Solar Energy

Is it worth investing in solar PV with batteries at home?

Published

4 years ago

March 21, 2021

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Is it worth investing in solar PV with batteries at home?

Solar energy is a clean, renewable source of electricity that could potentially play a significant part in fulfilling the world’s energy requirements, but there are still some challenges to fully capitalizing on this potential. Researchers looked into some of the issues that hamper the uptake of solar energy and proposed different policies to encourage the use of this technology.

Installing solar panels to offset energy costs and reduce the environmental impact of their homes has been gaining popularity with homeowners in recent years. On a global scale, an increasing number of countries are similarly encouraging the installation of solar photovoltaics (PV) at residential buildings to increase the share of renewable energy in their energy mix and enhance energy security. Despite the promising advantages this mode of electricity generation offers there are still a number of challenges that need to be overcome.

Batteries to store excess electricity

Solar PV electricity generation peaks during the day when electricity demand is low, resulting in overproduction – especially on weekdays when people are usually not at home. Currently, this excess electricity supply is typically exported to the central electricity grid, but ideally, homes that have solar panels should be able to store overproduction of solar electricity, for example, using batteries, and consume it in the evening when demand is high and there is no solar electricity generation.

The problem is that the investment cost for batteries is currently quite high, which makes it economically unprofitable for consumers to pair their solar PV with a battery. In their new study published in the journal Applied Energy, researchers from IIASA, University College London, UK, and Aalto University, Finland, looked into this challenge and proposed different policies to encourage residential electricity consumers to pair solar PV with battery energy storage.

“We wanted to determine whether investing in residential solar PV combined with battery energy storage could be profitable under current market conditions for residential consumers and what kind of support policies can be used to enhance the profitability of stand-alone batteries or PV-battery systems.

On top if this, we also wanted to compare the system (or regulatory) cost of each PV-battery policy to the benefit of that particular policy for residential consumers who invest in these technologies,” explains lead author Behnam Zakeri, a researcher with the IIASA Energy, Climate, and Environment Program.

Benefits of using battery storage

The study shows that without a battery, homeowners only use 30-40% of the electricity from their solar PV panels, while the rest of the electricity is exported to the grid with very little to no benefit for the owner. With a home battery, the self-consumption of solar PV in the building almost doubles, allowing the residents to reduce electricity imports from the grid by up to 84%, which can in turn help the owner to become less dependent on the grid and electricity prices.

In addition, the researchers found that while PV-batteries are presently not really profitable for residential consumers, they can become so with the implementation of slightly different policies and regulations, even in high-latitude countries where solar irradiation is relatively low.

Energy policies for a decentralized energy system

The authors propose some novel energy storage polices that offer a positive return on investment between 40% and 70% for residential PV-battery storage, depending on the policy. These include, among others that national renewable energy policies adopt more innovative incentives to enhance the economic profitability of decentralized green energy solutions based on the contribution of these systems to the grid.

The results indicate that this can be easily achieved by, for example, rewarding consumers for using their solar PV generation onsite, instead of encouraging them to export the excess solar energy they produce to the grid.

The researchers further posit that the way utility companies and electricity distribution firms generate income today may itself be a hindrance to promoting the self-consumption of renewable energy in buildings, as these companies generally charge consumers for each unit of electricity imported from the grid.

If consumers therefore become independent from the grid, grid operators and utility companies would lose a significant part of their income. Such a scenario calls for new business models and operating modes to guarantee that central utilities do not see decentralized solutions as a threat to their revenues.

In today’s renewable electricity generation environment, capital subsidies are one option to partly pay for investment in batteries. The study points out that these policies are costly for the system, and may not automatically result in system-level benefits as they do not reward the optimal use of batteries. In this regard, Zakeri and his colleagues propose a “storage policy” that rewards residential battery owners to store and discharge electricity whenever the system needs it.

The profitability of PV-battery systems of course also depends on the type of retail pricing mechanism in the system. The findings indicate that dynamic electricity pricing at the consumer side, such as hourly electricity prices with an enhanced gap between off-peak and peak prices, will encourage consumers to use home batteries to benefit from charging at low price hours and discharging the battery when the electricity price is high. This way of operating a home battery could help reduce the pressure on the electricity grid at peak times, which has significant benefits for the system.

“Traditional, central energy structures are transitioning to new systems based on decentralized, renewable energy solutions. This requires more flexible, modern, and effective policies that can guarantee the social and economic benefits of the energy transition. We hope our analysis contributes to a better understanding of the role of some energy policies that can promote decentralized energy solutions,” Zakeri concludes.

