DPM Wong, India’s PM Modi discuss clean energy and fintech cooperation

(From left) Minister for Trade and Industry Gan Kim Yong, DPM Lawrence Wong, Indian PM Narendra Modi and Indian finance minister Nirmala Sitharaman. PHOTO: PRIME MINISTER’S OFFICE

NEW DELHI, 20 Sep (The Straits Times) – Singapore Deputy Prime Minister Lawrence Wong and Indian Prime Minister Narendra Modi discussed new areas of cooperation such as clean energy and fintech during a meeting in Indian capital city New Delhi on Monday.

Mr Modi was also briefed about the outcomes of the inaugural session of the India-Singapore Ministerial Roundtable (ISMR), which was held last Saturday.

He conveyed his good wishes for Prime Minister Lee Hsien Loong and the people of Singapore, and expressed his hope that initiatives such as the ISMR “would help further strengthen the bilateral relations between the two countries”.

Mr Wong, who is also Finance Minister, is on a five-day visit to India aimed at expanding cooperation between the two countries.

“We had excellent discussions on new areas of cooperation such as green hydrogen, solar energy, fintech, as well as data links,” said Mr Wong on Facebook following Monday’s meeting, which was also attended by Singapore Minister for Trade and Industry Gan Kim Yong and Minister of Finance and Corporate Affairs of India Nirmala Sitharaman.

“India is an important strategic partner of Singapore across many sectors. I am glad that the pace of bilateral engagements has picked up substantially as the pandemic subsides,” he added.

He also said he looked forward to restarting the Singapore-India Hackathon, which was disrupted by Covid-19, “to build bridges between our young talents”.

The hackathon was held in 2018 and then in 2019 with mixed teams of university students from both countries racing to create software solutions to real-life problems in areas such as education and clean energy.

India and Singapore share close economic and political ties, with regular high-level political exchanges that have picked up again with an exchange of visits in recent months.

Singapore Foreign Minister Vivian Balakrishnan was in India for the Special Asean-India Foreign Ministers’ Meeting in June, while Senior Minister Tharman Shanmugaratnam, who is also Coordinating Minister for Social Policies, visited India in July.

The two sides held the 16th Foreign Office Consultations in Singapore in August.

Mr Wong, Dr Balakrishnan, Mr Gan, and Minister for Transport and Minister-in-charge of Trade Relations S. Iswaran formed the Singapore ministerial delegation at Saturday’s ISMR.

The Indian side included Ms Sitharaman, External Affairs Minister S. Jaishankar and Commerce and Industry Minister Piyush Goyal.

Economic ties between the two countries have been guided by the Comprehensive Economic Cooperation Agreement, which was signed in 2005.

In 2021, annual bilateral trade in goods stood at $26.8 billion. Singapore was the top source of foreign direct investment into India in the financial year 2021-22, accounting for 27 per cent of the country’s record-high US$83.5 billion (S$117.6 billion) inflow.

During his ongoing visit to India, Mr Wong met both federal and state leaders.

On Sunday, he met Gujarat chief minister Bhupendra Patel.

In a speech in Gujarat state on Sunday, Mr Wong highlighted the close ties between the two countries and the potential of cooperation in newer emerging areas such as fintech amid India’s growing digital economy.

“Singapore has long believed in the potential and promise of India,” he said on Sunday

“That is why we have been investing in India. Over the last 20 years, our investments in India have grown by about 20 times,” he said.

Author: Nirmala Ganapathy, India Bureau Chief

Light-scattering structures to boost solar performance

Scientists at Penn State have found that a light-scattering structure could improve perovskite performance. Image: Penn State

An international team of scientists developed a nanoparticle structure which, when added to a solar cell, was shown to scatter light and potentially reflect it many times within the cell, contributing to a noticeable jump in current.

From pv magazine

A range of different additives and extra layers could change the way a solar cell surface interacts with light, and thus improve its performance. Among these is light scattering, where sunlight hits tiny particles embedded into the cell, and is reflected around the device rather than straight back out of it.

