Secondary Energy Carrier Research Articles

A Comprehensive Review on Nanofuel : Bringing Clean Energy to Reality

In recent years, the depletion of fossil fuels has become a pressing concern with the world’s ever increasing energy demands. The rapid consumption of fossil fuels, such as coal, natural gas, and oil has given rise to significant environmental and economic consequences. These non-renewable energy sources are limited and their extraction as well as usage contributes to pollution, harmful emissions eventually leading to global climate change. To address this challenge, many researchers have been exploring the potential of nanofuel as a secondary energy carrier. Nanofuels are a class of alternative fuels that incorporate nanoparticles to enhance combustion efficiency, reduce emissions, and improve overall energy output. This paper presents an innovatory concept of nanofuel wherein the enhancement of the fuel efficacy by suspension of nanoparticles in a liquid carrier is described and major challenges are identified, which urges researchers in materials, chemistry, physics , and engineering to collaborate across disciplines. Key Words : Nanofuel, Metal-oxide nanoparticles, Performance, Combustion, Emission

Realism at the end of the rainbow? An argument towards diversifying hydrogen in EU regulation

Abstract The European Union’s (EU) decarbonization strategy involves hydrogen as an integral pillar. Since hydrogen is a secondary energy carrier, meaning it must be manufactured, not all hydrogen is made equal. Renewable hydrogen or RFNBOs (Renewable Fuel of Non-Biological Origins) have been given high priority by the EU in their strategy to establish a market for hydrogen. The EU’s creation of RFNBO usage objectives is a step towards establishing a demand-side market. One such goal is to bring into the EU up to 10 million tonnes of renewable hydrogen. However, it is doubtful that this large amount can be reached given the strict criteria for what qualifies as renewable hydrogen and, thus, as RFNBO. This article analyses key provisions of the EU framework that affect the EU’s aim to produce and import up to 20 million tonnes of hydrogen overall. It concludes the EU’s emphasis on RFNBOs rather than a broader range of hydrogen pathways undermines the goal of rapidly developing a hydrogen market. Using turquoise hydrogen as a case study, the article shows how the EU’s decarbonization efforts would be aided, trade would be enabled, and fragmentation would be decreased if targets were expanded to encompass additional forms of hydrogen.

The race between hydrogen and heat pumps for space and water heating: A model-based scenario analysis

This paper analyses different levels and means of the electrification of space and hot water heating using an explorative modelling approach. The analysis provides guidance to the ongoing discussion on favourable pathways for heating buildings and the role of secondary energy carriers such as hydrogen or synthetic fuels. In total, 12 different scenarios were modelled with decarbonisation pathways until 2050, which cover all 27 member states of the European Union. Two highly detailed optimisation models were combined to cover the building stock and the upstream energy supply sector. The analysis shows that decarbonisation pathways for space and water heating based on large shares of heat pumps have at least 11% lower system costs in 2050 than pathways with large shares of hydrogen or synthetic fuels. This translates into system cost savings of around €70 bn. Heat pumps are cost-efficient in decentralised systems and in centralised district heating systems. Hence, heat pumps should be the favoured option to achieve a cost-optimal solution for heating buildings. Accordingly, the paper makes a novel and significant contribution to understanding suitable and cost-efficient decarbonisation pathways for space and hot water heating via electrification. The results of the paper can provide robust guidance for policymakers.

How to size regional electrolysis systems - Simple guidelines for deploying grid-supporting electrolysis in regions with renewable energy generation

