scholarly journals Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold

2021 ◽  
Author(s):  
Moritz Kölbach ◽  
Kira Rehfeld ◽  
Matthias May
Keyword(s):  
Fossil Fuels ◽  
High Efficiency ◽  
Scale Up ◽  
Global Scale ◽  
Catalyst Loading ◽  
Major Question ◽  
Solar Hydrogen ◽  
Electricity Grid ◽  
Ambient Temperatures ◽  
Solar Water Splitting

Hydrogen produced from water using solar energy constitutes a sustainable alternative to fossil fuels, but solar hydrogen is not yet economically competitive. A major question is whether the approach of coupling photovoltaics via the electricity grid to electrolysis is preferential to higher levels of device integration in ‘artificial leaf’ designs. Here, we scrutinise the effects of thermally coupled solar water splitting on device efficiencies and catalyst footprint for sub-freezing ambient temperatures of -20C. These conditions are found for a significant fraction of the year in many world regions. Using a combination of electrochemical experiments and modelling, we demonstrate that thermal coupling broadens the operating window and significantly reduces the required catalyst loading when compared to electrolysis decoupled from photovoltaics. Efficiency benefits differ qualitatively for double- and triple junction solar absorbers, which has implications for the general design of outdoor-located photoelectochemical devices. Similar to high-efficiency photovoltaics that reached technological maturity in space, application cases in polar or alpine climates could support the scale-up of solar hydrogen at the global scale.

scholarly journals Efficiency Gains for Thermally Coupled Solar Hydrogen Production in Extreme Cold

2021 ◽  
Author(s):  
Moritz Kölbach ◽  
Kira Rehfeld ◽  
Matthias May
Keyword(s):  
Fossil Fuels ◽  
High Efficiency ◽  
Scale Up ◽  
Global Scale ◽  
Catalyst Loading ◽  
Major Question ◽  
Solar Hydrogen ◽  
Electricity Grid ◽  
Ambient Temperatures ◽  
Solar Water Splitting

Hydrogen produced from water using solar energy constitutes a sustainable alternative to fossil fuels, but solar hydrogen is not yet economically competitive. A major question is whether the approach of coupling photovoltaics via the electricity grid to electrolysis is preferential to higher levels of device integration in ‘artificial leaf’ designs. Here, we scrutinise the effects of thermally coupled solar water splitting on device efficiencies and catalyst footprint for sub-freezing ambient temperatures of -20C. These conditions are found for a significant fraction of the year in many world regions. Using a combination of electrochemical experiments and modelling, we demonstrate that thermal coupling broadens the operating window and significantly reduces the required catalyst loading when compared to electrolysis decoupled from photovoltaics. Efficiency benefits differ qualitatively for double- and triple junction solar absorbers, which has implications for the general design of outdoor-located photoelectochemical devices. Similar to high-efficiency photovoltaics that reached technological maturity in space, application cases in polar or alpine climates could support the scale-up of solar hydrogen at the global scale.

Nanostructure designs for effective solar-to-hydrogen conversion

Nanophotonics ◽  
2012 ◽  
Vol 1 (1) ◽  
pp. 31-50 ◽  
Author(s):  
Shaohua Shen ◽  
Samuel S. Mao
Keyword(s):  
Surface Engineering ◽  
High Efficiency ◽  
Solar Light ◽  
Catalyst Loading ◽  
Solar Hydrogen ◽  
New Concepts ◽  
Ion Doping ◽  
First Results ◽  
Solar Hydrogen Production ◽  
Surface Reaction Kinetics

AbstractConversion of energy from photons in sunlight to hydrogen through solar splitting of water is an important technology. The rising significance of producing hydrogen from solar light via water splitting has motivated a surge of developing semiconductor solar-active nanostructures as photocatalysts and photoelectrodes. Traditional strategies have been developed to enhance solar light absorption (e.g., ion doping, solid solution, narrow-band-gap semiconductor or dye sensitization) and improve charge separation/transport to prompt surface reaction kinetics (e.g., semiconductor combination, co-catalyst loading, nanostructure design) for better utilizing solar energy. However, the solar-to-hydrogen efficiency is still limited. This article provides an overview of recently demonstrated novel concepts of nanostructure designs for efficient solar hydrogen conversion, which include surface engineering, novel nanostructured heterojunctions, and photonic crystals. Those first results outlined in the main text encouragingly point out the prominence and promise of these new concepts principled for designing high-efficiency electronic and photonic nanostructures that could serve for sustainable solar hydrogen production.

