THE POTENTIAL FOR THE DEVELOPMENT OF THE HYDRO- GEN ECONOMY IN UKRAINE UNTIL 2030

Carbon capture and utilization via calcium looping, sorption enhanced methanation and green hydrogen: A techno-economic analysis and life cycle assessment study

Biogas upgrading to quality of natural gas (NG) creates possibility to supply biomethane to the NG grid, easy transportation and production of electricity and heat in locations where there is guaranteed consumption of thermal energy. Biomethane as a close NG analogue can be used for heat and electricity production, as soon as motor fuel and raw material for chemical industry.
 The International Energy Agency (IEA) estimates that the world's annual biomethane production potential is 730 bcm (20% of current world's NG consumption). World biomethane production reached almost 5 bcm/yr in 2019. According to forecast of the European Biogas Association the biogas and biomethane sector may almost double its production by 2030. According to IEA estimates, annual world biomethane production could reach 200 bcm in 2040 in case the sustainable development strategy is implemented
 Currently, the Bioenergy Association of Ukraine estimates the potential for biogas/biomethane production in Ukraine using fermentation technology as 7,8 bcm/yr (25% of the country's current NG consumption). The roadmap of bioenergy development in Ukraine until 2050 envisages growth of biomethane production to 1,7 bcm in 2035 and up to 3 bcm in 2050.
 Currently the prospects for green hydrogen development are well known. The authors support the need of hydrogen technologies as one of the way for production and use of renewable gases. However, they believe that biomethane has no less prospects.
 Transporting of one cubic meter of biomethane through gas pipeline at 60 bar pressure transmits almost four times more energy than transporting of one cubic meter of hydrogen. This is fundamental advantage of biomethane. Another advantage is the full readiness of gas infrastructure for biomethane. Given the cost of gas infrastructure modernization to use hydrogen, it is more cost-effective to convert green hydrogen to synthetic methane.
 Currently, biomethane is in average three times cheaper than green hydrogen, the cost of the two renewable gases is expected to equalize by 2050, and only further possible reduction in the cost of green hydrogen below $2/kg will make green hydrogen cheaper than biomethane. Therefore, the greatest prospects can be seen in the combination of the advantages of both renewable gases and conversion of green hydrogen into synthetic methane (power-to-gas process).
 Authors believe that after adoption of legislation to support the development of biomethane production and use in Ukraine, the bulk of biomethane produced in the country will be exported to EU, where more favourable conditions for biomethane consumption are developed. As Ukraine's economy grows, more and more of the biomethane produced will be used for domestic consumption.

The objective of this study was to evaluate the sorghum silage with the addition of guandu using in vitro semi automated gas production technique. Total gas production, methane production, the dry matter degradability (DMD) and organic matter (OMD) were estimated. PEG was used to measure the possible effect of tannins of sorghum silage on methane and gas production. The results indicated that the presence of PEG in the sorghum silage in the level of 25% and 50% inclusion of guandu were the highest (P < 0.05) in the gas and methane production, respectively compared with the other levels. For the gas and methane production increment, the results varied, the highest (P < 0.01) increment of gas production and methane production were found with the levels of 25% 50% inclusion of guandu, respectively. DMD and OMD increased with the increasing of pigeon pea levels with sorghum silage, these variables were greater (P< 0.01) wfhen PEG was added compared to without PEG. This evaluation of the silages showed that the presence of tannin in sorghum silage can interfere in the rumen fermentation and methane production in vitro especially identified when the substrates were incubated in the presence of PEG.

