Search Results
Preparation of Photoactive Transition-Metal Layered Double Hydroxides (LDH) to Replace Dye-Sensitized Materials in Solar Cells
This work highlights the use of Fe-modified MgAl-layered double hydroxides (LDHs) to replace dye and semiconductor complexes in dye-sensitized solar cells (DSSCs), forming a layered double hydroxide solar cell (LDHSC). For this purpose, a MgAl-LDH and a Fe-modified MgAl LDH were prepared. X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectroscopy were used to analyze the structural properties, morphology, and success of the Fe-modification of the synthesized LDHs. Ultraviolet-visible (UV-Vis) absorption spectroscopy was used to analyze the photoactive behavior of these LDHs and compare it to that of TiO2 and dye-sensitized TiO2. Current-voltage (I–V) solar simulation was used to determine the fill factor (FF), open circuit voltage (VOC), short circuit current (ISC), and efficiency of the LDHSCs. It was shown that the MgFeAl-LDH can act as a simultaneous photoabsorber and charge separator, effectively replacing the dye and semiconductor complex in DSSCs and yielding an efficiency of 1.56%.
Social innovation in community energy in Europe: A review of the evidence
Citizen-driven Renewable Energy (RE) projects of various kinds, known collectively as community energy (CE), have an important part to play in the worldwide transition to cleaner energy systems. On the basis of evidence from 8 European countries, we investigate CE, over approximately the last 50 years (c.1970-2018), through the lens of Social Innovation (SI). We carry out a detailed review of literature around the social dimension of renewable energy; we collect, describe and map CE initiatives from Belgium, France, Germany, Italy, Poland, Spain, Sweden, and the UK; and we unpack the SI concept into 4 operational criteria which we suggest are essential to recognizing SI in CE. These are: (1) Crises and opportunities; (2) the agency of civil society; (3) reconfiguration of social practices, institutions and networks; (4) new ways of working. We identify three main phases of SI in CE. The environmental movements of the 1960s and the "oil shocks" of the 1970s provided the catalyst for a series of innovative societal responses around energy and self-sufficiency. A second wave of SI relates to the mainstreaming of RE and associated government support mechanisms. In this phase, with some important exceptions, successful CE initiatives were mainly confined to those countries where they were already embedded as innovators in the previous phase. The third phase of CE innovation relates to the societal response to the Great Recession that began in 2008 and lasted most of the subsequent decade. CE initiatives formed around this time were also strongly focused around democratization of energy and citizen empowerment in the context of rising energy prices, a weak economy, and a production and supply system dominated by excessively powerful multinational energy firms. CE initiatives today are more diverse than at any time previously, and are likely to continue to act as incubators for pioneering initiatives addressing virtually all aspects of energy. However, large multinational energy firms remain the dominant vehicle for delivery of the energy transition, and the apparent excitement in European policy circles for "community energy" does not extend to democratization of energy or genuine empowerment of citizens. © 2019 Hewitt, Bradley, Baggio Compagnucci, Barlagne, Ceglarz, Cremades, McKeen, Otto and Slee.
Formic Acid Dehydrogenation by a Cyclometalated κ3-CNN Ruthenium Complex
Hydrogen utilization as a sustainable energy vector is of growing interest. We report herein a cyclometalated ruthenium complex [Ru(κ3-CNN)(dppb)Cl], originally described by Baratta, to be active in the selective dehydrogenation (DH) of formic acid (FA) to H2 and CO2. TON's of more than 10000 were achieved under best conditions without observation of CO (detection limit 10 ppm). The distinguished behavior of the catalyst was explored varying the starting conditions. Our observation revealed the complex [Ru(κ3-CNN)(dppb)(OOCH)] as key species in the catalytic cycle. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.