A group of US scientists led by Penn State University have demonstrated a 1% efficiency increase in perovskite solar cells by adding a nanoscale light trapping structure to the front of the cell. The achievement is also notable they started out investigation a completely different route to solar cell optimization, and ultimately discovered most of the gains thought to come from this are actually attributable to an accompanying light scattering effect.

“Some researchers in the literature have hypothesized and showed results that up-conversion nanoparticles provide a boost in performance,” said Shashank Priya, professor of materials science and engineering at Penn State. “But this research shows that it doesn’t matter if you put in up-conversion nanoparticles or any other nanoparticles – they will show the boosted efficiency because of the enhance light scattering.”

Up-conversion is a process where a material added to a cell converts infrared radiation into visible light, which can be absorbed by the solar cell. This has long been pursued as a possible to way to reach efficiencies beyond what is thought to be theoretically possible in a single junction device. In this case, scientists at Macquarie University in Australia provided another crystalline material that does not exhibit the up-conversion effect, allowing the Penn State researchers to compare results.

They described their work in “Homogenization of Optical Field in Nanocrystal-Embedded Perovskite Composites,” which was published in ACS Energy Letters. The results showed that the materials were equally effective in improving the perovskite solar cell’s conversion efficiency. And with further calculations, the researchers were able to prove that the efficiency boost primarily came from light scattering, with up-conversion only having a negligible effect.

“We started to basically play around with nanoparticle distribution in the model, and we started to see that as you distribute the particles far away from each other, you start to see some enhanced scattering,” said Thomas Brown, associate professor at the University of Rome. “Then we had this breakthrough.”

The group says it will now investigate the optimization of the size, shape and distribution of particles in nanostructures to optimize performance even further.


High-performance aqueous calcium-ion battery

Image: RPI

Researchers from Rensselaer Polytechnic Institute in the United States have developed a special class of materials for bulky calcium ions, providing pathways for their facile insertion into battery electrodes.

From pv magazine

Against a backdrop of soaring prices and predicted shortfalls of lithium-ion battery materials, the search for inexpensive, abundant, safe, and sustainable battery chemistries has never been more critical. Calcium has been considered in batteries, but the larger size and higher charge density of its ions, relative to lithium, have posed challenges for their insertion into electrode materials.

Now, researchers from Rensselaer Polytechnic Institute in the United States have reported progress in addressing this issue and unlocking the potential of high-performing calcium-ion batteries.

“The calcium ion is divalent, and hence one ion insertion will deliver two electrons per ion during battery operation,” said Nikhil Koratkar, the John A. Clark and Edward T. Crossan Professor of Engineering at Rensselaer. “This allows for a highly efficient battery with reduced mass and volume of calcium ions.”

However, the larger size and higher charge density of calcium ions relative to lithium impairs diffusion kinetics and cyclic stability, he added. The team has overcome this problem by developing oxide structures containing big open spaces (heptagonal and hexagonal channels). In their work, an aqueous calcium-ion battery is demonstrated using orthorhombic and trigonal polymorphs of molybdenum vanadium oxide (MoVO) as a host for calcium ions.

The researchers have demonstrated that calcium ions can be rapidly inserted and extracted from the material, with these tunnels acting as “conduits” for reversible and fast ion transport. The findings indicate that MoVO provides one of the best performances reported to date for the storage of calcium ions.

Specifically, for trigonal MoVO, a specific capacity of ∼203 mAh g−1 was obtained at 0.2C and at a 100 times faster rate of 20C, an ∼60 mAh g−1 capacity was achieved. The open-tunnel trigonal and orthorhombic polymorphs also promoted cyclic stability and reversibility. These findings were recently published in Proceedings of the National Academy of Sciences (PNAS).

“Calcium-ion batteries might one day, in the not-so-distant future, replace lithium-ion technology as the battery chemistry of choice that powers our society,” says Koratkar. “This work can lead of a new class of high-performing calcium-based batteries that use earth abundant and safe materials and are therefore affordable and sustainable. Such batteries could find widespread use in portable and consumer electronics, electric vehicles, as well as grid and renewable energy storage.”


World’s largest underground hydrogen storage project

Image: Mitsubishi Power

Mitsubishi Power Americas and Magnum Development are set to begin construction on a 300 GWh underground storage facility in the US state of Utah. It will consist of two caverns with capacities of 150 GWh, to store hydrogen generated by an adjacent 840 MW hydrogen-capable gas turbine combined cycle power plant.

