Energy efficiency evaluation method for full-life-cycle residual value analysis of newly-built and reconstructed ocean-going ship

Abstract

The invention discloses a full-life-cycle residual value analysis energy efficiency evaluation method for a newly-built and reconstructed ocean vessel. The method comprises the following steps: S1, calculating ship building energy consumption based on ship cost and unit GDP energy consumption; s2, calculating a ship residual value attenuation carbon intensity index CIIr; for a newly built ship, calculating a current ship residual attenuation carbon strength index CIIr by adopting a ship residual attenuation model in combination with unit GDP energy consumption of a ship building year; for the transformed ship, calculating a shipbuilding cost partial residual value attenuation carbon strength index CIIr1 by combining shipbuilding cost partial residual value attenuation energy consumption with unit GDP energy consumption of a shipbuilding year, and calculating a transformation cost partial residual value attenuation carbon strength index CIIr2 by combining transformation cost partial residual value attenuation energy consumption with unit GDP energy consumption of a transformation year; summing to obtain a current ship residual value attenuation carbon intensity index CIIr; and S3, adding the existing ship operation carbon intensity index CII and the current ship residual value attenuation carbon intensity index CIIr to obtain a ship full life cycle operation carbon intensity index CIIL.

Description

Technical Field

[0001] The present invention relates to the field of ship emissions, and in particular to an energy efficiency evaluation method for residual value analysis of the entire life cycle of new and rebuilt ocean-going ships. Background Art

[0002] Among ship energy efficiency evaluation methods, the most commonly used are EEDI, EEXI, and CII. Their advantages lie in their simple principles and ease of use. However, their disadvantages are that they take into account a limited range of factors. A ship's life cycle encompasses design, construction, operation, modification, and dismantling, and EEDI, EEXI, and CII only address a portion of this. While the EEDI, known as the Ship Energy Efficiency Design Index, is used to guide ship construction, it does not actually consider energy consumption during the design, construction, modification, and dismantling phases. Similarly, the CII only considers the operation phase. A ship's energy consumption occurs not just during operation but throughout its entire life cycle. Throughout a ship's life cycle, energy consumption during design, construction, modification, operation, and dismantling cannot be ignored. Evaluating energy consumption solely during the operational phase overlooks energy consumption during non-operational periods, potentially leading to further energy waste.

[0003] The most similar implementation to the present invention is the paper "Research on Ship Main Engine Energy System Optimization and Ship Energy Efficiency Evaluation Method Based on Thermoeconomic Principles." This paper proposes converting shipbuilding costs into energy consumption using energy consumption per unit of GDP, and using ship depreciation prices to introduce shipbuilding energy consumption into the energy efficiency evaluation index system, thereby correcting the EEOI energy efficiency evaluation index. The main difference between the present invention and this solution is that the present invention proposes a full life cycle residual value analysis energy efficiency evaluation method applicable to new and converted ocean-going vessels. This method not only corrects the CII, the current mainstream energy efficiency evaluation index, but can also be applied to energy efficiency evaluation indicators such as EEDI and EEXI. Furthermore, the present invention can evaluate not only the shipbuilding energy consumption of new ships, but also the conversion energy consumption of converted ships, giving it a wider range of applicability. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides an energy efficiency evaluation method for residual value analysis of the entire life cycle of new and converted ocean-going vessels. To avoid energy waste caused by ignoring energy consumption during non-operating periods, the ship construction cost is converted into energy consumption through unit GDP energy consumption, and the ship depreciation price is used to introduce shipbuilding energy consumption into the energy efficiency evaluation index system. The current energy efficiency index is revised and a new ship energy efficiency evaluation index is proposed: the Ship Life Cycle Operation Carbon Intensity Index (CIIL). The CIIL is an indicator that measures the energy efficiency level of different stages of the ship's entire life cycle, such as design, construction, operation, modification, and dismantling. It is applicable to new and converted ocean-going vessels.

[0005] To achieve the above objectives, the present invention provides a method for energy efficiency evaluation of residual value analysis throughout the life cycle of new and rebuilt ocean-going vessels, which comprises:

[0006] S1: Calculate shipbuilding energy consumption based on shipbuilding cost and energy consumption per unit GDP;

[0007] S2: Calculate the carbon intensity index (CII) of the ship's residual value r ;

[0008] For newly built ships, the ship residual value decay model is used to calculate the current ship residual value decay carbon intensity index (CII) in combination with the unit GDP energy consumption in the shipbuilding year. r ;

[0009] For the converted ships, the residual value attenuation energy consumption of the shipbuilding cost is combined with the unit GDP energy consumption in the shipbuilding year to calculate the carbon intensity index (CII) of the residual value attenuation of the shipbuilding cost. r1 The residual value of the renovation cost is calculated by combining the energy consumption per unit GDP in the renovation year to calculate the carbon intensity index (CII) of the residual value of the renovation cost. r2 , and sum to get the current ship residual value attenuation carbon intensity index CII r ;

[0010] S3: Compare the existing ship operation carbon intensity index CII with the current ship residual value attenuation carbon intensity index CII r Add up to get the ship's life cycle operation carbon intensity index CII L .

