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Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse. Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available. Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance. Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2 were used as control variables.Standard optimization settings were defined in order to compare the grower's strategy with the optimal solution. This optimization resulted in a theoretical 47% reduction in heating, 15% reduction in cooling, and 10% reduction in CO2 injection for the year 2012. The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice. When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.We also analyzed the effect of different bounds on optimal energy input. We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds. Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse. Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available. Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance. Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2 were used as control variables.Standard optimization settings were defined in order to compare the grower's strategy with the optimal solution. This optimization resulted in a theoretical 47% reduction in heating, 15% reduction in cooling, and 10% reduction in CO2 injection for the year 2012. The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice. When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.We also analyzed the effect of different bounds on optimal energy input. We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds. Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

This study presents the clockspeed analysis of a peer group comprising six major integrated US energy companies with substantial US interstate natural gas pipeline business activities: El Paso, Williams, NiSource, Kinder Morgan, MidAmerican and CMS Energy. For this peer group, the three clockspeed accelerators have been benchmarked at both corporate level and gas transmission business level, using time-series analysis and cross-sectional analysis over a 6-year period (2002–2007). The results are visualized in so-called clockspeed radargraphs. Overall corporate clockspeed winners – over the performance period studied – are: Williams, El Paso and Kinder Morgan; MidAmerican is a close follower. Corporate clockspeed laggards are: CMS Energy and NiSource. The peer group ranking for the natural gas transmission business segment shows similar clockspeed winners, but with different ranking in the following order: Kinder Morgan, MidAmerican and El Paso; Williams is a close follower. Clockspeed laggards for the natural gas transmission segments coincide with the corporate clockspeed laggards of the peer group: CMS Energy and NiSource (over the performance period studied); laggards of the past may become clockspeed leaders of the future if adjustments are made. Practical recommendations are formulated for achieving competitive clockspeed optimization in the US gas transmission industry as a whole. Recommendations for clockspeed acceleration at individual companies are also given. Although the US natural gas market is subject to specific regulations and its own geographical dynamics, this study also provides hints for improving the competitive clockspeed performance of gas transmission companies elsewhere, in other world regions.

This study presents the clockspeed analysis of a peer group comprising six major integrated US energy companies with substantial US interstate natural gas pipeline business activities: El Paso, Williams, NiSource, Kinder Morgan, MidAmerican and CMS Energy. For this peer group, the three clockspeed accelerators have been benchmarked at both corporate level and gas transmission business level, using time-series analysis and cross-sectional analysis over a 6-year period (2002–2007). The results are visualized in so-called clockspeed radargraphs. Overall corporate clockspeed winners – over the performance period studied – are: Williams, El Paso and Kinder Morgan; MidAmerican is a close follower. Corporate clockspeed laggards are: CMS Energy and NiSource. The peer group ranking for the natural gas transmission business segment shows similar clockspeed winners, but with different ranking in the following order: Kinder Morgan, MidAmerican and El Paso; Williams is a close follower. Clockspeed laggards for the natural gas transmission segments coincide with the corporate clockspeed laggards of the peer group: CMS Energy and NiSource (over the performance period studied); laggards of the past may become clockspeed leaders of the future if adjustments are made. Practical recommendations are formulated for achieving competitive clockspeed optimization in the US gas transmission industry as a whole. Recommendations for clockspeed acceleration at individual companies are also given. Although the US natural gas market is subject to specific regulations and its own geographical dynamics, this study also provides hints for improving the competitive clockspeed performance of gas transmission companies elsewhere, in other world regions.

To promote the sustainable development of supply chains, numerous manufacturers are embracing corporate environmental responsibility to mitigate the ecological consequences of production activities. The environmental benefit concern (EBC) of enterprises not only affects their operations strategies but also impacts other enterprises within the supply chains. Therefore, it is essential to study the influences of EBC behaviors on supply chain performances under various competitive scenarios. This paper examines a supply chain comprising two manufacturers and one retailer under two distinct competitive settings: Competition between non-green and green products (OE), and competition between green products from small and big brands (SB). The study analyzes the effects of unilateral, bilateral or multilateral EBC behaviors on both the economic and environmental benefits of the supply chain. Key findings emerge from this study. Firstly, prioritizing environmental benefits throughout the supply chain has the potential to enhance environmental performance. Secondly, unilateral EBC behavior can lead to a vertical altruistic effect, where the focus on environmental benefit by a manufacturer (retailer) increases the retailer's (manufacturer) profit but reduces its own profit. Additionally, unilateral EBC behavior among manufacturers creates a competitive squeezing effect on each other, potentially diminishing competitor profits. Notably, the retailer's focus on environmental benefit can also reduce the profit of the non-green manufacturer. Thirdly, when the levels of EBC are relatively low, bilateral or multilateral through EBC leads to a positive effect on economic performance, resulting in increased profits for both the green manufacturers and retailer. In conclusion, bilateral EBC has the potential to enhance both economic and environmental benefits in the OE scenario.

To promote the sustainable development of supply chains, numerous manufacturers are embracing corporate environmental responsibility to mitigate the ecological consequences of production activities. The environmental benefit concern (EBC) of enterprises not only affects their operations strategies but also impacts other enterprises within the supply chains. Therefore, it is essential to study the influences of EBC behaviors on supply chain performances under various competitive scenarios. This paper examines a supply chain comprising two manufacturers and one retailer under two distinct competitive settings: Competition between non-green and green products (OE), and competition between green products from small and big brands (SB). The study analyzes the effects of unilateral, bilateral or multilateral EBC behaviors on both the economic and environmental benefits of the supply chain. Key findings emerge from this study. Firstly, prioritizing environmental benefits throughout the supply chain has the potential to enhance environmental performance. Secondly, unilateral EBC behavior can lead to a vertical altruistic effect, where the focus on environmental benefit by a manufacturer (retailer) increases the retailer's (manufacturer) profit but reduces its own profit. Additionally, unilateral EBC behavior among manufacturers creates a competitive squeezing effect on each other, potentially diminishing competitor profits. Notably, the retailer's focus on environmental benefit can also reduce the profit of the non-green manufacturer. Thirdly, when the levels of EBC are relatively low, bilateral or multilateral through EBC leads to a positive effect on economic performance, resulting in increased profits for both the green manufacturers and retailer. In conclusion, bilateral EBC has the potential to enhance both economic and environmental benefits in the OE scenario.