Discard Rate Research Articles

Histological and clinical evaluation of discarded kidneys in a European cohort of deceased brain death donor kidneys of marginal quality.

Despite organ shortages, the discard rate of deceased donor kidneys is high. Risk factors for this trend warrant further study. We investigated reasons for discard in a cohort of brain death donors with marginal kidneys and procurement biopsies. Paraffin embedded procurement biopsies were systematically reevaluated and graded for the purpose of the study. Assessment included percentage of global glomerulosclerosis, Banff Lesion scores and tubular epithelial damage. Donor-, transplant process-, perfusion quality-, histopathology-, and recipient-related parameters were compared between discarded and transplanted organs. Although most clinical characteristics were similar between donors whose kidneys were transplanted and those whose kidneys were procured but discarded, discarded kidneys were more likely to be from donors with hepatitis C, to have undergone wedge biopsies, to show changes of acute and chronic injury and to be deemed poor quality. Except for obvious anatomic abnormalities, kidneys were often discarded due to the findings of procurement biopsies. Donors of kidneys discarded for histologic reasons more often had hypertension, coronary artery disease, stroke, and increased serum creatinine. The reason for discard was unknown in 20% of cases. Discarded kidneys came from donors who appeared to be clinically similar to donors whose kidneys were utilized for transplant. A considerable proportion of discarded kidneys were of acceptable quality. The analysis of theoutcome of every recovered organ could help to overcome this problem. Procurement biopsies more often lead to discard than to transplantation of recovered organs. Proper handling during allocation has to be determined.

The effect of an organ procurement organization surgeon on pediatric organ utilization.

Organ procurement organizations (OPO) have started to employ transplant-trained surgeons dedicated to organ procurement with the aim to increase allograft utilization and enhance the use of procured organs. We investigated the effects of an OPO-employed surgeon on the procurement and utilization of organs from pediatric donors within the Southwestern Transplant Alliance OPO. OPO data were obtained for all procurements that were performed between 2014 and 2019. The analysis was performed to see if the presence of an OPO donor surgeon impacted the utilization of pediatric livers. Donor and recipient demographic data were examined between allografts procured with the presence of an OPO surgeon (OPO-Present) and those without an OPO surgeon (OPO-Absent). A p-value of <.05 was considered significant. Of 149 pediatric procurements, 91 included an OPO-donor surgeon. In procurements with OPO-Present, donors were younger (8.2 vs. 11.2, p < .05) and had longer distances to travel to the recipient center (334 vs. 175 miles p < .05), but had comparable cold ischemic times. In terms of organ share type, more OPO-Present livers were shared nationally and there was no difference in discard rate between OPO-Present and OPO-Absent procurements. Finally, OPO-Present livers were more likely to be transplanted to pediatric recipients compared to OPO-Absent (47.3% vs. 24.1% p < .05). The presence of an OPO surgeon has impacted organ utilization, leading to increased transplantation of pediatric livers in pediatric recipients, and has expanded the geographical share of pediatric livers.

P‐BB‐56 | Mitigation Steps to Reduce Platelet Discard Rates due to Aggregates

P‐BB‐56 | Mitigation Steps to Reduce Platelet Discard Rates due to Aggregates

The effects of two different net modifications on reducing discards in the trammel net fishery for prawn in Mersin Bay

The discarded species caught in prawn trammel nets damage the nets and cause a serious labor loss problem for fishers. In the present study, a 15 cm high greenhouse plastic film and a greenhouse shade cloth net were fitted between the lower parts of the nets and the lead collars to reduce discards in the trammel net fishery. The modified nets were tested in Mersin Bay with twenty-one fishing operations between September and December 2021. The results showed that, compared to commercial trammel nets, the nets equipped with greenhouse plastic film and greenhouse shade cloth did not significantly reduce the catch of the target species green tiger prawn (Penaeus semisulcatus). However, the total number of discards significantly decreased. The discard rates in the commercial net, greenhouse plastic film net, and greenhouse shade cloth net were 45%, 26%, and 22%, respectively. Furthermore, when the incomes from the nets’ hauls were calculated, the net equipped with greenhouse garden film and the net equipped with greenhouse shade cloth generated 24.77% and 14.41% more profit than the commercial net, respectively.

Genetic analysis for semen quality traits in buffalo bulls.