Research Report: “Policy options for enhancing economic profitability of residential solar photovoltaic with battery energy storage”

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Solar Energy

Identifying Key Organic-Inorganic Interaction Sites for Enhanced Emission in Hybrid Perovskites via Pressure Engineering

Published

6 hours ago

March 14, 2025

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Identifying Key Organic-Inorganic Interaction Sites for Enhanced Emission in Hybrid Perovskites via Pressure Engineering

by Simon Mansfield

Sydney, Australia (SPX) Mar 14, 2025

A research team from Jilin University has developed a new approach using pressure engineering to pinpoint organic-inorganic interaction sites in non-hydrogen-bonded hybrid metal perovskites. This innovative method provides valuable insight into the photophysical mechanisms governing hybrid perovskites and offers guidance for designing materials with tailored optical properties.

“Previous research has primarily focused on the role of hydrogen bonding in shaping the photophysical properties of hybrid perovskites,” explained Guanjun Xiao, the study’s lead researcher. “However, the lack of investigation into the interaction mechanisms of non-hydrogen-bonded hybrid perovskites has hindered precise material design for targeted applications.”

By employing high-pressure techniques, Xiao and his team studied the specific interaction sites within the non-hydrogen-bonded hybrid perovskite (DBU)PbBr3. Their findings highlighted that the spatial arrangement of Br-N atomic pairs plays a crucial role in influencing organic-inorganic interactions.

The research was published on September 16 in *Research*, a Science Partner Journal launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST). Xiao is a professor at the State Key Laboratory of Superhard Materials at Jilin University.

The study involved synthesizing microrod (DBU)PbBr3 using the hot injection method and systematically analyzing its optical and structural properties under high pressure. The researchers observed that the material’s emission exhibited enhancement and a blue shift under pressure, with photoluminescence quantum yield reaching 86.6% at 5.0 GPa. Additionally, photoluminescence lifetime measurements indicated a suppression of non-radiative recombination under pressure.

A significant discovery was the presence of an abnormally enhanced Raman mode in the pressure range where emission enhancement occurred. “This suggests a potential connection between the two phenomena,” Xiao noted. Further analysis identified the Raman mode as being linked to organic-inorganic interactions, likely associated with N-Br bonding.

To deepen their understanding, the team conducted structural evolution studies under pressure, supported by first-principles calculations. They confirmed that the primary determinants of interaction strength were the spatial arrangement of N and Br atoms, including their distance and dihedral angle. A notable isostructural phase transition at 5.5 GPa altered the primary compression direction, initially strengthening organic-inorganic interactions before leading to a subsequent decrease-trends that aligned with observed optical property changes.

“These findings bridge a significant knowledge gap in understanding organic-inorganic interactions in non-hydrogen-bonded hybrid halides, offering valuable design principles for materials with specific optical performance targets,” Xiao stated.

Research Report:Identifying Organic-Inorganic Interaction Sites Toward Emission Enhancement in Non-Hydrogen-Bonded Hybrid Perovskite via Pressure Engineering

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Solar Energy

Groundbreaking Discovery Links Small Polaron Effect to Enhanced Spin Lifetime in 2D Lead Halide Perovskites

Published

6 hours ago

March 14, 2025

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Groundbreaking Discovery Links Small Polaron Effect to Enhanced Spin Lifetime in 2D Lead Halide Perovskites

by Simon Mansfield

Sydney, Australia (SPX) Mar 14, 2025

Two-dimensional lead halide perovskites have emerged as highly promising materials for optoelectronic applications due to their superior carrier transport and defect tolerance. However, a comprehensive understanding of charge carrier dynamics in these materials has remained elusive, primarily due to their inherently soft polar lattice and pronounced electron-phonon interactions. While extensive studies have characterized charge behavior in bulk three-dimensional perovskites, the unique carrier dynamics of their two-dimensional counterparts have yet to be fully deciphered.

A recent study employed advanced transient spectroscopic methods combined with theoretical modeling to uncover the presence of small polarons in Dion-Jacobson phase 2D perovskites, particularly in the compound (4AMP)PbI4. Researchers determined that strong charge-lattice coupling induces a substantial deformation potential of 123 eV-approximately 30 times greater than those typically observed in conventional 2D and 3D perovskites. This extraordinary interaction significantly influences carrier dynamics within the material.

