Search Results (13)

The global transition towards clean energy sources is becoming essential to reduce reliance on conventional fuels and mitigate carbon emissions. In the future, the clean energy storage landscape, green hydrogen, and green ammonia (powered by renewable energy sources) are emerging as key players. This study explores the prospectives and feasibility of producing and storing offshore green hydrogen and green ammonia. The potential power output of Hornsea one and Hornsea two winds farms in the United Kingdom was calculated using real wind data. The usable electricity from the Hornsea one wind farm was 5.83 TWh/year, and from the Hornsea two wind farm, it was 6.44 TWh/year, harnessed to three different scenarios for the production and storage of green ammonia and green hydrogen. Scenario 1 fulfil the requirement of green hydrogen storage for flexible ammonia production but consumes more energy for green hydrogen compression. Scenario 2 does not offer any hydrogen storage which is not favourable in terms of flexibility and market demand. Scenario 3 offers both, a direct routed supply of produced hydrogen for green ammonia synthesis and a storage facility for green hydrogen storage. Detailed mathematical calculations and sensitivity analysis was performed based on the total energy available to find out the energy storage capacity in terms of the mass of green hydrogen and green ammonia produced. Sensitivity analysis in the case of scenario 3 was conducted to determine the optimal percentage of green hydrogen going to the storage facility. Based on the cost evaluation of three different presented scenarios, the levelized cost of hydrogen (LCOH) is between USD 5.30 and 5.97/kg, and the levelized cost of ammonia (LCOA) is between USD 984.16 and USD 1197.11/tonne. These prices are lower compared to the current UK market. The study finds scenario 3 as the most appropriate way in terms of compression energy savings, flexibility for the production and storage capacity that depends upon the supply and demand of these green fuels in the market, and a feasible amount of green hydrogen storage. Full article

Additive manufacturing and digital warehouses are transforming the way industries manage and maintain their spare parts inventory. Considering digital warehouses and on-demand manufacturing for spare parts during the project phase is a strategic decision that involves trade-offs depending on the operational needs and pricing structure. This paper aims to explore the spare part evaluation process considering both physical and digital warehouse inventories. A case asset is purposefully selected and four spare part management concepts are studied using a simulation modeling approach. The results highlight that the relevant digital warehouse scenario, used in this case, managed to completely reduce all emissions related to global spare parts supply; however, this was at the expense of reducing availability by 15.1%. However, the hybrid warehouse scenario managed to increase availability by 11.5% while completely reducing all emissions related to global spare parts supply. Depending on the demand rate, the digital warehousing may not be sufficient alone to keep the production availability at the highest levels; however, it is effective in reducing the stock amount, simplifying the inventory management, and making the supply process more green and resilient. A generic estimation model for spare parts engineers is provided to determine the optimal specifications of their spare parts supply and inventory while considering digital warehouses and on-demand manufacturing. Full article

Along with the new stage of prevention and control of the COVID-19 pandemic and the vision and goals of combatting climate change, the challenges of the transition to a green economy have become more severe. The need for green recovery of the economy, stability and security of energy production and consumption, and the coordination of low-carbon transformation and socio-economic development has become increasingly urgent. This paper proposes a new theoretical framework to study the effect of carbon emission reduction on the mutual application of the carbon market, fiscal policy and monetary policy under the non-homothetic preference of energy product consumption. By constructing an environmental dynamic stochastic general equilibrium (E-DSGE) model with residents’ non-homothetic preferences, this paper finds that coordinating the carbon market and macroeconomic policies can achieve economic and environmental goals. However, the transmission paths for each are different. The carbon market influences producers’ abatement efforts and costs through carbon prices. Monetary policy controls carbon emissions by adjusting interest rates, while fiscal policy controls carbon emissions by adjusting total social demand. Improving non-homothetic preferences will amplify business cycle fluctuations caused by exogenous shocks, thus assuming the role of a “financial accelerator”. Further research shows that non-homothetic preferences influence the heterogeneity of different policy mixes. Finally, this paper discovers that the welfare effects, the relative size and difference of long-term and short-term effects resulting from the different policy mixes, also depend on the level of non-homothetic preferences. The intertemporal substitution mechanism due to the improvement of non-homothetic preferences endows low-carbon production with “option” characteristics. Our study reveals the role of non-homothetic preferences on the effectiveness of policy implementation. It highlights the importance of matching monetary and fiscal policies with the carbon market based on the consumption and production side. It provides ideas for policy practice to achieve the goal of “dual carbon” and promoting coordinated socio-economic development. Full article

Global emphasis on sustainable development is widespread, with industries playing a pivotal role in advancing global sustainability within the business and retail sectors. Consumer awareness of environmental concerns, such as pollution, prompts a focus on product biodegradability and eco-friendliness. Consequently, customers are drawn to products with higher green credentials. This study delves into the effectiveness of green attributes in retail industries, exploring the optimization of profit through a variable production rate and variable unit production cost, considering the selling price and the demand dependent on the product’s green level. In the long run, production systems may shift to an “out-of-control” state, resulting in the random production of imperfect items that must be remanufactured to maintain the industry’s positive brand image. To mitigate the impact of defective items, the industry opts to partially outsource a percentage of items, preventing shortages. However, this complex retailing system generates a significant amount of carbon emissions. This study introduces investments aimed at reducing carbon emissions to address this issue. In contrast with the existing literature, a green-level-dependent unit raw material cost is considered here for variable unit production cost. Ultimately, this study seeks to maximize the overall system’s profit by optimizing the selling price, order quantity, production rate, green level, and carbon emission reduction investments. The classical optimization technique is utilized to obtain analytic optimum results for the decision variables and total profit. Special cases and sensitivity analyses illustrate the real-world applicability and impact of green levels. Numerical findings indicate that considering the product’s green-level-dependent demand and unit production rate is $22.44\%$ more beneficial than nongreen products, partial outsourcing provides a $1.28\%$ advantage, and flexibility in the production rate yields a $69.60\%$ benefit over traditional systems without green elements. Additionally, technological investments to reduce carbon emissions result in a notable reduction of up to $4.53\%$. Full article

The classical joint economic lot-sizing (JELS) policy in a single-vendor single-buyer system generates an equal production quantity in all cycles, where the input parameters remain static indefinitely. In this paper, a new two-echelon supply chain inventory model is developed involving a hybrid production system. The proposed model simultaneously focuses on green and regular production methods with an optimal allocation fraction of green and regular productions. Unlike the classical mathematical formulation, cycles do not depend on each other, and consequently, each model parameter can be adjusted to be responsive to the dynamic nature of demand rate and/or price fluctuation. A rigorous heuristic approach is used to derive a global optimal solution for a joint hybrid production system. This paper accounts for carbon emissions from production and storage activities related to green and regular produced items along with transportation activity under a multi-level emission-taxing scheme. The results emphasize the significant impact of green production on emissions. That is, the higher the allocation fraction of green production, the lower the total amount of emissions generated by the system, i.e., the system becomes more sustainable. Adopting a hybrid production method not only decreases the greenhouse gas (GHG) emissions dramatically, but also reduces the minimum total cost per unit time when compared with regular production. One of the main findings is that the total system cost generated by the base closed-form formula of the proposed model is considerably lower in the first cycle (subsequent cycles) than that of the existing literature, i.e., 33.59% (16.13%) when the regular production method is assumed. Moreover, the optimal production rate generated by the proposed model is the one that minimizes the emissions production function. In addition, the system earns further revenue by utilizing a mixed transportation policy that combines the Truck Load (TL) and Less than Truck Load (LTL) services. Illustrative examples and special cases that reflect different realistic situations are compared to outline managerial insights. Full article

As traditional supply chains face increasingly severe environmental issues, and as countries promote green development and sustainable development policy concepts, cultivating green supply chain operation models is gradually coming to be highly valued by governments and enterprises. Generally speaking, the production of green products incurs higher additional costs, and thus, their total production costs also increase. In this work, we studied the coordination mechanism, by considering carbon emissions and product green level dependent demand, in which the product green level is related to the random demand. Under the green supply chain buyback contract with the green product $R\&D$ cost sharing between the manufacturer and the retailer, both the product green level and the order quantity need to be decided, to maximize the channel profit. In order to coordinate the green supply chain, the manufacturer needs to share both the risk of good salvage and the green product $R\&D$ cost with the retailer. We found that both the wholesale price and the buyback price increase in the manufacturer’s proposition of the green product $R\&D$ cost, but decrease in the emission reduction efficiency coefficient or carbon trading price. In addition, the product green level, the optimal order quantity and the channel profit increase in the emission reduction efficiency coefficient, but decrease in the $R\&D$ cost coefficient of the product green level. Interestingly, we found that if the carbon trading price is low, the manufacturer will set a low product green level, and the product carbon emission trading is a cost for the supply chain. The increment of the carbon trading price leads to a higher cost, such that the channel profit is decreased. However, if the carbon trading price is high, the manufacturer will set a high product green level, and the product carbon emission trading is a revenue for the supply chain. The increment of the carbon trading price leads to a higher revenue, such that the channel profit is increased. Full article

