̽��ֱ�� of Cambridge - Chris Howe

Green energy and better crops: tinted solar panels could boost farm incomes

jg533 — Tue, 04 Aug 2020 08:37:54 +0000

By allowing farmers to diversify their portfolio, this novel system could offer financial protection from fluctuations in market prices or changes in demand, and mitigate risks associated with an unreliable climate. On a larger scale it could vastly increase capacity for solar-powered electricity generation without compromising agricultural production.

This is not the first time that crops and electricity have been produced simultaneously using semi-transparent solar panels – a technique called ‘agrivoltaics’. But in a novel adaptation, the researchers used orange-tinted panels to make best use of the wavelengths - or colours - of light that could pass through them.

̽��ֱ��tinted solar panels absorb blue and green wavelengths to generate electricity. Orange and red wavelengths pass through, allowing plants underneath to grow. While the crop receives less than half the total amount of light it would get if grown in a standard agricultural system, the colours passing through the panels are the ones most suitable for its growth.

“For high value crops like basil, the value of the electricity generated just compensates for the loss in biomass production caused by the tinted solar panels. But when the value of the crop was lower, like spinach, there was a significant financial advantage to this novel agrivoltaic technique,” said Dr Paolo Bombelli, a researcher in the ̽��ֱ�� of Cambridge’s Department of Biochemistry, who led the study.

̽��ֱ��combined value of the spinach and electricity produced using the tinted agrivoltaic system was 35% higher than growing spinach alone under normal growing conditions. By contrast, the gross financial gain for basil grown in this way was only 2.5%. ̽��ֱ��calculations used current market prices: basil sells for around five times more than spinach. ̽��ֱ��value of the electricity produced was calculated by assuming it would be sold to the Italian national grid, where the study was conducted.

“Our calculations are a fairly conservative estimate of the overall financial value of this system. In reality if a farmer were buying electricity from the national grid to run their premises then the benefit would be much greater,” said Professor Christopher Howe in the ̽��ֱ�� of Cambridge’s Department of Biochemistry, who was also involved in the research.

̽��ֱ��study found the saleable yield of basil grown under the tinted solar panels reduced by 15%, and spinach reduced by around 26%, compared to under normal growing conditions. However, the spinach roots grew far less than their stems and leaves: with less light available, the plants were putting their energy into growing their ‘biological solar panels’ to capture the light.

Laboratory analysis of the spinach and basil leaves grown under the panels revealed both had a higher concentration of protein. ̽��ֱ��researchers think the plants could be producing extra protein to boost their ability to photosynthesise under reduced light conditions. In an additional adaptation to the reduced light, longer stems produced by spinach could make harvesting easier by lifting the leaves further from the soil.

“From a farmer’s perspective, it’s beneficial if your leafy greens grow larger leaves - this is the edible part of the plant that can be sold. And as global demand for protein continues to grow, techniques that can increase the amount of protein from plant crops will also be very beneficial,” said Bombelli.

“With so many crops currently grown under transparent covers of some sort, there is no loss of land to the extra energy production using tinted solar panels,” said Dr Elinor Thompson at the ̽��ֱ�� of Greenwich, and lead author of the study.

All green plants use the process of photosynthesis to convert light from the sun into chemical energy that fuels their growth. ̽��ֱ��experiments were carried out in Italy using two trial crops. Spinach (Spinacia oleracea) represented a winter season crop: it can grow with fewer daylight hours and can tolerate colder weather. Basil (Ocimum basilicum) represented a summer season crop, requiring lots of light and higher temperatures.

̽��ֱ��researchers are currently discussing further trials of the system to understand how well it would work for other crops, and how growth under predominantly red and orange light affects the crops at the molecular level.

This research was conducted in partnership with Polysolar Ltd. It was funded by the Leverhulme Trust and the Italian Ministry of ̽��ֱ�� and Research.

Reference
Thompson, E. et al: Tinted Semi-Transparent Solar Panels allow Concurrent Production of Crops and Electricity on the Same Cropland. Advanced Energy Materials, 2 Aug 2020. DOI: 10.1002/aenm.202001189

Researchers have demonstrated the use of tinted, semi-transparent solar panels to generate electricity and produce nutritionally-superior crops simultaneously, bringing the prospect of higher incomes for farmers and maximising use of agricultural land.

