Renewable Energy Global Innovations features: Fe-Based Metal-Organic Framework and Its Derivatives for Reversible Lithium Storage

Significance Statement

Researchers led by Professor Cai Shen from Ningbo Institute of Materials Technology and Engineering in China used iron-based metal organic framework as an anode for the first time in lithium ion battery applications. The research work is now published in Journal of Materials Science & Technology.

They synthesized MIL-88B_(Fe) as the iron-based metal organic framework followed by production of Fe₂O₃ and Fe₃O₄/C  composites via thermal treatment. In current density of 200mAg^-1, the columbic efficiency increases up to 100% of the 100th cycle with an increase in discharge and charge capacity. After 200 cycles, the cyclic performance of the metal organic framework was up to 700mA hg^-1 and reduced to an approximate value of 680mA hg^-1 after 500 cycles, showing a high cyclic stability. An increase in current density up to 2.0Ag^-1 maintained a capacity as high as 475mA hg^-1, indicating a high cyclic performance despite reduction in discharge capacity of the metal organic framework.

Following the successful preparation of Fe₂O₃ and Fe₃O₄/C composites, They found that the metal oxide of Fe₂O₃ had a discharge capacity of 460mA hg^-1 at a current density of 0.5C which remained after 100th cycle with a columbic efficiency of 100%. The discharge capacity was 180mA hg^-1 at a current density of 5C, but attained a discharge capacity of 700mA hg^-1 when current density was reversed to 0.2C, indicating high cycling stability.

For composites of Fe₃O₄/C, discharge capacity was approximately 800mA hg^-1 in the 100th cycle and attained a value of 928mA hg^-1 when the number of cycles was 200. As current density increases to 5C, a steady discharge capacity was attained, showing high cycling stability.

The iron-based metal organic framework MIL-88B(Fe) coupled with metal oxides of Fe₂O₃  and Fe₃O₄/C  composites both demonstrated high capacity and excellent cycling stability.

About The Author

Dr. Cai Shen received his Ph. D. in Chemistry from the University of St Andrews at UK in 2008. Before joining Ningbo institute of Materials Technology and Engineering, Chinese Academy of Science as an Associate Professor, he worked as a postdoc fellow in the University of Maryland (USA) and Aarhus University (Denmark).

His current research area involves lithium-ion batteries and the application of scanning probe microscopy techniques (in-situ electrochemical STM, AFM) to investigate the surface chemistry of nano materials.

Journal Reference

Jin, Y., Zhao, C., Lin, Y., Wang, D., Chen, L., Shen, C. Fe-Based Metal-Organic Framework and Its Derivatives for Reversible Lithium Storage, Journal of Materials Science & Technology (2016), doi: 10.1016/j.jmst.2016.11.021.

Chinese Academy of Sciences, Ningbo Institute of Materials Technology & Engineering, Ningbo 315201, China.

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Renewable Energy Global Innovations features: Design and optimization of spectral beamsplitter for hybrid thermoelectric-photovoltaic concentrated solar energy devices

Significance Statement

Spectrally selective beam splitting or filtering of radiation can be applied in various types of systems that convert solar energy into electricity. In thermophotovoltaics it was proposed to apply a filter between a heat source and a long-wavelength solar cell transmitting only thermal radiation in a narrow spectral window with high conversion efficiency in the solar cell. Multilayer interference structures for spectrally selective beam splitting are of interest for increasing the conversion efficiency of systems combining a number of solar cells, being efficient at various wavelengths.

A type of system of special interest in which spectrally selective beam splitting is utilized is in a hybrid system consisting of a beamsplitter, a PV cell (solar cell), and a thermoelectric (TE) generator. Here the basic idea is to spectrally split the sunlight incident on the beamsplitter, such that the short wavelengths are reflected onto the solar cell. The longer wavelengths that cannot be converted in the solar cell are instead transmitted onto the TE generator, and in this way the efficiency of the hybrid system can exceed that of a single solar cell. Previous work on this type of beam splitting system assumed an ideal beamsplitter that reflects all the short wavelengths onto the solar cell and transmits all the long wavelengths onto the TE generator with a perfectly sharp cutoff and no losses. Under this assumption, theoretical studies have shown a potential for increasing the efficiency of the hybrid system beyond that of a single solar cell. The optimal cut-off wavelength has been studied in order to maximize the total efficiency, but the question of how to actually construct the beamsplitter has not been addressed, nor has the study of how close it is possible to get to the ideal beamsplitter using a constructed beamsplitter.

Therefore Associate professor Thomas Søndergaard and his master student Enok Skjølstrup from Aalborg University in Denmark have now examined how to actually construct a beamsplitter in practice. It is designed for maximizing the output of the hybrid system taking into account the spectral efficiency of realistic solar cells based on amorphous (a-Si) or microcrystalline (mc-Si) silicon, efficiencies of the TE generator of either 4% or 8%, and the AM1.5 solar spectrum. They have constructed the beamsplitter using thin-film layers of silicon nitride (Si₃N₄) and silicon dioxide (SiO₂) deposited on N-BK7 glass. As an initial design, the beamsplitter consists of different blocks, where each block consists of a certain number of unit cells serving as a layered bandgap structure with large reflection in a certain wavelength interval. When combining several blocks appropriately the structure reflects almost 100% within a much larger wavelength interval than a single block would. For a given TE generator and solar cell, and a given solar radiation spectrum, the conversion efficiency of the hybrid system is a function of all the layer thicknesses of the beamsplitter, which here can vary from app. 20 to 200. Thus the authors have optimized a function of a large number of variables, where the initial block structure is used as the initial guess in the optimization procedure.

The beamsplitter is optimized for both the a-Si and mc-Si solar cells, and in both cases the efficiency of the hybrid system is found to remarkably exceed that of a single solar cell, and the number of layers required to construct a useful beamsplitter is determined. The efficiency of the hybrid system is found to scale approximately linear with the TE efficiency, and the relative improvement compared to a single solar cell is found to be 21.4% for the a-Si solar cell. The beamsplitter is optimized for an incident angle of 45^o but the efficiency as a function of incident angle is found to be relative insensitive to the angle of light incidence from 35-55^o. Furthermore, due to higher order band gaps it was found impossible to construct a useful beamsplitter for the reverse configuration with the TE generator and solar cell interchanged.

