Publications

Hydrogen is a low or zero-carbon energy source that is considered the most promising and potential energy carrier of the future. In this study the energy sources feedstocks and various methods of hydrogen production from power generation are comparatively investigated in detail. In addition this study presents an economic assessment to evaluate cost-effectiveness based on different economic indicators including sensitivity analysis and uncertainty analysis. Proton exchange membrane fuel cell (PEMFCs) technology has the most potential to be developed compared to several other technologies. PEMFCs have been widely used in various fields and have advantages (i.e. start-up zero-emissions high power density). Among the various sources of uncertainty in the sensitivity analysis the cost estimation method shows inflationary deviations from the proposed cost of capital. This is due to the selection process and untested technology. In addition the cost of electricity and raw materials as the main factors that are unpredictable.

Hydrogen energy is considered one of the cleanest and most promising alternatives to fossil fuel because the only combustion product is water. The development of water splitting electrocatalysts with Earth abundance cost-efficiency and high performance for large current density industrial applications is vital for H2 production. However most of the reported catalysts are usually tested within relatively small current densities (< 100 mA cm−2 ) which is far from satisfactory for industrial applications. In this minireview we summarize the latest progress of effective non-noble electrocatalysts for large current density hydrogen evolution reaction (HER) whose performance is comparable to that of noble metal-based catalysts. Then the design strategy of intrinsic activities and architecture design are discussed including self-supporting electrodes to avoid the detachment of active materials the superaerophobicity and superhydrophilicity to release H2 bubble in time and the mechanical properties to resist destructive stress. Finally some views on the further development of high current density HER electrocatalysts are proposed such as scale up of the synthesis process in situ characterization to reveal the micro mechanism and the implementation of catalysts into practical electrolyzers for the commercial application of as-developed catalysts. This review aimed to guide HER catalyst design and make large-scale hydrogen production one step further.

This paper presents an analysis of the potential economic-wide energy and CO2 emissions implications of hydrogen vehicle penetration into the Portuguese road transport over the time-horizon 2010-2050. The energy and emissions implications are obtained using PATTS (Projections for Alternative Transportation Technologies Simulation) an excel spreadsheet model based on forecast scenarios. Historical data and trends of gasoline versus diesel share fleet scrappadge representative light-duty vehicle technologies life cycle energy and emission factors are used to estimate on a yearly basis the total fleet life cycle energy consumption CO2 emissions and air quality related impact. The macroeconomic effects are assessed with a Computable General Equilibrium model that is solved as a non-linear optimization problem formulated in GAMS software capable of dealing with substitution between labour capital stock electric energy and non-electric energy factors of production. It integrates parameter inputs obtained from PATTS tool where the transportation sector becomes hydrogen driven and a wide hydrogen refuelling infrastructure is deployed. The simulation experiments show that "hydrogen technologies" are likely to become economically viable. Household consumption real GDP and investment increase from baseline. The positive impact upon the economic variables is supplemented by energy costs reductions of just -0.1 to -0.3 percent per annum in both high-price and low-price cases. The economy grows faster in the low-price case where the reductions in energy costs are also more pronounced. CO2 avoided emissions due to hydrogen economy reach a maximum of 2 kton/km in 2050 if the natural gas steam reforming production method is adopted.

About 95% of the hydrogen presently produced is from natural gas and coal and the remaining 5% is generated as a by-product from the production of chlorine through electrolysis1 . In the hydrogen economy (Crabtree et al. 2004; Penner 2006; Marbán and Valdés-Solís 2007) hydrogen is produced entirely from renewable energy. The easiest approach to advance renewable energy production is through solar photovoltaic and electrolysis a pathway of high technology readiness level (TRL) suffering however from two downfalls. First of all electricity is already an energy carrier and transformation with a penalty into another energy carrier hydrogen is in principle flawed. The second problem is that the efficiency of commercial solar panels is relatively low. The cadmium telluride (CdTe) thin-film solar cells have a solar energy conversion efficiency of 17%. Production of hydrogen using the current best processes for water electrolysis has an efficiency of ∼70%. As here explained the concentrated solar energy may be used to produce hydrogen using thermochemical water-splitting cycles at much global higher efficiency (fuel energy to incident sun energy). This research and development (R&D) effort is therefore undertaken to increase the TRL of this approach as a viable and economical option.