Our calculations are a fairly conservative estimate of the overall financial value of this system. In reality if a farmer were buying electricity from the national grid to run their premises then the benefit would be much greater

Christopher Howe

Paolo Bombelli ( ̽��ֱ�� of Cambridge)

Greenhouse with tinted solar panels

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Caterpillar found to eat shopping bags, suggesting biodegradable solution to plastic pollution

fpjl2 — Mon, 24 Apr 2017 15:52:27 +0000

Scientists have found that a caterpillar commercially bred for fishing bait has the ability to biodegrade polyethylene: one of the toughest and most used plastics, frequently found clogging up landfill sites in the form of plastic shopping bags.

̽��ֱ��wax worm, the larvae of the common insect Galleria mellonella, or greater wax moth, is a scourge of beehives across Europe. In the wild, the worms live as parasites in bee colonies. Wax moths lay their eggs inside hives where the worms hatch and grow on beeswax – hence the name.

A chance discovery occurred when one of the scientific team, Federica Bertocchini, an amateur beekeeper, was removing the parasitic pests from the honeycombs in her hives. ̽��ֱ��worms were temporarily kept in a typical plastic shopping bag that became riddled with holes.

Bertocchini, from the Spanish National Research Council (CSIC), collaborated with colleagues Paolo Bombelli and Christopher Howe at the ̽��ֱ�� of Cambridge’s Department of Biochemistry to conduct a timed experiment.

Around a hundred wax worms were exposed to a plastic bag from a UK supermarket. Holes started to appear after just 40 minutes, and after 12 hours there was a reduction in plastic mass of 92mg from the bag.

Scientists say that the degradation rate is extremely fast compared to other recent discoveries, such as bacteria reported last year to biodegrade some plastics at a rate of just 0.13mg a day. Polyethylene takes between 100 and 400 years to degrade in landfill sites.

"If a single enzyme is responsible for this chemical process, its reproduction on a large scale using biotechnological methods should be achievable," said Cambridge's Paolo Bombelli, first author of the study published today in the journal Current Biology.

"This discovery could be an important tool for helping to get rid of the polyethylene plastic waste accumulated in landfill sites and oceans."

Polyethylene is largely used in packaging, and accounts for 40% of total demand for plastic products across Europe – where up to 38% of plastic is discarded in landfills. People around the world use around a trillion plastic bags every single year.

Generally speaking, plastic is highly resistant to breaking down, and even when it does the smaller pieces choke up ecosystems without degrading. ̽��ֱ��environmental toll is a heavy one.

Yet nature may provide an answer. ̽��ֱ��beeswax on which wax worms grow is composed of a highly diverse mixture of lipid compounds: building block molecules of living cells, including fats, oils and some hormones.

̽��ֱ��researchers say it is likely that digesting beeswax and polyethylene involves breaking similar types of chemical bonds, although they add that the molecular detail of wax biodegradation requires further investigation.

“Wax is a polymer, a sort of ‘natural plastic,’ and has a chemical structure not dissimilar to polyethylene,” said CSIC’s Bertocchini, the study’s lead author.

̽��ֱ��researchers conducted spectroscopic analysis to show the chemical bonds in the plastic were breaking. ̽��ֱ��analysis showed the worms transformed the polyethylene into ethylene glycol, representing un-bonded ‘monomer’ molecules.

To confirm it wasn’t just the chewing mechanism of the caterpillars degrading the plastic, the team mashed up some of the worms and smeared them on polyethylene bags, with similar results.

“ ̽��ֱ��caterpillars are not just eating the plastic without modifying its chemical make-up. We showed that the polymer chains in polyethylene plastic are actually broken by the wax worms,” said Bombelli.

“ ̽��ֱ��caterpillar produces something that breaks the chemical bond, perhaps in its salivary glands or a symbiotic bacteria in its gut. ̽��ֱ��next steps for us will be to try and identify the molecular processes in this reaction and see if we can isolate the enzyme responsible.”

As the molecular details of the process become known, the researchers say it could be used to devise a biotechnological solution on an industrial scale for managing polyethylene waste.

Added Bertocchini: “We are planning to implement this finding into a viable way to get rid of plastic waste, working towards a solution to save our oceans, rivers, and all the environment from the unavoidable consequences of plastic accumulation.”