About The Author

Enok Johannes Haahr Skjølstrup is a Ph.d student at the Department of Physics and Nanotechnology at Aalborg University, Denmark. In his Master Thesis, which he wrote during the spring 2016, he worked with the design and optimization of a beamsplitter to be implemented in a hybrid system consisting of a solar cell and a thermoelectric generator in order for the efficiency of the hybrid system to exceed that of a single solar cell. Co-author Thomas Søndergaard was Enoks supervisor, and the present paper is Enoks first publication. Enok got his Master degree in June 2016 and during the autumn 2016 he was employed as a research assistant, where he amongst other things studied the optics of multiple ultrasharp grooves in metal. He started as a Ph.d student in January 2017, where he is now theoretically studying the interaction between light and matter on nanoscale. The interaction involves field enhancement in and near plasmonic structures due to nonlocal and quantum effects, why surface plasmons is one of his research interests.

About The Author

Thomas Søndergaard is associate professor within the area of nano optics at the Department of Physics and Nanotechnology, Aalborg University, Denmark. He received the M.Sc. and the Ph.D. in Electrical Engineering from the Technical University of Denmark, respectively in 1999 and 2002. He was then employed in the company Micro Managed Photons A/S for three years working with modeling and design of optical components based on a combination of surface plasmon polaritons and photonic crystals. He obtained a grant from the Danish Agency for Science, Technology, and Innovation for a three-year Post. Doc. at Aalborg University working with plasmonic nanostructures for bio-molecular spectroscopy and microscopy. This was followed by his present position. He received the Danish Independent Research Councils’ Young Researcher’s Award in 2006, and the Danish Optical Society Award in 2008.

His research interests are centered around theoretical modeling of electromagnetic fields in nanostructures, which includes for example work on increasing the efficiency of thin-film silicon solar cells by utilizing surface micro- and nanostructures and embedding of nanoparticles, multilayer coatings for solar power concentrator systems, development of Greens function integral equation methods and other methods for theoretical studies, and basic research within nano-plasmonics. He is presently also interested in antennas and lenses for THz radiation.

He is the author of 84 peer-reviewed journal papers (35 first-authored), and a co-author of the book Numerical Methods in Photonics, CRC Press, 2015. Web-of-science h-index: 27. A detailed list of publications is available . He has won both silver (2006) and bronze (2007) in the Danish national marathon running championships.

Reference

Enok J.H. Skjølstrup and Thomas Søndergaard. Design and optimization of spectral beam-splitter for hybrid thermoelectric-photovoltaic concentrated solar energy devices. Solar Energy, volume 139 (2016), pages 149-156.

Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220 Aalborg East, Denmark.

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Renewable Energy Global Innovations features: Cultivation of Chlorella sp. with livestock waste compost for lipid production

Significance Statement

Microalgae have received significant attention as a biodiesel feedstock. This is in response to energy shortage, climate change and global warming. Microalgae offer many advantages for use in biodiesel production. They have high photosynthetic efficiency, which translates to high growth rate. Moreover, most algal species have high lipid content. Furthermore, it is possible to launch algal biorefinery facilities in lands with low economic value, such as saline and arid lands therefore microalgae cultivation does not compete with food production for farmlands.

Liandong Zhu and colleagues from University of Vaasa in Finland developed a method to determine algal biomass accumulation for biodiesel production when algal cultivation with livestock waste compost was combined. In their work, an optimal concentration level for algal cultivation was found, and the productivities of biomass and lipids was specified. The work is published in peer-reviewed journal, Bioresource Technology.

Chlorella sp. microalgae were used in this study. It was isolated from local fresh-water habits by Utex and grown in a BG11 medium. Livestock waste compost from a local collection point was used. Windrow composting technology was applied to compost cattle waste. The compost was immersed in water, and stirred with a magnetic stirrer. The mixture was then filtered to eliminate non-soluble particulate solids.

Livestock waste compost medium was diluted using fresh water to four varying concentrations (200, 1500, 1000 and 500 mg L^-1 COD). The undiluted media and four diluted media were applied as cultures for microalgal cultivation for 10 days. For comparison, BG11 media (control group) were also used to grow algae. The livestock waste compost with the variable chemical oxygen demand concentrations were introduced into 0.4L flasks.  The optical density of Chlorella sp. was measured every day using spectrophotometer.

The authors determined the lipid contents of chlorella sp. in five cultures with varying nutrient concentration. The culture with the initial chemical oxygen demand concentration at 500 mg L^-1 experienced the highest algal lipid accumulation (44.30% of dry weight). They attributed this to the fact that low biomass concentration in the culture could make more algal cells access and receive more light that triggered and benefited lipid storage. As the initial chemical oxygen demand concentration increased from 500 mg L^-1 to 2680 mg L^-1 the lipid content decreased from 44.30% to 33.90%.

The authors also found that about one third to one fourth of lipids would be converted into fatty acid methyl esters; efficient biodiesel ingredients. This is because some lipids such as phospholipid, chlorophyll and glycolipid are not efficient ingredients for biodiesel production.

This study successfully found the optimal concentration level for algal cultivation and productivities of biomass. The authors concluded the following parameters: specific growth rate of Chlorella sp. grown in the five cultures ranged from 0.275 to 0.375 day^-1. Initial nutrient concentration affected lipid accumulation, and the lipid content ranged from 33.90% to 44.30%. The 2000 mg L^-1 chemical oxygen demand culture was found to be the optimum medium for algal cultivation, since the highest biomass and lipid productivities were realized.

This study was possible with partial funding from TranAlgae. A network of relevant stakeholders within the algae industry in the Botnia-Atlantica region with the aim of implementing innovative solutions for the production of micro- and macroalgae biomass from waste streams at industrial scale.

About The Author

Professor Zhaohua Li is the Dean of the School of Resources and Environmental Science. He was born in 1964 at Hubei Province in China, educated at China, the U.K. and Germany. His research spans including plant ecology, aquatic ecology, and environmental ecology.

