Investment Payback Period Research Articles

Comprehensive methodology for the integrating of the organic rankine Cycle-ORC with diesel generators in off-grid areas: Application to a Colombian case study

Efficient fuel management in diesel generator sets for power generation in non-grid areas is a persistent concern. In this context, the use of an Organic Rankine Cycle (ORC) to recover heat from exhaust gases from diesel generator sets represents a promising route for additional power generation. To undertake such projects, it is necessary to understand the critical parameters related to diesel engines, including the specific fuel consumption, mass flow, and exhaust gas temperature. These parameters are fundamental to the sizing process of the ORC heat recovery system. This study introduces an innovative methodology for evaluating the operation of diesel-ORC systems based on the load demand of off-grid communities. The proposed system is a viable solution for the generation of additional power with the objective of improving the overall efficiency and meeting higher energy demands in isolated areas. Four organic fluids were selected for the ORC: R245fa, benzene, cyclopentane, and toluene. This selection was made based on many criteria, including global warming potential (GWP), ozone depletion potential (ODP), and safety classification (ASHRAE 34). In addition, the exergy behaviors of these fluids were reviewed. A comparative analysis was subsequently conducted for a non-interconnected region of Colombia to evaluate the performance of a diesel generator operating independently and in conjunction with the diesel ORC system. The key indicators employed were fuel consumption savings (L/year), energy produced (MWh/year), levelized cost of energy (LCOE, USD/kWh), and payback period (years). The results demonstrated that, over the course of a 1-year simulation period, the benzene ORC system exhibited the highest overall energy efficiency, achieving a value of 41.38%. The exergy analysis indicated that toluene had lower irreversibilities, achieving an exergy efficiency of 44.78%, followed by benzene (43.5%. Furthermore, the diesel-ORC system using benzene demonstrated a notable decrease in the specific fuel consumption from 0.282 to 0.247 L/kWh, signifying a 10.52% reduction in the annual CO2eq emissions. The cost of electricity generation decreased by 4.3%, with investment payback periods not exceeding 14 years.

Research on Energy-Saving Transformation of Rural Residential Building Envelope Structures and Heating Modes in Northeast China

Rural areas in Northeast China present a large demand for heating energy in winter, but there are problems in such areas with poor thermal performance of building envelopes and poor indoor thermal comfort. In addition, coal-fired boilers are still widely used. China’s “Dual-Carbon Goals” and “Clean Heating” policy call for the creation of a green and comfortable living environment for rural residential buildings. This paper considers the impact of the improvement of the thermal performance of envelope structures on the initial investment of the transformation program and the rated power of the ASHP and proposes an energy-saving transformation method to replace traditional coal-fired boilers with the ASHP on the basis of the improvement of the thermal performance of envelope structures. By establishing a typical rural residential building model in Northeast China, this energy-saving method is simulated based on TRNSYS. The results show that the payback period of investment of the transformation method of “envelope structure + heating system” is not superior to that of the transformation method of only improving the thermal performance of the envelope structure, but it has advantages in the comprehensive life-cycle benefits and it has great advantages in improving the satisfaction of rural residents in the use of heating systems.

Energy and Economic Analysis of a New Combination Cascade Waste Heat Recovery System of a Waste-to-Energy Plant

Waste incineration has become the main treatment method for urban household waste, and it can produce a large amount of electricity. The efficiency of waste incineration plants is reduced due to the large amount of waste heat carried away by the flue gas. Recycling and utilizing the waste heat from flue gas are important in improving the economic benefits of waste incineration, which is necessary for energy conservation and emission reduction. Based on the principle of cascade waste heat recovery from waste incineration flue gas whilst considering system safety and efficiency, this study proposed a new combination cascade waste heat recovery system consisting of a Rankine cycle, an organic Rankine cycle and a heat pump cycle. Thermodynamic and economic analyses of the combined system were conducted in detail. The results indicated that the energy efficiency of the combined system could reach up to 73%. The maximum net present value of the system was million USD 1.59 million, and the dynamic investment payback period was about 6.5 years. The isentropic efficiency of the combined system’s pumps and turbines had a significant impact on the system’s performance. A higher isentropic efficiency resulted in better system performance. The exergy analysis showed that the evaporator of the heat pump system had the highest irreversible loss.

