Production & Supply Chain
Energy-Efficient Distributed Carbon Capture in Hydrogen Production from Natural Gas
Apr 2011
Publication
Lowering the energy penalty associated with CO2 capture is one of the key issues of Carbon Capture and Storage (CCS) technologies. The efficiency of carbon capture must be improved to reduce the energy penalty because capture stage is the most energy-consuming stage in the entire process of CCS. Energy-efficient distributed carbon capture in hydrogen production has been demonstrated with an advanced membrane reformer system. We have already developed and operated an advanced 40 Nm3 /h-class membrane reformer system and demonstrated its high hydrogen production efficiency of 81.4% (HHV) which is the world highest efficiency in terms of hydrogen production from natural gas. The system has another significant feature that the CO2 concentration in the reactor off-gas is as high as 70~90% and CO2 can be liquefied and separated easily with little energy loss. An apparatus for CO2 capture was combined to the membrane reformer system and over 90% of CO2 in the reactor off-gas was captured by cryogenic separation. The total energy efficiency of hydrogen production even with CO2 capture was still as high as 78.6% (HHV) which is 510% higher than the conventional reforming technologies. The total CO2 emission from hydrogen production was decreased by 50% with only a 3% energy loss. A sensitivity analysis was also carried out to evaluate the effects of the operating conditions of the system on hydrogen production efficiency and CO2 reduction rate.
Sensing Hydrogen Seeps in the Subsurface for Natural Hydrogen Exploration
Jun 2022
Publication
The recent detection of natural hydrogen seeps in sedimentary basin settings has triggered significant interest in the exploration of this promising resource. If large economical resources exist and can be extracted from the sub-surface this would provide an opportunity for natural hydrogen to contribute to the non-carbon-based energy mix. The detection and exploration of hydrogen gas in the sub-surface is a significant challenge that requires costly drilling sophisticated instrumentation and reliable analytical/sampling methods. Here we propose the application of a commercial-based sensor that can be used to detect and monitor low levels of hydrogen gas emissions from geological environments. The sensitivity selectivity (K > 1000) and stability (<1 ppm/day) of the sensor was evaluated under various conditions to determine its suitability for geological field monitoring. Calibration tests showed that the hydrogen readings from the sensor were within ±20% of the expected values. We propose that chemical sensing is a simple and feasible method for understanding natural hydrogen seeps that emanate from geological systems and formations. However we recommend using this sensor as part of a complete geological survey that incorporates an understanding of the geology along with complementary techniques that provide information on the rock properties.
Delivering Clean Growth: CCUS Cost Challenge Taskforce Report
Jul 2018
Publication
An independent report by the CCUS Cost Challenge Taskforce setting out the industry’s view on how best to progress carbon capture usage and storage (CCUS) in the UK in order to enable the UK to have the option of deploying CCUS at scale during the 2030s subject to costs coming down sufficiently.
Transient Reversible Solid Oxide Cell Reactor Operation – Experimentally Validated Modeling and Analysis
Oct 2018
Publication
A reversible solid oxide cell (rSOC) reactor can operate efficiently in both electrolysis mode and in fuel cell mode. The bidirectional operability enables rSOC reactors to play a central role as an efficient energy conversion system for energy storage and sector coupling for a renewable energy driven society. A combined system for electrolysis and fuel cell operation can result in complex system configurations that should be able to switch between the two modes as quickly as possible. This can lead to temperature profiles within the reactor that can potentially lead to the failure of the reactor and eventually the system. Hence the behavior of the reactor during the mode switch should be analyzed and optimal transition strategies should be taken into account during the process system design stage. In this paper a one dimensional transient reversible solid oxide cell model was built and experimentally validated using a commercially available reactor. A simple hydrogen based system model was built employing the validated reactor model to study reactor behavior during the mode switch. The simple design leads to a system efficiency of 49% in fuel cell operation and 87% in electrolysis operation where the electrolysis process is slightly endothermic. Three transient operation strategies were studied. It is shown that the voltage response to transient operation is very fast provided the reactant flows are changed equally fast. A possible solution to ensure a safe mode switch by controlling the reactant inlet temperatures is presented. By keeping the rate of change of reactant inlet temperatures five to ten times slower than the mode switch a safe transition can be ensured.