[0011] The present invention is further improved in that: the ship life cycle operation carbon intensity index CII L The calculation expression is:

[0012]

[0013] Where: CII is the carbon intensity index of ship operation; C FO is the carbon emission coefficient; Capacity is the carrying capacity; D is the actual sailing distance; F Zm F represents the depreciation of the ship construction cost in the mth year; ZSm represents the depreciation of the transformation cost in the mth year; E PGDP E′ is the energy consumption per unit GDP in the year of ship construction; PGDP The energy consumption per unit GDP in the year of ship transformation;

[0014] A further improvement of the present invention is that in the process of calculating the residual value decay energy consumption of the shipbuilding cost, the ship residual value decay models adopted include: straight-line depreciation method, years' digits and sum depreciation method, and declining balance depreciation method.

[0015] (1) Straight-line depreciation method

[0016] The straight-line depreciation method for ships assumes that the residual value of a ship decreases linearly with its useful life. The residual value of a ship is equal to the difference between the original investment and the total depreciation at a certain point in time. Over a given period of time, the depreciation of a ship is primarily determined by the following factors: the original investment, the expected useful life, and the residual value at the end of its useful life. The depreciation cost of the straight-line depreciation method for new shipbuilding S2 is:

[0017]

[0018] Where, F Z is the annual depreciation expense; △S V The residual value of the ship at the end of its planned service life is usually a percentage of the ship's construction cost (usually 10%). Nz is the estimated service life of the ship. The depreciation cost F for the mth year can be obtained by multiplying the annual depreciation cost by the number of years of service. Zm .

[0019] (2) Years'-Digits Depreciation Method

[0020] The years' and sum's digits method is an accelerated depreciation technique that depreciates most of a ship's value quickly in the first third of its life. That is, the depreciation charge is very high in the first few years and then decreases rapidly in the later years of the ship's life.

[0021] Using the years-plus-the-numbers depreciation method, the first step is to calculate the sum of the ship's service life from 1 to N. This sum is the years-plus-the-numbers. The depreciation expense for a particular year is equal to the ship's investment minus its residual value, multiplied by the quotient of the remaining depreciable years (including the current year) and the years-plus-the-numbers, that is:

[0022]

[0023] Where, F Zm represents the depreciation expense in year m.

[0024] The total depreciation expense from year 1 to year m is:

[0025]

[0026] The residual value BV in the mth year m for:

[0027]

[0028] (3) Declining balance depreciation method

[0029] The declining balance method is another accelerated depreciation method, also known as the equal amount or fixed percentage method. It is also an exponential depreciation method. The calculation formula is:

[0030] Depreciation expense in year m:

[0031] F Zm =(e τ -1)S V e -τm

[0032] If N is known z The residual value △P after 2 years can be used to calculate the required exponential depreciation factor τ:

[0033]

[0034] so

[0035]

[0036] Energy consumption E of ship residual value decay in year m dm The calculation formula is:

[0037] E dm =F Zm E PGDP .

[0038] Energy consumption E for shipbuilding in shipbuilding S1 P The calculation formula is:

[0039] E P =S V E PGDP

[0040] Where S V For ship construction cost, E PGDP Energy consumption per unit of GDP. Internationally, energy consumption per unit of GDP is measured in two units: oil equivalent and standard coal. Each country can choose one based on its own energy consumption structure. China consumes the highest proportion of coal in its energy consumption, so it is recommended to use standard coal to measure China's energy consumption per unit of GDP.

[0041] Assume that the initial ship cost is S V , the service life is N z , assuming that energy-saving transformation is carried out in the kth year, the transformation investment cost is S. The energy consumption of ship transformation in the transformed ship S2 is E S The calculation formula is:

[0042] E S =SE' PGDP

[0043] Where S is the transformation cost, E′ PGDP To transform the energy consumption per unit GDP in that year.

[0044] For the modified ocean-going vessels, the calculation method for the residual value attenuation energy consumption of the shipbuilding cost is as follows:

[0045] Assume that the initial ship cost is S V , the service life is N z , assuming that energy-saving transformation is carried out in the kth year, the transformation investment cost is S. After the transformation in the kth year, based on the ship residual value decay model, calculate the ship residual value BV in the kth year k , re-evaluate the remaining service life of the ship after transformation N z ', the residual value of the ship in year k BV k As the new "ship cost", the remaining service life after transformation N z As the new "planned useful life of the ship", the annual residual value of the original ship BV is recalculated according to the residual value decay depreciation model m and the corresponding depreciation cost F Zm Calculate the residual value attenuation energy consumption E of the shipbuilding cost based on the unit GDP energy consumption in the shipbuilding year dm1 .

