scholarly journals Operational use of marginal cost curves for hydropower plants as decision support in real-time balancing markets

Author(s):  
Hans Ivar Skjelbred ◽  
Jiehong Kong ◽  
Tellef Juell Larsen ◽  
Fredd Kristiansen
2017 ◽  
Vol 21 (7) ◽  
pp. 3507-3524 ◽  
Author(s):  
Abebe D. Chukalla ◽  
Maarten S. Krol ◽  
Arjen Y. Hoekstra

Abstract. Reducing the water footprint (WF) of the process of growing irrigated crops is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs) that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3  ha−1 per season) or to a certain WF benchmark (expressed in m3  t−1 of crop). This paper aims to develop MCCs for WF reduction for a range of selected cases. AquaCrop, a soil-water-balance and crop-growth model, is used to estimate the effect of different management packages on evapotranspiration and crop yield and thus the WF of crop production. A management package is defined as a specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip); irrigation strategy (full or deficit irrigation); and mulching practice (no, organic or synthetic mulching). The annual average cost for each management package is estimated as the annualized capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy and labour). Different cases are considered, including three crops (maize, tomato and potato); four types of environment (humid in UK, sub-humid in Italy, semi-arid in Spain and arid in Israel); three hydrologic years (wet, normal and dry years) and three soil types (loam, silty clay loam and sandy loam). For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF by reducing water consumption at negligible yield reduction while reducing the cost for irrigation water and the associated costs for energy and labour. Next, moving from no to organic mulching has a high cost-effectiveness, reducing the WF significantly at low cost. Finally, changing from sprinkler or furrow to drip or subsurface drip irrigation reduces the WF, but at a significant cost.


2017 ◽  
Author(s):  
Abebe D. Chukalla ◽  
Maarten S. Krol ◽  
Arjen Y. Hoekstra

Abstract. Reducing the water footprint (WF) of the process of growing irrigated crop is an indispensable element in water management, particularly in water-scarce areas. To achieve this, information on marginal cost curves (MCCs) that rank management packages according to their cost-effectiveness to reduce the WF need to support the decision making. MCCs enable the estimation of the cost associated with a certain WF reduction target, e.g. towards a given WF permit (expressed in m3 per hectare per season) or to a certain WF benchmark (expressed in m3 per tonne of crop). This paper aims to develop MCCs for WF reduction for a range of selected cases. The soil-water-balance and crop-growth model, AquaCrop, is used to estimate the effect on evapotranspiration and crop yield and thus WF of crop production due to different management packages. A management package is defined as specific combination of management practices: irrigation technique (furrow, sprinkler, drip or subsurface drip); irrigation strategy (full or deficit irrigation); and mulching practice (no, organic or synthetic mulching). The annual average cost for each management package is estimated as the annualised capital cost plus the annual costs of maintenance and operations (i.e. costs of water, energy, and labour). Different cases is considered, including: three crops (maize, tomato and potato); four types of environment; three hydrologic years (wet, normal and dry years) and three soil types (loam, silty clay loam and sandy loam). For each crop, alternative WF reduction pathways were developed, after which the most cost-effective pathway was selected to develop the MCC for WF reduction. When aiming at WF reduction one can best improve the irrigation strategy first, next the mulching practice and finally the irrigation technique. Moving from a full to deficit irrigation strategy is found to be a no-regret measure: it reduces the WF by reducing water consumption at negligible yield reduction, while reducing the cost for irrigation water and the associated costs for energy and labour. Next, moving from no to organic mulching has a high cost-effectiveness, reducing the WF significantly at low cost. Finally, changing from sprinkler or furrow to drip or sub-surface drip irrigation reduces the WF but at significant cost.


Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1254 ◽  
Author(s):  
Perica Ilak ◽  
Ivan Rajšl ◽  
Josip Đaković ◽  
Marko Delimar

1993 ◽  
Vol 7 (3) ◽  
pp. 185-192 ◽  
Author(s):  
Stanley L Brue

From introductory economics to theoretical papers, the law of diminishing returns is a part of every economist's tool kit. But the evolution of this law in the history of economic analysis reveals more complexity than is perhaps generally understood. Even among those most responsible for its evolution, the law has been loosely defined, and many so-called “proofs” of the law have been weak and incomplete. Moreover, those who expounded the law and its economic implications rarely offered empirical evidence to support it. In fact, economists have offered alternative explanations for rising short-run marginal cost curves and other implications of the law of diminishing returns. This last point raises an interesting question: Have economists used the law of diminishing returns simply for convenience, or is the law fundamental to economic analysis?


Author(s):  
Ane Froyen Dideriksen ◽  
Susanne Sekkesater ◽  
Stein-Erik Fleten ◽  
Ellen Krohn Aasgord ◽  
Hans-Ivar Skjelbred

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