Hydrogen is believed as a promising energy carrier that contributes to deep decarbonization especially for the sectors hard to be directly electrified. A grid-connected wind/hydrogen system is a typical configuration for hydrogen production. For such a system a critical barrier lies in the poor cost-competitiveness of the produced hydrogen. Researchers have found that flexible operation of a wind/hydrogen system is possible thanks to the excellent dynamic properties of electrolysis. This finding implies the system owner can strategically participate in day-ahead power markets to reduce the hydrogen production cost. However the uncertainties from imperfect prediction of the fluctuating market price and wind power reduce the effectiveness of the offering strategy in the market. In this paper we proposed a decision-making framework which is based on data-driven robust chance constrained programming (DRCCP). This framework also includes multi-layer perception neural network (MLPNN) for wind power and spot electricity price prediction. Such a DRCCP-based decision framework (DDF) is then applied to make the day-ahead decision for a wind/hydrogen system. It can effectively handle the uncertainties manage the risks and reduce the operation cost. The results show that for the daily operation in the selected 30 days offering strategy based on the framework reduces the overall operation cost by 24.36% compared to the strategy based on imperfect prediction. Besides we elaborate the parameter selections of the DRCCP to reveal the best parameter combination to obtain better optimization performance. The efficacy of the DRCCP method is also highlighted by the comparison with the chance-constrained programming method.

Carbon dioxide (CO2 ) and hydrogen (H2 ) are essential energy vectors in the green energy transition. H2 is a fuel produced by electrolysis and is applied in heavy transportation where electrification is not feasible yet. The pollutant substance CO2 is starting to be captured and stored in different European locations. In Denmark the energy vision aims to use this CO2 to be reacted with H2 producing green methanol. Typically the production units are not co-located with consumers and thus the required transportation infrastructure is essential for meeting supply and demand. This work presents a novel scheme to allocate the transportation costs of CO2 and H2 in pipeline networks which can be applied to any network topology and with any allocation method. During the tariff formation process coordinated adjustments are made by the novel scheme on the original tariffs produced by the allocation method employed considering the location of each customer connected to pipeline network. Locational tariffs are provided as result and the total revenue recovery is guaranteed to the network owner. Considering active customers the novel scheme will lead to a decrease of distant pipeline flows thereby contributing to the prevention of bottlenecks in the transportation network. Thus structural reinforcements can be avoided reducing the total transportation cost paid by all customers in the long-term.

Over the last years the European Union has seen a rapid increase in installed capacity of generating units based on renewable energy sources (RES). The most significant increase in installed capacity was recorded in 2015 in wind farms and solar PV installations. One of the most serious is the volatile character of RES on a time basis. Therefore for a further expected increase in the use of RES and their effectiveness improvements investments are needed allowing for electricity to be stored. One of the electricity storage options is to use excess electricity in order to produce hydrogen by electrolysis of water. Although this process plays a marginal role in obtaining hydrogen on a worldwide basis due to high costs experience in recent years has shown that periodically low (negative) electricity prices developing on the power exchanges in the situation where there is surplus electricity available affect economic requirements for hydrogen production technologies. The paper shows activities undertaken by European countries (mainly Germany) aiming at making it possible for hydrogen to be stored in the natural gas grids. A particular attention is given to material resource issues and possible operational problems that might arise while blending natural gas with hydrogen into the grid. The experiences of selected European countries are of particular interest from the Polish perspective having regard to significant increase of RES in electricity generation during the last few years and adopted objectives for the growing importance of RES in the Poland’s energy balance.