Roadmap towards a sustainable hydrogen economy in Mexico

The aim of this study was to determine whether the inclusion of a marine algae found in South African waters, Ulva lactuca, can reduce total gas and methane production in vitro when it replaces lucerne hay in a mixed sheep feed at incremental levels. Four treatments were prepared and incubated using bovine rumen fluid as inoculum: (1) 0 g U. lactuca kg-1 feed dry matter (DM) (0U), (2) 25 g U. lactuca kg-1 feed DM (25U), (3) 50 g U. lactuca kg-1 feed DM (50U), and (4) 100 g U. lactuca kg-1 feed DM (100 U). Total gas and CO2 production was determined with the aid of an automated system and methane production was estimated by difference. Cumulative gas production data were fitted to a non-linear model (Y = b(1- exp-c(t-L))) to estimate values for total gas production (b, mL), rate of gas production (c, mL/h), and a discrete lag time (L, hours). The extent of total gas production was lower for 100U than for 25U, but neither differed from 0U or 50 U. The lag time observed was lower for 50U than 0U, but neither differed from 25U or 100U. No differences were found for the rate of gas production. No differences for any gas production values were observed between treatments. The ratio between methane and total gas production was highest for 100U, which differed from 25U, but not from 0U or 50U. The higher methane ratio observed in the 100U treatment may be attributed to the lower total gas production in this treatment due to the lower fermentability of U. lactuca compared to lucerne.

Higher penetration of renewable energy sources in the energy mix and increasing pressure to decarbonize society introduces new challenges. Energy storage and grid stabilization systems are necessary to address the intermittent nature of renewable energy sources (wind, solar etc.) [1]–[4]. Renewable energy storage in form of hydrogen offers an attractive option for energy storage [5], [6]. With advent of hydrogen economy and growing number of fuel cell vehicles, local production and supply of hydrogen infrastructure for refueling stations is essential [7]–[9]. An r-SOC electrochemical reactor system is capable addressing these multiple challenges of energy storage and coupling the energy storage sector with hydrogen economy sector. Electricity storage is achieved by operating such a system in electrolysis mode (reduction of H2O). Electrical energy is converted to chemical energy in form of hydrogen. The produced hydrogen can be supplied into gas grids or stored locally which can be supplied to hydrogen refueling stations. During high demand for electricity, the system can be switched to fuel cell mode during which the stored hydrogen is efficiently converted to electricity. r-SOC systems offer an interesting feasible solution for the following challenges: 1) Efficient electricity storage, 2) Grid stabilization required for intermittent renewable energy, 3) Sector coupling of energy storage sector with hydrogen economy supply chain and 4) A decentralized solution for the above challenges via e.g. hydrogen refueling stations. An r-SOC system as described above poses certain technical challenges as requirements of a stand-alone SOEC (solid oxide electrolysis cell) system and a stand-alone SOFC (solid oxide fuel cell) system are different from each other. The simplest design approach for an r-SOC system calls for thermoneutral or exothermic electrolysis operation, although this will yield low round trip efficiencies in the range of 35 % [10]. Coupling highly efficient endothermic electrolysis and exothermic fuel cell mode allows for significantly higher round trip efficiencies up to 60 %. Therefore thermal integration, storage and management between the two modes of operation are crucial. In this study, a process system study of an r-SOC electrochemical reactor system is performed. Process system analysis is performed based on experimental investigation of a commercially available r-SOC reactor carried out under pressurized conditions. Opportunities of integrating thermal energy storage are investigated. Detailed process system architectures are discussed and effects of key system operating parameters are analyzed. Achievable system roundtrip efficiencies for the different scenarios using currently available r-SOC reactor technology are quantified. Reference [1] P. J. Hall and E. J. Bain, “Energy-storage technologies and electricity generation,” Energy Policy, vol. 36, no. 12, pp. 4352–4355, Dec. 2008. [2] H. Ibrahim, A. Ilinca, and J. Perron, “Energy storage systems—Characteristics and comparisons,” Renew. Sustain. Energy Rev., vol. 12, no. 5, pp. 1221–1250, Jun. 2008. [3] A. Evans, V. Strezov, and T. J. Evans, “Assessment of sustainability indicators for renewable energy technologies,” Renew. Sustain. Energy Rev., vol. 13, no. 5, pp. 1082–1088, Jun. 2009. [4] R. M. Dell and D. A. J. Rand, “Energy storage - A key technology for global energy sustainability,” J. Power Sources, vol. 100, pp. 2–17, 2001. [5] A. Sternberg and A. Bardow, “Power-to-What? - Environmental assessment of energy storage systems,” Energy Environ. Sci., vol. 8, no. 2, pp. 389–400, 2015. [6] H. Chen, T. N. Cong, W. Yang, C. Tan, Y. Li, and Y. Ding, “Progress in electrical energy storage system: A critical review,” Prog. Nat. Sci., vol. 19, no. 3, pp. 291–312, Mar. 2009. [7] J. a Turner, “Sustainable hydrogen production.,” Science, vol. 305, no. 5686, pp. 972–974, 2004. [8] M. Ball and M. Wietschel, “The future of hydrogen - opportunities and challenges,” Int. J. Hydrogen Energy, vol. 34, no. 2, pp. 615–627, 2009. [9] G. Mulder, J. Hetland, and G. Lenaers, “Towards a sustainable hydrogen economy: Hydrogen pathways and infrastructure,” Int. J. Hydrogen Energy, vol. 32, no. 10–11, pp. 1324–1331, 2007. [10] J. Mermelstein and O. Posdziech, “Development and Demonstration of a Novel Reversible SOFC System for Utility and Micro Grid Energy Storage,” 2016, vol. 306, no. July, pp. 59–70.