Professor Li is of broad members of Chinese Geographical Association and Chinese Association of Agricultural Resources and Zonning. He received an Honorary of National Advanced Workers from Chinese government and more than 10 awards from Chinese ministries and Hubei Province. He has published 22 research works and 176 papers.

About The Author

Dr. Liandong Zhu is an assistant professor at the Faculty of Technology of the University of Vaasa and Vaasa Energy Institute, Finland. Through Talent Program, he has also been selected as a professor in several leading Chinese universities. In January 2014 he graduated from the University of Vaasa as a doctor in the area of biofuels. He is also the recipient of the Åbo Akademi Award and Chinese Government Award for Outstanding Self-financed Student Abroad. His background is environmental engineering and his doctoral and current research resides in biodiesel production by integration of microalgae cultivation with wastewater treatment.

Until now, he has published more than 50 papers in many esteemed peer-reviewed scientific journals, such as Water Research, Renewable and Sustainable Energy Reviews, Energy, Bioresource Technology, Applied Energy, Biofuels, Bioproducts and Biorefining (Biofpr) and Ecological Engineering. In total, the current impact factor (IF) of his papers has reached up to 101 points. According to Google Scholar, his papers have been well cited and the current H-index reaches 13. According to the Web of Science (ESI), three of his papers were marked as highly cited papers. In addition, Dr. Zhu serves as the Lead Guest Editor of the BioMed Research International, Associate Editor of the JSM Environmental Science & Ecology and the reviewer for more than 40 journals including Environmental Science & Technology, Water Research, Energy, Applied Energy, etc.

Currently Dr. Zhu is working on TransAlgae project, receiving funding from EU’s Botnia-Atlantica Programme. Dr. Zhu’s previous research has also been well reported by two local Finnish newspapers (Pohjalainen and Ilkka) on their cover pages. Dr. Zhu’s research interests fall into the scopes of wastewater treatment, biofuels, waste recycling, and sustainable development. Dr. Zhu welcomes all kinds of cooperation in research, project application, publications and academic exchange or visits.

Journal Reference

L.-D. Zhu^1,2,5, Z.-H. Li¹, D.-B. Guo³, F. Huang⁴, Y. Nugroho², and K. Xia². Cultivation of Chlorella sp. with livestock waste compost for lipid production. Bioresource Technology, volume 223 (2017), pages 296–300.

Show Affiliations

1. Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, and Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, China
2. Department of Energy Technology, Faculty of Technology, University of Vaasa, Vaasa 65101, Finland
3. School of Environmental Science & Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
4. Laboratory of Tropical Agro-Environment, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, China
5. Renewable Energy Research Group, Vaasa Energy Institute, Vaasa 65101, Finland

 

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Renewable Energy Global Innovations features: Catalytic Combustion of Hydrogen for Residential Heat Supply Application

Significance Statement

Various means of deriving energy from hydrogen has been effectively studied as it serves as an important source of renewable energy. One of the means which involves catalytic combustion of hydrogen offers several advantages such as low temperature combustion and favorable heat supply.

Incorporation of a platinum catalyst in catalytic combustion of hydrogen achieves a low temperature process which is far more preferable for domestic heat supply uses. Despite this, there requires more knowledge on provision of a basic design of a catalytic hydrogen burner and an effective heat supply system at low temperatures.

Researchers at China Jiliang University designed an industrial-scale heat acquisition system based on hydrogen catalytic combustion with the aim of obtaining an improved combustion and heat efficiency coupled with a reduced effect of hydrogen combustion in air. The research work is now published in International Journal of Energy Research.

The authors synthesized 1wt% platinum catalyst in glass fiber felts via a wet impregnation process before installing them into a catalytic hydrogen burner of a stainless steel reactor with heat capacity of 1KW. The authors further fabricated a prototype heat supply based on the hydrogen catalytic combustion.

A stable heat supply by the simple regulation of hydrogen-to-air ratio became founding. The catalytic hydrogen burner was also capable of attaining a hydrogen conversion rate of 100% at different hydrogen-to-air ratio with respect to time.

Following authors’ fabrication of the prototype heat supply system, a heating efficiency of 82% found at the stable phase. This obtained efficiency was higher than that of the previously reported ones involving the catalytic hydrogen combustion process. The result also shows that an adequate heat supply could be gotten from the proposed catalytic hydrogen burner which would be of relevance to residential heat supply applications.

In addition to the required features attained, inhibition of catalytic hydrogen combustor which occurs at very low temperature as a result of presence of platinum catalyst could also be resolved during the cooling process of the burner.

Schematic diagram of the prototype heat supply system based on hydrogen catalytic combustion (1-air compressor; 2-hydrogen supply unit based on metal hydride storage pack; 3-flow rate controller; 4-pre-mixed chamber; 5-catalytic burner; 6-Pt loaded glass fiber felt catalyst; 7-aluminum clapboard; 8- thermocouples; 9-heat exchanger; 10-water tank; 11-system controller)

About The Author

Dr. Yuexiang Huang is currently a professor at China Jiliang University. He received his BSc degree in 1987 from Zhejiang University, and his PhD in 1998 from University of Aveiro, Portugal. He carried out postdoctoral research in Shanghai Institute of Metallurgy, Chinese Academy of Sciences, from 1999 to 2001. Since 2001, he then worked as a general manager in Tianjin Highland Energy Technology Development Co. Ltd, mainly responsible for the development of hydrogen storage alloys and its systems for fuel cells. In November 2007, he joined China Jiliang University.

He has received several awards, including the Elite returned postdoctor by Shanghai Personnel Bureau (2000), the K.C. Wong Education Foundation of Hong Kong (2000), the special-subsidized specialist by the State Council (2004), and the Third Prize for Progress in Science & Technology of Tianjin (2010) and the Third Prize of Natural Science Award of Zhejiang Province (2016).

His current research interests include the design and synthesis of functional energy materials for energy conversion and storage and environmental treatment, as well as the technological design for hydrogen energy applications.

Reference

Wang, S., Chen, L., Niu, F., Chen, D., Qin, L., Sun, X., Huang, Y. Catalytic combustion of hydrogen for residential heat supply application, International Journal of Energy Research 40 (2016) 1979-1985.

