Can a new network of African solar researchers lead the way on solar power for the continent? Christine Ottery finds out.

It was a surprise to Daniel Egbe to discover, at a 2010 conference in Tunisia, that two of his colleagues, both solar researchers from Africa, were not acquainted.

So the Cameroonian scientist introduced [...]]]>

SciDev

Can a new network of African solar researchers lead the way on solar power for the continent? Christine Ottery finds out.

It was a surprise to Daniel Egbe to discover, at a 2010 conference in Tunisia, that two of his colleagues, both solar researchers from Africa, were not acquainted.

So the Cameroonian scientist introduced Teketel Yohannes, a professor at Addis Ababa University, Ethiopia, to Samir Romdhane, a professor at the University of Bizerte, Tunisia.

The result was the creation of the African Network for Solar Energy (ANSOLE), which is striving to harness local know-how to electrify the continent.

“I said ‘let’s see if us Africans can sit down and work together’,” Egbe, currently a professor of organic chemistry at Johannes Kepler University in Linz, Austria, tells SciDev.Net. “We realised that we are working in related fields of semi-conductors and solar energy, and that’s how ANSOLE materialised.”

It is a compelling dream — to harness the abundant sunshine in an energy-deprived continent to fuel a better future for everyone. But African solar power researchers face many challenges.

Loss of talent to the brain drain, lack of money to follow up ideas, little connection between like-minded colleagues across the continent, and few opportunities to entice scientists to turn their attentions to solar energy — all these plague the field.

Its mission includes strengthening the links not just within Africa but between African countries and the rest of the world, so researchers from Europe, Turkey and the United States were also present.

The network now has around 200 members — most of them scientists — from 22 African, and ten non-African, nations.

“We want the coming generation not to worry about where to study, who to work with,” says Getachew Adam, a PhD student at the University of Addis Ababa, in Ethiopia, and ANSOLE member. “We want to make African scientists come together [to solve the] African energy problem.”

Sub-Saharan African countries need money and coordinated research if they are to harness the power of the sun, says Egbe.

Mammo Muchie, founding editor of the African Journal of the Science, Technology, Innovation and Development, agrees, telling SciDev.Net that solar power will become the major renewable energy source on the continent only by organised research, training, design and engineering.

“Our approach is to build capacity, especially when it comes to research,” says Egbe, who is now the co-ordinator of ANSOLE. “Through our network many African researchers, especially physicists and chemists, are now directing their research in solar and renewable energy.”

The group also wants to train more people to university level and promote use of decentralised solar energy through educational programmes in local languages.

Aiming high

Connecting researchers is key, especially in a field where the continent’s scientists have little interaction with those in richer countries, a continent which is expensive and time-consuming to traverse.

ANSOLE provides a platform for a mix of online and real-world networking. Each February ‘ANSOLE Days’ will bring African researchers and international collaborators face to face, says Egbe.

The first such meeting will be held this month (17–19 February) in Cameroon, followed by South Africa in 2013.

African scientists will also be able to start new collaborations through the ANSOLE website, which will hold a database of solar researchers and link people up to create joint proposals for scarce funding.

But can African scientists ever catch up to the extent that they lead the way in solar research?

Cédric Philibert, an expert in renewable energy at the International Energy Agency, says Africa “is not yet a significant player in the field of ‘hard’ solar science”, which includes areas such as photovoltaic technologies, concentrated solar power and solar fuels research [such as artificial photosynthesis].

“To expect Africans to compete internationally in the already very advanced area of silicon-based photovoltaics is not realistic,” says Egbe. “But members of ANSOLE are saying that we can do internationally competitive research in organic and hybrid organic–silicon photovoltaics.”

Traditionally, crystalline silicone has been used as the light-absorbing semi-conductor in solar cells, but organic photovoltaics use carbon-based molecules to conduct light and create an electrical charge.

Yohannes, the Ethiopian co-founder and now a regional representative for ANSOLE in East Africa, says: “Organic solar cell research has attracted researchers’ attention in the last three decades, because of its ease of processing, low cost and the flexibility of organic polymer-based solar cells”.