Kelayakan Usaha Madu Berbasis Eduwisata Lebah Tanpa Sengat Di Pondok Pesantren Kabupaten Lebong

The demand for honey has increased from year to year, based on BPS data, the number of honey imports has increased significantly every year, however, according to the Indonesian Beekeeping Association, honey consumption in Indonesia is still low per year, namely 15-20 grams/capita/year. The Nurul Qur'an Islamic boarding school in Lebong Regency has a stingless bee educational tour to provide education about bees and honey directly as a promotion to visitors. The aim of this research is (1) to determine the feasibility of various non-financial aspects of an edutourism-based honey business through market aspects, technical aspects, legal aspects, management aspects, social, economic and cultural and environmental aspects. (2) to measure the financial feasibility analysis without a training package and homestay facilities (scenario 1) compared to an edutourism-based honey business with a training package and homestay facilities (scenario 2) using investment criteria, namely NPV, Net B/C, IRR, and Payback Period, . Data collection methods include surveys, interviews and document studies, the sampling technique uses purposive sampling. The results of the analysis of non-financial aspects which include market aspects, technical aspects, management and legal aspects, social and economic aspects, and environmental aspects show that this business is feasible to run. The results of the financial analysis seen from the calculation of Payback Period, IRR, NPV and Net B/C show that scenario 1 is more profitable compared to scenario 2. Then for the results of sensitivity analysis using switching values product prices and honey production are more sensitive compared to total fixed costs. costs) and variable costs, so it is recommended to maintain product availability and quality and improve marketing with various effective approaches.

A Farmer-Centric Cost–Benefit Analysis of Climate-Smart Agriculture in the Gandaki River Basin of Nepal

Climate-smart agriculture (CSA) is a climate-resilient practice that stands out globally as an important practice through which we can deal with emerging challenges through adaptation and mitigation to increase crop productivity and resilience. Despite its significance, a comprehensive cost–benefit analysis of the adoption of these practices has not yet been carried out. This study aims to bridge the knowledge gap between the cost and effectiveness of CSA practices adopted by small-scale farmers in growing rice, wheat and maize, the most staple crops in the Gandaki River Basin of Nepal. In this study, net present value (NPV), internal rate of return (IRR), benefit–cost (BC) ratio, net benefit investment (NK) ratio and payback period, along with the value of externalities (social and environmental), were employed to assess the profitability of CSA practices. The findings indicate that almost all the CSA practices analyzed were profitable, with the exception of solar water management in maize with very low IRR (6%) and a longer payback period. The outcome of this study offers valuable insights for farmers in choosing profitable CSA technology and for policy makers in promoting better CSA technology, upscaling CSA practices, and formulating new agricultural policies and programs in the context of the changing climate.

Thermodynamic, economical and environmental performance evaluation of a 330 MW solar-aided coal-fired power plant located in Niger

The integration of solar thermal energy into a coal-fired power plant is one of the best ways to reduce the environmental impact of the latter linked to the release of carbon dioxide (CO2) into the atmosphere. In this paper, solar energy is used before the boiler, just after the first high-pressure feed water heater via a solar preheater (Water/Heat Transfer Fluid exchanger). It should be noted that in this study, there is no feed water heater displacement, and so the plant will operate in pure fuel-saving mode. To carry out an analysis of the integration of solar thermal energy in a coal-fired power plant, a 330 MW Solar Aided Coal Power Plant (SACPP) in northern Niger was studied. The results bring out that the annual solar energy production is 208 GWh, and solar energy can contribute up to approximately 15 % in the production of electricity. The considered SACPP significantly reduces the environmental impact of coal-fired power plants, leading to a reduction in CO2 emissions of around 381358 tons/year. In addition, the annual energy production cost from solar energy in the hybrid system is obtained as 0.0357 $/kWh and the investment payback period is around 12 months.

European Green Deal: Substantiation of the Rational Configuration of the Bioenergy Production System from Organic Waste

A review of the current state of the theory and practice of bioenergy production from waste allowed us to identify the scientific and applied problem of substantiating the rational configuration of a modular anaerobic bioenergy system, taking into account the volume of organic waste generated in settlements. To solve this problem, this paper develops an approach and an algorithm for matching the configuration of a modular anaerobic bioenergy production system with the amount of organic waste generated in residential areas. Unlike the existing tools, this takes into account the peculiarities of residential areas, which is the basis for accurate forecasting of organic waste generation and, accordingly, determining the configuration of the bioenergy production system. In addition, for each of the scenarios, the anaerobic digestion process is modeled, which allows us to determine the functional indicators that underlie the determination of a rational configuration in terms of cost and environmental performance. Based on the use of the developed tools for the production conditions of the Golosko residential area, Lviv (Ukraine), possible scenarios for the installation of modular anaerobic bioenergy production systems are substantiated. It was found that the greatest annual benefits are obtained from the processing of mixed food and yard waste. The payback period of investments in modular anaerobic bioenergy production systems for given conditions of a residential area largely depends on their configuration and ranges from 3.3 to 8.4 years, which differ from each other by 2.5 times. This indicates that the developed toolkit is of practical value, as it allows the coordination of the rational configuration of modular anaerobic bioenergy production systems with real production conditions. In the future, it is recommended to use the proposed decision support system to model the use of biomass as an energy resource in residential areas, which ensures the determination of the rational configuration of a modular anaerobic bioenergy production system for given conditions.

Simulation and Economic Analysis of Helium Extraction Process from Natural Gas

The investment estimation of the helium extraction project from natural gas is a crucial step in economically obtaining helium from both domestic and international projects. This article employs Aspen HYSYS to simulate the process and estimate the investment levels of Linde and Exxon Mobil integrated helium extraction processes. We investigate the influence of feed composition and processing capacity on investment costs and product returns. The results indicate that higher helium content of feed correlates with increased equipment investment costs and total capital cost (CAPEX), and that the Linde integrated process is significantly more sensitive to changes in helium content of feed than the Exxon Mobil integrated process. As the helium content of feed rises, the product returns of the two processes are evidently improved, leading to reduced investment payback periods. Both techniques exhibit favorable payback periods when the feed helium content exceeds 0.5 vol%. Nevertheless, elevated nitrogen content in the feed notably escalates the equipment investment costs and total capital costs. Furthermore, an increase in the processing capacity of feed gas leads to a nonlinear increase in total capital costs and annual operating costs. However, the cost per unit of helium extraction diminishes with increasing capacity. In general, the Linde integrated process requires higher separation energy consumption in comparison with the Exxon Mobil integrated process at similar processing capacities. Moreover, the sensitivity analysis shows that helium breakeven price is strongly affected by the price of both LNG and feed gas.

Techno-economic assessment of swine manure biochar production in large-scale piggeries in China

Biochar production using swine manure (SM) from large-scale piggeries is increasingly needed. However, little is known about the economic feasibility for SM biochar production. Herein, SM biochar production was simulated via Aspen Plus, and techno-economic model was applied to calculate the net present value (NPV), internal rate of return (IRR), and discounted payback period (DPP) for SM biochar production with a processing capacity of 8000 tons SM per year. Results suggest that this project is susceptible to biochar selling price and operation cost. When the biochar price is > 116 USD/ton, the NPV is positive. When the biochar selling price is increased from 154 to 193 USD/ton, the IRR is increased from 11 % to 41 %. The DPP analyses show that the investment payback period for this project is 4.6 years. Moreover, compared to conventional SM treatment routes, valorization of SM into biochar in large-scale piggery in China has a shorter investment period. Finally, this study suggests that swine manure biochar production in large-scale piggeries in China is profitable, deserving investment.