A general vision of a sustainable energy economy relying substantially on hydrogen produced from renewables is sketched as a potential solution to the twin global crises of climate change and depleting oil reserves. Core differences between this 'sustainable hydrogen economy' (SHE) and the original hydrogen economy (HE) proposed in the early 1970s are discussed. In transport, rather than posing a binary choice between hydrogen fuel cell and battery electric vehicles, it is argued that the old maxim of 'horses for courses' should be followed, with complementary deployment of these two technologies depending on the transport service to be supplied. Other key features of SHE are the use of distributed bulk hydrogen storages for season-to-season storage on electricity grids, and as a strategic energy reserve. The conduct of detailed energy-economic-environmental modelling is recommended to evaluate the SHE vision in particular national and regional contexts, and hence globally.

Hydrogen has gained increasing attention recently as an alternative energy carrier leading towards a sustainable hydrogen economy [1]. Green hydrogen has less pollution (water as the only byproduct) and higher energy density than its counterpart fossil fuels. Additionally, it has much higher refueling speed than lithium-ion batteries, which makes it’s more suitable for mobility applications.Proton exchange membrane (PEM) water electrolysis is one of the most popular approaches for green hydrogen generation due to its high efficiency and high differential pressure operation capability [2]. The membrane electrode assembly (MEA) is the core of a PEM electrolyzer in which water molecules are spilt into hydrogen and oxygen molecules. In this overview, the challenges and paths regarding the MEA materials, operation/diagnosis/maintenance, and final recycling will be discussed.An electrolyzer MEA contains an anode and cathode made of platinum group metal (PGM) catalysts, a perfluorosulfonic acid (PFSA) membrane, and other gasketing materials. PGM catalysts are a major source of the cost of the PEM electrolyzer stack. Ir black based catalysts have been used for decades in the PEM electrolyzer industry. Due to the high cost and scarcity of Ir, efforts have been dedicated to reducing the catalyst loading and developing highly active catalysts [3]. The membrane is another major component of a PEM electrolyzer. 5 mil and 7 mil thick membranes have been used in electrolyzer industries. However, the ionic resistive losses of these relatively thick PEMs significantly reduce the efficiency of the MEA. Hence, reducing membrane thickness has been a central topic for PEM electrolyzer membrane development. With the progressive thinning of the PEM, the hydrogen gas crossover will become significant, which will compromise the safe operation of a PEM electrolyzer system. An effective gas recombination layer in the PEM is therefore urgently needed to mitigate the resulting higher hydrogen crossover. Additionally, the mechanical stresses imposed due to operation at high differential pressure operation (up to 40 bar) increases the attractiveness of a reinforcement layer.The unique properties of the membrane and catalysts in an MEA also require ultra-pure feed water. However, this cannot always be guaranteed. Metal ions will leach out from system plumbing and the DI system can’t always effectively remove all ions from tap water. The contamination will also poison the catalysts in an MEA. It is therefore critical to establish a universal method to efficiently identify the issue and recover the MEA performance.It is expected that the MEA can last 60k to 90k hours [4]. Though functionality may be compromised at the this point, the value in the PGM catalysts, and to a lesser extent membrane, and other carbon-based materials [5] remains. MEA recycling thus needs to be considered at the very early stage of the large-scale PEM electrolyzer application. Tradition calcination approaches for catalyst refinery is not optimized for PEM MEAs due to the presence of the PFSA membrane. The burning of MEAs will not only waste costly PFSA material but also poses a threat to the environment due to carbon and fluoride emissions. Current research efforts have focused on catalyst recycling and reuse/repurpose of PFSA based materials.[1] Oliveira, A. M., Beswick, R. R. & Yan, Y. A green hydrogen economy for a renewable energy society. Current Opinion in Chemical Engineering 33, 100701 (2021).[2] Ayers, K. et al. Perspectives on low-temperature electrolysis and potential for renewable hydrogen at scale. Annual review of chemical and biomolecular engineering 10 (2019).[3] Mittelsteadt, C. (Invited) Ir Strangelove: Or How I Learned to Stop Worrying and Embrace the PEM. ECS Meeting s MA2022-01, 1335-1335 (2022).[4] Schmidt, O., Future cost and performance of water electrolysis: an expert elicitation study. International journal of hydrogen energy 42 (2017), 30470-30492.[5] Sverdrup, H. U. & Ragnarsdottir, K. V. A system dynamics model for platinum group metal supply, market price, depletion of extractable amounts, ore grade, recycling and stocks-in-use. Resources, Conservation and Recycling 114, 130-152 (2016)

