a postdoctoral researcher in Liu’s lab. “They could be exposed to different temperatures; one person has different charging habits than another; and every electric vehicle owner has their own driving style. This all matters.”

In conducting this study, Liu and his team worked closely with UT’s Fire Research Group, led by mechanical engineer Ofodike Ezekoye. They paired infrared imaging methods with their in-house x-ray technology at UT Austin and Sigray Inc. To expand their scope, they then teamed up with some of the world’s most advanced x-ray facilities.

Their collaborators included researchers from SLAC National Accelerator Laboratory’s Stanford Synchrotron Radiation Lightsource, Brookhaven National Laboratory’s National Synchrotron Light Source II, Argonne National Laboratory’s Advanced Photon Source, and the European Synchrotron Radiation Facility (ESRF) in France. These partnerships allowed them to observe battery behavior under more authentic operating conditions.

“Most of the time, in the lab, we’re looking at either pristine and stable conditions or extremes,” said Xiaojing Huang, a physicist at Brookhaven National Laboratory. “As we discover and develop new types of batteries, we must understand the differences between lab conditions and the unpredictability of the real world and react accordingly. X-ray imaging can offer valuable insights for this.”

Looking ahead, Liu says his team will continue analyzing battery performance in the settings people experience every day. They plan to expand their approach to larger batteries, such as those in smartphones, laptops, and electric vehicles, to learn more about their degradation patterns.

Research Report:In-device Battery Failure Analysis

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Solar Energy

Quantum factors elevate plant energy transport efficiency

Published

2 days ago

February 5, 2025

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Quantum factors elevate plant energy transport efficiency

by Robert Schreiber

Munich, Germany (SPX) Feb 05, 2025

For countless engineers, converting sunlight into easily stored chemical energy stands as an enduring goal. Yet nature perfected this challenge billions of years ago. A recent study reveals that quantum mechanics, once thought to be limited to physics, is also essential for key biological processes.

Green plants and other photosynthetic organisms draw on quantum mechanical mechanisms to capture the sun’s energy. According to Prof. Jurgen Hauer: “When light is absorbed in a leaf, for example, the electronic excitation energy is distributed over several states of each excited chlorophyll molecule; this is called a superposition of excited states. It is the first stage of an almost loss-free energy transfer within and between the molecules and makes the efficient onward transport of solar energy possible. Quantum mechanics is therefore central to understanding the first steps of energy transfer and charge separation.”

Classical physics alone cannot completely describe how this phenomenon unfolds throughout green plants and in certain photosynthetic bacteria. Although the exact details remain only partly understood, Prof. Hauer and first author Erika Keil consider their new findings an important step toward uncovering how chlorophyll, the pigment behind leaf coloration, functions. Applying these insights to engineered photosynthesis devices could unlock unprecedented solar energy conversion efficiencies for both power production and photochemical applications.

In their investigation, the researchers focused on two portions of the light spectrum absorbed by chlorophyll: the low-energy Q band (yellow to red) and the high-energy B band (blue to green). In the Q region, two electronic states are quantum mechanically coupled, promoting virtually loss-free energy movement. The system subsequently relaxes via “cooling”, i.e. by releasing energy in the form of heat. These observations demonstrate that quantum mechanical processes can play a major role in shaping key biological functions.

Research Report:Reassessing the role and lifetime of Qx in the energy transfer dynamics of chlorophyll a

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Solar Energy

HZB sets new efficiency record for CIGS perovskite tandem solar cells

Published

2 days ago

February 5, 2025

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HZB sets new efficiency record for CIGS perovskite tandem solar cells

by Robert Schreiber

Berlin, Germany (SPX) Feb 05, 2025

Researchers at Helmholtz Center Berlin for Materials and Energy (HZB) and Humboldt University Berlin have developed a CIGS-perovskite tandem solar cell that has set a new world record for efficiency, achieving 24.6%. The performance of the cell has been officially certified by the Fraunhofer Institute for Solar Energy Systems.

Thin-film solar cells, such as those based on copper, indium, gallium, and selenium (CIGS), require minimal material and energy to manufacture, making them an environmentally friendly alternative to conventional silicon-based solar cells. CIGS thin films can also be applied to flexible substrates, expanding their potential applications.

The new tandem solar cell developed by HZB and Humboldt University combines a CIGS bottom cell with a perovskite top cell. By optimizing the contact layers between these two components, the research team successfully increased efficiency to a record-breaking 24.6%. This milestone was confirmed by the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany.

This achievement was made possible through a collaborative effort among researchers. The top cell was developed by Thede Mehlhop, a master’s student at TU Berlin, under the supervision of Stefan Gall. The perovskite absorber layer was created in the joint laboratory of HZB and Humboldt University Berlin, while the CIGS sub-cell and contact layers were fabricated by HZB researcher Guillermo Farias Basulto. Additionally, the KOALA high-performance cluster system at HZB was used to deposit the perovskite and contact layers in a vacuum.

“At HZB, we have highly specialized laboratories and experts who are top performers in their fields. With this world record tandem cell, they have once again shown how fruitfully they work together,” said Prof. Rutger Schlatmann, spokesman for the Solar Energy Department at HZB.

HZB has a strong track record in achieving world records in solar cell efficiency, including past accomplishments in silicon-perovskite tandem cells and now in CIGS-perovskite tandem technology.

“We are confident that CIGS-perovskite tandem cells can achieve much higher efficiencies, probably more than 30%,” said Prof. Rutger Schlatmann.