Improving dairy manure hydrolysis and acidification through microbial community restructuring by adaptation to hyperthermophilic conditions

Dairy manure (DM) contributes significantly to greenhouse gas emissions and ecosystem degradation, yet its resistance to biodegradation hinders widespread bioprocessing applications. Lignocellulosic materials in DM pose a particular challenge because of their recalcitrance. Bioprocessing under hyperthermophilic (≥70 °C) conditions potentially offers an advantage over traditional fermentation temperatures due to enhanced activity of enzymes and the kinetics of enzymatic reactions. This can lead to a higher conversion rate and a greater extent of biomass hydrolysis and acidification. To test the validity of this hypothesis, the current study evaluated the efficacy of anaerobic hydrolysis and acidogenic fermentation of DM under mesophilic, thermophilic, and hyperthermophilic conditions. All inocula were adapted to corresponding temperatures but were derived from the same mesophilic source. Hyperthermophilic conditions resulted in superior DM hydrolysis efficiency (53%) compared to mesophilic (34%) and thermophilic (42%) conditions. The hyperthermophilic environment was particularly favorable to the decomposition of crude proteins and hemicellulose, which were reduced by 64% and 54%, respectively. Furthermore, hyperthermophilic fermentation also yielded the highest volatile fatty acid (VFA) production rate of 460 mg/L/day during the first four days, representing improvements of 50% and 90% over mesophilic and thermophilic conditions. In part, this was attributed to the enhanced production of branched-chain VFAs, including an increase of 6–10% in isobutyric acid and 12–13% in isovaleric acid. At hyperthermophilic conditions, however, there was no accumulation of VFAs during the days 5–8 of fermentation, which could be due to acetate conversion by the syntrophic acetate-oxidizing bacteria. A considerable gain in hydrolysis efficiency and VFA production rate were accompanied by a reduction in microbial diversity, which suggests that hyperthermophilic temperature is a favorable environment for the selection of organisms with enhanced DM hydrolysis and fermentation capabilities. A significantly increased relative abundance of xylanolytic Caldicoprobacter (23% of population) and proteolytic Thermovirga (9% of population) could be the major contributors to improved decomposition of hemicellulose and protein. As revealed by the techno-economic analysis, acidogenic fermentation of DM at 70 °C and a retention period of 4 days provides the greatest positive net present value, highest internal rate of return of 9.2%, and shortest investment payback period of 9 years. This study demonstrates that hyperthermophilic conditions enable superior deconstruction and bioconversion of lignocellulose-containing biomass into VFAs under reduced retention times, offering a promising approach for improving DM management and generating bioproducts.

Proposal and thermo-economic analysis of a comprehensive framework for energy recovery and emission reduction in natural gas depressurization stations

One of the largest urban natural gas pressure reducing stations (CGS) with a nominal capacity of 300,000 (Nm3/h) in Iran has been investigated for the generation of electricity using the energy recovered in the gas depressurization process. Currently, natural gas pressure is reduced by using the regulating valve; consequently, the energy is wasted. To harness this wasted energy, an energy recovery plan was proposed that utilizes a turbo-expander. Comprehensive analytical environmental and thermo-economic analysis of the proposal was performed. Effects of various parameters, including turbo-expander and preheater efficiencies, electricity and natural gas price, nominal power of expansion turbine, turbine price and the temperature of gas leaving the expansion turbine was fully investigated on the system performance. The findings illustrated that 14.73 (GWh) of electricity can be produced annually using the recovered wasted energy in the studied station. The investment payback period was calculated as 4 years. The generalization of the results to all Iran’s CGS stations showed that 3.24 (TWh) of electrical energy and an average of 370 (MW) of electric power are possible to produce each year. Also, by using the proposed plan, 640,000 tons of CO2 emissions can be avoided annually.