College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, Zhejiang, China.

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Renewable Energy Global Innovations features: Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock

Significance Statement

As the transition to cleaner energy grows, researchers have been working endless hours to achieve green energy that is economically feasible. Microalgae accepted as a source of cleaner energy and can replace use of cultivated crops as food feedstock. Moreover, microalgae present a promising alternative source for the production of biodiesel, due to a high lipid content in microalgal cells. During the photosynthesis of microalgae, neutral lipids are accumulated as triacylglycerols in microalgal cells, improving lipid content in microalgal cells would lead to a sustainable development of microalgal biodiesel.

To induce microalgal lipid accumulation, it involves application of feasible strategies. Liandong  Zhu and colleagues wrote a recent review published in BioMed Research International, aimed to bridge the gap and to systematically concentrate on the main lipid induction strategies that can evidently promote microalgal lipid production.

The authors discussed two types of lipids, neutral lipids that serve as the energy reserves and polar lipids that are constituents of organelles and membranes. To improve the lipid production, external cultivation conditions, such as light intensity, temperature, carbon dioxide, nutrient starvation, salinity stress, and metal stress must be considered.

From the researchers’ observation, positive light intensity increases lipid accumulation functions only up to a limit while extremely high light intensity will cause photoinhibition, damaging the microalgal photosystems, and thus reduce lipid accumulation. The effect of the temperature is said to be same as light intensity in that it varies directly with temperature. The salinity stress created inside the cells results in increment in the lipid content, on the other hand nutrient starvation was found to be feasible and environmentally friendly approach for the control of the cell cycle to enhance lipid productivity.

This paper strategized on promoting microalgae lipid production and the authors identified the application of nutrient starvation as the most efficient strategy to work with and optimum lipid production can be achieved by combining strategies together.

The research undertaken is partially funded by TranAlgae. This is a network of relevant stakeholders within the algae industry in the Botnia-Atlantica region with the aim of implementing innovative solutions for the production of micro- and macroalgae biomass from waste streams at industrial scale. This study is said to provide stakeholders, authorities, and practitioners with the foundation for better understanding microalgal lipid induction strategies and their significances in practice.

About The Author

Dr. Liandong Zhu is an assistant professor at the Faculty of Technology of the University of Vaasa and Vaasa Energy Institute, Finland. Through Talent Program, he has also been selected as a professor in several leading Chinese universities. In January 2014 he graduated from the University of Vaasa as a doctor in the area of biofuels. He is also the recipient of the Åbo Akademi Award and Chinese Government Award for Outstanding Self-financed Student Abroad.

His background is environmental engineering and his doctoral and current research resides in biodiesel production by integration of microalgae cultivation with wastewater treatment. Until now, he has published more than 50 papers in many esteemed peer-reviewed scientific journals, such as Water Research, Renewable and Sustainable Energy Reviews, Energy, Bioresource Technology, Applied Energy, Biofuels, Bioproducts and Biorefining (Biofpr) and Ecological Engineering. In total, the current impact factor (IF) of his papers has reached up to 101 points. According to Google Scholar, his papers have been well cited and the current H-index reaches 13. According to the Web of Science (ESI), three of his papers were marked as highly cited papers.

In addition, Dr. Zhu serves as the Lead Guest Editor of the BioMed Research International, Associate Editor of the JSM Environmental Science & Ecology and the reviewer for more than 40 journals including Environmental Science & Technology, Water Research, Energy, Applied Energy, etc.

Currently Dr. Zhu is working on TransAlgae project, receiving funding from EU’s Botnia-Atlantica Programme: http://ift.tt/2oTKlXK. Dr. Zhu’s previous research has also been well reported by two local Finnish newspapers (Pohjalainen and Ilkka) on their cover pages. Dr. Zhu’s research interests fall into the scopes of wastewater treatment, biofuels, waste recycling, and sustainable development. Dr. Zhu welcomes all kinds of cooperation in research, project application, publications and academic exchange or visits.

About The Author

Professor Zhaohua Li is the Dean of the School of Resources and Environmental Science. He was born in 1964 at Hubei Province in China, educated at China, the U.K. and Germany. His research spans including plant ecology, aquatic ecology, and environmental ecology. Professor Li is of broad members of Chinese Geographical Association and Chinese Association of Agricultural Resources and Zonning.

He received an Honorary of National Advanced Workers from Chinese government and more than 10 awards from Chinese ministries and Hubei Province. He has published 22 research works and 176 papers.

About The Author

Erkki Hiltunen is a Professor and Research Director of the Faculty of Technology of the University of Vaasa, Finland. He is also the leader of Renewable Energy Research Group of the Faculty of Technology of the University of Vaasa.

His research interests are renewable energy, environmental protection and sustainable development. He has published more than 80 articles in journals and conference proceedings.

Journal Reference

L.D. Zhu^1,2, Z. H. Li², and E. Hiltunen¹, Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock, BioMed Research International, Volume 2016 (2016), Article ID 8792548, 8 pages.

Show Affiliations

1. Faculty of Technology, University of Vaasa and Vaasa Energy Institute, P.O. Box 700, 65101 Vaasa, Finland
2. Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources and Faculty of Resources and Environmental Science, Hubei University, Wuhan 430062, China

 

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Renewable Energy Global Innovations features: Biorefinery as a Promising Approach to Promote Microalgae Industry: An Innovative Framework

Significance Statement

Microalgae, which grow in aquatic environments, are widely used as feedstock for traditional applications in cosmetics, pharmacy and nutrition sectors. In response to energy crisis, such as global warming and climatic changes, biofuels a renewable and alternative energy types have become the spotlight of research in an effort to search for sustainable development. Microalgae, which constitute lipids, carbohydrates and proteins in large amounts, have come under increased research interest with regard to the production of biofuels. The microalgae has advantages such as high photosynthetic efficiency, high lipid content, noncompetition for farmlands, and toleration to wastewaters during cultivation, applications appear to be strongly economically convenient only in conjunction with wastewater treatment.