Everything About Hydrogen Podcast: Going "Green"
May 2021
Publication
Founded in 2007 and based in Denmark Green Hydrogen Systems designs and manufactures efficient standardized and modular electrolysers for the production of green hydrogen with renewable energy. Niels-Arne Baden has led the company to the upper echelons of the electrolysis sector and he now leads the company's strategy and and public-facing initiatives as the Vice President for Strategy and Public Affairs. On this episode of the Everything About Hydrogen podcast the EAH team sits down with Niels to talk about the journey of the clean hydrogen sector over the recent decades and its rise to prominence in the transition to a decarbonized energy future and how modular electrolysis fits into that picture.
The podcast can be found on their website
The podcast can be found on their website
SNG Generation via Power to Gas Technology: Plant Design and Annual Performance Assessment
Nov 2020
Publication
Power to gas (PtG) is an emerging technology that allows to overcome the issues due to the increasingly widespread use of intermittent renewable energy sources (IRES). Via water electrolysis power surplus on the electric grid is converted into hydrogen or into synthetic natural gas (SNG) that can be directly injected in the natural gas network for long-term energy storage. The core units of the Power to synthetic natural gas (PtSNG) plant are the electrolyzer and the methanation reactors where the renewable electrolytic hydrogen is converted to synthetic natural gas by adding carbon dioxide. A technical issue of the PtSNG plant is the different dynamics of the electrolysis unit and the methanation unit. The use of a hydrogen storage system can help to decouple these two subsystems and to manage the methanation unit for assuring long operation time and reducing the number of shutdowns. The purpose of this paper is to evaluate the energy storage potential and the technical feasibility of the PtSNG concept to store intermittent renewable sources. Therefore different plant sizes (1 3 and 6 MW) have been defined and investigated by varying the ratio between the renewable electric energy sent to the plant and the total electric energy generated by the renewable energy source (RES) facility based on a 12 MW wind farm. The analysis has been carried out by developing a thermochemical and electrochemical model and a dynamic model. The first allows to predict the plant performance in steady state. The second allows to forecast the annual performance and the operation time of the plant by implementing the control strategy of the storage unit. The annual overall efficiencies are in the range of 42–44% low heating value (LHV basis). The plant load factor i.e. the ratio between the annual chemical energy of the produced SNG and the plant capacity results equal to 60.0% 46.5% and 35.4% for 1 3 and 6 MW PtSNG sizes respectively.
A Combined Chemical-Electrochemical Process to Capture CO2 and Produce Hydrogen and Electricity
Sep 2021
Publication
Several carbon sequestration technologies have been proposed to utilize carbon dioxide (CO2 ) to produce energy and chemical compounds. However feasible technologies have not been adopted due to the low efficiency conversion rate and high-energy requirements. Process intensification increases the process productivity and efficiency by combining chemical reactions and separation operations. In this work we present a model of a chemical-electrochemical cyclical process that can capture carbon dioxide as a bicarbonate salt. The proposed process also produces hydrogen and electrical energy. Carbon capture is enhanced by the reaction at the cathode that displaces the equilibrium into bicarbonate production. Literature data show that the cyclic process can produce stable operation for long times by preserving ionic balance using a suitable ionic membrane that regulates ionic flows between the two half-cells. Numerical simulations have validated the proof of concept. The proposed process could serve as a novel CO2 sequestration technology while producing electrical energy and hydrogen.
Recent Advances in Hybrid Water Electrolysis for Energy-saving Hydrogen Production
Nov 2022
Publication
Electricity-driven water splitting to convert water into hydrogen (H2) has been widely regarded as an efficient approach for H2 production. Nevertheless the energy conversion efficiency of it is greatly limited due to the disadvantage of the sluggish kinetic of oxidation evolution reaction (OER). To effectively address the issue a novel concept of hybrid water electrolysis has been developed for energy– saving H2 production. This strategy aims to replace the sluggish kinetics of OER by utilizing thermodynamically favorable organics oxidation reaction to replace OER. Herein recent advances in such water splitting system for boosting H2 evolution under low cell voltage are systematically summarized. Some notable progress of different organics oxidation reactions coupled with hydrogen evolution reaction (HER) are discussed in detail. To facilitate the development of hybrid water electrolysis the major challenges and perspectives are also proposed.