Optimization strategies for carbon neutrality in a maize-soybean rotation production system from farm to gate

Agricultural food production stands as a primary source of global greenhouse gas emissions, with residue management widely acknowledged as an effective avenue to achieve carbon neutrality. However, there is a lack of comprehensive assessment of the carbon footprint of agricultural residue production, processing, and recycling from farm to gate. Here we conducted a hybrid approach that integrated the DeNitrification-DeComposition (DNDC) model and life cycle carbon footprint to co-optimize water and residue management, targeting carbon neutrality and yield increase. The results revealed that controlled drainage with sub-irrigation (CDSI) served as a potent water management strategy to mitigate greenhouse gas emissions (15.65 %) while increasing yield (24.34 %) compared to free drainage. Regardless of the type of bioproduct, incorporating CDSI with downstream residue utilization exhibited substantial potential for carbon-negative emissions, reducing the average farm carbon footprint to −1538.15 kg CO2 eq yr−1. Among those scenarios, the CDSI with bioethanol scenario particularly stands out with its robust carbon mitigation capability (−1994.94 kg CO2 eq yr−1), driven by the enormous energy demand throughout the agricultural production process and the environmental friendliness of bioethanol, which substantially exceeds that of gasoline. However, challenges such as high plant construction costs and extended investment payback periods associated with residue conversion underscore the need for the urgent establishment of national subsidies and market mechanisms to foster carbon neutrality in agricultural production.

A macro-level life cycle environmental-economic impact and benefit assessment of sponge cities in China

Urban runoff source control facilities (URSCFs) are integral components of Sponge City (SC), playing a pivotal role in providing ecosystem services and managing water quality and quantity. To accurately assess the performance of URSCFs, it is crucial to quantify their environmental and economic impacts. However, previous studies have predominantly focused on location-specific case studies, lacking a macro-level perspective necessary for informing public policy development pertaining to SC initiatives. This study aims to bridge this gap by conducting a macro-level life cycle assessment across China's 16 initial pilot SCs, categorized into three zones based on their annual rainfall volume control rate α (i.e., Zone II (80 % to 85 % for α), Zone III (75 % to 85 % for α), and Zone IV (70 % to 85 % for α)). By simulating five rainfall drainage scenarios, we delve into the environmental benefits of SC construction. The results indicate that Zone III incurs the highest environmental and economic costs during the construction phase, followed by Zones II and IV. In Zone III, bioretention contribute significantly to the environmental impact and economic cost, while constructed wetland and detention cells are the key contributors for Zone II. During the operation phase, Zone III demonstrates the largest environmental and economic benefits, with Zone IV and II trailing behind. The investment payback period for SCs in all zones is less than eight years, with Zone IV recovering costs the fastest (3.9 years) and Zone II the slowest (7.5 years). Facilities like detention cells, green roofs, and permeable pavements tend to have longer payback periods. Based on our findings, we recommend that Zone II exercise caution in constructing detention cells, permeable pavements, and wetlands, while Zone III should carefully consider green roofs and bioretention to optimize SC investments. Due to the fewer URSCFs constructed in Zone IV, it exhibits the lowest environmental impact compared to Zones II and III. Our research provides valuable insights to support policymaking with regards to future SC planning and development.

Thermo-economic assessments on building heating by a sewage source heat pump coupled with heat storage system

To enhance the economic feasibility of building heating systems, phase change heat storage materials are often utilized to utilize renewable energy and address system peak loads. This article presents an innovative method of integrating a sewage source heat pump with a heat storage device. Upon an industrial building in Xilinhot as a case study, numerical models for the heat accumulator coupled with the energy consumption of buildings are established, taking into account dynamic hourly loads and meteorological conditions. Through a comprehensive analysis, the thermophysical properties of the heat accumulator as well as the economic implications of the multi-energy complementary heating system are investigated. Results demonstrate that the complete melting time for a 95 % filling rate is significantly reduced, 87.11 % shorter than that of pure phase change material, achieving the highest heat storage efficiency. Furthermore, the phase change storage device with a 75 % filling rate had the shortest investment payback period, requiring only 6 years. These findings have significant implications for guiding green renovation projects in building heating systems.

