Record efficiency milestone reached in ecofriendly organic solar technology

by Riko Seibo

Tokyo, Japan (SPX) Apr 30, 2025

As global momentum builds toward sustainable energy solutions, researchers have made a major breakthrough in solar technology by developing all-organic solar cells with record-setting efficiency. Unlike conventional silicon or perovskite solar cells, which pose environmental hazards due to their metallic and toxic components, these carbon-based alternatives promise cleaner disposal and reduced costs.

Led by Associate Professor Masahiro Nakano from Kanazawa University’s Institute of Science and Engineering, in partnership with REIKO Co., Ltd. and Queen’s University at Kingston, the team successfully engineered organic solar cells that achieve 8.7% power conversion efficiency (PCE) – more than double the previous benchmark of 4%.

This leap in performance overcomes two longstanding technological barriers. First, earlier organic solar cells lacked suitable transparent electrodes that could be produced without harming the device’s organic layers. Conventional fabrication methods relied on corrosive chemicals or temperatures exceeding 150oC. The team instead utilized the conductive polymer PEDOT:PSS to produce transparent electrodes at just 80oC, without strong acids or bases, achieving sheet resistance below 70 O/sq.

Second, traditional solution-based processes risk damaging underlying layers when stacking new films. The researchers addressed this by creating a lamination technique using carbon nanotube electrodes. These electrodes are fabricated independently and then affixed to the solar cell, preserving the integrity of internal layers during assembly.

The implications of this innovation are significant. All-organic solar cells are lightweight, flexible, and free from hazardous materials, making them ideal for use in agriculture, wearable technology, and installations where traditional panels are impractical. The research team aims to further boost efficiency by enhancing the conductivity of organic electrode materials.

Research Report:Unlocking High-Performance in All-Organic Solar Cells by the Development of Organic Electrodes with no Acid and High-Temperature Treatment and the Effective Preparation Thereof on Organic Multi-layer Films

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Photovoltaic rooftops could supply over one third of Vitoria Gasteiz energy needs

by Hugo Ritmico

Madrid, Spain (SPX) Apr 30, 2025

In a new study by the University of the Basque Country (UPV/EHU), researchers found that rooftop solar installations in Vitoria-Gasteiz could supply up to 38% of the city’s annual electricity consumption. The analysis highlights rooftop photovoltaic systems as a key renewable energy strategy for urban decarbonization, especially where land availability is limited.

The research assessed the energy potential of rooftops across the capital of Alava-Araba, concluding that half of the total rooftop area is viable for solar installations. “In contrast to large-scale photovoltaic projects in rural zones, we aimed to understand the capacity of already urbanized environments, avoiding further land use impacts,” said lead researcher Alex Tro.

A major advance in this study is the deployment of a new high-precision methodology developed by Ekopol at UPV/EHU. This approach leverages open-source Geographic Information Systems (GIS) software to assess rooftop potential using detailed local data rather than generalized assumptions. The tool incorporates variables such as building orientation, shading, tilt, solar radiation, ambient temperatures, and the projected efficiency and lifespan of photovoltaic panels.

Unlike standard assessments focused solely on economic return, the study introduces an energy viability filter based on Energy Return on Investment (EROI). This ensures that only rooftops capable of generating more energy than is consumed during panel installation and operation are considered viable. “This innovative criterion allows us to exclude technically possible but energetically inefficient installations,” Tro explained.

Findings also show that solar generation potential is significantly higher on the city’s outskirts, where rooftops are less obstructed by surrounding buildings. Central areas, dense with tall structures, pose greater challenges due to shadowing and spatial limitations.

The methodology, which uses publicly accessible data, is designed to be easily replicated for urban energy planning in other cities. It calculates solar output potential down to each square meter of rooftop area, offering a practical planning tool for municipalities and energy agencies.

Tro emphasized that while rooftop photovoltaics offer meaningful contributions, they are not a standalone solution. “Even under ideal implementation scenarios, solar rooftops alone cannot satisfy current urban energy demands. Real progress will also require systemic changes, such as shifting consumption habits and embracing an eco-social transition,” he said.

Research Report:A methodology for assessing rooftop solar photovoltaic potential using GIS open-source software and the EROI constraint

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University of the Basque Country

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China says wind and solar energy capacity exceeds thermal for first time

By Sam Davies and Luna Lin

Beijing (AFP) April 25, 2025

China’s wind and solar energy capacity has surpassed that of mostly coal-powered thermal for the first time, the national energy body said Friday.

China, the world’s largest emitter of greenhouse gases that drive climate change, has pledged to peak carbon emissions by 2030 and achieve carbon neutrality by 2060.

While around 60 percent of China’s energy comes from coal, the country is also a renewable energy powerhouse, building almost twice as much wind and solar capacity as every other country combined, according to research published last year.

“In the first quarter of 2025, China’s newly installed wind and photovoltaic power capacity totalled 74.33 million kilowatts, bringing the cumulative installed capacity to 1.482 billion kilowatts,” the national energy body said.

That surpassed the installed capacity of thermal power (1.451 billion kilowatts) for the first time.

President Xi Jinping said on Wednesday that “no matter how the international situation changes”, the country’s efforts to combat climate change “will not slow down”.

Xi also said China would announce its 2035 greenhouse gas reduction commitments, known as Nationally Determined Contributions (NDCs), before COP30 in November and that it would cover all greenhouse gases, not just carbon dioxide.

President Donald Trump meanwhile has pulled the United States, the world’s second-largest polluter, out of the Paris climate accord while pledging a vast expansion in fossil fuel exploitation.

-‘Structural change’-

China’s new milestone comes as the country experiences explosive growth in renewable energy.

Last year, China added a record 357 gigawatts of wind and solar, 10 times the US’s additions.

It met a 2030 target to install 1,200 GW of solar and wind capacity almost six years early.

Friday’s announcement said that wind and solar additions in the first quarter had “far exceeded” China’s total increase in electricity consumption.

“This trend is very likely to continue in the following months and quarters in 2025,” Yao Zhe, Global Policy adviser at Greenpeace East Asia, told AFP.

That suggests China’s power sector is undergoing “structural change and the sector’s carbon emissions are one small step away from peaking”.

However, coal continues to play a key role in China’s energy mix.

“The intermittency of variable renewables like wind and solar… means it’s generally inappropriate to compare them to firm, dispatchable power sources like coal,” according to David Fishman, senior manager at the Lantau Group.

“There is indeed some combination of wind plus solar plus storage that equals one coal plant, but the determination is different everywhere in the world.”

And China’s energy consumption continues to grow — by 4.3 percent last year.

Covering that growth with renewable power is a “tough proposition for a developing country with a huge heavy industrial segment and a residential population that frankly doesn’t even use that much electricity on a per capita basis”, Fishman said.

Despite the renewable energy boom, China also began construction on 94.5 gigawatts of coal power projects in 2024, 93 percent of the global total, according to a February report from the Finland-based Centre for Research on Energy and Clean Air (CREA) and Global Energy Monitor (GEM) in the United States.

China’s coal production has risen steadily in recent years, from 3.9 billion tons in 2020 to 4.8 billion tons in 2024.

That is despite Xi pledging to “strictly control” coal power before “phasing it down” between 2026 and 2030.

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