Our energy system is facing major challenges in the course of the unavoidable shift from fossil fuels to fluctuating renewable energy sources. Regional hydrogen production by electrolysis, utilizing regional available excess energy, can support the expansion of renewable energy by converting surplus energy into hydrogen and supplying it to the end energy sectors as a secondary energy carrier or process media. We developed a methodology which allows the identification of the regional optimal electrolysis scaling, the achievable Levelized Costs of Hydrogen (LCOH) as well as the annually producible amount of hydrogen for Central European regions, using renewable surplus energy from PV and wind production. The results show that as best case currently LCOH of 4.5 €/kg can be achieved in regions with wind energy and LCOH of 5.6 €/kg in regions with PV energy at 1485 €/kW initial investment costs for the hydrogen production infrastructure. In these cases, regions with wind energy require electrolysis systems with a capacity of 60% of the wind peak power. Regions with PV energy require a scaling factor of only 45% of the PV peak power. However, we show that the impact of regional electricity demand and grid expansion has a significant influence on the LCOH and the scaling of the electrolysis. These effects were illustrated in clear heatmaps and serve as a guideline for the dimensioning of grid-supporting electrolysis systems by defining the renewable peak power, the regional electricity demand as well as the existing grid capacity of the region under consideration.

Screening and ranking Japanese gas fields for underground H2 storage potential: Impact of the reservoir drive mechanism

To accomplish the net-zero goal, Japan intends to increase its reliance on renewable energies such as solar power (36–38 % in 2030). However, considering the intermittent nature of solar power, the resulting energy must be transformed to a secondary energy carrier such as H2. Japan, on the other hand, is expected to import 20 × 106 tons of H2 each year by 2050. Because of these large volumes, new H2 storage techniques must be developed, in particular underground hydrogen storage (UHS). This paper ranks eight gas reservoirs out of 106 oil and gas fields in four Japanese prefectures regarding their suitability for UHS, and then suggests a H2 injection and withdrawal scheme based on the history of electricity consumption and solar power curtailment. Then, a reservoir simulation study was performed to investigate the effects of factors such as hysteresis, repeated cycles and cushion gas on the performance of these fields. The outcomes for water-drive and volumetric gas reservoirs were compared to better understand the effects of an aquifer on the long-term performance of a gas reservoir when used for UHS. Finally, it was demonstrated that the technology sought for the conversion of H2 back to electricity after withdrawal from a UHS site governs the overall efficiency of a power-H2-power process.

WS2-Pt Nanostructure-Based Composite for Hydrogen Gas Sensing with Ultra-Fast Response and Recovery Rates

Hydrogen is regarded as a secondary energy carrier derived from hydrogen evolution reactions. To ensure safety when utilizing this hazardous gas, hydrogen gas sensors with rapid response and recovery times, high sensor sensitivity, and stability are essential. A high surface-to-volume ratio with complete adsorption and desorption of ions renders WS2 a promising candidate for hydrogen gas sensor applications. This study introduces a novel high-performance hydrogen gas sensor based on a metal sulfide-platinum (WS2-Pt) composite. The WS2-Pt composite was successfully synthesized using a solution-based process and spin-coating techniques. WS2-Pt nanostructures were densely distributed on a gallium nitride/sapphire substrate, and a hydrogen sensing device was fabricated. The metal sulfide/platinum composite demonstrated ultra-fast sensor response of approximately 3 s toward 500 ppm hydrogen with a satisfactory sensor sensitivity. The response rate was notably encouraging. This research represents the first attempt in the sensor domain to enhance the performance of hydrogen sensing devices using metal sulfide/Pt active layers.

Metal-Polymer Functional Materials for Hydrogen-Oxygen Fuel Cells with Enhanced Performance

The most promising direction in alternative energy is hydrogen energy, using hydrogen as a secondary energy carrier. A key component in hydrogen energy is a fuel cell, especially on solid polymer membranes. Increasing the efficiency, reducing the cost and increasing the service life of such elements is the primary task of this direction. These tasks need to be solved from two sides: by improving the parameters of platinum catalysts in electrochemical reactions of energy sources, as well as by improving the qualities of the membrane. The aim of the work is to synthesize and study composites with palladium and platinum nanoparticles in hydrogen-oxygen fuel cells.

ANALYSIS OF THE PROSPECTS OF THE IMPLEMENTATION OF HYDROGEN ENERGY IN THE ENERGY BALANCE OF COMPANIES IN THE AVIATION INDUSTRY

Hydrogen energy technologies, such as hydrogen storage of energy from renewable sources of electricity, by storing hydrogen as a battery for autonomous and distributed generation and refueling for hydrogen transport, are actively being introduced into the transport industry of developed countries. The transport industry of Ukraine is inextricably linked with the energy industry and has its own characteristics. World experience shows that the introduction of the latest technologies in the transport sector definitely gives a number of unambiguous bonuses for further stable development. Meanwhile, the objects of the transport industry of Ukraine have significant territories that are technologically not involved in the agricultural industry and cannot be used for the development of the cultural and social sphere. In turn, the objects of the transport industry of Ukraine make up its transport infrastructure and are located throughout the territory of Ukraine. Today, hydrogen energy includes a set of technologies for production, transportation, accumulation and use of the universal secondary energy carrier – hydrogen. Thus, in the concept of hydrogen energy, hydrogen complements the most important secondary energy carrier – electricity, the energy use of hydrogen is determined by the possibility of environmentally clean production of electricity and long-term storage with the minimization of losses, including in large volumes. The development of renewable energy, which receives energy from variable natural resources of solar and wind energy, as well as the active implementation of technologies of distributed generation and “smart” networks stimulate the urgency of solving the problem of long-term energy storage. The approach is also designed to settle the issue of the use of wind turbines and SPPs in power supply systems by stabilizing the return of the electric energy generated by them to the network. Undoubtedly, WPPs and SPPs can be connected to the network if necessary, meanwhile, using the proposed approach there is an opportunity to reduce the loss of energy obtained from natural sources and to use it rationally and efficiently. In the conditions of aviation industry enterprises, it is relevant and possible to introduce into the general structure of power supply systems based on renewable energy sources. The proposed approach to the introduction of hydrogen energy in the conditions of aviation industry enterprises allows to effectively use sources of electrical energy based on renewable energy sources both in autonomous power supply systems and to integrate them into existing power supply systems

Hydrogen Production through Water Vapors using Optimized Corona-DBD Hybrid Plasma Micro-Reactor

Hydrogen as secondary energy carrier is one of the promising routes to meet renewable and sustainable energy demand. Hydrogen production using water plasmolysis, so far, has been considered as energy intensive. However, recent developments in the field of microplasmas has reduced energy requirement of water plasmolysis on par with electrolysis. However, there’s still room for improvement as water vapors dissociation efficiencies are less than thermodynamic and kinetic limits. One of the ways to do that is to split microchannel in plasma into sub-micron channels by packing beads inside the reactor. The current study investigates the plasmolysis of water vapours (steam) and argon gas with (1) empty channel plasma reactor and (2) glass beads packed plasma reactor. A custom-made Corona-DBD hybrid microplasma reactor has been designed and employed for water steam plasmolysis. This study aims to investigate the feasibility of water vapors dissociating into hydrogen at a relatively small interelectrode gap at atmospheric pressure. The minimum breakdown voltage has been found to be 3.7 kVpk-pk at 5 mA current. The maximum hydrogen production rate was observed 23.9 g/kWh at optimized conditions for the glass beads packed plasma reactor. So, in current study glass beads packed plasma microreactor yielded 23.9g of H2/kWh which is significantly higher than any previously published study

Conditioned hydrogen for a green hydrogen supply for heavy duty-vehicles in 2030 and 2050 – A techno-economic well-to-tank assessment of various supply chains

Hydrogen, seen as a promising secondary renewable energy carrier, can becompressed or liquefied as well as chemically bound to enable a more economic storage and transportation. All conditioned hydrogen options obtain specific advantages and disadvantages. Thus, this paper assess the energy efficiency and the cost of a green hydrogen supply from well to tank exemplified for fuel cell heavy-duty vehicles in Germany related to the years 2030 and 2050. Therefore, compressed gaseous hydrogen, liquid hydrogen, liquid organic hydrogen carriers, methanol and ammonia are considered and different hydrogen production regions in North and Central Germany, as well as an import from Tunisia and Argentina (Patagonia) are assumed. The assessment shows that a hydrogen supply chain in its state of aggregation as finally demanded is the lowest cost option leading to 700 bar compressed gaseous hydrogen filling costs of 5 €2020/kgH2 in 2030 and 4 €2020/kgH2 in 2050 and liquid hydrogen filling costs around 7 €2020/kgH2 in 2030 and 6 €2020/kgH2 in 2050.

Business Model Development for a High-Temperature (Co-)Electrolyser System

There are increasing international efforts to tackle climate change by reducing the emission of greenhouse gases. As such, the use of electrolytic hydrogen as an energy carrier in decentralised and centralised energy systems, and as a secondary energy carrier for a variety of applications, is projected to grow. Required green hydrogen can be obtained via water electrolysis using the surplus of renewable energy during low electricity demand periods. Electrolysis systems with alkaline and polymer electrolyte membrane (PEM) technology are commercially available in different performance classes. The less mature solid oxide electrolysis cell (SOEC) promises higher efficiencies, as well as co-electrolysis and reversibility functions. This work uses a bottom-up approach to develop a viable business model for a SOEC-based venture. The broader electrolysis market is analysed first, including conventional and emerging market segments. A further opportunity analysis ranks these segments in terms of business attractiveness. Subsequently, the current state and structure of the global electrolyser industry are reviewed, and a ten-year outlook is provided. Key industry players are identified and profiled, after which the major industry and competitor trends are summarised. Based on the outcomes of the previous assessments, a favourable business case is generated and used to develop the business model proposal. The main findings suggest that grid services are the most attractive business sector, followed by refineries and power-to-liquid processes. SOEC technology is particularly promising due to its co-electrolysis capabilities within the methanol production process. Consequently, an “engineering firm and operator” business model for a power-to-methanol plant is considered the most viable option.

Simultaneity of green energy and hydrogen production: Analysing the dispatch of a grid-connected electrolyser

Hydrogen is a promising supplement in future energy systems with high penetration rates of renewable energy (RE) generation. As conversion technology between the two secondary energy carriers, hydrogen and electricity, particularly grid-connected electrolysers, have a role to play. During the market ramp-up, grid-connected electrolysers could cause unwanted side-effects through inducing additional CO2 emissions in the power sector. Since the reduction of CO2 constitutes the overall goal, a simultaneity obligation between RE generation and hydrogen production is discussed to prevent indirect emissions from an electrolyser's energy consumption. The paper presents a model framework including a mixed-integer linear program and a Markov chain Monte Carlo simulation for stochastic electricity prices to assess a grid-connected electrolyser's dispatch. Within a case study of the German electricity market, the effect of simultaneity on the dispatch is assessed. The results show that simultaneity reduces the CO2 emission intensity of hydrogen while constraining profits. The choice of the simultaneity interval length affects the electrolyser's average contribution margin from hydrogen production and the corresponding profit at risk, which results from fluctuating RE generation. Regulations aiming at the interface between hydrogen and electricity must consider the trade-off between economic viability, full load hours, and associated emissions of electricity-based hydrogen.

Bottom-up assessment of local agriculture, forestry and urban waste potentials towards energy autonomy of isolated regions: Example of Réunion

This work assesses the role of biomass and municipal solid waste in isolated energy systems. For this, La Réunion, a French overseas territory in the Indian Ocean with a population of about 850,000, serves as a case study. Methodically, the study assesses technical biomass-based potentials based on an island-wide digital landscape model, detailed information on land use, soil, and climate, and a dynamic yield simulation tool, while technical waste-based energy potentials are calculated from local data. In total, 9 crops, 11 waste streams, and forested areas are considered. The potential contribution of biomass and waste to the energy system is studied in three scenarios. In all, unsustainable outcomes are avoided by valorizing only crop residues and applying sustainable harvesting rates to forests. Depending on the scenario, biomass or waste based energy could cover between 19% and 22% of 2019 electricity demand compared to an actual value of 6% (2019). Furthermore, prioritizing the production of secondary energy carriers allows to meet 8% of 2019 energy demand in the transport sector. These results are in good accordance with previous studies and scenarios on Réunion's energy transition. Given its bottom-up approach based on standard geoinformatic data, the proposed method is in principle transferable to other isolated regions, also in developing countries. A first, high-level assessment of four comparable island (states) shows that in three cases similar contributions of biomass and waste as in Réunion can be expected. As a next step, the purely technical assessment shall be complemented by economic considerations.

Effect of biomass fuel ash and bed material on the product gas composition in DFB steam gasification

Gasification is a thermochemical process that transforms carbonaceous matter into a gaseous secondary energy carrier, referred to as product gas. This product gas can be used for heat and power generation but also for syntheses. One possible gasification technology suitable for further synthesis is dual fluidised bed (DFB) steam gasification. The H2:CO ratio, which determines the suitability of the product gas for further synthesis, is influenced by the catalytic activity inside the gasification reactor. Eleven DFB steam gasification experiments were performed comparing the catalytic activity for various bed material and fuel combinations. The bed materials used were K-feldspar, fresh and layered olivine, and limestone, and the fuels gasified were softwood, chicken manure, a bark–chicken manure mixture and a bark-straw-chicken manure mixture. The water-gas-shift (WGS) equilibrium deviation was used to evaluate the catalytic activity inside the gasification reactor. It was shown that both the fuel ash and bed material have an effect on the catalytic activity during gasification. Scanning electron microscopy and energy dispersive X-ray spectrometry showed the initial layer formation for experiments with ash-rich fuels. Isolated WGS experiments were performed to further highlight the influence of bed material, fuel ash and fuel ash layers on the WGS equilibrium.

Physical Macroeconomics: Part VI - Global Energy Prices

The paper continues a series of publications on the natural science foundations of the global economy. Physical macroeconomics treats the global economy as a living system, formed during biological and socio-economic evolution. In this Part VI of physical macroeconomics, qualitatively differential pricing for global secondary energy carriers, such as electricity, oil and grain, is discussed. It is demonstrated that pricing is primarily determined by the two-component nature of economic value. Currently, the one-component paradigm of economic value is unable to explain these differences. It is demonstrated, that, in developed economies with independent electric energy systems, the average electricity price is an empirical indicator of macroeconomic efficiency. Unlike electricity, the price of crude oil contains a non-zero information component, so the oil price ranges from the cost of production to a maximum magnitude, being greatly dependent on the information component of the price. Grain production is an indispensable and the most energy consuming process in the global economy. The fundamental properties of the world's grain basket – constant production per capita and flat price – means that the grain basket can be considered as an implicit global currency. The impact of energy prices on the competitiveness of local economies existing in different climates is also considered. Indices of climatic impacts are calculated for major world cities.

Modern directions for the development of hydrogen energy technologies

Hydrogen energy combines a set of technologies for the production, transportation, storage and use of a versatile secondary energy carrier — hydrogen. The energy use of hydrogen is formed from the possibilities of environmentfriendly generation of electricity and long-term storage without loss, including on a large scale. Questions related to the consumption of hydrogen as a promising environment-friendly and versatile energy carrier and energy storage in various sectors of the national economy were formulated in the early 70s of the last century after the first oil fuel crisis. It has become obvious that it is necessary to develop new, ecologically optimal energy technologies based on the use of renewable energy sources, nuclear energy, coal and versatile environment-friendly energy carriers, making it possible to replace non-renewable energy resources as these are depleted and become more expensive. Hydrogen as a secondary energy carrier reveals its potential in a global strategy for sustainable energy development in the 21st century, which confronts the challenges of irreversible climate change, unsustainable oil production and increasing environmental pollution. Hydrogen can play a key role in mainline transportation by road and rail, in coastal and international shipping, in air transport, as well as in long-term and seasonal storage of electricity in networks, relying mainly on local renewable energy sources and local raw materials. The decisive element in the commercialization of hydrogen fuel technologies in Russia at the current stage is the formation of cost-effective hydrogen-transport-energy complexes, in particular, within power generating facilities.

(Invited) Rechargeable-Liquid Fuel Cells and Hydrogen Carriers: Recent Progress and Key Challenges

It has been approximately sixty years since polymer electrolyte fuel cells (PEFCs) were first invented at G.E. [1], and thirty years since Los Alamos National Laboratory (LANL) invented the ionomer impregnated PEFC catalyst layer [2] and demonstrated the modern membrane-electrode assembly (MEA), which is still the heart of the state-of-the-art PEFC [3]. This new MEA architecture developed by LANL initiated a renaissance in PEFC technology, since it became apparent that high performance could be obtained with dramatically reduced catalyst loadings [4]. The result has been tremendous progress in the performance and durability of PEFCs over the past thirty years, which has enabled the growth of deployed PEFC systems, including many types of fuel cell electric vehicles (FCEVs), which has been accelerating over the past few years [5]. However, state-of-the-art FCEVs can be fueled only by hydrogen, which presents significant barriers to market adoption, such as the development of hydrogen-refueling infrastructure, as well as the compression and storage of high pressure hydrogen gas. The need to create a viable H2 infrastructure is the motivation for the U.S. DOE’s H2@Scale initiative, which goes beyond enabling FCEVs, since hydrogen can potentially be used as a clean secondary energy carrier if the economics of the production, distribution, storage, and utilization of hydrogen can be improved [6]. Liquid organic hydrogen carriers (LOHCs) are an alternative to distributing and storing hydrogen; however, the vast majority of the work on LOHC conversions has been done using thermal processes that operate at high temperatures and pressures [7]. Electrochemical hydrogenation and dehydrogenation (EHD) of LOHCs offers the potential for higher round-trip efficiencies, simpler systems, and significantly lower operating temperatures and pressures. Some of the early work, which focused on LOHCs with very high H2 contents, delivered poor results because of complex reaction mechanisms [8-9]. The EHD conversion of more kinetically facile carriers (albeit with lower H2 contents) is deserving of attention, since the energy-density requirements for the distribution and storage of hydrogen are more modest than what is required for transportation applications. Some work has been done with “organic chemical hydrides” (e.g., cyclohexane, isopropanol) [10], and with redox flow battery (RFB) reactants [11], which have demonstrated the concept of rechargeable-liquid fuel cells (RLFCs) using PEFCs. However, the maximum power density of these early cells was poor relative to hydrogen-fueled PEFCs, e.g., 78 mW-cm-2 on neat isopropanol (IPA) and oxygen [10] and 30 mW-cm-2 on 1.6 M V2+/3+ and air [11]. Additionally, two different types of cells were used to charge and discharge these liquids. UTRC has leveraged our experience in the development of high performance PEFCs and RFB cells [12] to demonstrate RLFCs with improved discharge performance (e.g., 190 and 140 mW cm-2 at 0.6 V with 2 M IPA and oxygen and air, respectively, and 420 mW cm-2 at 0.7 V with 1.5M V2+/3+ and air ). These proof-of-concept cells were also used to demonstrate a novel and efficient recharging method with the identical cell used for both charging and discharging the liquid. RLFCs are a low maturity technology, with many opportunities for substantial improvements. The key barriers identified by UTRC to further improvements in both the power and energy densities of RLFCs will be presented. These include electrocatalysts designed for the desired EHD reactions, as well as membranes that selectively transport the desired charge carrier while minimizing the crossover of the reactants. PEFC and RFB researchers are well suited to developing the technologies required to make RLFCs and EHD conversion of hydrogen carriers potentially compelling for a variety of applications. Acknowledgements The author would like to thank his UTRC colleagues who obtained the original research results that will be included here. A portion of this work was supported by the U.S. DOE as an ARPA-E Open IDEAS project (DE-AR0001002). References W. T. Grubb, U.S. Pat. 2,913,511 (1959).I. D. Raistrick, U.S. Pat. 4,876,115 (1989).M. Wilson and S. Gottesfeld, JES, 139, L28 (1992).M. Perry and T. Fuller, JES, 149, S59 (2002).S. Satyapal, DOE FCTO Annual Merit Revew (2018).B. Pivovar, N. Rustagi, S. Satyapal, ECS Interface, 27, 47 (2018).P. Preuster, et.al., Acc. Chem. Res., 50, 74 (2017).P. Driscoll, J. Kerr, et.al., JES, 160, G3152 (2013).J. Ferrell III, G. Pez, A. Herring, et.al., JES, 159, B371 (2012).N. Kariya, A. Fukuoka, and M. Ichikawa, Phys. Chem. Chem. Phys., 8, 1724 (2006).J. Noack, et.al., 218th ECS Meeting s, 10 (2010)M. Perry, R. Darling, and R. Zaffou, ECS Trans., 53, 7 (2013).

ANALYSIS OF ENERGY PERFORMANCE OF FERROUS METALLURGY ENTERPRISES BASED ON THE SCHEME OF DECOMPOSITION

The task of determining specific electricity consumption is complex, as it is necessary to take into account a large number of factors affecting the energy indicators that determine the level of these indicators. At the same time, the type and technical condition of the main and auxiliary process equipment in the process of melting, the nomenclature of metal, the volume of consumed components of the process and secondary energy carriers (compressed air, nitrogen, oxygen and other auxiliary components), etc. are taken into account. The error in taking these factors into account may lead to deviations from the actual values of the predicted power consumption, as well as energy indicators. The energy intensity of products and the level of energy consumption also depends on changes in the structure of energy consumption, the latter depending on the need for such process components as compressed air, oxygen, nitrogen, etc. The article considers the results of the analysis of energy indicators of enterprises of ferrous metallurgy, in particular, electrosmelting shop by types of output products on the basis of decomposition scheme. It is shown that the set task is solved by means of construction of dependences of normative energy characteristics on the volume of output products, and also the final decomposition tree is formed - the tree of tasks designed to achieve solutions of energy problems, including the main one - to obtain the value of specific energy consumption. In addition, the article presents the method of determining the share of participation of auxiliary components of the technological process for example of compressed air, nitrogen and oxygen. At calculations the account of the above-stated components gives the chance to define more precisely specific expense of the electric power.

Investigation on PEM water electrolysis cell design and components for a HyCon solar hydrogen generator

Hydrogen as a secondary energy carrier promises a large potential as a long term storage for fluctuating renewable energies. In this sense a highly efficient solar hydrogen generation is of great interest especially in southern countries having high solar irradiation. The patented Hydrogen Concentrator (HyCon) concept yields high efficiencies combining multi-junction solar cells with proton exchange (PEM) membrane water electrolysis. In this work, a special PEM electrolysis cell for the HyCon concept was developed and investigated. It is shown that the purpose-made PEM cell shows a high performance using a titanium hybrid fiber sinter function both as a porous transport layer and flow field. The electrolysis cell shows a high performance with 1.83 V at 1 A/cm2 and 24 °C working under natural convection with a commercially available catalyst coated membrane. A theoretical examination predicts a total efficiency for the HyCon module from sunlight to hydrogen of approximately 19.5% according to the higher heating value.

A Review of Biogas Utilisation, Purification and Upgrading Technologies

Biogas is a valuable renewable energy and also a secondary energy carrier produced from biodegradable organic materials via anaerobic digestion. It can be used as a fuel or as starting material for the production of chemicals, hydrogen and/or synthesis gas etc. The main constituents of biogas are methane (CH4) and carbon dioxide (CO2), with various quantities of contaminants, such as ammonia (NH3), water vapour (H2O), hydrogen sulfide (H2S), methyl siloxanes, nitrogen (N2), oxygen (O2), halogenated volatile organic compounds (VOCs), carbon monoxide (CO) and hydrocarbons. These contaminants presence and quantities depend largely on the biogas source, which could be anaerobic digestion of many substrates and landfill decompositions. The removal of these contaminants especially H2S and CO2 will significantly improve the quality of the biogas for its further uses. In parallel, biogas upgrading market is facing challenges in term of operating costs and energy consumption. The selection of appropriate technology depends on the specific biogas requirements, site specific, local circumstances and is case sensitive. This paper reviews the present state-of-the-art of biogas cleaning and upgrading technologies, including its composition, upgrading efficiency, methane recovery and loss. In addition, biogas production, utilization and the corresponding requirements on gas quality for grid injection and vehicle usage are investigated. Based on the results of comparisons of various technologies, recommendations are made on further research on the appropriate low cost technologies, especially using solid waste as low cost materials for biogas purification and upgrading.