Energy-saving potential benchmarking method of office buildings based on probabilistic forecast

Building energy consumption represents a substantial portion of China's total energy usage profile. Conducting a quantitative assessment of the energy-saving potential in buildings is crucial, as it aids in estimating the investment risk and payback period for energy-efficient projects. This evaluation also informs the development and formulation of policies promoting building retrofits and energy conservation. However, this field's present state of research exhibits a significant gap. This study takes 8 typical office buildings as case objects and conducts relevant research on quantitative evaluation of energy-saving potential. On the basis of quantile regression, three corresponding probabilistic forecasting models for building energy consumption are established by combining the classic time series prediction algorithm Long Short-Term Memory (LSTM) in data-driven methods, Gradient Boosting Decision Tree (GBDT) in known building energy benchmarking, and a relatively simple linear model. The evaluation results demonstrate that the LSTM-QR model can serve effectively as a probabilistic forecasting model for estimating building energy-saving potential. Based on the LSTM-QR model results, a quantitative evaluation method for building energy-saving potential benchmarking is proposed, utilizing linearized Cumulative Distribution Function (CDF) curves. This method can quantitatively assess the energy-saving potential of the studied buildings. By analyzing and comparing these buildings' hourly energy consumption data over the past three years, it is evident that the quantitative scoring results from this method can provide directional guidance for building renovation projects to enhance energy efficiency.

Investigating the techno-economic and environmental feasibility of biogas-based power generation potential using food waste in Bangladesh

This study investigates the environmental, economic, and technological viability of sustainable energy production from food waste in Bangladesh through anaerobic digestion (AD) technology along with the challenges in developing such biogas plants. The tri-fold criteria of technical feasibility, economic viability, and environmental sustainability—all of which were examined in this research work. Results indicate that the amount of food waste is 40.86 million tons in 2021 and is projected as 62.82 million tons in the year 2043 in Bangladesh. The power generation potential from the food waste is estimated at 2667.40 MW and 4466.24 MW for the same period. The net present value of the project in Bangladesh is 55,234.93 million dollars. The investment payback period and internal rate of return are 6.73 yr And 11 %, respectively. Techno-economic and environmental feasibility is also calculated for the eight major cities in Bangladesh for the year 2021. The biogas-based power plant substantially reduces CO2 emissions as compared to coal-based and a diesel-based power plant. Additionally, 4.93 million tons of bio-fertilizer, could be produced from food waste. This study will offer scientific guidance for the investment in biogas-based electricity-generating projects in Bangladesh.

Techno-economic, techno-environmental assessments, and deep learning optimization of an integrated system for CO2 capturing from a gas turbine: Tehran case study

This study investigates methods to reduce heat losses, CO2 emissions, and improve the overall efficiency of micro gas turbine power plants, considering economic viability as gas turbines are a major component of the global energy supply chain. Heat recovery and carbon capture techniques were employed to achieve these goals. First, a steam Rankine cycle and a greenhouse were designed to integrate with an existing micro gas turbine. Second, the entire system was simulated using thermodynamic, economic, and environmental models. Finally, an optimization process was conducted through a machine learning model using the integrated model. By adding a Rankine cycle, 80 % of the heat losses in a traditional power plant were recovered, converted into electricity and cooling, and resulted in a 3 % efficiency improvement. Additionally, implementing a CO2 separation and capture unit with utilization in a nearby greenhouse not only enhanced greenhouse profitability but also significantly reduced CO2 emissions into the atmosphere. While the system's cost rate increased by $40/hour, the investment payback period is only 0.97 years. Furthermore, CO2 emission rate was reduced by 15 %.

Energy, economic and environmental evaluation of the energy storage capabilities of artificial lakes based on pumped-hydro storage systems with a case study of Daghgoli artificial recreational lake

