Solar Energy

Study finds plants would grow well in solar cell greenhouses

Published

4 years ago

March 18, 2021

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Study finds plants would grow well in solar cell greenhouses

A recent study shows that lettuce can be grown in greenhouses that filter out wavelengths of light used to generate solar power, demonstrating the feasibility of using see-through solar panels in greenhouses to generate electricity.

“We were a little surprised – there was no real reduction in plant growth or health,” says Heike Sederoff, co-corresponding author of the study and a professor of plant biology at North Carolina State University. “”It means the idea of integrating transparent solar cells into greenhouses can be done.””

Because plants do not use all of the wavelengths of light for photosynthesis, researchers have explored the idea of creating semi-transparent organic solar cells that primarily absorb wavelengths of light that plants don’t rely on, and incorporating those solar cells into greenhouses. Earlier work from NC State focused on how much energy solar-powered greenhouses could produce. Depending on the design of the greenhouse, and where it is located, solar cells could make many greenhouses energy neutral – or even allow them to generate more power than they use.

But, until now, it wasn’t clear how these semi-transparent solar panels might affect greenhouse cropsTo address the issue, researchers grew crops of red leaf lettuce (Lactuca sativa) in greenhouse chambers for 30 days – from seed to full maturity. The growing conditions, from temperature and water to fertilizer and CO2 concentration, were all constant – except for light.

A control group of lettuces was exposed to the full spectrum of white light. The rest of the lettuces were dived into three experimental groups. Each of those groups was exposed to light through different types of filters that absorbed wavelengths of light equivalent to what different types of semi-transparent solar cells would absorb.
“The total amount of light incident on the filters was the same, but the color composition of that light was different for each of the experimental groups,” says Harald Ade, co-corresponding author of the study and the Goodnight Innovation Distinguished Professor of Physics at NC State.

“Specifically, we manipulated the ratio of blue light to red light in all three filters to see how it affected plant growth,” Sederoff says.

To determine the effect of removing various wavelengths of light, the researchers assessed a host of plant characteristics. For example, the researchers paid close attention to visible characteristics that are important to growers, grocers and consumers, such as leaf number, leaf size, and how much the lettuces weighed. But they also assessed markers of plant health and nutritional quality, such as how much CO2 the plants absorbed and the levels of various antioxidants.

“Not only did we find no meaningful difference between the control group and the experimental groups, we also didn’t find any significant difference between the different filters,” says Brendan O’Connor, co-corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State.

“”There is also forthcoming work that delves into greater detail about the ways in which harvesting various wavelengths of light affects biological processes for lettuces, tomatoes and other crops,” Sederoff says.

“”This is promising for the future of solar-powered greenhouses,” Ade says. “Getting growers to use this technology would be a tough argument if there was a loss of productivity. But now it is a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and savings.””

“Based on the number of people who have contacted me about solar-powered greenhouses when we’ve published previous work in this space, there is a lot of interest from many growers,” O’Connor says. “I think that interest is only going to grow. We’ve seen enough proof-of-concept prototypes to know this technology is feasible in principle, we just need to see a company take the leap and begin producing to scale.””

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Solar Energy

Huge US lithium mine gets govt approval

Published

2 days ago

October 25, 2024

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Huge US lithium mine gets govt approval

By Romain FONSEGRIVES

Los Angeles, United States (AFP) Oct 24, 2024

An enormous lithium mine in the Nevada desert was granted final government approval Thursday in a project the miner predicts will quadruple US production of a mineral critical to the renewable energy revolution.

Operations at Rhyolite Ridge will produce enough lithium to supply the batteries for more than 370,000 electric vehicles every year, Australian operator Ioneer said.

The plant will create 500 construction jobs over the next few years and 350 jobs during its decades of extraction, the company said.

“There are few deposits in the world as impactful as Rhyolite Ridge,” said Ioneer Executive Chairman James Calaway, heralding the permit issued Thursday by the Bureau of Land Management.

The company’s managing director, Bernard Rowe, said construction would begin next year.

“This permit gives us a license to commence construction in 2025 and begin our work in creating hundreds of good-paying rural jobs, generating millions in tax revenue for Esmeralda County, and bolstering the domestic production of critical minerals,” he said.

The news comes less than two weeks before Americans go to the polls to elect a new president, and will be welcomed in Nevada, where unemployment is well above the national average.

The administration of President Joe Biden has made the green transition a key plank of its economic policy, investing heavily in technologies aimed at slashing the pollution that is causing the climate to change.

Scientists say electric vehicles are a vital link in that chain, and their widespread adoption in the car-dependent US will be vital if the country is to meet its carbon reduction targets.

Biden has tried to nudge the US auto industry to re-tool and shift production away from gas-guzzlers and into electric cars, in a move he says will help create jobs at home.

Subsidies for consumers have rewarded automakers who produce EVs in the United States, even while they struggle to source lithium batteries — a sector dominated by strategic rival China.