The coal industry contributes significantly to the social economy but the emission of greenhouse gases puts huge pressure on the environment in the process of mining transportation and power generation. In the integrated energy system (IES) the current research about the power-to-gas (P2G) technology mainly focuses on the injection of hydrogen generated from renewable energy electrolyzed water into natural gas pipelines which may cause hydrogen embrittlement of the pipeline and cannot be repaired. In this paper sufficient hydrogen energy can be produced through P2G technology and coal-to-hydrogen (C2H) of coal gasification considering the typical scenario of coal district is rich in coal and renewable energy. In order to transport the mined coal to the destination hydrogen heavy trucks have a broad space for development which can absorb hydrogen energy in time and avoid potentially dangerous hydrogen injection into pipelines and relatively expensive hydrogen storage. An optimized scheduling model of electric-gas IES is proposed based on second-order cone programming (SOCP). In the model proposed above the closed industrial loop (including coal mining hydrogen production truck transportation of coal and integrated energy systems) has been innovatively studied to consume renewable energy and coordinate multi-energy. Finally an electric-gas IES study case constructed by IEEE 30-node power system and Belgium 24-node natural gas network was used to analyze. The results show that by introducing the proposed hydrogen production technology typical daily operating costs are effectively reduced by 7.7%. Under China’s carbon emissions trading system the operating costs of hydrogen heavy trucks have been reduced by 0.95 and 4.68% respectively compared with electric vehicles and diesel trucks. Under Europe’s stricter carbon emissions trading system the percentages of cost reduction are 2.56 and 9.12% respectively. The above technical results verify the feasibility economy low carbon and effectiveness of the proposed mechanism.

Decarbonisation of the iron and steel industry would require the use of innovative low-carbon production technologies. Use of 100% hydrogen in a shaft furnace (SF) to reduce iron ore has the potential to reduce emissions from iron and steel production significantly. In this work results from the techno-economic assessment of a H2-SF connected to an electric arc furnace(EAF) for steel production are presented under two scenarios. In the first scenario H2 is produced from molten metal methane pyrolysis in an electrically heated liquid metal bubble column reactor. Grid connected low-temperature alkaline electrolyser was considered for H2 production in the second scenario. In both cases 59.25 kgH2 was required for the production of one ton of liquid steel (tls). The specific energy consumption (SEC) for the methane pyrolysis based system was found to be 5.16 MWh/tls. The system used 1.51 MWh/tls of electricity and required 263 kg/tls of methane corresponding to an energy consumption of 3.65 MWh/tls. The water electrolysis based system consumed 3.96 MWh/tls of electricity at an electrolyser efficiency of 50 KWh/kgH2. Both systems have direct emissions of 129.4 kgCO2/tls. The indirect emissions are dependent on the source of natural gas pellet making process and the grid-emission factor. Indirect emissions for the electrolysis based system could be negligible if the electricity is generated from renewable energy sources. The levellized cost of production(LCOP) was found to be $631 and $669 respectively at a discount rate of 8% for a plant-life of 20 years. The LCOP of a natural gas reforming based direct reduction steelmaking plant of operating under similar conditions was found to be $414. Uncertainty analysis was conducted for the NPV and IRR values.

Hydrogen technologies are promising candidates of new energy technologies for electric power load smoothing. However regardless of long-term public investment hydrogen economy has not been realized. In Japan the National Research and Development Institute of New Energy and Industrial Technology Development Organization (NEDO) a public research-funding agency has invested more than 200 billion yen in the technical development of hydrogen-related technologies. However hydrogen technologies such as fuel cell vehicles (FCVs) have not been disseminated yet. Continuous and strategic research and development (R&D) are needed but there is a lack of expertise in this field. In this study the transition of the budgetary allocations by NEDO were analyzed by classifying NEDO projects along the hydrogen supply chain and research stage. We found a different R&D focus in different periods. From 2004 to 2007 empirical research on fuel cells increased with the majority of research focusing on standardization. From 2008 to 2011 investment in basic research of fuel cells increased again the research for verification of fuel cells continued and no allocation for research on hydrogen production was confirmed. Thereafter the investment trend did not change until around 2013 when practical application of household fuel cells (ENE-FARM) started selling in 2009 in terms of hydrogen supply chain. Hydrogen economy requires a different hydrogen supply infrastructure that is an existing infrastructure of city gas for ENE-FARM and a dedicated infrastructure for FCVs (e.g. hydrogen stations). We discussed the possibility that structural inertia could prevent the transition to investing more in hydrogen infrastructure from hydrogen utilization technology. This work has significant implications for designing national research projects to realize hydrogen economy.