System Dynamic Model for the Accumulation of Renewable Electricity using Power-to-Gas and Power-to-Liquid Concepts
Feb 2016
Publication
When the renewable energy is used the challenge is match the supply of intermittent energy with the demand for energy therefore the energy storage solutions should be used. This paper is dedicated to hydrogen accumulation from wind sources. The case study investigates the conceptual system that uses intermitted renewable energy resources to produce hydrogen (power-to-gas concept) and fuel (power-to-liquid concept). For this specific case study hydrogen is produced from surplus electricity generated by wind power plant trough electrolysis process and fuel is obtained by upgrading biogas to biomethane using hydrogen. System dynamic model is created for this conceptual system. The developed system dynamics model has been used to simulate 2 different scenarios. The results show that in both scenarios the point at which the all electricity needs of Latvia are covered is obtained. Moreover the methodology of system dynamics used in this paper is white-box model that allows to apply the developed model to other case studies and/or to modify model based on the newest data. The developed model can be used for both scientific research and policy makers to better understand the dynamic relation within the system and the response of system to changes in both internal and external factors.
Investigation on Green Hydrogen Generation Devices Dedicated for Integrated Renewable Energy Farm: Solar and Wind
Oct 2022
Publication
This study presents a comprehensive methodology to evaluate plants that integrate renewable energy sources and hydrogen generation devices. The paper focuses on presenting the methods for devices’ operation assessment taking into account the annual operation. Multiple effectiveness indices have been presented. On the basis of experimental investigation with the hydrogen generator the methods for assessing its operation during start-up phase and sudden change in the supply current were proposed. The results of the experiments and the provided mathematical models show that dynamics of the hydrogen generator should be taken into account when selecting the suitable device for cooperation with variable renewable energy. It is especially important for multiple start-ups throughout the day due to significant differences in the amount of hydrogen produced by devices characterized by the same efficiency yet various time constants. Methodology for selecting the optimal nominal power for hydrogen generator to cooperate with given renewable sources was developed. It was proven the optimal power depends on the type of the renewable source and minimal load of the hydrogen generator. Several case studies including the integration of wind and solar energy farms to yield a 10 MW renewable energy farm were considered and the minimal load of the hydrogen generator impacts the annual operation of the device has been presented. The paper provides a set of tools to contribute to the development of sustainable energy plants. The methods proposed in this paper are universal and can be used for various renewable energy sources.
Advances in Hydrogen Production from Natural Gas Reforming
Jun 2021
Publication
Steam natural gas reforming is the preferred technique presently used to produce hydrogen. Proposed in 1932 the technique is very well established but still subjected to perfections. Herein first the improvements being sought in catalysts and processes are reviewed and then the advantage of replacing the energy supply from burning fuels with concentrated solar energy is discussed. It is especially this advance that may drastically reduce the economic and environmental cost of hydrogen production. Steam reforming can be easily integrated into concentrated solar with thermal storage for continuous hydrogen production.
Decarbonization in Ammonia Production, New Technological Methods in Industrial Scale Ammonia Production and Critical Evaluations
Oct 2021
Publication
With the synthesis of ammonia with chemical methods global carbon emission is the biggest threat to global warming. However the dependence of the agricultural industry on ammonia production brings with it various research studies in order to minimize the carbon emission that occurs with the ammonia synthesis process. In order to completely eliminate the carbon emissions from ammonia production both the hydrogen and the energy needed for the operation of the process must be obtained from renewable sources. Thus hydrogen can be produced commercially in a variety of ways. Many processes are discussed to accompany the Haber Bosch process in ammonia production as potential competitors. In addition to parameters such as temperature and pressure various plasma catalysts are being studied to accelerate the ammonia production reaction. In this study various alternative processes for the capture storage and complete removal of carbon gas released during the current ammonia production are evaluated and the current conditions related to the applicability of these processes are discussed. In addition it has been discussed under which conditions it is possible to produce larger capacities as needed in the processes studied in order to reduce carbon gas emissions during ammonia production in order to provide raw material source for fertilizer production and energy sector. However if the hydrogen gas required for ammonia production is produced using a solid oxide electrolysis cell the reduction in the energy requirement of the process and in this case the reduction of energy costs shows that it will play an important role in determining the method to be used for ammonia production. In addition it is predicted that working at lower temperature (<400 °C) and pressure (<10 bar) values in existing ammonia production technologies despite increasing possible energy costs will significantly reduce process operating costs.