Pyrazolium Phase Change Materials for Solar-Thermal and Wind Energy Storage

2019 ◽  
Author(s):  
Karolina Matuszek ◽  
R. Vijayaraghavan ◽  
Craig Forsyth ◽  
Surianarayanan Mahadevan ◽  
Mega Kar ◽  
...  
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
High Efficiency ◽  
Scale Up ◽  
Solar Thermal ◽  
Energy Storage Materials ◽  
Solar Thermal Energy ◽  
Storage Materials

Renewable energy has the ultimate capacity to resolve the environmental and scarcity challenges of the world’s energy supplies. However, both the utility of these sources and the economics of their implementation are strongly limited by their intermittent nature; inexpensive means of energy storage therefore needs to be part of the design. Distributed thermal energy storage is surprisingly underdeveloped in this context, in part due to the lack of advanced storage materials. Here, we describe a novel family of thermal energy storage materials based on pyrazolium cation, that operate in the 100-220°C temperature range, offering safe, inexpensive capacity, opening new pathways for high efficiency collection and storage of both solar-thermal energy, as well as excess wind power. We probe the molecular origins of the high thermal energy storage capacity of these ionic materials and demonstrate extended cycling that provides a basis for further scale up and development.

scholarly journals Wittichenite semiconductor of Cu3BiS3 films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dingwang Huang ◽  
Lintao Li ◽  
Kang Wang ◽  
Yan Li ◽  
Kuang Feng ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Water Splitting ◽  
Low Cost ◽  
Solar Hydrogen ◽  
Onset Potential ◽  
Term Stability ◽  
Long Term Stability ◽  
Solar Water Splitting ◽  
Current Densities

AbstractA highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu3BiS3 film-based photocathode meets the abovementioned requirements. The Cu3BiS3-based photocathode presents a remarkable onset potential over 0.9 VRHE with excellent photoelectrochemical current densities (~7 mA/cm2 under 0 VRHE) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu3BiS3-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm2 assisted by the BiVO4 photoanode. A tandem device of Cu3BiS3-BiVO4 with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm2 large Cu3BiS3-BiVO4 tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.

scholarly journals Maintaining paediatric cardiac services during the COVID-19 pandemic in a developing country in sub-Saharan Africa: guidelines for a “scale up” in the face of a global “scale down”

2020 ◽  
Vol 30 (11) ◽  
pp. 1588-1594
Author(s):  
Ogochukwu J. Sokunbi ◽  
Ogadinma Mgbajah ◽  
Augustine Olugbemi ◽  
Bassey O. Udom ◽  
Ariyo Idowu ◽  
...  
Keyword(s):  
Scale Up ◽  
Global Scale ◽  
International Travel ◽  
Sub Saharan Africa ◽  
African Continent ◽  
Tertiary Centre ◽  
The Face ◽  
Scale Down ◽  
Sub Saharan ◽  
International Experts

AbstractThe COVID-19 pandemic is currently ravaging the globe and the African continent is not left out. While the direct effects of the pandemic in regard to morbidity and mortality appear to be more significant in the developed world, the indirect harmful effects on already insufficient healthcare infrastructure on the African continent would in the long term be more detrimental to the populace. Women and children form a significant vulnerable population in underserved areas such as the sub-Saharan region, and expectedly will experience the disadvantages of limited healthcare coverage which is a major fall out of the pandemic. Paediatric cardiac services that are already sparse in various sub-Saharan countries are not left out of this downsizing. Restrictions on international travel for patients out of the continent to seek medical care and for international experts into the continent for regular mission programmes leave few options for children with cardiac defects to get the much-needed care.There is a need for a region-adapted guideline to scale-up services to cater for more children with congenital heart disease (CHD) while providing a safe environment for healthcare workers, patients, and their caregivers. This article outlines measures adapted to maintain paediatric cardiac care in a sub-Saharan tertiary centre in Nigeria during the COVID-19 pandemic and will serve as a guide for other institutions in the region who will inadvertently need to provide these services as the demand increases.