From pv magazine

Aces Delta, a joint venture between Mitsubishi Power Americas and Magnum Development LLC, plans to build an underground storage project with a capacity of 300 GWh in Delta, Utah.

Advanced Clean Energy Storage I, LLC recently won a $504.4 million loan guarantee from US Department of Energy’s (DOE) Loan Programs Office for the construction of the storage facility. The project will store hydrogen generated by the Intermountain Power Agency’s IPP Renewed Project – an 840 MW hydrogen-capable gas turbine combined cycle power plant located in the area.

“The plant will initially run on a blend of 30% green hydrogen and 70% natural gas starting in 2025 and incrementally expand to 100% green hydrogen by 2045,” Aces Delta said in a statement.

US-based contractor WSP USA has secured an engineering, procurement and construction management contract (EPCM) to build the two underground hydrogen storage caverns, each with a capacity of 150 GWh.

“This stored green hydrogen becomes an energy reserve that can be released to produce fuel for electric power generation at any time,” said WSP USA.

The storage caverns and the power plant will form the Advanced Clean Energy Storage hub, which Aces Delta says will convert renewable energy via 220 MW of electrolyzers to produce up to 100 metric tons of green hydrogen per day. The development of the project began in May 2019.

“Central Utah is the ideal location for this project, and Utah is a business-friendly state for projects like this,” said Craig Broussard, CEO of Magnum. “Magnum’s site adjacent to the Intermountain Power Project is positioned to take full advantage of existing regional electricity grid connections, fully developed transportation infrastructure, ample solar and wind development capacity, a skilled workforce currently transitioning away from coal, and, of course, the unique salt dome opportunity.”

Magnum Development also owns a domal-quality salt formation in the western United States and five operational salt caverns for liquid fuel storage.


Storing renewables in soil mounds via water balloons

Image: Aahrus University

Scientists in Denmark have developed a storage technology that utilizes large underground water balloons and the pressure of the soil to activate a turbine to generate power. They are currently building a first 10 m x 10 m demonstrator to select critical technologies related to the membrane and to the construction of the “movable hill” that will form the terrain part of the battery.

From pv magazine

Researchers from the Aarhus University in Denmark have conceived an energy storage technology to store large amounts of power from renewable energy sources such as wind and solar.

The scientists said the new technology is similar to pumped-hydro storage, as it uses water as a storage medium and responds to the same basic mechanism, but explained that it can be used in a flat country such as Denmark, where no hydropower plants have ever been built. The new tech uses surplus power from wind and photovoltaics to pump water from a reservoir into giant underground water balloons.

According to AquaNamic, which is a Danish startup partnering on the project, a full-scale balloon may reach a size of 330 m x 330 m and, when buried under thousands of cubic meters of soil, can be raised up to 14 meters when the balloon is filled up with water in the charging phase. This balloon would reportedly have a storage capacity of 230 MWh. In the discharging phase, a valve opens and the pressure of the soil pushes the water out of the balloon and through a turbine to generate power. According to the scientists, this system has an efficiency of around 85%, which they say is in line with most pumped-hydro stations.

AquaNamic and the Aarhus University are currently planning to build a 10 m x 10 m demonstrator and have secured DKK 4.9 million ($674.147) from the Energy Technology Development and Demonstration Program. “We’re about to begin analyzing, designing and testing selected critical technologies related to the membrane and to the construction of the ‘movable hill’ that will form the terrain part of the battery,” said researcher Kenny Sørensen. “Naturally, we’ll have a strong focus on abrasion testing for the membrane, and we’ll need to develop a specially designed test rig to carry out lifetime tests for representative membrane solutions.”

One of the crucial aspects of the demonstrator will be assessing the extent of possible energy losses. “We want to retain as much energy in the system as possible, and this is a complex process with such a large system, which in principle will fill up every night, when the turbines are spinning and the world is sleeping, and then empty every day, when the energy is needed,” Sørensen further explained. “But every time the soil moves, the system is deformed, and these deformations contribute to the energy loss. They’re called plastic deformations. Our job is to optimize the system, using advanced calculation models.”

The new technology is also being developed in partnership with Danish wind energy giant Vestas and renewable energy developer European Energy.


Straight to storage via solar integrated batteries

A solar redox flow cell (SRFC). Image: University of Porto

Scientists in China evaluated the prospects for various approaches to integrating both solar generation and energy storage in a single device. Their work outlines several ways this could increase the efficiency of solar energy storage, and recommends that future research on this area should focus on integration of materials with the highest specific capacity for energy storage, alongside the dual function of solar energy harvesting.

From pv magazine

Maximizing the efficiency of energy storage, to make good use of every electron generated from intermittent renewables, will be an ongoing challenge for scientists over the coming decades, and one that will likely see a whole host of new technologies and materials introduced to increasingly specialized markets.

Among the less explored approaches here is single-device integrated solar generation and energy storage, or solar-powered redox batteries (SPRBs). These promise to eliminate much of the additional power electronics and other equipment needed to shuttle energy from a PV system to a battery, meaning both cheaper and more efficient energy storage. So far, a few different approaches to fabricating such a device have emerged, and while progress has been made, none has yet achieved the type of performance that would bring interest from commercial developers.

Scientists led by China’s Nanjing University of Information Science and Technology conducted an extensive review of recent progress with SPRBs, focusing on the development of high-performance dye sensitizer materials, the photoelectrochemical performance of different electrode materials, and the mechanism and structure of such devices. Their review and recommendations can be found in the paper Integrated Photovoltaic Charging and Energy Storage Systems: Mechanism, Optimization, and Future, published in Small.

The paper notes that dye sensitizer materials and semiconductor photocatalysts have shown the most promising results so far, and recommend a range of strategies focused on enhanced light absorption, charge separation, energy matching and overall device optimization. It also states that working with materials that exhibit a high specific capacity for energy storage will be key in developing commercially relevant types. If this potential can be realized, the review finds multiple applications including capacitors, solid-state batteries, microdevices, and smart wearables that could all benefit from such integrated technology.


Graphene/silicon heterojunction solar cell with 18.8% efficiency

hotoluminescence intensity map of a 3 × 3 cm2 solar cell without (left) or with (right) GO:Nafion film. Image: Hebei University, Advanced Materials Interfaces, Creative Commons License CC BY 4.0

A Chinese-German research group developed the cell with an ink of graphene oxide (GO) mixed with Nafion that can be spin-coated on an n-type silicon wafer to form a high-quality passivating contact scheme. The GO:Nafion layer simultaneously creates a p–n junction with silicon and passivates the surface defects at the GO:silicon interface.

From pv magazine

An international research group has unveiled a heterojunction solar cell based on graphene-oxide (GO) and silicon with a large area of 5.5 cm2.

GO is a compound of carbon, oxygen and hydrogen that is obtained by treating graphite with oxidizers and acids. It consists of a single-layer sheet of graphite oxide that is commonly used to produce graphene-family nanomaterials for various applications, including electronics, optics, chemistry and energy storage.

The scientists developed an ink of GO mixed with Nafion that can be spin-coated on an n-type silicon wafer to form a high-quality passivating contact scheme. “Low interface recombination is provided by the Nafion and carrier selection by the GO,” they explained, noting that the passivation scheme also includes an electron-selective passivation contact comprising n-doped hydrogenated amorphous silicon with an indium tin oxide (ITO) overlayer aimed at improving light trapping and reducing surface recombination.

“Graphene was also shear force mixed in Nafion at a concentration of 8 mg mL–1,” they further explained. “Either of these inks were then spin-coated onto the back of the Si wafer, a thin film of Ag was evaporated on top of this and finally an electrical Ag paste was applied for encapsulation and to block the ingress of small quantities of water. Atomic force microscopy (AFM) revealed that the GO:Nafion layers completely covered the Si surface and a root mean roughness of 89 nm was recorded.”

According to the researchers, the GO:Nafion layer simultaneously creates a p–n junction with silicon and passivates the surface defects at the GO:Si interface. The graphene-silicon solar cell is reportedly able to achieve a power conversion efficiency of 18.8%. “Pseudo JV curve shows a pseudo fill factor of 80.6% without the serious resistance effect, and potentially predicts that an efficiency of 21.59% could be achieved with further optimization.”

They presented the solar cell in the paper “High-Efficiency Graphene-Oxide/Silicon Solar Cells with an Organic-Passivated Interface,” published in Advanced Materials Interfaces. The research team comprises academics from the Karlsruhe Institute of Technology (KIT) in Germany, the Hebei University in China, and Chinese module manufacturer Yingli Green Energy Holding Co., Ltd. “The scalable fabrication and good wettability of the GO:Nafion ink provides a favorable direction toward development of carbon-based PV in the future,” they concluded.


Large-area organic solar cell with 14.7% efficiency

Image: KIST

Scientists in Korea built an organic solar cell that is reportedly able to prevent aggregation in photoactive layers. The device could be used for applications in buildings, vehicles, and the Internet of Things.

From pv magazine

Scientists at the Korea Institute of Science and Technology (KIST) have fabricated an organic solar cell based on polymer additives that they claim are able to solve the performance degradation issue of large-area organic solar cells.

“The spin coating method, a solution process mainly used in the laboratory research stage, creates a uniform photoactive layer mixture as the solvent evaporates rapidly while the substrate rotates at a high speed,” the researchers explained. “However, the large-area, continuous solution process designed for industrial use caused solar cell performance deterioration because the solar cell material solution’s solvent evaporation rate was too slow. Consequently, unwanted aggregation between the photoactive materials can be formed.”

The Korean group designed the cell with ternary photoactive layers that contain polymer additives and, as a result, prevent aggregation in photoactive layers. It also engineered nano-level structure control to improve sunlight trapping.

The solar cell achieved a power conversion efficiency of 14.7%, which the academics said is 23.5% higher than that of a conventional binary system. The device was also able to retain 84% of its initial efficiency after 1,000 hours at a temperature of 85 C.

“We have gotten closer to organic solar cell commercialization by proposing the core principle of a solar cell material capable of high-quality, large-area solution processing,” said KIST researcher Hae Jung Son. “Commercialization through follow-up research will make eco-friendly self-sufficient energy generation possible that is easily applicable to exterior building walls and automobiles and also utilized as an energy source for mobile and IoT devices.”


Forecast methodology for photovoltaic power yield during solar eclipses

Image: Doinkster, pixabay

In October there will be a partial solar eclipse in Central Europe. The Fraunhofer IEE has developed a solution that reportedly enables the most accurate forecast possible of the photovoltaic feed-in power during the extreme event.

From pv magazine

The more photovoltaic systems are installed, the more relevant are precise forecasts of how their feed-in will develop in the event of weather events such as solar eclipses. Extreme meteorological events in particular pose major challenges to secure network operation.

Researchers at the Fraunhofer Institute for Energy Economics and Energy System Technology (IEE) in Germany have addressed this issue by developing a new forecast methodology that will soon be tested under real conditions. On October 25, in fact, there will be a partial solar eclipse in Central Europe, which will significantly reduce the photovoltaic feed-in. So far, such rare extreme events have not been routinely included in weather forecasts.

The scientists claim their solution is able to combine the degree of coverage specifically for location and time with all important weather forecasts. This would allow regional and local PV feed-in forecasts to be optimally adjusted in the future, with minimal errors.

Although the effect of the solar eclipse is slower and smaller than the influence of changing clouds, it still plays a significant role in the result. Volatile self-consumption also has a massive effect on the feed-in profile of photovoltaic systems, which can be forecast separately, according to the researchers.

Fraunhofer IEE validated its results with the data from the eclipse that occurred in Central Europe on June 10, 2021, in two steps: through ground-based measurement of global radiation based on data from German weather service DWD and feed-in measurements from thousands of photovoltaic power plants that are used for extrapolation and forecasting processes. The simulation also included weather forecasts and performance data from Fraunhofer IEE. The solution is also available as an algorithm or software for direct integration with the user.

The researchers are considering the proposed methodology as a tool to further strengthen the grid integration of renewable energy sources in Germany. For new locations or regions that have not yet been measured, an extrapolation process is possible by using current measurements from comparable areas and systems.

The October solar eclipse, with a 25% degree of coverage, will be about twice as strong as the result in June 2021, according to the researchers. Weather forecasts a few days beforehand are expected to provide information about cloud density and the effects the solar eclipse may ultimately have.

“In addition to the already good forecast models for the feed-in of individual photovoltaic parks or entire portfolios — including self-consumption — an important contribution can be made to avoiding or reducing errors,” said Rafael Fritz of Fraunhofer IEE.


Solar tree-based photovoltaic plants for mountainous areas

Solar tree installed around the space used as farmland. Image: Korea Maritime Institute, scientific reports, Creative Commons License CC BY 4.0

Scientists in land-scarce Korea are proposing to use solar trees to build PV installations in forest areas. Although more expensive than conventional ground-mounted facilities, solar plants made of solar trees may capture carbon from forest land and produce energy at the same time.

From pv magazine

Researchers from the Korea Maritime Institute have proposed the use of solar trees to build photovoltaic plants in mountainous forest areas in land-scarce South Korea.

They defined the new concept as forest-photovoltaic and explained that it would both maintain carbon absorption activities under the solar trees and produce solar power on the upper part of forest land.

“Compared to a general flat fixed panel, the solar tree has a higher structure and a stronger support base, increasing construction costs,” they explained. “As the demand for solar trees increases due to the development of new technology, more companies enter the market. Therefore, it is expected that solar trees can be installed at a cost that can compete with the current flat fixed panel in the not-too-distant future.”

Using Google Earth satellite imagery, the Korean group assessed the concept’s operational potential by simulating solar tree installations in a mountainous area at 400 meters above sea level, where there is an operating agrivoltaic plant relying on solar trackers. “The solar power plant was constructed by cutting a mountainous ridge available in the highly elevated plateau into flat land,” they explained. “The solar panels installed on the 3-meter-high structure made a space for farming in the ground. One kind of ginseng, mountain garlic, is being grown in the space at the bottom of solar power facilities.”

The academics used Google Earth 3D to reflect solar tree size and the distance between the trees. As a reference, they considered a 4.8 m × 4.1 m panel with a rated power of 1.2 kW developed by Korea-based module manufacturer Hanwha Q Cells. “The slope distance was measured using the built-in elevation path measurement function in Google Earth Pro to arrange the solar tree at 100 m intervals in the three-dimensional image,” they specified. “The forest area, solar panel, and open space were calculated using the polygon measurement function provided by Google Earth Pro to quantitatively evaluate changes in mountain landscape before and after solar tree installation.”

The researchers performed their analysis with criteria developed by Germany’s Fraunhofer Institute for Solar Energy Systems (ISE) for agrivoltaic projects. One of the important factors they considered is the distance between the solar trees, which is crucial for determining their impact on the surrounding natural environment. They ascertained that, if the trees are installed according to the scale of the 3D image, a considerable number of solar trees could be deployed throughout the 1,100,872-square-meter study area. If too many solar trees are placed in a limited space, however, the solar trees displayed as too small in size, causing significant limitations in terms of visual effect, they noted.

Despite their higher costs compared to conventional PV installations, solar trees may have a strategic advantage as they occupy a much lower amount of land. “The land purchase cost is the most important parameter in calculating LCOE on the solar power plant in South Korea,” the research team said. “Compared to other countries, South Korea ranks third in the world in terms of land price. So, purchasing the land is much higher than the money required to build a solar power plant.” On the other hand, in the South Korean Energy Agency’s most recent renewables auction, the final average price was KRW 143.120 per kWh ($0.11), which shows prices quite above the average prices seen in the world’s largest and most mature solar markets.

“The solar tree has not been popularized yet, so the forest-photovoltaic field has many problems to be solved and is only in its infancy,” the scientists admitted, noting that most major module manufacturers haven’t entered the business yet. “The procedure for the solar tree to be commercialized has to deal with different international standardization and regulation schemes.”

They introduced their concept in the study “Exploring the operational potential of the forest-photovoltaic utilizing the simulated solar tree,” published in scientific reports. “A follow-up study is needed to initiate legally binding international standards for solar trees’ wind and snow load operation,” they concluded.