This study was attempted to estimate the genetic parameters of semen quality traits in buffalo bulls. The study data consisted of 10975 ejaculates from 45 Murrah buffalo bulls (aged 24-72months) used for breeding program during year 2010 to 2020. Semen quality traits (ejaculate volume, concentration of sperm, mass activity, initial and post-thaw motility, number of sperms per ejaculate, motile sperm number and discard rates) were studied. It was observed that average ejaculate volume was 2.82 ± 1.45mL with mean concentration of 1040.12 ± 523.26 million/mL. Higher heritability was observed for number of sperms per ejaculate, number of motile sperm and sperm concentration. Significant phenotypic correlation was obtained between volume and number of sperms per ejaculate as well as volume and number of motile sperms. Likewise, significant phenotypic correlation was evident between sperm concentration with sperm number per ejaculate. Highest phenotypic correlation was obtained between sperm count per ejaculate and motile sperm count. Estimated genetic trends showed significant change in volume and motile sperm number. In conclusion, this study ascertains that genetic parameters of semen traits can be considered during the selection of buffalo bulls in breeding program.

Semi-Supervised Classification with A*: A Case Study on Electronic Invoicing

This paper addresses the time-intensive task of assigning accurate account labels to invoice entries within corporate bookkeeping. Despite the advent of electronic invoicing, many software solutions still rely on rule-based approaches that fail to address the multifaceted nature of this challenge. While machine learning holds promise for such repetitive tasks, the presence of low-quality training data often poses a hurdle. Frequently, labels pertain to invoice rows at a group level rather than an individual level, leading to the exclusion of numerous records during preprocessing. To enhance the efficiency of an invoice entry classifier within a semi-supervised context, this study proposes an innovative approach that combines the classifier with the A* graph search algorithm. Through experimentation across various classifiers, the results consistently demonstrated a noteworthy increase in accuracy, ranging between 1% and 4%. This improvement is primarily attributed to a marked reduction in the discard rate of data, which decreased from 39% to 14%. This paper contributes to the literature by presenting a method that leverages the synergy of a classifier and A* graph search to overcome challenges posed by limited and group-level label information in the realm of electronic invoicing classification.

Joint task offloading and resource allocation for multi-user and multi-server MEC networks: A deep reinforcement learning approach with multi-branch architecture

Mobile Edge Computing (MEC) is a promising computing paradigm in the context of 5G networks, as it enables the migration of workloads from User Equipments (UEs) to nearby MEC servers, thereby providing additional computing resources to UEs. In this paper, we propose a joint optimization approach to offloading decisions and resource allocation in a multi-user and multi-server MEC system, which operates in a time-varying environment. Our objective is to minimize the average task latency and discard rate under the constraints of latency and limited computing resources of the server. While traditional optimization methods have been used to solve computational offloading problems in static environments, these methods are not suitable for time-varying systems. Deep reinforcement learning can be an effective method for solving optimization problems in time-varying environments, as it can be used to adjust strategies in real-time in response to changes in the environment. However, the increased number of UEs in the system leads to a combinatorial increase in the number of possible actions, making it difficult for the algorithm to learn. To address this issue, we propose a multi-branch network based Deep Q Network (DQN) algorithm called Branch Deep Q Network (BDQN), which modifies the action generation network into a multi-branch network structure, each branch generates one-dimensional action. This modification makes the number of network outputs increase linearly. Numerical results show that the BDQN algorithm outperforms other baseline algorithms in terms of average task latency and discard rate.

Small-scale fisheries discards in the eastern Mediterranean Sea: Discarding species, quantities, practices and drivers

Discarding is major issue globally in terms of conservation, fisheries management and economics. To date, studies on fisheries discards have been primarily focused on large-scale fisheries and little attention was given to small-scale fisheries (SSF) discards. The multi-species and multi-gear nature of SSF in the Mediterranean makes any scientific effort to study discards and management action to regulate discards challenging. The study attempted, for the first time in Levantine Sea, to quantify discards, identify discarded species, and comprehend the causes and drivers of SSF discarding in Cyprus through 208 fishing trips by observing the fishers' regular fishing operations using trammel nets, gillnets, monofilament nets and bottom set longline. Out of the total catch, 1408.385 kg were landed and 956.581 kg were discarded. The majority of discarded individuals were non-indigenous species (73.7 %). Results exhibited a discard rate of 9.92 individuals (4.6 Kg) and a mortality rate of 0.86 per sampled fishing trip, indicating that almost all individuals discarded were released dead. The proportional discards rate (%) out of the total catch was calculated at about 41 % and the average landings/discards ratio in terms of weight was 1.5:1. The five most common discarded species in terms of numbers belonged to osteichthyes and were Sargocentron rubrum followed by Lagocephalus sceleratus, Torquigener flavimaculosus, Scorpaena scrofa and Pterois miles representing 27.8 %, 25.2 %, 13.9 %, 4.7 % and 2.4 %, respectively, of all discarded species. ‘Poisonous fish’, ‘undersized fish’ and ‘low’ and ‘no commercial value’ fish were the main reasons for discarding. Other reasons included ‘prohibited’ to land species, ‘poor condition’ and ‘depredated’ fish. Elasmobranchs were the second most abundant class accounting for 4.3 % of the total discarded taxa, including threatened, endangered and critically endangered species. Net length, soak time, gear type, and seasonality are the main factors driving discards. The findings of the current work could support the development of national fishery-specific management action plans to mitigate discards and impact on marine ecosystems.