A common insect larva that eats beeswax has been found to break down chemical bonds in the plastic used for packaging and shopping bags at uniquely high speeds. Scientists say the discovery could lead to a biotechnological approach to the polyethylene waste that chokes ocean ecosystems and landfill sites.

̽��ֱ��caterpillar produces something that breaks the chemical bond, perhaps in its salivary glands or a symbiotic bacteria in its gut

Paolo Bombelli

̽��ֱ��research team.

Close-up of wax worm next to biodegraded holes in a polyethylene plastic shopping bag from a UK supermarket as used in the experiment.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Bacteria in the world’s oceans produce millions of tonnes of hydrocarbons each year

sc604 — Mon, 05 Oct 2015 19:00:00 +0000

An international team of researchers, led by the ̽��ֱ�� of Cambridge, has estimated the amount of hydrocarbons – the primary ingredient in crude oil – that are produced by a massive population of photosynthetic marine microbes, called cyanobacteria. These organisms in turn support another population of bacteria that ‘feed’ on these compounds.

In the study, conducted in collaboration with researchers from the ̽��ֱ�� of Warwick and MIT, and published today (5 October) in the journal Proceedings of the National Academy of Sciences of the USA, the scientists measured the amount of hydrocarbons in a range of laboratory-grown cyanobacteria and used the data to estimate the amount produced in the oceans.

Although each individual cell contains minuscule quantities of hydrocarbons, the researchers estimated that the amount produced by two of the most abundant cyanobacteria in the world – Prochlorococcus and Synechococcus – is more than two million tonnes in the ocean at any one time. This indicates that these two groups alone produce between 300 and 800 million tonnes of hydrocarbons per year, yet the concentration at any time in unpolluted areas of the oceans is tiny, thanks to other bacteria that break down the hydrocarbons as they are produced.

“Hydrocarbons are ubiquitous in the oceans, even in areas with minimal crude oil pollution, but what hadn’t been recognised until now is the likely quantity produced continually by living oceanic organisms,” said Professor Christopher Howe from Cambridge’s Department of Biochemistry, the paper’s senior author. “Based on our laboratory studies, we believe that at least two groups of cyanobacteria are responsible for the production of massive amounts of hydrocarbons, and this supports other bacteria that break down the hydrocarbons as they are produced.”

̽��ֱ��scientists argue that the cyanobacteria are key players in an important biogeochemical cycle, which they refer to as the short-term hydrocarbon cycle. ̽��ֱ��study suggests that the amount of hydrocarbons produced by cyanobacteria dwarfs the amount of crude oil released into the seas by natural seepage or accidental oil spills.

However, the hydrocarbons produced by cyanobacteria are continually broken down by other bacteria, keeping the overall concentrations low. When an event such as an oil spill occurs, hydrocarbon-degrading bacteria are known to spring into action, with their numbers rapidly expanding, fuelled by the sudden local increase in their primary source of energy.

̽��ֱ��researchers caution that their results do not in any way diminish the enormous harm caused by oil spills. Although some microorganisms are known to break down hydrocarbons in oil spills, they cannot repair the damage done to marine life, seabirds and coastal ecosystems.

“Oil spills cause widespread damage, but some parts of the marine environment recover faster than others,” said Dr David Lea-Smith, a postdoctoral researcher in the Department of Biochemistry, and the paper’s lead author. “This cycle is like an insurance policy – the hydrocarbon-producing and hydrocarbon-degrading bacteria exist in equilibrium with each other, and the latter multiply if and when an oil spill happens. However, these bacteria cannot reverse the damage to ecosystems which oil spills cause.”

̽��ֱ��researchers stress the need to test if their findings are supported by direct measurements on cyanobacteria growing in the oceans. They are also interested in the possibility of harnessing the hydrocarbon production potential of cyanobacteria industrially as a possible source of fuel in the future, although such work is at a very early stage.

Reference:
Lea-Smith, D. et. al. “Contribution of cyanobacterial alkane production to the ocean hydrocarbon cycle.” PNAS (2015). DOI: 10.1073/pnas.1507274112

Scientists have calculated that millions of tonnes of hydrocarbons are produced annually by photosynthetic bacteria in the world’s oceans.

This cycle is like an insurance policy – the hydrocarbon-producing and hydrocarbon-degrading bacteria exist in equilibrium with each other

David Lea-Smith

Image courtesy SeaWiFS Project

Global chlorophyll

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes