Cyprus
Hydrogen Production Technologies: Current State and Future Developments
Mar 2013
Publication
Hydrogen (H2) is currently used mainly in the chemical industry for the production of ammonia and methanol. Nevertheless in the near future hydrogen is expected to become a significant fuel that will largely contribute to the quality of atmospheric air. Hydrogen as a chemical element (H) is the most widespread one on the earth and as molecular dihydrogen (H2) can be obtained from a number of sources both renewable and nonrenewable by various processes. Hydrogen global production has so far been dominated by fossil fuels with the most significant contemporary technologies being the steam reforming of hydrocarbons (e.g. natural gas). Pure hydrogen is also produced by electrolysis of water an energy demanding process. This work reviews the current technologies used for hydrogen (H2) production from both fossil and renewable biomass resources including reforming (steam partial oxidation autothermal plasma and aqueous phase) and pyrolysis. In addition other methods for generating hydrogen (e.g. electrolysis of water) and purification methods such as desulfurization and water-gas shift reactions are discussed.
Pulsed-Supplied Water Electrolysis via Two-Switch Converter for PV Capacity Firming
Mar 2022
Publication
Hydrogen constitutes the only carbon-free fuel that can be used for energy conversion producing water as the only by-product. With water being one of the most abundant and inexhaustible raw materials in the world and the required electricity input being provided by renewable resources the produced hydrogen via water electrolysis constitutes a green pathway towards sustainability. In this work a hybrid PV power-to-hydrogen storage and fuel cell system is proposed to satisfy the domestic load of a residential building. Identifying alkaline as a mandatory electrolysis technology the performance of alkaline electrolysis cells is assessed considering the inclusion of a two-switch buck-boost converter. Following a comprehensive formulation with respect to each distinguished system component the balance condition at DC and AC buses is determined. The proposed configuration is evaluated taking into account PV systems of different ratings namely 3 kW 5 kW and 7 kW. Based on actual data relating to both PV generation and domestic load for the year 2020 the obtained results from the annual simulations are compared with feed-in tariff and net-metering schemes. According to the results PV capacity firming is achieved creating great opportunities for autonomy enhancement not only for electricity but also in other energy sectors.
Decarbonization in Shipping Industry: A Review of Research, Technology Development, and Innovation Proposals
Apr 2021
Publication
This review paper examines the possible pathways and possible technologies available that will help the shipping sector achieve the International Maritime Organization’s (IMO) deep decarbonization targets by 2050. There has been increased interest from important stakeholders regarding deep decarbonization evidenced by market surveys conducted by Shell and Deloitte. However deep decarbonization will require financial incentives and policies at an international and regional level given the maritime sector’s ~3% contribution to green house gas (GHG) emissions. The review paper based on research articles and grey literature discusses technoeconomic problems and/or benefits for technologies that will help the shipping sector achieve the IMO’s targets. The review presents a discussion on the recent literature regarding alternative fuels (nuclear hydrogen ammonia methanol) renewable energy sources (biofuels wind solar) the maturity of technologies (fuel cells internal combustion engines) as well as technical and operational strategies to reduce fuel consumption for new and existing ships (slow steaming cleaning and coating waste heat recovery hull and propeller design). The IMO’s 2050 targets will be achieved via radical technology shift together with the aid of social pressure financial incentives regulatory and legislative reforms at the local regional and international level.
A Review of the Latest Trends in the Use of Green Ammonia as an Energy Carrier in Maritime Industry
Feb 2022
Publication
This review paper examines the key barriers to using green ammonia as an alternative fuel in maritime industry. A literature survey is performed based on research articles and grey literature with the aim of discussing the technoeconomic problems with and benefits of ammonia and the relevant technologies. The limitations of ammonia as a maritime fuel and its supply chain the expected percentage demand by 2030 and 2050 its economic performance compared to other shipping fuels such as hydrogen and the current regulations that may impact ammonia as a maritime fuel are discussed. There are several key barriers to ammonia’s wide adoption: (1) High production costs due to the high capital costs associated with ammonia’s supply chain; (2) availability specifically the limited geographical locations available for ammonia bunkering; (3) the challenge of ramping up current ammonia production; and (4) the development of ammonia-specific regulations addressing issues such as toxicity safety and storage. The general challenges involved with blue ammonia are the large energy penalty and associated operational costs and a lack of technical expertise on its use. Regardless of the origin for ammonia to be truly zero-carbon its whole lifecycle must be considered—a key challenge that will aid in the debate about whether ammonia holds promise as a zero-carbon maritime fuel.
A Thorough Emission-Cost Analysis of the Gradual Replacement of Carbon-Rich Fuels with Carbon-Free Energy Carriers in Modern Power Plants: The Case of Cyprus
Aug 2022
Publication
Global efforts towards de-carbonization give rise to remarkable energy challenges which include renewable energy penetration increase and intermediate energy carriers for a sustainable transition. In order to reduce the dependence on fossil fuels alternative sources are considered by commodities to satisfy their increasing electricity demand as a consequence of a rise in population and the quantity of residential appliances in forthcoming years. The near-term trends appear to be in fuel and emission reduction techniques through the integration of carbon capture and storage and more efficient energy carriers exploiting alternative energy sources such as natural gas and hydrogen. Formulating both the fuel consumption and emission released the obtained experimental results showed that the total production cost can be reduced by making use of natural gas for the transition towards 2035’s targets. Maximum profits will be achieved with hydrogen as the only fuel in modern power plants by 2050. In this way the lowest electricity production can be achieved as well as the elimination of carbon dioxide emissions. Since the integration of renewable energy resources in the sectors of electricity heating/cooling and transportation will continuously be increased alternative feedstocks can serve as primary inputs and contribute to production cost profits improved utilization factors and further environmental achievements.
Recent Research Progress in Hybrid Photovoltaic–Regenerative Hydrogen Fuel Cell Microgrid Systems
May 2022
Publication
Hybrid photovoltaic–regenerative hydrogen fuel cell (PV-RHFC) microgrid systems are considered to have a high future potential in the effort to increase the renewable energy share in the form of solar PV technology with hydrogen generation storage and reutilization. The current study provides a comprehensive review of the recent research progress of hybrid PV-RHFC microgrid systems to extract conclusions on their characteristics and future prospects. The different components that can be integrated (PV modules electrolyzer and fuel cell stacks energy storage units power electronics and controllers) are analyzed in terms of available technology options. The main modeling and optimization methods and control strategies are discussed. Additionally various application options are provided which differentiate in terms of scale purpose and further integration with other power generating and energy storage technologies. Finally critical analysis and discussion of hybrid PV-RHFC microgrid systems were conducted based on their current status. Overall the commercialization of hybrid PV-RHFC microgrid systems requires a significant drop in the RHFC subsystem capital cost. In addition it will be necessary to produce complete hybrid PV-RHFC microgrid systems with integrated energy management control capabilities to avoid operational issues and ensure flexibility and reliability of the energy flow in relation to supply storage and demand.
A Review on Experimental Studies Investigating the Effect of Hydrogen Supplementation in CI Diesel Engines—The Case of HYMAR
Aug 2022
Publication
Hydrogen supplementation in diesel Compression Ignition (CI) engines is gaining more attention since it is considered as a feasible solution to tackle the challenges that are related to the emission regulations that will be applied in the forthcoming years. Such a solution is very attractive because it requires only limited modifications to the existing technology of internal combustion CI engines. To this end numerous work on the investigation of an engine’s performance and the effects of emissions when hydrogen is supplied in the engine’s cylinders has been completed by researchers. However contradictory results were found among these studies regarding the efficiency of the engine and the emission characteristics achieved compared to the diesel-only operation. The different conclusions might be attributed to the different characteristics and technology level of the engines that were utilized as well as on the chosen operational parameters. This paper aims to present an overview of the experimental studies that have examined the effects of hydrogen addition in CI four-stroke diesel engines reporting the characteristics of the utilized engines the quantities of hydrogen tested the method of hydrogen induction used as well as the operational conditions tested in order to help interested researchers to easily identify relevant and appropriate studies to perform comparisons or validations by repeating certain cases. The presented data do not include any results or conclusions from these studies. Furthermore an experimental configuration along with the appropriate modifications on a heavy-duty auxiliary generator-set engine that was recently developed by the authors for the purposes of the HYMAR project is presented.
Can Africa Serve Europe with Hydrogen Energy from Its Renewables?—Assessing the Economics of Shipping Hydrogen and Hydrogen Carriers to Europe from Different Parts of the Continent
Apr 2023
Publication
There exists no single optimal way for transporting hydrogen and other hydrogen carriers from one port to the other globally. Its delivery depends on several factors such as the quantity distance economics and the availability of the required infrastructure for its transportation. Europe has a strategy to invest in the production of green hydrogen in Africa to meet its needs. This study assessed the economic viability of shipping liquefied hydrogen (LH2 ) and hydrogen carriers to Germany from six African countries that have been identified as countries with great potential in the production of hydrogen. The results obtained suggest that the shipping of LH2 to Europe (Germany) will cost between 0.47 and 1.55 USD/kg H2 depending on the distance of travel for the ship. Similarly the transportation of hydrogen carriers could range from 0.19 to 0.55 USD/kg H2 for ammonia 0.25 to 0.77 USD/kg H2 for LNG 0.24 to 0.73 USD/kg H2 for methanol and 0.43 to 1.28 USD/kg H2 for liquid organic hydrogen carriers (LOHCs). Ammonia was found to be the ideal hydrogen carrier since it recorded the least transportation cost. A sensitivity analysis conducted indicates that an increase in the economic life by 5 years could averagely decrease the cost of LNG by some 13.9% NH3 by 13.2% methanol by 7.9% LOHC by 8.03% and LH2 by 12.41% under a constant distance of 6470 nautical miles. The study concludes with a suggestion that if both foreign and local participation in the development of the hydrogen market is increased in Africa the continent could supply LH2 and other hydrogen carriers to Europe at a cheaper price using clean fuel.
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