Operation Performance Analysis of a Novel Renewable Energy‐Driven Multienergy Supply System Based on Wind, Photovoltaic, Concentrating Solar Power, Proton Exchange Membrane Electrolyzers, and Proton Exchange Membrane Fuel Cell

In pursuing clean energy systems and carbon neutrality, the efficient use of renewable energy is key. This research introduces a novel wind–solar–hydrogen multienergy supply (WSH‐MES) system, powered by renewables, designed to stabilize power output through regulated concentrating solar power (CSP) and proton exchange membrane electrolyzers (PEMEs). An active regulation strategy for thermal and hydrogen storage is developed to counterbalance the volatility of wind and photovoltaic power. Key results reveal that the WSH‐MES system surpasses WP–PV and WP–PV–CSP systems in reliability, reducing power supply loss probability to 2.81%. This improvement is largely due to the controlled CSP and PEME, which effectively mitigates the stochastic fluctuations in wind and solar power generation, thereby ensuring more stable and reliable power output. Moreover, the system achieves an 80.97% primary renewable energy rate and a 0.12 power discard rate. In conclusion, this research comprehensively examines the operational characteristics of the WSH‐MES system, elucidates the practical advantages of the WSH‐MES system in terms of reliability, renewable energy utilization, and adaptability under various conditions. The results offer valuable insights into the design and operation of multienergy supply systems, potentially fostering the large‐scale implementation of renewable energy systems and leading toward a sustainable energy future.

Geo-spatial distribution and trends of trawl catch and bycatch off the south Konkan coast, Maharashtra, India

Trawl fishing is well-known for its high catch rate, but due to its non-selective nature, it is now widely acknowledged to have an impact on biodiversity and habitat. The geographical and temporal aspects of trawl catch, bycatch, discard, and ichthyofaunal trawl diversity along the south Konkan coast of Maharashtra, India, are contemplated in the current study. The data of 177 georeferenced trawl hauls, towed between 15°53’38”N to 17°34’52”N latitude and 72°54’29”E to 73°25’48”E longitude, revealed that maximum bycatch (70–110 kg/haul) and discard (60–110 kg/haul) regions were found towards the southern direction, near ecologically sensitive estuarine areas off the south Konkan coast, Maharashtra. The post and pre-monsoon seasons were found to be much more productive in terms of catches, while the post-monsoon and winter seasons had the highest species diversity 38.15% and 33.86%, respectively, with the winter season having higher discard rates. In the present study, bycatch contributed nearly 49% of the total catch, with the maximum catch per hour recorded in October (62.20 kg) and the discard per hour in January (14.59 kg). There were 134 different species of fish and shellfish recorded, and the family Carangidae (8.21%) was prominent in terms of species richness, followed by Penaeidae (6.72%), Clupeidae (5.22%), Engraulidae (5.22%), and Sciaenidae (4.48%). The results of various biodiversity indices confirmed that the studied region is blessed with rich and evenly distributed biodiversity. The mapped predictive values of trawl fishing showed a high fishing pressure zone towards the south off the Maharashtra coast, and it highlighted the need for suitable strategies for the conservation and management of fisheries resources to achieve long-term sustainability in that region.

Initial experiments to assess potential short-term discard survival of cod (Gadus morhua) in the Baltic Sea set-net fishery

The European Union’s landing obligation includes an exemption for species with documented high survival rates. This is highly relevant for the cod (Gadus morhua) stock in the Baltic Sea, being in a critical state. This study provides initial information on potential discard survival rates for cod (Gadus morhua) caught in trammel nets in the Baltic Sea. Catch-damage-index (CDI) and Reflex Action Mortality Predictor (RAMP) scores were used to assess fish condition immediately after capture and at the end of observation periods. A total of 61 cod were caught in eight different net fleets fished during three trials. Two cod died in the net and three cod died during the observation period from two to 10 days. The results indicate a potential in dedicating resources to cod discard survival studies.