The aim of current experiment was to determine the effect of replacement of alfalfa hay with ribwort plantain (Plantago lanceolata) hay in ruminant diets on the fermentation parameters such as gas production, methane (CH4) production, true digestible dry matter (TDDM), true digestibility (TD), partitioning factor, microbial protein, and efficiency of microbial protein using in vitro gas production technique. The alfalfa hay was replaced with P. lanceolata hay in a diets isocaloric (2650 kcal/kg DM) and nitrogenic (17% CP kg DM) at the ratio of 0, 5, 10 and 15%. Partial substitution of alfalfa hay with P. lanceolata hay had no significant effect on gas and methane (ml/incubated substrate or %) production whereas the partial substitution had a significant effect on TDDM, TD, gas (ml/digested DM), CH4 (ml ml/digested DM) and microbial MP of diets. The replacement of alfalfa hay with ribwort plantain hay shifted the fermentation pattern from gas and methane production to microbial protein production. Therefore alfalfa hay can be replaced with ribwort plantain hay with high digestibility and anti-methanogenic potential in ruminant diets up to 15% to decrease methane production and improve microbial protein production. However further in vivo experiments are required to determine the effect of replacement on feed intake and animal production.

BackgroundHydrogen energy, a type of renewable energy if produced without fossil fuel, has a critical issue in that most of it is still produced from carbon footprint heavy industries such as the fossil fuel industry. It is imperative to produce hydrogen from renewable sources on a global level so that the carbon footprint can be curbed. South Korea, along with other global economies such as the US, the EU, Japan and China, has shown its resolution to build a hydrogen economy with green hydrogen produced only from renewable sources. Since 2017, South Korea has been actively shaping its political actions and policies to develop the necessary technology for this transition. This study focuses on South Korea's actions and policies, using a political system model to better understand the shift towards a green hydrogen economy.ResultsThe analysis shows that budgeting for R&D projects has had a significant impact on scientific breakthroughs, advancements, and product development in the field of green hydrogen in South Korea. These actions have also affected market performance, resulting in increased interest and investment in green hydrogen. Although there have been significant advancements in the field of green hydrogen in South Korea, the current state of technology remains in its early stages of development. Most of the breakthroughs have been in water-to-hydrogen and biomass-to-hydrogen technologies. However, these technologies show promise as the foundation of a thriving hydrogen economy in South Korea. The analysis also indicates a strong market demand for green hydrogen technology. To support these efforts, the political system has focused its financial support on water-to-hydrogen technology and projects at the TRL 1–3 stage.ConclusionsThe study concludes that ongoing financial and political support is necessary for areas showing outstanding performance to vitalize the hydrogen economy and facilitate the transition to a green hydrogen society in the future. Additionally, a robust legal framework is crucial to ensure steady growth of the green hydrogen economy, similar to those in other major hydrogen economies such as the US and Germany. This study serves as a case study of South Korea, showcasing the impact of political actions on the advancement of scientific technology.