An Overview of Water Electrolysis Technologies for Green Hydrogen Production
Oct 2022
Publication
Decarbonizing the planet is one of the major goals that countries around the world have set for 2050 to mitigate the effects of climate change. To achieve these goals green hydrogen that can be produced from the electrolysis of water is an important key solution to tackle global decarbonization. Consequently in recent years there is an increase in interest towards green hydrogen production through the electrolysis process for large-scale implementation of renewable energy based power plants and other industrial and transportation applications. The main objective of this study was to provide a comprehensive review of various green hydrogen production technologies especially on water electrolysis. In this review various water electrolysis technologies and their techno-commercial prospects including hydrogen production cost along with recent developments in electrode materials and their challenges were summarized. Further some of the most successful results also were described. Moreover this review aims to identify the gaps in water electrolysis research and development towards the techno-commercial perspective. In addition some of the commercial electrolyzer performances and their limitations also were described along with possible solutions for cost-effective hydrogen production Finally we outlined our ideas and possible solutions for driving cost-effective green hydrogen production for commercial applications. This information will provide future research directions and a road map for the development/implementation of commercially viable green hydrogen projects.
Biohydrogen—A Green Fuel for Sustainable Energy Solutions
Oct 2022
Publication
Energy plays a crucial role in the sustainable development of modern nations. Today hydrogen is considered the most promising alternative fuel as it can be generated from clean and green sources. Moreover it is an efficient energy carrier because hydrogen burning only generates water as a byproduct. Currently it is generated from natural gas. However it can be produced using other methods i.e. physicochemical thermal and biological. The biological method is considered more environmentally friendly and pollution free. This paper aims to provide an updated review of biohydrogen production via photofermentation dark fermentation and microbial electrolysis cells using different waste materials as feedstocks. Besides the role of nanotechnology in enhancing biohydrogen production is examined. Under anaerobic conditions hydrogen is produced during the conversion of organic substrate into organic acids using fermentative bacteria and during the conversion of organic acids into hydrogen and carbon dioxide using photofermentative bacteria. Different factors that enhance the biohydrogen production of these organisms either combined or sequentially using dark and photofermentation processes are examined and the effect of each factor on biohydrogen production efficiency is reported. A comparison of hydrogen production efficiency between dark fermentation photofermentation and two-stage processes is also presented.
Prospect of Green Hydrogen Generation from Hybrid Renewable Energy Sources: A Review
Feb 2023
Publication
Hydrogen is one of the prospective clean energies that could potentially address two pressing areas of global concern namely energy crises and environmental issues. Nowadays fossil‐ based technologies are widely used to produce hydrogen and release higher greenhouse gas emis‐ sions during the process. Decarbonizing the planet has been one of the major goals in the recent decades. To achieve this goal it is necessary to find clean sustainable and reliable hydrogen pro‐ duction technologies with low costs and zero emissions. Therefore this study aims to analyse the hydrogen generation from solar and wind energy sources and observe broad prospects with hybrid renewable energy sources in producing green hydrogen. The study mainly focuses on the critical assessment of solar wind and hybrid‐powered electrolysis technologies in producing hydrogen. Furthermore the key challenges and opportunities associated with commercial‐scale deployment are addressed. Finally the potential applications and their scopes are discussed to analyse the important barriers to the overall commercial development of solar‐wind‐based hydrogen production systems. The study found that the production of hydrogen appears to be the best candidate to be employed for multiple purposes blending the roles of fuel energy carrier and energy storage modality. Further studies are recommended to find technical and sustainable solutions to overcome the current issues that are identified in this study.
Green and Blue Hydrogen Production: An Overview in Colombia
Nov 2022
Publication
Colombia a privileged country in terms of diversity availability of natural resources and geographical location has set a roadmap for hydrogen as part of the energy transition plan proposed in 2021. To reduce its emissions in the mid-term and foster its economy hydrogen production should be green and blue with specific targets set for 2030 for the hydrogen costs and produced quantities. This work compares the state-of-the-art production of blue and green hydrogen and how Colombia is doing in each pathway. A deeper analysis considers the advantages of Colombia’s natural resources the possible paths the government could follow and the feedstock’s geographical location for hydrogen production and transportation. Then one discusses what may be the next steps in terms of policies and developments to succeed in implementing the plan. Overall it is concluded that green hydrogen could be the faster more sustainable and more efficient method to implement in Colombia. However blue hydrogen could play an essential role if oil and gas companies assess the advantages of carbon dioxide utilization and promote its deployment.