The relative low cost of organic solar technology and modest infrastructure requirements make it especially attractive to African researchers.

“With a little bit of money you can build your research labs and carry out your research. On this level we can compete with Europeans and Americans,” Egbe says. “When it comes to silicon-based research, you need a lot of money and a clean room, which costs a lot.”

However, organic semiconductors are still inefficient — the ratio between sunlight input and energy output is low — and they degrade when exposed to air or water. African researchers, such as Yohannes and PhD student Adam, who studies organic photovoltatics, are working on ways to solve these challenges.

Meanwhile, another field where African researchers can push science forward is solar thermal energy, according to Egbe. This uses mirrored troughs, dishes or towers to harness sunlight for heat or electricity.

There is great potential for solar energy in Africa

Flickr/World Bank Collection

Bertrand Tchanche, a Cameroonian researcher of thermal fluids at the Agricultural University of Athens, Greece, agrees that there is potential for African scientists to make headway with solar thermal research.

But, he says, “The lack of research facilities and funding are major obstacles”.

“ANSOLE can help the movement of students from one country to the other, from poor countries to rich countries — in this way information will start to circulate between institutions,” says Egbe.

One of ANSOLE’s medium-term aims is to form an exchange programme for students to work in different institutions across Africa, improving the spread of knowledge.

But ANSOLE’s long-term vision is to create a new African research centre for renewable energy, as well as starting a graduate programme in renewable energy.

There could even be one centre in each of main regions of the continent, Egbe says.

ANSOLE does not lack ambition, but what it can achieve may be limited by a lack of funding. To keep it running while filing for charity status, Egbe has already had to reach into his own pockets — although he will not disclose how much he has spent so far.

He spends half of his time volunteering on ANSOLE, which is supported by his university.

“Our plans need funding,” says Egbe. “I hope that the UN can support such endeavours, since the UN has declared 2012 the year of renewable energies, and renewable energies are important for the protection of our environment.”

For upcoming events, including the meeting in Cameroon, ANSOLE needs around US$90,000. So far they have pledges from a variety of organisations but the total is still far from the needed budget.

ANSOLE hopes to solve the funding challenges by attracting international investment from solar energy companies.

Philibert says this collaborative public–private approach could transform solar research in Africa especially in northern and southern Africa where both public and private actors are willing to develop a solar power industry.

Egbe seems optimistic: “We believe this will, in the long run, contribute to development of Africa.”
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Zhu and his team have discovered [...]]]>

Maximum theoretical efficiency of solar cells could increase from 31 to 44 percent

AUSTIN, Texas — The efficiency of conventional solar cells could be significantly increased, according to new research on the mechanisms of solar energy conversion led by chemist Xiaoyang Zhu at The University of Texas at Austin.

Zhu and his team have discovered that it’s possible to double the number of electrons harvested from one photon of sunlight using an organic plastic semiconductor material.

“Plastic semiconductor solar cell production has great advantages, one of which is low cost,” said Zhu, a professor of chemistry. “Combined with the vast capabilities for molecular design and synthesis, our discovery opens the door to an exciting new approach for solar energy conversion, leading to much higher efficiencies.”

Zhu and his team published their groundbreaking discovery Dec. 16 in Science.

The maximum theoretical efficiency of the silicon solar cell in use today is approximately 31 percent, because much of the sun’s energy hitting the cell is too high to be turned into usable electricity. That energy, in the form of “hot electrons,” is instead lost as heat. Capturing hot electrons could potentially increase the efficiency of solar-to-electric power conversion to as high as 66 percent.

Zhu and his team previously demonstrated that those hot electrons could be captured using semiconductor nanocrystals. They published that research in Science in 2010, but Zhu says the actual implementation of a viable technology based on that research is very challenging.

“For one thing,” said Zhu, “that 66 percent efficiency can only be achieved when highly focused sunlight is used, not just the raw sunlight that typically hits a solar panel. This creates problems when considering engineering a new material or device.”