Dr. Liandong Zhu from University of Vaasa in Finland mapped an innovative biorefinery for microalgae industry development in an effort to search for a better understanding of microalgae-based biofuel production scenarios and paths forward for microalgal research and commercialization. The research is now published in Renewable and Sustainable Energy Reviews.

Prior to this research, many studies have been carried out to analyze the economic feasibility of commercializing microalgae production for biofuel use. Commercialization of microalgae production as fuel is feasible from the technical point of view, but from the economical point of view, it is yet to reach an acceptable level. The author pointed out that large scale microalgae cultivation can only be achieved by combining technical breakthroughs and innovative pathways.

To make microalgae production more economical, the microalgae product market sizes and their values needs to be reviewed, that is the cost gap between microalgae biofuels and fossil fuels must be reduced or closed and also cater for the leftovers after high values of microalgae biofuels are produced.

He also suggested multi-production through microalgae biorefinery. The microalgae biorefinery which involve different system integration and engineering technologies will not only produce multiple products but also maximize the value derived from different microalgae components.

To examine the feasibility of this work, two assessments were carried out that is relative net energy ratio and cost-effective assessment. The net energy ratio is calculated from energy lifecycle assessment perspective as the ratio of total energy produced to the energy required for all relative plant construction and operation. And the higher the net energy ratio, the positive the biorefinery chain will be.

This study also mapped out an innovative frame work which includes cultivation technologies developed on the basis of the desired end product, exploring new markets for high values, integration of both traditional microalgal industry and biofuel corporate, and creating of policy beneficial to microalgal biofuel development.

Finally the author concluded in his study that high-value products can help drive the economy through systematic integration and engineering application in microalgae biorefinery.

About The Author

Dr. Liandong Zhu is an assistant professor at the Faculty of Technology of the University of Vaasa and Vaasa Energy Institute, Finland. Through Talent Program, he has also been selected as a professor in several leading Chinese universities. In January 2014 he graduated from the University of Vaasa as a doctor in the area of biofuels. He is also the recipient of the Åbo Akademi Award and Chinese Government Award for Outstanding Self-financed Student Abroad.

His background is environmental engineering and his doctoral and current research resides in biodiesel production by integration of microalgae cultivation with wastewater treatment. Until now, he has published more than 50 papers in many esteemed peer-reviewed scientific journals, such as Water Research, Renewable and Sustainable Energy Reviews, Energy, Bioresource Technology, Applied Energy, Biofuels, Bioproducts and Biorefining (Biofpr) and Ecological Engineering. In total, the current impact factor (IF) of his papers has reached up to 101 points. According to Google Scholar, his papers have been well cited and the current H-index reaches 13. According to the Web of Science (ESI), three of his papers were marked as highly cited papers.

In addition, Dr. Zhu serves as the Lead Guest Editor of the BioMed Research International, Associate Editor of the JSM Environmental Science & Ecology and the reviewer for more than 40 journals including Environmental Science & Technology, Water Research, Energy, Applied Energy, etc.

Currently Dr. Zhu is working on TransAlgae project, receiving funding from EU’s Botnia-Atlantica Programme: http://ift.tt/2oTKlXK. Dr. Zhu’s previous research has also been well reported by two local Finnish newspapers (Pohjalainen and Ilkka) on their cover pages. Dr. Zhu’s research interests fall into the scopes of wastewater treatment, biofuels, waste recycling, and sustainable development. Dr. Zhu welcomes all kinds of cooperation in research, project application, publications and academic exchange or visits.

Journal References

Liandong Zhu^1,2, Biorefinery as a Promising Approach to Promote Microalgae Industry: An Innovative Framework, Renewable and Sustainable Energy Reviews 41 (2015) 1376– 1384.

Zhu, Huo, Shakeel and Li , Algal biorefinery for sustainable development and the challenges. Proceedings of the Institution of Civil Engineers, Energy 169 November 2016 Issue EN4, Pages 179–186.

Show Affiliations

1. Faculty of Technology, University of Vaasa, FI65101 Vaasa, Finland
2. Department of Civil and Environmental Engineering, Aalto University, FI00076 Espoo, Finland

 

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Renewable Energy Global Innovations features: Benchmarking of five typical Meteorological year Datasets dedicated to Concentrated-PV Systems

Significance Statement

Accurate analysis of meteorological and pyranometric data for long-term prediction is the basis of the conception and development, so as decision-making for banks and investors, regarding solar energy conversion systems, either photovoltaic (PV) concentrated solar power (CSP) or concentrated photovoltaic (CPV). This has led to the development of methodologies for the generation of Typical Meteorological Years (TMY). A TMY is a customized weather dataset of one-year of meteorological data that aims at representing climatic conditions judged to be typical over a long-term period. A TMY dataset has 12 calendar months. The most representative block of monthly data for each calendar month is selected based on the smallest Filkenstein-Schafer distance measuring the difference of two cumulative distribution functions.

The “standard” method for solar energy conversion systems was proposed in 1978 by the Sandia Laboratory. In 2012, a new approach was proposed in the framework of the European project FP7 ENDORSE introducing the concept of “driver” time series defined by the user as a function of the pyranometric and meteorological relevant variables to improve the representativeness of the TMY datasets with respect the specific solar energy conversion system of interest.

Ana M. Realpe and colleagues from SOLAÏS, MINES ParisTech and NEOEN, in France benchmarked the classical Sandia method of TMY generation with innovative methods based on the driver concept, in the particular case of a given CPV system in a given site. The research work is now published in Energy Procedia.

According to the team, using 18-year data of the meteorological station Desert Rock (United States), five types of TMY were created using hourly and 1-minute data. The construction of the meteorological year is achieved by comparing the CDF of each block of data at a given month to the CDF of the concatenation of all blocks of data for this month over the long-term. The energy generation output of the concentrated photovoltaic system over the long-term 18-years period was the quantity used for the comparison between the different TMY datasets. The team used a simulation tool for each TMY as input to determine the yield of the concentrated photovoltaic system. Then two analyses were performed: one comparing the long-term average yield with the yield associated to the TMY datasets and another comparing the corresponding CDFs using the Kolmogorov-Smirnov test Integral parameter (KSI), in order to measure the distance between two cumulative distribution functions.