Utilizing optical Kerr spectroscopy, the research team identified extended polarization response times at room temperature, surpassing 600 ps. The study attributes this prolonged response to the formation of small polarons, which span roughly two-unit cells in size due to the lattice distortions present in the material. Additional investigations involving temperature-dependent phonon studies, spin relaxation analyses, and X-ray diffraction further substantiated the presence of these small polarons. These findings highlight their role in modifying excitonic Coulomb exchange interactions, leading to an up to tenfold increase in spin lifetime.

Implications for Optoelectronic Advancements

This discovery holds considerable promise for the future of optoelectronic device engineering. By elucidating the impact of small polaron formation on spin dynamics, researchers can refine 2D perovskite materials to achieve superior carrier mobility, extended spin lifetimes, and enhanced energy conversion efficiency. Such improvements could accelerate the development of next-generation solar cells, photodetectors, and spintronic devices.

The study also paves the way for tailoring charge-lattice interactions through controlled deformation potential tuning, potentially optimizing perovskite-based device performance. Future investigations may delve deeper into fine-tuning polaronic effects to further capitalize on their benefits in commercial applications.

Future Prospects

This research provides direct evidence of small polaron formation in Dion-Jacobson phase 2D perovskites, underscoring the critical influence of lattice interactions on spin dynamics and optoelectronic efficiency. Continued exploration of these mechanisms is expected to drive the development of novel materials that could redefine perovskite-based optoelectronics. These findings mark a significant step toward realizing energy-efficient, high-performance electronic and photonic devices.

Research Report:Giant deformation potential induced small polaron effect in Dion-Jacobson two-dimensional lead halide perovskites

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Solar Energy

Cheap and environmentally friendly – the next generation LEDs may soon be here

Published

1 day ago

March 13, 2025

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Cheap and environmentally friendly – the next generation LEDs may soon be here

by Anders Torneholm

Linkoping, Sweden (SPX) Mar 13, 2025

Cost, technical performance and environmental impact – these are the three most important aspects for a new type of LED technology to have a broad commercial impact on society. This has been demonstrated by researchers at Linkoping University in a study published in Nature Sustainability.

“Perovskite LEDs are cheaper and easier to manufacture than traditional LEDs, and they can also produce vibrant and intense colours if used in screens. I’d say that this is the next generation of LED technology,” says Feng Gao, professor of optoelectronics at Linkoping University.

However, for a technological shift to take place, where today’s LEDs are replaced with those based on the material perovskite, more than just technical performance is required. That is why Feng Gao’s research group has collaborated with Professor Olof Hjelm and John Laurence Esguerra, assistant professor at LiU. They specialise in how innovations contributing to environmental sustainability can be introduced to the market.

Together, they have investigated the environmental impact and cost of 18 different perovskite LEDs, knowledge that is currently incomplete. The study was conducted using so-called life cycle assessment and techno-economic assessment.

Such analyses require a clear system definition – that is, what is included and not in terms of cost and environmental impact. Within this framework, what happens from the product being created until it can no longer be used is investigated. The life cycle of the product, from cradle to grave, can be divided into five different phases: raw material production, manufacturing, distribution, use and decommissioning.

“We’d like to avoid the grave. And things get more complicated when you take recycling into account. But here we show that it’s most important to think about the reuse of organic solvents and how raw materials are produced, especially if they are rare materials,” says Olof Hjelm.

One example where the life cycle analysis provides guidance concerns the small amount of toxic lead found in perovskite LEDs. This is currently necessary for the perovskites to be effective. But, according to Olof Hjelm, focusing only on lead is a mistake. There are also many other materials in LEDs, such as gold.

“Gold production is extremely toxic. There are byproducts such as mercury and cyanide. It’s also very energy-consuming,” he says.

The greatest environmental gain would instead be achieved by replacing gold with copper, aluminium or nickel, while maintaining the small amount of lead needed for the LED to function optimally.

The researchers have concluded that perovskite LEDs have great potential for commercialisation in the long term. Maybe they can even replace today’s LEDs, thanks to lower costs and less environmental impact. The big issue is longevity. However, the development of perovskite LEDs is accelerating and their life expectancy is increasing. The researchers believe that it needs to reach about 10,000 hours for a positive environmental impact, something they think is achievable. Today, the best perovskite LEDs last for hundreds of hours.

Muyi Zhang, PhD student at the Department of Physics, Chemistry and Biology at LiU, says that much of the research focus so far is on increasing the technical performance of LED, something he believes will change.

“We want what we develop to be used in the real world. But then, we as researchers need to broaden our perspective. If a product has high technical performance but is expensive and isn’t environmentally sustainable, it may not be highly competitive in the market. That mindset will increasingly come to guide our research.”

Research Report:Towards sustainable perovskite light-emitting diodes