The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

scholarly journals ESD Ideas: Photoelectrochemical carbon removal as negative emission technology

2019 ◽  
Vol 10 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Matthias M. May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
Large Scale ◽  
Energy Use ◽  
World Population ◽  
Low Carbon ◽  
Low Carbon Economy ◽  
Negative Emissions ◽  
Negative Emission ◽  
Viable Approach ◽  
Negative Emission Technologies

Abstract. The pace of the transition to a low-carbon economy – especially in the fuels sector – is not high enough to achieve the 2 ∘C target limit for global warming by only cutting emissions. Most political roadmaps to tackle global warming implicitly rely on the timely availability of mature negative emission technologies, which actively invest energy to remove CO2 from the atmosphere and store it permanently. The models used as a basis for decarbonization policies typically assume an implementation of such large-scale negative emission technologies starting around the year 2030, ramped up to cause net negative emissions in the second half of the century and balancing earlier CO2 release. On average, a contribution of −10 Gt CO2 yr−1 is expected by 2050 (Anderson and Peters, 2016). A viable approach for negative emissions should (i) rely on a scalable and sustainable source of energy (solar), (ii) result in a safely storable product, (iii) be highly efficient in terms of water and energy use, to reduce the required land area and competition with water and food demands of a growing world population, and (iv) feature large-scale feasibility and affordability.

scholarly journals Ideas: Photoelectrochemical carbon removal as negative emission technology

2018 ◽  
Author(s):  
Matthias M. May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
Large Scale ◽  
Energy Use ◽  
World Population ◽  
Low Carbon ◽  
Low Carbon Economy ◽  
Negative Emissions ◽  
Negative Emission ◽  
Viable Approach ◽  
Negative Emission Technologies

Abstract. The pace of the transition to a low-carbon economy – especially in the fuels sector – is not high enough to achieve the 2 °C target limit for global warming by only cutting emissions. Most political roadmaps to tackle global warming implicitly rely on the timely availability of mature negative emission technologies, which actively invest energy to remove CO2 from the atmosphere and store it permanently. The models used as a basis for decarbonisation policies typically assume an implementation of such large-scale negative emission technologies starting around the year 2030, ramped up to cause net negative emissions in the second half of the century and balancing earlier CO2 release. On average, a contribution of −10 Gt CO2/year is expected by 2050.(Anderson and Peters, 2016) A viable approach for negative emissions should (i) rely on an unlimited source of energy (solar), (ii) result in a safely storable product (e.g. liquid or solid, not gaseous), (iii) be highly efficient in terms of water and energy use, to reduce the required land area and competition with water and food demands of a growing world population and (iv) be large-scale feasibility and affordability.

scholarly journals The Component Test Facility: A National User Facility for Testing of High Temperature Gas-Cooled Reactor (HTGR) Components and Systems

2008 ◽  
Author(s):  
Vondell J. Balls ◽  
David S. Duncan ◽  
Stephanie L. Austad
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
High Efficiency ◽  
Scale Effects ◽  
Nuclear Plant ◽  
Department Of Energy ◽  
Test Facility ◽  
Component Test ◽  
User Facility ◽  
High Temperature Gas

The Next Generation Nuclear Plant (NGNP) and other High-Temperature Gas-cooled Reactor (HTGR) Projects require research, development, design, construction, and operation of a nuclear plant intended for both high-efficiency electricity production and high-temperature industrial applications, including hydrogen production. During the life cycle stages of an HTGR, plant systems, structures and components (SSCs) will be developed to support this reactor technology. To mitigate technical, schedule, and project risk associated with development of these SSCs, a large-scale test facility is required to support design verification and qualification prior to operational implementation. As a full-scale helium test facility, the Component Test facility (CTF) will provide prototype testing and qualification of heat transfer system components (e.g., Intermediate Heat Exchanger, valves, hot gas ducts), reactor internals, and hydrogen generation processing. It will perform confirmation tests for large-scale effects, validate component performance requirements, perform transient effects tests, and provide production demonstration of hydrogen and other high-temperature applications. Sponsored wholly or in part by the U.S. Department of Energy, the CTF will support NGNP and will also act as a National User Facility to support worldwide development of High-Temperature Gas-cooled Reactor technologies.

Design of a Novel High Temperature Gravity-Fed Solar Thermochemical Reactor for Solar-Fuels Production: Case Study - ZnO Powder

2011 ◽  
Author(s):  
Erik Koepf ◽  
Suresh G. Advani ◽  
Ajay K. Prasad
Keyword(s):  
Large Scale ◽  
High Efficiency ◽  
Combustion Engine ◽  
The United States ◽  
Solar Fuels ◽  
Thermochemical Cycle ◽  
Carbon Neutrality ◽  
Gravity Driven ◽  
Solar Thermochemical ◽  
Zno Powder

Solar fuels are emerging as a viable pathway towards closing the gap between fuel production and consumption in the United States. If these fuels can be produced on large scale and achieve carbon-neutrality, a truly sustainable energy solution may be realized. Hydrogen is among the list of attractive solar fuels. Whether used in a PEM fuel cell or combustion engine, hydrogen as a fuel produced from sunlight and water represents an elegant energy harvesting cycle, with zero-emissions, high efficiency, and exceptional power-density. A novel solar-thermochemical reactor has been designed and constructed for the reduction of ZnO at temperatures close to 2000K as the first step in a closed two-step thermochemical cycle to produce hydrogen from water as a solar fuel. Abbreviated as GRAFSTRR (Gravity-Fed Solar-Thermochemical Receiver/Reactor), the reactor is closed to the atmosphere, and features an inverted conical-shaped reaction surface along which ZnO powder descends continuously as a falling sheet and undergoes a thermochemical reaction upon exposure to highly concentrated sunlight. The reactant feed is vibration-induced, metered, and gravity-driven. Beam-down, highly concentrated sunlight enters the reaction cavity through a water-cooled aperture, and Zn product gas is siphoned into a centrally-located exit stream via a stabilized vortex flow of inert gas originating from above the aperture plane. Unreacted or partially reacted solids exit annularly around the product stream. In this paper the GRAFSTRR concept is presented. Select design choices and investigations are summarized.