The team found out that the monthly results obtained from the drivers, with hourly and 1-min data, are significantly better than those obtained with the Sandia method. The maximum annual deviations obtained with the Sandia method and with the drivers have no consistent pattern. From the monthly KSI test, the team observed that the maximum monthly deviations from the Sandia method approach exceed twice the deviations obtained by the drivers. Considering the annual KSI, the simplified and filtered drivers provide relative KSI values systematically less than 45 % from 8-year data.

Researchers were able to compare the innovative method which is based on driver concept, by using classical Sandia method as reference point. They found the driver concept to be more promising and efficient than the classical Sandia method.

About The Author

Ana Maria Realpe received her degree in Electrical Engineering from the Simon Bolivar University of Venezuela, in 2009. She carried out her research internship in the Fraunhofer Institute of Solar Energy in Germany, about the development of an encapsulation technique for Compact Concentrated Modules (CCM) used in high concentration photovoltaic (HCPV) systems. In 2011, she received her European Master’s degree in renewable energies (EUREC) from the Ecole MINES ParisTech in France, with a specialisation in hybrid systems at the Kassel University in Germany.

She joined SOLAÏS in 2012 where she has been continuously working in research and development projects with close collaboration with ARMINES / MINES ParisTech on various topics so as material assessment, mechanical structures and aerodynamic studies and solar resource analysis.

She is responsible of the innovation in SOLAÏS and leads the R&D activities related to the glare problematics regarding PV projects that may jeopardize the transportation safety (airports, networks of railways and motorways).

About The Author

Sébastien Pitaval is graduated from Ecole Nationale Supérieure d’Electrotechnique, d’Electronique, d’Informatique, d’Hydraulique et de Télécommunications (2000, Toulouse, France), with specialization in fluid mechanics and energy. He started his career working in the space industry, for Alcatel Space Industries then Thalès Alenia Space (2000-2008), occupying successive management positions for Herschel and Planck satellites: propelling system, Attitude and Orbit Control Systems (AOCS) then system integration.

His interest and convictions regarding renewable energies and his entrepreneurial spirit led him to co-create SOLAÏS in 2008. He developed R&D, Engineering and Export activities while setting up Corporate Social Responsability (CSR) within the company. He is also judicial expert at the Court of Appeal of Aix-en-Provence (France).

About The Author

Christophe Vernay is graduated from Ecole Supélec (1997), a general engineering school in France. He started his career by working in the space industry, for Alcatel Space Industries (1998-2001), as a Research Engineer in Attitude and Orbit Control Systems (AOCS). Then, he worked in the Telecom industry for Nortel Networks then Alcatel-Lucent (2001-2010) on several positions, from the integration to the engineering of 3G and 4G systems. His interest and convictions regarding renewable energies led him to attend photovoltaic and wind-power courses in 2010 at the Conservatoire national des arts et métiers (CNAM), Paris. In 2011, he post-graduated from Ecole Nationale Supérieure d’Arts et Métiers (ENSAM) with a specialized Master’s Degree in renewable energy.

He carried out its professional thesis in SOLAÏS, a French consulting company dedicated to photovoltaic, in collaboration with MINES ParisTech / Armines, about the characterizing of the measurements campaigns of the global irradiation. Since then, he is Technical Director in SOLAÏS, in charge of R&D, engineering, technical due diligence and commissioning.

Linkedin with publications 

About The Author

Prof. Philippe BLANC is graduated from the engineering school Telecom Bretagne (Ecole Nationale Supérieure de Télécommunications de Bretagne) and received his PhD degree from the MINES ParisTech in 1999 in the field of engineering sciences and applied mathematics. He has been working as a research engineer for Thales Alenia Space in signal and image processing and data fusion for Earth Observation systems and various projects where scientific support in signal and image processing, statistics, algorithmic prototyping and applied mathematics is required. He joined ARMINES / MINES ParisTech in 2007. He is working on the modelling of solar radiation and its assessment from in situ measurements or/and satellite images.

He is the head of the research group involved in renewable energy resource assessment within the research center Observation, Impacts, Energy. He has passed in 2015 his professoral habilitation (Habilitation à Diriger des Recherches) and is Professor at MINES ParisTech since then. In addition, he is currently a sub-task Leader of the Task 16 of the International Energy Agency program PVPS and associate editor for the Elsevier journal Solar Energy of the International Solar Energy Society (ISES).

Online access to publications 

Reference

Ana M. Realpe¹, Christophe Vernay¹, Sébastien Pitaval¹, Camille Lenoir², Philippe Blanc³, Benchmarking of five typical Meteorological year Datasets dedicated to Concentrated-PV Systems, Energy Procedia 97 ( 2016 ) 108 – 115.

Show Affiliations

1. SOLAÏS, 400 avenue Roumanille, BP 309, F-06906 Sophia Antipolis Cedex, France.
2. NEOEN, 4 rue Euler, 75008 Paris, France.
3. MINES ParisTech, PSL Resear University, O.I.E. – Center of Observation, Impacts, Energy, 1 Rue Claude Daunesse, CS 10207, F-06904 Sophia Antipolis Cedex, France.

 

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Renewable Energy Global Innovations features: Using Apparent Activation Energy as a Reactivity Criterion for Biomass Pyrolysis

Significance Statement

Understanding thermal properties of plant biomass will give insight to its industrial application, such as converting biomass efficiently into fuels or valuable chemicals. Biomass possesses three main building components; they are hemicelluloses, cellulose, and lignin with different chemical reactivity. Identifying the kinetic properties of pyrolysis has been a challenge, previous work suggested the possibility of using thermal analysis techniques, such as thermogravimetric analysis.

A collaborative research between scientists at Aston University in the UK and Stellenbosch University in South Africa allowed Marion Carrier and colleagues to propose using the classical differential isoconversional analysis also called Friedman’s method to evaluate the activation energy dependency as a function of the conversion degree without any previous knowledge of the reaction model. The research paper is now published in peer-reviewed journal, Energy & Fuel.

They implemented a robust experimental guideline and MATLAB program to determine reliable apparent activation energy, a kinetic parameter that assesses the global reactivity of the chemically isolated biopolymers α-cellulose, holocellulose and lignin. A rigorous preparation method to conduct thermogravimetric experiments was used by the research team to minimize or correct systematic error in the temperature measurement that may affect determination of kinetic parameters.

The research team observed that the activation energy, Eα, dependencies obtained for the slow pyrolysis of the extractive-free Eucalyptus grandis, isolated α-cellulose and holocellulose remained constant for 0.05 < α < 0.80 and equal to 173 ± 10, 208 ± 11, and 197 ± 11 kJ/mol. According to the team, this confirmed the single-step nature of pyrolysis. They also found out large and significant variations in Eα for the Klason lignin from 174 ± 10 to 322 ± 11 kJ/mol in the conversion region of 0.05 and 0.79 and reported this trend for the first time. The team pointed out that non-monotonic nature of weight loss at low and high conversions had a direct consequence on the confidence levels of activation energy, Eα. The authors confirmed the Eα values obtained for α-cellulose and holocellulose in their work agree with values reported in the literature while Eα values for technical lignin pyrolysis were different which could be explained by different methods used in extraction as well as the occurrence of different lignin chemical structures. The model presented in this study is an important step forward to provide more accurate and reliable kinetic parameters of biomass pyrolysis.  

About The Author

Dr. Marion Carrier is a Marie Curie research fellow at the European Biomass Research Institute of Aston University, Birmingham (UK). She obtained degrees in Chemical engineering from CPE Lyon (MEng), in Analytical Science (MSc) and in Chemistry (PhD) from Claude Bernard University in Lyon (France). Trained as an interdisciplinary researcher, she has been applying her current skills and knowledge in the field of pyrolysis for the last 8 years at leading research organisations in France, South Africa, Chile and England.

Her research contributed to a wide range of research fields such as chemical mechanistic, pyrolysis chemical analysis, bioprocessing, thermochemical processing and soil sciences. Since October 2015, she joined Prof. Bridgwater’s team to pursue her research on molecular mapping of fast pyrolysis using fractionation and isotopic characterisation techniques along with molecular dynamics calculations.

About The Author

Dr. Lidia Auret is a senior lecturer at Stellenbosch University (South Africa). She obtained a BEng Chemical Engineering: Mineral Processing and a PhD in Extractive Metallurgical Engineering at Stellenbosch University.

Currently, she leads the research group of Process Monitoring which activities include the development of new process measurement systems (e.g. using image data to determine the efficiency of certain mineral processing units); research on novel methods with which to extract informative features from process data; and investigation into data-driven approaches for root cause analysis of abnormal behaviour on process plants.

About The Author

Prof. Anthony Bridgwater (BSc Tech, PhD, DSc., CEng. FIChemE, FIE) is a professor of chemical engineering and head of the European Bioenergy Research Institute (EBRI) at Aston University (UK). He has been working in bioenergy and biofuels since 1978, focussing on initially gasification for biofuels and later fast pyrolysis for direct production of liquids from biomass in high yields. He led the UK national centre of excellence in bioenergy and has participated in over 25 EC funded R&D projects.

About The Author

Prof. Hansie Knoetze (BEng, PhD) is the Dean Faculty of Engineering at Stellenbosch University since 2012. He has been teaching and researching in interconnected disciplines such as Engineering Propelling Science, thermochemistry and separation; then promoting Research in the field of energy and environmental engineering with the emphasis on the production of fuels and chemicals from renewable biomass, but also supporting progress in the understanding of the underlying thermodynamics and kinetics of the separation processes.

Reference

Marion Carrier¹, Lidia Auret², Anthony Bridgwater¹, and Johannes H. Knoetze², Using Apparent Activation Energy as a Reactivity Criterion for Biomass Pyrolysis, Energy Fuels 2016, 30, 7834 −7841.

Show Affiliations

1. Bioenergy Research Group, European Bioenergy Research Institute (EBRI), Aston University, Birmingham B4 7ET, UnitedKingdom
2. Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa

 

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Renewable Energy Global Innovations features: Calculation of Solar Irradiation Prediction Intervals combining Volatility and Kernel Density Estimates

Significance Statement

The need for precise information on solar energy forecasting is of high importance to the energy demanding world as the reduced forecasting errors favor economic feasibility. Most of the previous techniques used in estimating solar energy forecasting solely depend on point forecasts. However, it was being discovered that both uncertainty and variability forecasting also play a major role in providing a long-time solar energy forecasting which would be of relevance for energy control.

Professor Juan R. Trapero from the University of Castilla-La Mancha in Spain discussed ways at which solar energy forecasting could be improved. The technique he used incorporates that of an uncertainty forecast, associated with the previous single use of point forecasts to derive prediction intervals. The research work is now published in peer-reviewed journal, Energy.

The prediction interval involves the combination of a non-parametric approach, which is the kernel density estimation and the second, a parametric approach which involves the volatility forecast model with adaptation of a time-varying variance solution followed by generalized autoregressive conditional heteroskedastic GARCH model and single exponential smoothing SES model estimations.

In the case study, global horizontal irradiance GHI data were provided by solar irradiance measurements for the Spanish Institute for Concentration Photovoltaics Systems. The author also employed a seasonal autoregressive integrated moving average ARIMA model, which was estimated with that of GARCH model.

From the results observed, the SES model provided a better volatility forecast compared to the GARCH model. Further results revealed that despite a higher hit rate observed for the non-parametric kernel density estimation, a higher average interval width was observed as unconditional coverage test was not passed. The latter result negates a desired prediction interval forecasting.

The parametric models of the GARCH and SES, however, passed the independence test unlike the non-parametric kernel density estimation, but a low hit rate and failure to unconditional coverage test was discovered when considering the Christoffersen conditional coverage test p-value.

The combination of non-parametric kernel density estimation approach and a parametric model of the SES showed a close hit rate value to the desired coverage which did not implicate a higher interval width. All the Christoffersen tests passed successfully, making the combined approach the best method in achieving the desired confidence level with a lower average interval width.

This study with the aid of the combined parametric and non-parametric approach provides a reliable prediction interval for solar energy forecasting.