Trends in pediatric donor heart discard rates and the potential use of unallocated hearts for allogeneic valve transplantation

ObjectivesAllogeneic valve transplantation is an emerging therapy that delivers a living valve from a donor heart. We reviewed the national discard rate of pediatric and young adult (aged 25 years or younger) donor grafts to estimate the number of hearts potentially available to source valve allotransplantation. MethodsWe queried the United Network for Organ Sharing database to identify pediatric and young adult heart donors from 1987 to 2022. Donor heart discard was defined as nontransplantation of the allograft. ResultsOf 72,460 pediatric/young adult heart donations, 41,065 (56.7%) were transplanted and 31,395 (43.3%) were unutilized. The average annual number of discarded hearts in era 1 (1987-2000), era 2 (2000-2010), and era 3 (2010-2022) was 791 (42.8%), 1035 (46.3%), and 843 (41.2%), respectively. From 2017 to 2021, the average annual number of discards by age was: 39 (31.8%) neonates/infants, 78 (38.0%) toddlers, 41 (49.4%) young children, 240 (38.0%) adolescents, and 498 (40.1%) young adults. High-volume procurement regions had the greatest proportion of nonutilization, with the national average discard rate ranging from 39% to 49%. The most frequently documented reasons for nonallocation were distribution to the heart valve industry (26.5%), presumably due to suboptimal graft function, poor organ function (22.7%), and logistical challenges (10.8%). ConclusionsWith ∼900 pediatric/young adult donor hearts discarded annually, unutilized grafts represent a potential source of valves for allogeneic valve transplant to supplement current conduit and valve replacement surgery. The limited availability of neonatal and infant hearts may limit this technique in the youngest patients, for whom cryopreserved homografts or xenografts will likely remain the primary valve substitute.

Viability of Transplanted Organs Based on Donor’s Age

Organ transplantation is becoming a major public health issue in many countries due to its attributable death rate and the excessive cost. There is a growing gap between organ supply and demand for organ transplantation in the US, which is causing major public health crisis. Twenty people on average die each day while waiting for a transplant because the supply of available organs from deceased donors does not meet the demand. National organ donation has increased in the past two decades; however, the number of individuals who need transplants has risen much faster as new patient is added to the national transplant waiting list every ten minutes. To address this disparity, not only the number of donors must be increased, but also the discard rate of available organs must be reduced. The kidney discard rate has increased by almost four times from the late 1980s to 2009, from approximately five percent to nearly 20 percent. So, it is important to investigate factors that may decrease the chance of an organ to be discarded as well as increase the survival time of transplanted organs. In this paper, we perform statistical survival analysis to study the impact of donor’s age on organ survival. Transplanted kidneys, livers, and intestines between 1987 and 2010 are investigated in this study. The results show that donor's age is an important factor for transplanted kidneys and livers donated by younger donors and survive for longer times while donor's age does not seem to be correlated with the survival time of transplanted intestines.

Evaluating the inventory impact of utilizing low titer platelets in regional hospitals.

As a result of constrained supply, it is sometimes necessary to provide patients with ABO-mismatched platelets. Such practices increase the risk of acute hemolytic transfusion reaction (AHTR). Providing patients with platelets suspended in O plasma having low-titer Anti-A and Anti-B antibodies (LtABO) could reduce the incidence of AHTR. However, natural scarcity limits the number of such units that can be produced. In this paper we present a study to evaluate strategies for deploying LtABO at regional hospitals in Canada. Regional hospitals often experience demand for platelets on an irregular basis. They are, however, required to stock some number of platelets (typically one A-unit and one O-unit) for emergencies; outdates are common, with discard rates sometimes >>50%. A simulation study was completed to determine the impact of replacing a (1A, 1O) inventory with 2 or 3 units of LtABO at regional hospitals. A significant decreases in wastage and shortage can be expected by replacing a (1A, 1O) inventory policy with 2 units of LtABO. In tested cases, a 2-unit LtABO dominated a (1A, 1O) policy, resulting in statistically fewer outdates and instances of shortage. Holding 3 units of LtABO, increases product availability, but results in an increase in outdates when compared to a (1A, 1O) policy. Providing LtABO platelets to smaller, regional hospitals will lower wastage rates and improve patient access to care, when compared to existing (1A, 1O) inventory policies.