In the present study, Daghgoli artificial recreational lake has been investigated as an energy storage system. This lake with a capacity of 54,000 (m3) is located in the largest metropolis of northwestern Iran, above the Eynali Mountains, in the vicinity of the city. The elevation of this lake is about 450 (m) from the downstream lake with a capacity of 60,000 (m3). The energy storage capacity of the lake has been evaluated based on the pumped-hydro method. Then, the capacity of this large “battery” to store a part of the excess energy generated by the Tabriz thermal power plant has been evaluated. In addition to the technical evaluation, a full economic analysis as well as environmental investigation of application of the lake as an energy storage system has been conducted. The capacity that can be develop the existing small wind farm in the vicinity of the lake so that its generated energy can be fully stored by the energy storage system based on Daghgoli Lake has also been determined. Finally, the capacity of the photovoltaic solar power plant that can be established in the flat plain adjacent to the lake to store its generated electricity by the lake to be used at night or peak hours has been also evaluated. The results showed that using the presented energy storage plan, 74.7(MWh) of excess electrical energy generated by the thermal power plant can be stored daily. By releasing this energy during peak hours, 13.24 (MW) of electricity can be generated with an energy conversion efficiency about 71 %. At the same time, the emission of 8508 tons of carbon dioxide can be prevented during a year. The investment payback period of the project is estimated to be 4.7 years. By using the designed energy storage system, a wind farm consisting of 16 turbines with a capacity of 660 (kW) or a photovoltaic solar plant with a capacity of 9.34 (MW) can be created.

REDUCING OF WATER AND ENERGY RESOURCES CONSUMPTION IN IRRIGATION BASED ON RESOURCE OPTIMISATION

The need for further development of irrigation practices on the basis of nature oriented and ecologically efficient solutions is considered primarily regarding the saving of water and energy resources for the adaptation of irrigated agricultural production to the current global challenges and threats, the achievement of sustainable development goals. It is shown that there is an objective need to change methodological approaches to the assessment of overall efficiency and justification of optimal solutions in design, reconstruction, and operation projects of irrigation systems based on the principles of resource optimization. On the basis of the indicator of the level of irrigation sufficiency (introduced by the authors), which reflects the reduction of the studied watering and irrigation rates in relation to their design values, a study of the impact of reducing the use of water and energy resources under different modes of sprinkler irrigation on the corresponding decrease in the level of cultivated crops productivity was carried out. At the same time, it was experimentally determined that the intensity (rate) of the decrease in the cultivated crops productivity, which occurs due to the decrease in the usage of water and energy resources during the application of irrigation, is significantly lower than the intensity (rate) of the decrease in the usage of the resources themselves. The studied options for reducing the consumption on water and energy resources as a whole turned out to be economically profitable when with a decrease in water and electricity usage by 27–48% there is more than two times lower decrease in the costs of gross products by 10,80–18,06% with the achievement of a net income of 11,4 to 5,7 thousand UAH. The influence of various options of reducing water and electricity consumption on the discounted investment payback period shows that several options may be acceptable, for which the investment payback period does not exceed 10 years, and the choice of the optimal solution requires taking into account the conditions of a specific object, limitations of water resources, and the interests of investors and land users. At the same time, the ecological component of the overall efficiency of irrigation practices consists in the decrease in the use of water and energy resources that a priori reflects the decrease in the negative impact of irrigation on the environment. Thus, reducing the usage of water and energy resources is a fully justified decision on the way to adapt irrigated agriculture production to the modern conditions and requirements, and the presented results can be a scientific basis for the implementation of this approach while practically applying irrigation.

Storing Electric Energy Generated by a Photovoltaic Installation to Increase Profit from Its Sale—Case Study in Poland

Battery systems enable the sustainable use of energy from renewable energy installations that are characterized by variable time availability. The present study investigated the benefits of implementing an electrical energy storage system to a photovoltaic (PV) installation in the Polish climatic conditions. The impact of such a system on increasing profits from energy sales was verified. The use of storage allows for shifting the process of feeding energy into the grid to later hours when it is more expensive. The production volume and timing of energy generation were considered using the example of a 5 kWp research installation located in the Laboratory of Renewable Energy. The yields and energy prices were analyzed on an hourly basis for the year 2023. The considered system is additionally equipped with a battery with a capacity of 15 kWh. Analyses have shown that this system covers 55.6% of days in a year where the entire daily production from the PV installation can be stored. Additionally, the feasibility of using different energy storage capacities to shift the sale of the maximum energy volume was examined. Also the payback period of investments was considered for four scenarios (from the most expensive devices to the cheapest ones with subsidies). Prices were compared with profits resulting from the use of storage systems of a given capacity, as well as with the lengths of warranties covering the devices.