The demand for organic food products has increased in recent years due to them being perceived healthier, safer, and eco-friendlier by consumers, boosting the development of this industry. The higher retailing price of organic products increases the risk of fraudulent practices, making it necessary to establish control mechanisms to authenticate these products. However, the authentication of organic foodstuffs is a great analytical challenge that still requires further research. In the case of organic agriculture, regulations mainly determine the nutrient inputs that can be used by farmers, and generally prohibit the use of pesticides and/or synthetic fertilisers, aiming at maintaining soil fertility using green manures, composts, animal manures, etc. These inputs affect the final food product, and numerous analytical attempts, based on the measurement of multiple markers or complex chemical/physical profiles, have been tested over recent years. However, the high variability of these measurements due to weather condition factors reduces their efficiency and limits their use. In this sense, stable isotopes have emerged as an analytical technique with great potential for the authentication of organic agricultural products, due to their lower dependence on weather conditions and capability to reflect the origin of plant nitrogen, in the case of stable nitrogen isotopes. In this work, the feasibility was assessed using stable isotopes of bulk nitrogen for the organic authentication of four important horticultural crops (zucchini, cucumber, tomato, and pepper) produced in Almeria, southern Spain, which is the largest producing region with the highest export levels in Europe. To this end, 360 samples of vegetables were collected and their δ¹⁵N values were determined by combustion coupled to stable isotope ratio mass spectrometry (EA/IRMS). The results allowed an authentication framework to be established based on three ranges delimited by δ¹⁵N = 2‰ and δ¹⁵N = 5‰, which made it possible to detect with a high degree of confidence vegetables produced under proper organic practices (δ¹⁵N > 5‰), conventional practices (δ¹⁵N < 2‰), and samples that should be tracked over time to be considered organically produced (middle range). The results of this study demonstrated the potential of using δ¹⁵N as a single measure to authenticate organic vegetables, providing official bodies with a tool to make decisions about the organic accreditation of regularly inspected farmers. Full article

In this study, we consider robust emission reduction strategies for a monopolistic manufacturer facing demand uncertainty under governments’ cap-and-trade regulations. We model the manufacturer’s decision making and associated profits under four different emission reduction strategies: no mitigation measure, undertaking remanufacturing, improving the greening level, and both remanufacturing and improving the greening level. We find that the cap-and-trade regulation enhances the manufacturer’s motivation to be engaged in reducing carbon emissions. Furthermore, the manufacturer’s optimal choice of emissions reduction strategy depends on the level of carbon trading price and the degree of demand uncertainty. Specifically, there exists a threshold of carbon trading price at which the manufacturer’s optimal emissions reduction strategy will change. When the carbon trading price is low (below the threshold), the best strategy for the manufacturer to reduce emissions is to improve the greening level of the products. When the carbon trading price is high (above the threshold), the manufacturer should consider both remanufacturing and improving the greening level. Moreover, the threshold of the carbon trading price is further impacted by the demand uncertainty. With market demand uncertainty rising, the threshold of carbon trading price increases as well. Finally, we find raising the carbon trading price may not necessarily benefit the environment. Overpriced carbon trading may hurt the manufacturer’s production instead of encouraging them to take emission reduction measures. Full article

The goal of this research is to investigate an inventory model for degrading commodities with linear selling prices and nonlinear green level-dependent demand for an item. The pre-payment option with a one-time flat reduction on the product’s selling price is considered here. The governing differential equations are used to mathematically define the model and solve numerically to optimize the model’s average profit. After that, the model is tested using a numerical example, and sensitivity analyses are run to see how changing inventory factors affects the best strategy. The concavity of the objective function is shown graphically with the help of MATLAB software. Finally, some applications of this approach and future scopes are discussed. Full article