About The Author

Juan R. Trapero is with the department of Business Administration at Universidad de Castilla-La Mancha (UCLM). He received the Ingeniero Industrial, M.B.A., and Ph.D. degrees from UCLM, Spain, in 2003, 2004, and 2008, respectively.

His research interests include system identification, forecasting and control, particularly applied to supply chain management and energy systems. He is one of the directors of the predictive analytics laboratory research group at UCLM.

Reference

Trapero, J.R. Calculation of Solar Irradiation Prediction Intervals combining Volatility and Kernel Density Estimates, Energy 114 (2016) 266-274.

University of Castilla-La Mancha, Department of Business Administration, Ciudad Real 13071, Spain.

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Renewable Energy Global Innovations features: Compression Ignition of Low-Octane Gasoline: Life Cycle Energy Consumption and Greenhouse Gas Emissions

Significance Statement

The high need for control of greenhouse gas emissions is of importance due to the adverse effect it poses on health and environment. This is not far-fetched as the transport industry, despite its rule plays in society has contributed immensely to greenhouse gas emissions.

An improved vehicle technology which uses low-octane gasoline on the gasoline compression ignition engines offer various advantages compared with other vehicle technologies. It offers a lower ratio of octane compared with conventional gasoline engine, and in terms of energy efficiency and resourcefulness, a higher thermal efficiency compared to the conventional gasoline spark ignition engine and a demand balance between gasoline and diesel can also be achieved. Also, the ease in refinery process due to the use of low-octane gasoline is worthy to notice.

As various researches highlights the significant improvement of low-octane gasoline on gasoline compression ignition engines, a life cycle assessment of energy consumption and greenhouse gas emissions in view of this vehicle technology would also give details on the impacts achieved during the refinery process.

Researchers led by Professor Fuquan Zhao from the State Key Laboratory of Automotive Safety and Energy at Tsinghua University in China reported a life-cycle assessment on the application of low-octane gasoline on the gasoline compression ignition engines in view of finding its effect on energy consumption and greenhouse gas emissions, followed by a comparison study with the conventional gasoline-spark ignition engines. The research work is now published in Applied Energy.

The authors considered a system boundary, well-to-wheel concept. The well-to-wheel concept had two phases; well-to-tank phase and tank-to-wheel phase coupled with evaluations on energy consumption and greenhouse gas emissions related with crude oil extraction, transportation, petroleum refining, products transportation for the former and vehicle use for the latter, based on relevant data. They also made use of a mass-based method for allocation of energy consumption and greenhouse gas emissions in the refinery process.

At the well-to-tank phase, lower energy consumption and greenhouse gas emissions occurred in the refining process of the low-octane gasoline compared to the conventional gasoline. This was due to the non-existence of the isomerization and catalytic reforming units.

With consideration of vehicle fuel consumption rate of related data, low energy consumption and greenhouse gas emissions was also attained for low-octane gasoline and its application on the gasoline compression ignition engine when observed in both phases of the well-to-tank and tank-to-wheel respectively.

Figure 1 Life cycle energy consumption and GHG emissions

Figure 2 The contributions of the WtT and TtW phases in reducing energy consumption and GHG emissions

Outcomes from the life cycle assessment indicated a lesser energy consumption and greenhouse gas emissions by 24.6% and 22.8% for the low-octane gasoline on the gasoline compression ignition system compared to the conventional gasoline on spark ignition system, as Figure 1 shows. The WtT phase contributes to 29% of energy consumption reduction and 34% of GHG emissions reduction. The other 71% of energy consumption reduction and 66% of GHG emissions reduction are attributed to the TtW phase, as Figure 2 shows. The results indicate that both WtT and TtW phases play essential roles in realizing reductions in energy consumption and GHG emissions. Relatively, the TtW phase makes larger contributions.

The authors were able to show that low-octane gasoline on gasoline compression ignition engines would definitely lessen energy consumption and greenhouse gas emissions and provide a major improvement in vehicle technology.

About The Author

Prof. Fuquan (Frank) Zhao is the director of Tsinghua Automotive Strategy Research Institute (TASRI), the President of the International Federation of Automotive Engineering Societies (FISITA 2018-2020), and the member of Global Future Council on Mobility for the World Economic Forum.

Prof. Zhao joined Tsinghua University in 2013. Before, he worked more than 20 years in the automotive industry. He has been a leading author of more than 300 academic papers in English, Japanese and Chinese, written 5 books in English and Chinese, and led the development of about 20 vehicle models and 10 powertrain products.

His research is focus on strategy in fields of automotive industry development, corporate management and technology development roadmaps.

He holds Master and PhD degrees in Mechanical Engineering, Hiroshima University, Japan, and a Bachelor degree in Jilin University of Technology, China.

About The Author

Dr. Hao is the assistant researcher in Tsinghua Automotive Strategy Research Institute (TASRI). He is the contributing author of Intergovernmental Panel on Climate Change (IPCC) the 5th Assessment Report, the member of editorial Committee of China Automotive Energy Outlook and the member of editorial committee of Sustainable Automotive Energy System in China.

Dr. Hao is the journal reviewers of the following SCI journals: Renewable & Sustainable Energy Reviews, Energy, Transportation Research Part A: Policy and Practice, Transportation Research Part D: Transport and Environment, Transport Policy, Energy Conversion and Management and Applied Mathematical Modeling.

His research field is mainly on automotive industry research, with focus on industrial development and planning, life cycle evaluation methods, technical strategy methodology, etc.

He holds Bachelor and PhD degrees in Department of Automotive Engineering from Tsinghua University.

About The Author

Feiqi Liu is the doctoral candidate in Tsinghua Automotive Strategy Research Institute (TASRI). Her research interests are vehicle fleet carbon emissions and life cycle evaluation methods. She holds the Bachelor degree in School of Transportation Science and Engineering, Beihang University.

Journal Reference

Hao, H., Liu, F., Liu, Z., Zhao, F. Compression ignition of low-octane gasoline: Life cycle energy consumption and greenhouse gas emissions, Applied Energy 181 (2016) 391–398.

State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China

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