Electrochemical Carbon Separation in a SOFC-MCFC Poly-Generation Plant With Near-Zero Emissions

2017 ◽  
Author(s):  
Luca Mastropasqua ◽  
Stefano Campanari ◽  
Jack Brouwer
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Carbon Capture ◽  
Large Scale ◽  
High Efficiency ◽  
Molten Carbonate Fuel Cell ◽  
Small Scale ◽  
Total Efficiency ◽  
Molten Carbonate

High temperature fuel cells have been studied as a suitable solution for Carbon Capture and Storage (CCS) purposes at a large scale (>100 MW). However, their modularity and high efficiency at small-scale make them an interesting solution for Carbon Capture and Utilisation at the distributed generation scale when coupled to appropriate use of CO2 (i.e., for industrial uses, local production of chemicals etc.). These systems could be used within low carbon micro-grids to power small communities in which multiple power generating units of diverse nature supply multiple products such as electricity, cooling, heating and chemicals (i.e., hydrogen and CO2). The present work explores fully electrochemical power systems capable of producing a highly pure CO2 stream and hydrogen. In particular, the proposed system is based upon integrating a Solid Oxide Fuel Cell (SOFC) with a Molten Carbonate Fuel Cell (MCFC). The use of these high temperature fuel cells has already been separately applied in the past for CCS applications. However, their combined use is yet unexplored. Moreover, both industry and US national laboratories have expressed their interest in this solution. The reference configuration proposed envisions the direct supply of the SOFC anode outlet to a burner which, using the cathode depleted air outlet, completes the oxidation of the unconverted species. The outlet of the burner is then fed to the MCFC cathode inlet which separates the CO2 from the stream. Both the SOFC and MCFC anode inlets are supplied with pre-reformed and desulfurized natural gas. The MCFC anode outlet, which is characterised by a high concentration of CO2, is fed to a CO2 separation line in which a two-stage Water Gas Shift (WGS) reactor and a PSA/membrane system respectively convert the remaining CO into H2 and remove the H2 from the exhaust stream. This has the significant advantage of achieving the required CO2 purity for liquefaction and long-range transportation without requiring the need of cryogenic or distillation plants. Moreover, the highly pure H2 stream can either be sold as transportation fuel or a valuable chemical. Furthermore, different configurations are considered with the final aim of increasing the Carbon Capture Ratio (CCR) and maximising the electrical efficiency. Moreover, the optimal power ratio between SOFC and MCFC stacks is also explored. Complete simulation results are presented, discussing the proposed plant mass and energy balances and showing the most attractive configurations from the point of view of total efficiency and CCR.

Thermodynamics and Transport Phenomena in High Temperature Steam Electrolysis Cells

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
James E. O’Brien
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
High Efficiency ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
High Temperature Process ◽  
Electrolysis Cells ◽  
High Temperature Steam ◽  
Electrolysis Mode ◽  
High Temperature Electrolysis

Hydrogen can be produced from water splitting with relatively high efficiency using high temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high temperature process heat. The overall thermal-to-hydrogen efficiency for high temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. An overview of high temperature electrolysis technology will be presented, including basic thermodynamics, experimental methods, heat and mass transfer phenomena, and computational fluid dynamics modeling.

scholarly journals Large Scale Hydrogen Production From Nuclear Energy Using High Temperature Electrolysis

2010 ◽  
Author(s):  
James E. O’Brien
Keyword(s):  
High Temperature ◽  
Hydrogen Production ◽  
Oil Sands ◽  
Large Scale ◽  
Fossil Fuels ◽  
High Efficiency ◽  
Liquid Fuels ◽  
Low Grade ◽  
Transportation Fuel ◽  
High Temperature Electrolysis

Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

Pressure Cooker with Composite Bottom Thermo-Mechanical Coupling Simulation

2013 ◽  
Vol 712-715 ◽  
pp. 1058-1061 ◽  
Author(s):  
Xiang Hong Zhang ◽  
Han Yang ◽  
Hao Zhang ◽  
He Liu ◽  
Hong Fen Guo
Keyword(s):  
High Temperature ◽  
Large Scale ◽  
High Efficiency ◽  
Coupling Effect ◽  
Operating Pressure ◽  
Breakdown Pressure ◽  
Mechanical Coupling ◽  
Simulating Calculation ◽  
Long Time ◽  
Type Pressure

t is required to use specialized large-scale pressure cooker to process and cook rice in high altitude. The design of large-scale pressure cooker with composite bottom is a very complicated process, involving in nominal operating pressure, safe pressure and breakdown pressure, etc., especially the advantage of composite-bottom pressure cooker possesses, which are fast heat conduction, high efficiency and energy conservation, but it is very easy to ignore thermo-mechanical coupling effect which the compound aluminum steel of pressure cooker with composite bottom exerted in the hot operation working condition in the process of designing pressure cooker, once the bottom is dropped due to the condition of high temperature, the whole feeding equipment will not work properly. Analysis software ANSYS is applied to make simulating calculation for thermo-mechanical coupling of super-huge type pressure cooker with composite bottom, verifying if it can operate properly in the field condition of long time and high temperature.

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