Adaptation of a microbial community to demand-oriented biological methanation
Background: Biological conversion of the surplus of renewable electricity and carbon dioxide (CO2) from biogas plants to biomethane (CH4) could support energy storage and strengthen the power grid. Biological methanation (BM) is linked closely to the activity of biogas-producing Bacteria and methanogenic Archaea. During reactor operations, the microbiome is often subject to various changes, e.g., substrate limitation or pH-shifts, whereby the microorganisms are challenged to adapt to the new conditions. In this study, various process parameters including pH value, CH4 production rate, conversion yields and final gas composition were monitored for a hydrogenotrophic-adapted microbial community cultivated in a laboratory-scale BM reactor. To investigate the robustness of the BM process regarding power oscillations, the biogas microbiome was exposed to five hydrogen (H2)-feeding regimes lasting several days. Results: Applying various “on–off” H2-feeding regimes, the CH4 production rate recovered quickly, demonstrating a significant resilience of the microbial community. Analyses of the taxonomic composition of the microbiome revealed a high abundance of the bacterial phyla Firmicutes, Bacteroidota and Thermotogota followed by hydrogenotrophic Archaea of the phylum Methanobacteriota. Homo-acetogenic and heterotrophic fermenting Bacteria formed a complex food web with methanogens. The abundance of the methanogenic Archaea roughly doubled during discontinuous H2-feeding, which was related mainly to an increase in acetoclastic Methanothrix species. Results also suggested that Bacteria feeding on methanogens could reduce overall CH4 production. On the other hand, using inactive biomass as a substrate could support the growth of methanogenic Archaea. During the BM process, the additional production of H2 by fermenting Bacteria seemed to support the maintenance of hydrogenotrophic methanogens at non-H2-feeding phases. Besides the elusive role of Methanothrix during the H2-feeding phases, acetate consumption and pH maintenance at the non-feeding phase can be assigned to this species. Conclusions: Taken together, the high adaptive potential of microbial communities contributes to the robustness of BM processes during discontinuous H2-feeding and supports the commercial use of BM processes for energy storage. Discontinuous feeding strategies could be used to enrich methanogenic Archaea during the establishment of a microbial community for BM. Both findings could contribute to design and improve BM processes from lab to pilot scale.
Tightening EU ETS targets in line with the European Green Deal: Impacts on the decarbonization of the EU power sector
The EU Green Deal calls for climate neutrality by 2050 and emission reductions of 50–55% in 2030 in comparison to 1990. Achieving these reductions requires a substantial tightening of the regulations of the EU emissions trading system (EU ETS). This paper explores how the power sector would have to change in reaction to a tighter EU ETS target, and analyses the technological and economic implications. To cover the major ETS sectors, we combine a detailed power sector model with a marginal-abatement cost curve representation of industry emission abatement. We find that tightening the target would speed up the transformation by 3–17 years for different parts of the electricity system, with renewables contributing 74% of the electricity in 2030, EU-wide coal use almost completely phased-out by 2030 instead of 2045, and zero electricity generation emissions reached by 2040. Carbon prices within the EU ETS would more than triple to 129€/tCO2 in 2030, reducing cumulated power sector emissions from 2017 to 2057 by 54% compared to a scenario with the current target. This transformation would come at limited costs: total discounted power system costs would only increase by 5%. We test our findings against a number of sensitivities: an increased electricity demand, which might arise from sector coupling, increases deployment of wind and solar and prolongs gas usage. Not allowing transmission expansion beyond 2020 levels shifts investments from wind to PV, hydrogen and batteries, and increases total system costs by 3%. Finally, the unavailability of fossil carbon capture and storage (CCS) or further nuclear investments does not impact results. Unavailability of bioenergy-based CCS (BECCS) has a visible impact (18% increase) on cumulated power sector emissions, thus shifting more of the mitigation burden to the industry sector, but does not increase electricity prices or total system costs (<1% increase). © 2021 The Authors
Case Study Report "The Renewable Energy Sector: Solar PV Market"
The renewable energy industry is the future of power consumption. Green electricity or renewable energy is generated from natural resources which has less environment impact to our Earth compared to fossil fuel energy. Using renewable energy reduces the amount of carbon dioxide into the atmosphere. These will help to reduce climate change or global warming. Renewable energy sources like solar energy will reduce our dependence on fossil fuels and noble gases which are in a current state of depletion (Uswitch, 2017). The solar photovoltaic (PV) systems harness the solar energy from the sun and convert this to usable electricity. These systems have a huge amount of growth potential with exponential growth in population and a constant need for power supplies. There has been a steady increase in the current growth of solar PV systems with no indication of a future decline. It was found that this technology is more viable in Asian countries due to low production and wage costs for labour. The main variables causing growth in this sector is population growth and increased per capita income. There are also continuous environmental public policies being set which favour the use of renewable energy resources including solar PV systems. Crystalline silica is the most common main component used needed to produce these systems and the changing cost of this will affect the future market. Using Porter’s competitive model, it was found that the rivalry among competitors is medium to high. There is little threat of substitute products entering the market. Suppliers possess medium to high level of power to bargain. There has been an increasing number of installation of solar PV panels which indicates that in the future the bargaining power of customers could be considerably high. The price elasticity for the solar market was found to be relatively high. Overall there is high potential for growth within this industry and no indication that there would be a decline in the years to come.