In dairy cattle, the stomach tube method is not a feasible alternative to the rumen cannulation method to examine in vitro gas and methane production

Hydrogen plays a key role in many industrial applications and is currently seen as one of the most promising energy vectors. Many efforts are being made to produce hydrogen with zero CO2 footprint via water electrolysis powered by renewable energies. Nevertheless, the use of fossil fuels is essential in the short term. The conventional coal gasification and steam methane reforming processes for hydrogen production are undesirable due to the huge CO2 emissions. A cleaner technology based on natural gas that has received special attention in recent years is methane pyrolysis. The thermal decomposition of methane gives rise to hydrogen and solid carbon, and thus, the release of greenhouse gases is prevented. Therefore, methane pyrolysis is a CO2-free technology that can serve as a bridge from fossil fuels to renewable energies.

The use of natural feed additives to reduce methane (CH4) production through manipulation of ruminal fermentation patterns and improve animal performance has increasingly been evaluated. One of these strategies may be the use of Natural Zeolites (NZ), such as glauconite. This study aimed to evaluate in vitro dietary supplementation with levels of NZ on rumen fermentation patterns and dry matter digestibility (DMD). In the experiment, a basal diet (50% concentrate: 50% forage) was incubated without additive (control) and with natural zeolite (1 or 2 % of DM) for 24 h to assess their effect on ruminal fermentation, feed degradability, and gas and methane production using a semi-automatic system of in vitro gas production (GP). The GP was determined using the Ankom® RF Gas Production System (Ankom Technology, NY, USA), by incubating 0.5 g of samples (ground to 1 mm). Eight analytical repetitions (8 bottles/ treatment) and four blank bottles (rumen fluid and buffer solution) were used. The pressure of GP in all bottles at each measuring time was converted into volumes to calculate the total accumulative gas produced through 24 h. After this time, methane concentration was determined using a gas chromatograph., a gas sample was taken for methane analysis, a sample was taken for short chain fatty acid (SCFA) analysis, and DM was performed on the final residue from the bottles to estimate the disappearance of DM. Methane concentration was determined using a gas chromatograph. All data were analyzed as polynomials using SAS. Significant effects were adopted when P ≤ 0.05 and tendency was reported when 0.05 < P ≤ 0.10. The inclusion of NZ did not affect the VFA proportion (P ≥ 0.15). The inclusion of NZ in the diet linearly increased the rumen pH (P = 0.02), but not effect ruminal ammonia concentrations (P ≥ 0.21). The experimental treatments did not affect the DM digestibility (P ≥ 0.11), total gas (P ≥ 0.19), and methane production (P ≥ 0.43). In conclusion, the addition of NZ not affect in vitro dry matter digestibility and, at the same time, increasing rumen pH without affecting gas production, including methane.

A sustainable future hydrogen economy hinges on the development of green hydrogen and the shift away from grey hydrogen, but this is highly reliant on reducing production costs, which are currently too high for green hydrogen to be competitive. This study predicts the cost trajectory of alkaline and proton exchange membrane (PEM) electrolyzers based on ongoing research and development (R&D), scale effects, and experiential learning, consequently influencing the levelized cost of hydrogen (LCOH) projections. Electrolyzer capital costs are estimated to drop to 88 USD/kW for alkaline and 60 USD/kW for PEM under an optimistic scenario by 2050, or 388 USD/kW and 286 USD/kW, respectively, under a pessimistic scenario, with PEM potentially dominating the market. Through a combination of declining electrolyzer costs and a levelized cost of electricity (LCOE), the global LCOH of green hydrogen is projected to fall below 5 USD/kgH2 for solar, onshore, and offshore wind energy sources under both scenarios by 2030. To facilitate a quicker transition, the implementation of financial strategies such as additional revenue streams, a hydrogen/carbon credit system, and an oxygen one (a minimum retail price of 2 USD/kgO2), and regulations such as a carbon tax (minimum 100 USD/tonCO2 for 40 USD/MWh electricity), and a contract-for-difference scheme could be pivotal. These initiatives would act as financial catalysts, accelerating the transition to a greener hydrogen economy.

Development of an in vitro method for determination of methane production kinetics using a fully automated in vitro gas system—A modelling approach