But the project at Rhyolite Ridge has highlighted the trade-off between the need to adapt energy sources and the desire to protect the planet’s biodiversity.

Campaigners say the mine will threaten the unique habitat of the endangered Tiehm’s Buckwheat — a rare wildflower with delicate cream-colored blossoms that grows only in this corner of Nevada.

“By greenlighting this mine the Bureau of Land Management is abandoning its duty to protect endangered species like Tiehm’s Buckwheat and it’s making a mockery of the Endangered Species Act,” said Patrick Donnelly of the Center for Biological Diversity, a nonprofit conservation group.

“We need lithium for the energy transition, but it can’t come with a price tag of extinction.”

Ioneer admits that over the years the mine is in operation around a fifth of the flower’s habitat will be directly affected.

But the company, which has spent $2.5 million researching the plant, says mining will not affect its survival, insisting their experiments show it is already growing well in greenhouses.

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Solar Energy

Eramet suspends battery recycling project in France

Published

2 days ago

October 25, 2024

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Eramet suspends battery recycling project in France

By Isabel MALSANG

Paris (AFP) Oct 24, 2024

French mining firm Eramet said Thursday it was suspending plans to build a battery recycling plant, the second such project in France to fall through in a month as the electric vehicle sector struggles.

Batteries for electric cars are packed with costly critical minerals and recycling these to lower costs and make them more sustainable is a key challenge.

Eramet was looking to build a facility that would have been able to separate the minerals out from the black powder that used batteries are initially transformed into.

While the sale of new internal combustion engine cars is supposed to end in Europe in just over a decade, the shift towards electric vehicles has seen a setback recently with consumer demand flagging.

Battery manufacturers have since put expansion plans on hold, with firms that aim to recycle used batteries now following suit.

“Due to the lack of ramp-up in Europe of battery factories and their components… there are currently major uncertainties about the supply of raw materials to the plant, and about recycling opportunities for the metallic salts,” Eramet said in a statement.

“The required conditions for pursuing a hydro- metallurgical battery recycling plant project in France are therefore not met, and the Group has decided to suspend the project,” it added.

Company officials said if the project went forward it would likely have to export the minerals to Asia, which would not make economic sense.

Eramet’s partner Suez said it would go forward with building a plant outside Paris to break down used car batteries.

Last month carmaker Stellantis and mining group Orano similarly shelved plans to develop a battery recycling facility in France.

im-ngu/rl/sbk

ERAMET

Stellantis

SUEZ

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Solar Energy

New efficiency record set for eco-friendly nanocrystal solar cells

Published

2 days ago

October 25, 2024

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New efficiency record set for eco-friendly nanocrystal solar cells

by Erica Marchand

Paris, France (SPX) Oct 25, 2024

As climate change accelerates the shift towards renewable energy sources, solar cells are becoming increasingly vital. Solar power generation in Spain, for instance, grew by 28% in 2023 compared to the previous year, contributing to 20.3% of the country’s total energy mix. However, despite their widespread adoption, solar cells still rely on materials that are not always environmentally sustainable. Expanding solar technology to a broader range of applications, such as powering buildings, infrastructure, and vehicles, requires the development of flexible, lightweight, and cost-effective solar cells.

Colloidal silver bismuth sulfide (AgBiS2) nanocrystals have recently emerged as a promising eco-friendly material for ultra-thin solar cells. These nanocrystals possess an exceptionally high absorption coefficient, but current manufacturing techniques for such solar cells rely on multi-step processes that are costly and inefficient. A new single-step approach using nanocrystal inks could streamline production, but defects on the nanocrystal surfaces have limited efficiency.

To address this issue, researchers at the Institute of Photonic Sciences (ICFO), led by ICREA Prof. Gerasimos Konstantatos, have developed an innovative post-deposition in situ passivation (P-DIP) technique. This method enhances surface passivation, leading to nanocrystal ink films with superior optoelectronic properties. Their work, published in “Energy and Environmental Science”, achieved a power conversion efficiency of around 10%, surpassing the performance of previous AgBiS2-based solar cells.

Dr. Jae Taek Oh, the study’s first author, explained the importance of surface passivation: “Imagine a bumpy road that slows down cars. Surface passivation is like repaving the road, making it smoother so cars can move without getting stuck. In our case, the removal of surface defects is very important to facilitate the transportation of charge carriers created from light absorption in nanocrystal films.”

The research team’s P-DIP strategy improved the quality of the nanocrystal films by addressing surface defects, leading to a significant boost in efficiency. By using a multifunctional molecular agent containing chlorine, they were able to stabilize the nanocrystals and ensure even dispersion in the solution, which resulted in smooth film coatings and enhanced carrier transport.

This combination of techniques has set a new performance record for sustainable, eco-friendly solar cells.

Research Report:Post-deposition in situ passivation of AgBiS2 nanocrystal inks for high-efficiency ultra-thin solar cells