Proton Exchange Membrane Electrolyzer Emulator for Power Electronics Testing Applications
Mar 2021
Publication
This article aims to develop a proton exchange membrane (PEM) electrolyzer emulator. This emulator is realized through an equivalent electrical scheme. It allows taking into consideration the dynamic operation of PEM electrolyzers which is generally neglected in the literature. PEM electrolyzer dynamics are reproduced by the use of supercapacitors due to the high value of the equivalent double-layer capacitance value. Steady-state and dynamics operations are investigated in this work. The design criteria are addressed. The PEM electrolyzer emulator is validated by using a 400-W commercial PEM electrolyzer. This emulator is conceived to test new DC-DC converters to supply the PEM ELs and their control as well avoiding the risk to damage a real electrolyzer for experiment purposes. The proposed approach is valid both for a single cell and for the whole stack emulation.
Optimising Onshore Wind with Energy Storage Considering Curtailment
May 2022
Publication
Operating energy storage alongside onshore wind can improve its economics whilst providing a pathway for otherwise curtailed generation. In this work we present a framework to evaluate the economic potential of onshore wind co-located with battery storage (BS) and a hydrogen electrolyser (HE). This model is applied to a case study in Great Britain using historic data and considering local network charges and the cost of using curtailed power capturing an often neglected element of competition. We use a Markov Chain to model wind curtailment and determine the optimised scheduling of the storage as we vary price parameters and storage sizing. Finally by considering storage CAPEX and comparing against the case with no storage we can determine the value added (or lost) by different sized BS and HE for an onshore wind owner as a function of power purchase agreement (PPA) and green hydrogen market price. Results show that value added increases when HE is increased and when BS is decreased. Additionally a 10 MW electrolysers uses 27% more curtailed wind than 10 MW BS.
Optimization of Renewable Energy Supply Chain for Sustainable Hydrogen Energy Production from Plastic Waste
Dec 2023
Publication
Disposing of plastic waste through burial or burning leads to air pollution issues while also contributing to gas emissions and plastic waste spreading underground into seas via springs. Henceforth this research aims at reducing plastic waste volume while simultaneously generating clean energy. Hydrogen energy is a promising fuel source that holds great value for humanity. However achieving clean hydrogen energy poses challenges including high costs and complex production processes especially on a national scale. This research focuses on Iran as a country capable of producing this energy examining the production process along with related challenges and the general supply chain. These challenges encompass selecting appropriate raw materials based on chosen technologies factory capacities storage methods and transportation flow among different provinces of the country. To deal with these challenges a mixed-integer linear programming model is developed to optimize the hydrogen supply chain and make optimal decisions about the mentioned problems. The supply chain model estimates an average cost—IRR 4 million (approximately USD 8)—per kilogram of hydrogen energy that is available in syngas during the initial period; however subsequent periods may see costs decrease to IRR 1 million (approximately USD 2) factoring in return-on-investment rates.
Profitability Model of Green Hydrogen Production on an Existing Wind Power Plant Location
Feb 2024
Publication
This paper presents a new economic profitability model for a power-to-gas plant producing green hydrogen at the site of an existing wind power plant injected into the gas grid. The model is based on a 42 MW wind power plant for which an optimal electrolyzer of 10 MW was calculated based on the 2500 equivalent full load hours per year and the projection of electricity prices. The model is calculated on an hourly level for all variables of the 25 years of the model. With the calculated breakeven electricity price of 74.23 EUR/MWh and the price of green hydrogen production of 99.44 EUR/MWh in 2045 the wind power plant would produce 22410 MWh of green hydrogen from 31% of its total electricity production. Green hydrogen injected into the gas system would reduce the level of CO2 emissions by 4482 tons. However with the projected prices of natural gas and electricity the wind power plant would cover only 20% of the income generated by the electricity delivered to the grid by producing green hydrogen. By calculating different scenarios in the model the authors concluded that the introduction of a premium subsidy model is necessary to accelerate deployment of electrolyzers at the site of an existing wind power plant in order to increase the wind farm profitability.
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