Reconstructing past fisheries catches for large pelagic species in the Indian Ocean

Comprehensive catch data are fundamental to support the sustainable management of large pelagic fisheries. However, catch data reported by the Indian Ocean Tuna Commission (IOTC) on behalf of its member countries currently under-represent the extent of these fisheries in the Indian Ocean. We reconstructed fisheries catches of large pelagic species for the Indian Ocean from 1950 to 2020, aiming to improve the comprehensiveness of existing reported data and to provide more ecologically relevant datasets for research and management uses. We reconstructed catches for 42 countries operating five major gear groups (longline, purse seine, gillnet, pole-and-line, and other gears) in the large pelagic fisheries. Reconstructed catches were 30% higher than the data reported by the IOTC. We demonstrated that distant-water fishing fleets historically dominated large-scale industrial fishing but were gradually replaced by fleets flagged to Indian Ocean rim countries. Our results also indicated an average discard rate of ~14% over the 1950-2020 period, primarily attributable to extensive discarding practices associated with longline and gillnet vessels. Reporting over time has improved only for tunas, whereas shark catches still remain under-reported, accounting for 51% of total unreported landings and discards in 2020. We confirmed substantial taxonomic aggregation in the data reported by the IOTC on behalf of its member countries, masking important patterns and trends and further complicating the sustainable management of exploited species in the Indian Ocean. We recommend substantially increased observer coverage and far better and stronger support by all member countries to improve the fisheries statistics in the IOTC.

Audit-based corrective and preventive actions to reduce wastage of blood components at a single blood center: A quality improvement study.

The rate of discarded blood components or "wastage rate" reflects on the whole process, preparation, and production of blood and its quality control. It is the ratio of blood and blood components discarded to the total number of collections. The discard or unusability of blood products are many, and the ones that can be monitored and regarded as indicators to be improvised on are QC failure rate, transfusion-transmitted infection (TTI) positivity, and component discards (other than TTI), including those that caused transfusion reactions. These were studied over four intervention cycles to see if they could be improved. This was a clinical audit and quality improvement study. The clinical audit was conducted over four cycles over 16 months. Each cycle included three stages wherein the data required for calculating those key performance indicators (KPIs) of the blood center were studied and analyzed, and causes for the poorly performing ones were identified; a corrective plan was drawn and implemented, followed by data collection and interpretation of the same in the next cycle for improvement. The data were compiled using a Microsoft Excel spreadsheet and analyzed using SPSS version 19 (IBM Corporation, New York, USA). The overall discard rates due to all cumulative causes mentioned were at about 5% at the start of the first cycle. The various factors comprising preparatory, preparation, and the management of inventory and issue were analyzed, and corrective interventions were performed in every cycle. The discard rates were reduced to about 3% by the end of the four cycles. The difference was statistically significant, with a P < 0.05. The implementation of Corrective and preventive action measures can rectify the deviations in KPIs. The blood center director, staff, and doctors should be responsible for maintaining and continuously improving the quality indicators.

Rethinking Donor and Recipient Risk Matching in Europe and North America: Using Heart Transplant Predictors of Donor and Recipient Risk.

In Europe, there is greater acceptance of hearts from higher-risk donors for transplantation, whereas in North America, the donor heart discard rate is significantly higher. A Donor Utilization Score (DUS) was used to compare European and North American donor characteristics for recipients included in the International Society for Heart and Lung Transplantation registry from 2000 to 2018. DUS was further evaluated as an independent predictor for 1-year freedom from graft failure, after adjusting for recipient risk. Lastly, we assessed donor-recipient risk matching with the outcome of 1-year graft failure. DUS was applied to the International Society for Heart and Lung Transplantation cohort using meta-modeling. Posttransplant freedom from graft failure was summarized by Kaplan-Meier survival. Multivariable Cox proportional hazard regression was applied to quantify the effects of DUS and Index for Mortality Prediction After Cardiac Transplantation score on the 1-year risk of graft failure. We present 4 donor/recipient risk groups using the Kaplan-Meier method. European centers accept significantly higher-risk donor hearts compared to North America. DUS 0.45 versus 0.54, P<0.005). DUS was an independent predictor for graft failure with an inverse linear relationship when adjusted for covariates (P<0.001). The Index for Mortality Prediction After Cardiac Transplantation score, a validated tool to assess recipient risk, was also independently associated with 1-year graft failure (P<0.001). In North America, 1-year graft failure was significantly associated with donor-recipient risk matching (log-rank P<0.001). One-year graft failure was highest with pairing of high-risk recipients and donors (13.1% [95% CI, 10.7%-13.9%]) and lowest among low-risk recipients and donors (7.4% [95% CI, 6.8%-8.0%]). Matching of low-risk recipients with high-risk donors was associated with significantly less graft failure (9.0% [95% CI, 8.3%-9.7%]) than high-risk recipients with low-risk donors (11.4% [95% CI, 10.7%-12.2%]) Conclusions: European heart transplantation centers are more likely to accept higher-risk donor hearts than North American centers. Acceptance of borderline-quality donor hearts for lower-risk recipients could improve donor heart utilization without compromising recipient survival.