To circumvent that problem, Zhu and his team have found an alternative. They discovered that a photon produces a dark quantum “shadow state” from which two electrons can then be efficiently captured to generate more energy in the semiconductor pentacene.

Zhu said that exploiting that mechanism could increase solar cell efficiency to 44 percent without the need for focusing a solar beam, which would encourage more widespread use of solar technology.

The research team was spearheaded by Wai-lun Chan, a postdoctoral fellow in Zhu’s group, with the help of postdoctoral fellows Manuel Ligges, Askat Jailaubekov, Loren Kaake and Luis Miaja-Avila. The research was supported by the National Science Foundation and the Department of Energy.

Science Behind the Discovery

• Absorption of a photon in a pentacene semiconductor creates an excited electron-hole pair called an exciton.
• The exciton is coupled quantum mechanically to a dark “shadow state” called a multiexciton.
• This dark shadow state can be the most efficient source of two electrons via transfer to an electron acceptor material, such as fullerene, which was used in the study.
• Exploiting the dark shadow state to produce double the electrons could increase solar cell efficiency to 44 percent.

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Poor parts of the world can be supplied with affordable solar power by 2020 through a combination of cheap technology and services provided by cell phone companies, argues Carl Pope, chairman of the US grassroots organisation Sierra Club.

Progress in technology, finance and business models is overcoming traditional barriers to getting 

SciDev: Source: Yale Environment 360

Progress in technology, finance and business models is overcoming traditional barriers to getting renewable power to poor villages, he says. “The combination of dirt-cheap solar, the cell-phone revolution, and mobile phone banking has changed everything”.

Conventional grid power and fossil fuels will not reach those who need it by 2030, according to Pope, and they are becoming more expensive. But cheaper and more sophisticated new technologiescreate an opportunity to pull together the resources needed to finance solar power for the poor.

Cell-phone towers around the world are being converted to hybrid renewable power sources, offering phone companies a “powerful motivation to get renewable power into rural areas, to get electricity to their customers, and to charge for electricity through their mobile phone payment systems.”

Examples of innovative business models include Zimbabwe’s Econet Power, which provides its cell-phone customers with solar power at US$1 a week with bills tied to a user’s cell phone account.

Providing the poor with off-grid renewable energy requires capital to buy solar power; business models that allow households to pay for what they use, making electricity less expensive than kerosene; and supply chains and distribution networks. “The money is on the table. It’s just on the wrong plates,” says Pope.

He calls for Rio+20 negotiations to embrace distributed solar power and replace kerosene, an expensive and dirty fuel. This would save 1.5 million lives every year (kerosene emits almost as much greenhouse gas pollution as the UK economy), raise income for the world’s poorest fifth by 25–30 per cent, and create demand for expanding solar systems. And it could result in half of the world relying on renewable power, says Pope.

Link to full article in Yale Environment 360
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The Centre for Research in Transportation Technologies (Vehicle Design Project), College of Engineering, Design, Art and Technology has successfully conducted the first test drive of its flagship concept, the 2-seater Electric vehicle.

Codenamed the 

Uganda’s first electric car

The Centre for Research in Transportation Technologies (Vehicle Design Project), College of Engineering, Design, Art and Technology has successfully conducted the first test drive of its flagship concept, the 2-seater Electric vehicle.

Codenamed the Kiira-EV, the flashy green vehicle made its first test runs around campus roads on the bright Tuesday, 1st November 2011 afternoon, with crowds eagerly craning their necks to catch a glimpse of the car as it zipped around.

The KIIRA EV powertrain employs a simple   battery electric vehicle powertrain consisting of an Energy storage bank, energy converter and a rotary machine (induction motor).  It is powered by electricity which is stored in the in the battery bank through repetitive charging.

The battery system of the Kiira EV consists of Lithium-ion batteries with very high energy storage capabilities, high charge acceptance, high specific power and high energy density. The battery system banking is unique consisting of 4 battery banks of 64 cells connected in series. The banking ensures energy system modularity for effective battery monitoring, safety, increased reliability and maintenance. The battery bank capacity of 40 AH and  207 V is engineered to achieve an inter-charge distance 80 km, a requirement for a commuter student vehicle on Makerere University campus.