Green technology investment is an important factor that influences the sustainability and performance of the supply chain. In this paper, we use the game-theoretic approach, which is quite suitable to operation decision research, to model a supply chain consisting of one supplier and one retailer and discuss who should invest in green technology in a decentralized supply chain under demand uncertainty. An important result we found is that the retailer has a stronger investment motivation and higher investment efficiency compared to the supplier. The retailer also tends to invest in green technology himself when customers are not so sensitive to the product’s retail price. We analyze the supply chain sustainability, and find that high levels of green technology investments are not always necessarily good for environmental sustainability, it depends on the environmental impact’s sensitivity to green technology. Lastly, a joint investment mechanism is designed to induce the retailer to join in the green technology investment when he has no investment intention, and that realizes a Pareto improvement of the supply chain. Based on the results, we recommend designing more incentive mechanisms to induce the retailers to join in the green technology investment according to supply chain conditions. Full article

Environmental concerns make enterprises pay more attention to green manufacturing. The emerging green supply chain inevitably will compete with the traditional supply chain. In order to evaluate the competitiveness of supply chains and the impact on channel structure strategy, we develop four game models for two competing supply chains according to their channel structure strategies. Green marginal manufacturing cost, demand sensitivity of green level, and governmental interventions are considered. We study how retail prices, green levels, and profits are influenced by channel structure choice and governmental interventions. Analytical results indicate that the substitutability of products affects channel structure strategy. When the substitutability of products is relatively low, centralization–centralization is the unique Nash equilibrium. However, when the substitutability of products is relatively high, both centralization–centralization and decentralization–decentralization are the Nash equilibriums. Centralization–centralization is a prisoner dilemma, while decentralization–decentralization can make the green supply chain achieve optimal profit. Then, the green marginal manufacturing cost and demand sensitivities of the green level play important but different roles in channel structure strategy of the competing supply chains. Further, whether Nash equilibriums are the optimal strategy depends on governmental intervention. Relatively severe governmental intervention might realize a relatively higher green level, but may not always achieve the lowest retail price for the green supply chain. However, a relatively moderate governmental intervention might achieve a relatively lower green level. Full article

Regulators often use environmental policy to induce green initiatives by firms. This paper examines the emission-reduction-inducement effect of the environmental tax deduction (ETD) incentive by Stackelberg game models between an environmental regulator and a profit-maximizing monopolistic firm facing emission-dependent demand. Different cases, i.e., with/without considering the regulator’s environmental concerns, were used to investigate the ETD policy effects with a numerical example. This paper shows that the regulator’s tax policy will only affect the emission reduction level, but cannot influence the output, which combined with the firm’s operation factors mainly depends the consumers’ attitude toward green products and price sensitivity. Numerical simulation results showed that for the cases with a moderate level of environmental concern and emission standard, the regulator can set an ETD incentive to motivate the choice of a higher level of emission reduction and simultaneously increase social welfare; otherwise, the increase in environmental quality is at the expense of social welfare. When the market’s environmental consciousness increases, it is easier for the regulator to guide the firm to adopt an ETD solution. Therefore, improving consumers’ awareness of environmental protection is an effective way to promote green investment of firms. Full article

During the “13th Five-Year Plan” period, green energy is the top priority for China. China has realized that natural gas, as a low-carbon energy source, fits with the nation’s energy demand and will play a critical role in the energy transition, but the actual industry development is slower than expected. By analyzing the major gas corporations around the world, the paper finds that the key factors of the sector are supply and price of the energy resource. A comprehensive analysis on domestic and foreign imported gas reveals a trend of oversupply in China in the future. Given the critical import dependence, China has introduced a series of gas price reforms since 2013, which have led to negative impacts on important gas consumption sectors including power generation. With the levelized cost of electricity (LCOE) model, we find that under the prevailing gas supply structure and price level, the economy of utility gas power generation will remain unprofitable, while combined cooling heating and power (CCHP) is only commercially feasible in coastal developed regions. If continuing, such a trend will not only bring forth disastrous consequences to gas power industry, but also damage the upstream gas industry, more importantly, impede the energy transition. We conclude the paper with policy implications on pricing mechanism reform, developing domestic unconventional gas and the R&D of gas turbine. Full article