Current Evidence and Future Perspectives to Implement Continuous and End-Ischemic Use of Normothermic and Oxygenated Hypothermic Machine Perfusion in Clinical Practice.

The use of high-risk renal grafts for transplantation requires the optimization of pretransplant assessment and preservation reconditioning strategies to decrease the organ discard rate and to improve short- and long-term clinical outcomes. Active oxygenation is increasingly recognized to play a central role in dynamic preservation strategies, independent of preservation temperature, to recondition mitochondria and to restore the cellular energy profile. The oxygen-related decrease in mitochondrial succinate accumulation ameliorates the harmful effects of ischemia-reperfusion injury. The differences between normothermic and hypothermic machine perfusion with regard to organ assessment, preservation, and reconditioning, as well as the logistic and economic implications, are factors to take into consideration for implementation at a local level. Therefore, these different techniques should be considered complementary to the perfusion strategy selected depending on functional intention and resource availability. This review provides an overview of the current clinical evidence of normothermic and oxygenated hypothermic machine perfusion, either as a continuous or end-ischemic preservation strategy, and future perspectives.

Causes of blood product discard in the blood bank of tertiary health center over 5 years: A retrospective study

Abstract Background: Blood and its constituents are necessary for human survival, and no major surgical procedure can be completed without using blood. Wastage of blood and blood products should ideally never occur. This study aimed to examine the load of blood discarded in our blood bank, the causes of the discard, and to reduce blood discard to a minimum by using innovative procedures and approaches. Materials and Methods: A 5-year retrospective research was conducted at the Department of Blood Bank, D. Y. Patil Hospital and Research Centre, Navi Mumbai, from 2018 to 2022. Results: Throughout our research period of 5 years, the average number of blood units collected was 4655/year. With an average of 2.5 blood products made from every whole blood collected, there were, on average, 117167/year blood products made. There was an overall decreasing trend of blood products discarded from 11% in 2018 to around 5% in 2022. The main reasons for blood discard were expired blood products (average 4.9%/year), transfusion-transmitted diseases (TTDs) (average 2%/year), and less quantity (average 0.5%/year). Conclusion: Expiry/outdated units were determined to be our study’s most prevalent reason for disposal. Over the years, the discard percentage has been reduced by half to 5% in 2022. Better blood bag collection, storage, and usage management might eliminate this discard. The coronavirus disease pandemic has been a pivot point, in which the discard rate gradually decreased despite less blood collection. TTDs were another major cause of blood discard in our blood bank (2%). By arranging revision training courses and educating our blood bank workers, we can reduce TTD as a cause of blood wastage.

Photovoltaic-based energy system coupled with energy storage for all-day stable PEM electrolytic hydrogen production

Photovoltaic (PV) power generation coupled with proton exchange membrane (PEM) water electrolysis favors improving the solar energy utilization and producing green hydrogen. But few systems proposed focus on achieving all-day stable hydrogen production, which is important for the future large-scale hydrogen utilization. Herein, a PV-Battery-PEM water electrolysis system for hydrogen production was constructed. An energy management strategy (EMS) was proposed to achieve the goal of all-day stable hydrogen production, improve energy utilization efficiency and reduce light discard rate. The PV power generation system, battery system and PEM electrolyzer for hydrogen production system were first established by Matlab/Simulink platform. Then, the overall PV-Battery-PEM electrolyzer system for hydrogen production was constructed, and the effectiveness of EMS was verified. The energy efficiency of the system under different working conditions with and without battery for energy storage was analyzed. The results show that the proposed energy management strategy can meet the purpose of all-day stable hydrogen production. Under the same working conditions, the energy efficiency of the system with battery for energy storage increases by 2–4% compared with the system without battery for energy storage, which indicates that the addition of energy storage can improve the energy utilization and reduce the light discarding.