At the brief official flag off ceremony officiated by the Vice Chancellor Professor Venansius Baryamureeba, the audience; mostly made up of students and members of the media bore the assault of the afternoon sunshine to listen to remarks from the project’s Principal Investigator and Deputy Vice Chancellor (Finance and Administration) Dr. S.S. Tickodri-Togboa.

In his remarks, the Vice Chancellor commended the Principal, College of Engineering, Design, Art and Technology for successfully steering the college to the yet another historical event. He extolled the Principal Investigator and his team for working tirelessly to ensure that the concept was successfully transformed into Uganda’s First Electric Car.

Kiira-EV Design Specifications

• 2-Seater Electric Car
• 3000mm long, wheel base 2175mm, 1600mm wide and 1500mm high
• Front wheel Drive
• Aluminium-alloy chassis
• Target Speed 60 km/hr and Range 50 Km
• Curb and Cargo weight is 500kgs and 200kgs respectively

The discovery is reported in the latest issue of Nature Materials.

Quantum dots are nanoscale [...]]]>

TORONTO, ON – Researchers from the University of Toronto (U of T), the King Abdullah University of Science & Technology (KAUST) and Pennsylvania State University (Penn State) have created the most efficient solar cell ever made based on collodial-quatum-dots (CQD).

The discovery is reported in the latest issue of Nature Materials.

Quantum dots are nanoscale semiconductors that capture light and convert it into an energy source. Because of their small scale, the dots can be sprayed on to flexible surfaces, including plastics. This enables the production of solar cells that are less expensive to produce and more durable than the more widely-known silicon-based version. In the work highlighted by the Nature Materials paper entitled “Collodial-quantum-dot photovoltaics using atomic-ligand passivation,” the researchers demonstrate how the wrappers that encapsulate the quantum dots can be shrunk to a mere layer of atoms.

“We figured out how to shrink the passivating materials to the smallest imaginable size,” states Professor Ted Sargent, corresponding author on the work and holder of the Canada Research Chair in Nanotechnology at U of T.

A crucial challenge for the field has been striking a balance between convenience and performance. The ideal design is one that tightly packs the quantum dots together. The greater the distance between quantum dots, the lower the efficiency.

However the quantum dots are usually capped with organic molecules that add a nanometer or two. When working on a nanoscale, that is bulky. Yet the organic molecules have been an important ingredient in creating a colloid, which is a substance that is dispersed in another substance. This allows the quantum dots to be painted on to other surfaces.

To solve the problem, the researchers have turned to inorganic ligands, which bind the quantum dots together while using less space. The result is the same colloid characteristics but without the bulky organic molecules.

“We wrapped a single layer of atoms around each particle. As a result, they packed the quantum dots into a very dense solid,” explains Dr. Jiang Tang, the first author of the paper who conducted the research while a post-doctoral fellow in The Edward S. Rogers Department of Electrical & Computer Engineering at U of T.

The team showed the highest electrical currents, and the highest overall power conversion efficiency, ever seen in CQD solar cells. The performance results were certified by an external laboratory, Newport, that is accredited by the US National Renewable Energy Laboratory.

“The team proved that we were able to remove charge traps – locations where electrons get stuck – while still packing the quantum dots closely together,” says Professor John Asbury of Penn State, a co-author of the work.

The combination of close packing and charge trap elimination enabled electrons to move rapidly and smoothly through the solar cells, thus providing record efficiency.

“This finding proves the power of inorganic ligands in building practical devices,” states Professor Dmitri Talapin of The University of Chicago, who is a research leader in the field. “This new surface chemistry provides the path toward both efficient and stable quantum dot solar cells. It should also impact other electronic and optoelectronic devices that utilize colloidal nanocrystals. Advantages of the all-inorganic approach include vastly improved electronic transport and a path to long-term stability.”