Regional super power grids face political obstacles

2021 ◽  
Keyword(s):  
Electricity Generation ◽  
Fossil Fuels ◽  
Peak Load ◽  
Global Scale ◽  
Power Grids ◽  
Submarine Cable ◽  
Content Type ◽  
Cable Industry ◽  
Global Power ◽  
Load Generation

Significance Its proponents argue that interconnecting the world’s power grids would make it easier for renewable energy, however remotely it is generated, to replace most fossil fuels in electricity generation. Implementation remains a distant, and politically fraught, possibility but regional super-grids look increasingly feasible and could boost the submarine cable industry. Impacts Load-balancing on a global scale could reduce peak load generation needs by an estimated 5-10%, saving billions in investment. Power grids require estimated investment of USD14tn by 2050, nearly as much as projected spending on new renewables capacity. International rules on carbon pricing and taxing would be a prerequisite for a global power grid.

scholarly journals Achieving Net Zero Carbon Dioxide by Sequestering Biomass Carbon

2020 ◽  
Author(s):  
Jeffrey Amelse
Keyword(s):  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Co2 Emissions ◽  
Energy Demand ◽  
Co2 Sequestration ◽  
Fossil Fuels ◽  
Scale Up ◽  
Biomass Carbon ◽  
Net Zero ◽  
The World

Mitigation of global warming requires an understanding of where energy is produced and consumed, the magnitude of carbon dioxide generation, and proper understanding of the Carbon Cycle. The latter leads to the distinction between and need for both CO2 and biomass CARBON sequestration. Short reviews are provided for prior technologies proposed for reducing CO2 emissions from fossil fuels or substituting renewable energy, focusing on their limitations. None offer a complete solution. Of these, CO2 sequestration is poised to have the largest impact. We know how to do it. It will just cost money, and scale-up is a huge challenge. Few projects have been brought forward to semi-commercial scale. Transportation accounts for only about 30% of U.S. overall energy demand. Biofuels penetration remains small, and thus, they contribute a trivial amount of overall CO2 reduction, even though 40% of U.S. corn and 30% of soybeans are devoted to their production. Bioethanol is traced through its Carbon Cycle and shown to be both energy inefficient, and an inefficient use of biomass carbon. Both biofuels and CO2 sequestration reduce FUTURE CO2 emissions from continued use of fossil fuels. They will not remove CO2 ALREADY in the atmosphere. The only way to do that is to break the Carbon Cycle by growing biomass from atmospheric CO2 and sequestering biomass CARBON. Theoretically, sequestration of only a fraction of the world’s tree leaves, which are renewed every year, can get the world to Net Zero CO2 without disturbing the underlying forests.

scholarly journals Direct Carbon Fuel Cell-Cleaner and Efficient Future Power Generation Technology

2019 ◽  
Vol 6 (1) ◽  
pp. 14-30
Author(s):  
Uzair Ibrahim ◽  
Ahsan Ayub
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cell ◽  
Fossil Fuels ◽  
High Efficiency ◽  
Thermal Power ◽  
Gaseous State ◽  
Thermal Plant ◽  
Direct Carbon Fuel Cell ◽  
Pure Carbon ◽  
Pure Carbon Dioxide

Increasing greenhouse effect due to the burning of fossil fuels has stirred the attention of researchers towards cleaner and efficient technologies. Direct carbon fuel cell (DCFC) is one such emerging technology that could generate electricity from solid carbon like coal and biogas in a more efficient and environmental-friendly way. The mechanism involves electrochemical oxidation of carbon to produce energy and highly pure carbon dioxide. Due to higher purity, the produced carbon dioxide can be captured easily to avoid its release in the environment. The carbon dioxide is produced in a gaseous state while the fuel used is in a solid state. Due to different phases, all of the fuel can be recovered from the cell and can be reused, ensuring complete (100%) fuel utilization with no fuel losses. Moreover, DCFC operates at a temperature lower than conventional fuel cells. The electric efficiency of a DCFC is around 80% which is nearly double the efficiency of coal thermal plant. In addition, DCFC produces pure carbon dioxide as compared to the thermal power plant which reduces the cost of CO2 separation and dumping. In different types of DCFCs, molten carbon fuel cell is considered to be superior due to its low operating temperature and high efficiency. This paper provides a comprehensive review of the direct carbon fuel cell technology and recent advances in this field. The paper is focused on the fundamentals of fuel cell, history, operating principle, its types, applications, future challenges, and development.

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