“At KAUST we were able to visualize, with incredible resolution on the sub-nanometer lengthscale, the structure and composition of this remarkable new class of materials,” states Professor Aram Amassian of KAUST, a co-author on the work.

“We proved that the inorganic passivants were tightly correlated with the location of the quantum dots; and that it was this new approach to chemical passivation, rather than nanocrystal ordering, that led to this record-breaking colloidal quantum dot solar cell performance,” he adds.

As a result of the potential of this research discovery, a technology licensing agreement has been signed by U of T and KAUST, brokered by MaRS Innovations (MI), which will will enable the global commercialization of this new technology.

“The world – and the marketplace – need solar innovations that break the existing compromise between performance and cost. Through U of T’s, MI’s, and KAUST’s partnership, we are poised to translate exciting research into tangible innovations that can be commercialized,” said Sargent.

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‘Solar Lighting for the Base of the Pyramid — Overview of an Emerging Market’ was published by Lighting Africa, a joint [...]]]>

As many as 120 million households in Africa will be living off-grid by 2015, creating one of the world’s largest markets for portable solar lighting in the next five years, according to a report.

‘Solar Lighting for the Base of the Pyramid — Overview of an Emerging Market’ was published by Lighting Africa, a joint International Finance Corporation (IFC) and the World Bank initiative that is developing continent-wide programmes for solar lighting.

The report projects an up to 65 per cent growth rate in sales of portable solar lights, comparable to the recent explosion in mobile phone sales on the continent. Currently, only 0.5 per cent of some 140 million African people living without regular or reliable access to electricity have such lights.

The growth will be fuelled by entrepreneurs using the latest technologies and designing products to suit consumers’ tastes, the report says. But the market could grow even faster if distribution and financing were scaled up, it says.

Arthur Itotia, Lighting Africa programme manager, told SciDev.Net that the initiative does not just aim to light households but also to save people money and reduce the health risks associated with fuel lamps.

“By converting from kerosene to clean energy millions of consumers can improve their health, reduce their spending on expensive fuels and, ultimately, benefit from better illumination and more productive time in their homes, schools and businesses.”

The report also found that an average African household could spend US$225 less a year on kerosene by using solar lighting.

Lighting Africa is helping to build the market for off-grid lighting across Sub-Saharan Africa by investing in consumer education, improving access to financing and looking at new ways to distribute the lighting.

Dana Rysankova, senior energy specialist in the Africa Energy Unit at the World Bank, said that Africa’s high population growth and low levels of access to the grid mean that it will soon surpass Asia in the number of people without electricity.

The lessons learned from Africa, she said, are being used to give advice to other areas.

“For example, Lighting Africa advised another World Bank project in Haiti that was disseminating solar lanterns after the devastating earthquake there,” said Rysankova.

But other experts warn that such noble ideas risk being overridden by market forces — especially if left solely in the hands of private sector players.

“Much as the idea is great and tenable, the implementers need to shape the market to allow poor households to buy the lights,” said Simon Mugambi, an independent energy market consultant.

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The Sahara Solar Breeder Project is a joint initiative by universities in Japan and Algeria that aims [...]]]>

Life might take a hammering on the sun’s earthly anvil, the Sahara desert, but the two most abundant resources the desert has to offer – sunlight and sand – could help solar power to “breed” and thrive there.

The Sahara Solar Breeder Project is a joint initiative by universities in Japan and Algeria that aims to build enough solar power stations by 2050 to supply 50 per cent of the energy used by humanity.

The idea is to begin by building a small number of silicon manufacturing plants in the Sahara, each turning the desert sand into the high-quality silicon needed to build solar panels. Once those panels are operating, some of the energy they generate will be used to build more silicon plants, each churning out more solar panels and generating more energy that can be used to build even more plants, and so on.

Hideomi Koinuma at the University of Tokyo leads the Japanese end of the project. He admits that making silicon panels from the rough sands of the Sahara or other deserts has not been attempted before, but says it is a logical choice.

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