[0046] For modified ocean-going vessels, the calculation method for the residual value attenuation of the modification cost is as follows:

[0047] Compare the transformation cost S to the “ship construction cost” and the remaining service life N after transformation z As the new "planned useful life of the ship", the residual value BV of the annual transformation cost is calculated according to the residual value decay depreciation model Sm and the corresponding depreciation cost FZ Sm Calculate the residual value of the transformation cost based on the energy consumption per unit GDP in the transformation year. dm2 .

[0048] The advantages of the present invention are as follows:

[0049] (1) The present invention proposes an energy efficiency evaluation method for residual value analysis of the entire life cycle of new and rebuilt ocean-going ships. The method is applicable to new and rebuilt ships and can not only correct the ship operation carbon intensity index CII, but can also be extended to commonly used energy efficiency evaluation indicators such as EEDI and EEXI, and has broad application prospects.

[0050] (2) The present invention proposes an energy efficiency evaluation method for residual value analysis of the entire life cycle of ocean-going vessels for new and modified ocean-going vessels, which comprehensively considers the energy consumption in the operational and non-operational stages such as construction, modification, and actual operation, and the energy efficiency evaluation is more comprehensive.

[0051] (3) The energy efficiency evaluation method for residual value analysis of the entire life cycle of ocean-going ships proposed in this invention is applied to newly built and renovated ocean-going ships. By introducing a rating system (A to E), it is used to evaluate and encourage ships to improve their energy efficiency levels, thereby promoting the development of ships in the direction of green energy conservation. At the same time, it will also promote the development of energy-saving technologies in the shipbuilding and renovation stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A flow chart of the energy efficiency evaluation method for the life cycle residual value analysis of new ocean-going vessels;

[0053] Figure 2 Flowchart of the energy efficiency evaluation method for the residual value analysis of the entire life cycle of the modified ocean-going vessel. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0055] While some exemplary embodiments of the present invention have been described for purposes of illustration, it should be understood that the present invention may be implemented in other ways not specifically shown in the drawings.

[0056] The present invention proposes a full life cycle residual value analysis energy efficiency evaluation method applicable to new and modified ocean-going ships. In order to avoid energy waste caused by ignoring energy consumption during non-operating periods, the shipbuilding cost is converted into energy consumption through unit GDP energy consumption, and the shipbuilding energy consumption is introduced into the energy efficiency evaluation index system using the ship depreciation price, thereby revising the current energy efficiency index. The new shipbuilding energy efficiency evaluation process is as follows: Figure 1 As shown in Figure 2 The relevant parameters are shown in Table 1, and the specific calculation steps are as follows:

[0057] Table 1 Parameters of a 230,000-ton converted bulk carrier

[0058]

[0059] 1. Based on an energy efficiency evaluation method for residual value analysis of the entire life cycle of new and modified ocean-going ships, the shipbuilding cost is converted into ship energy consumption, thereby introducing the energy consumption in the shipbuilding stage into the ship energy consumption evaluation system. The shipbuilding energy consumption E in the new shipbuilding S1 is P for:

[0060] E P =S V E PGDP

[0061] Where S V The cost of the ship is US$100 million; E PGDPFor the unit GDP energy consumption, according to the China Statistical Yearbook issued by the State Statistics Bureau, China's GDP in 2011 was 487940.2 billion yuan, the total energy consumption was 387043 million tons of standard coal, and the exchange rate of RMB to US dollar on December 31, 2011 was 1 US dollar to RMB 6.3009 yuan, so E PGDP = 4.9980 tons of standard coal / 10,000 US dollars. Internationally, there are two kinds of measuring units for unit GDP energy consumption, equivalent oil and standard coal. Each country can choose one according to its own energy consumption structure. China's energy consumption is dominated by coal consumption, so it is recommended to use standard coal to measure China's unit GDP energy consumption.

[0062] 2. Based on a new and modified ocean-going ship, the residual value analysis energy efficiency evaluation method of ocean-going ship whole life cycle is selected. The more complex exponential balance decreasing depreciation method is used as the ship residual value decay model for calculation and explanation.

[0063] (1) Energy efficiency calculation of residual value analysis of whole life cycle before modification

[0064] The exponential depreciation coefficient τ of the exponential balance decreasing depreciation method in the ship residual value decay model is:

[0065]

[0066] In the formula, Nz is the planned service life of the ship, which is 25 years; ΔS V is the residual value of the ship to the planned service life, which is 10% of the ship cost, 1000 million US dollars.

[0067] The residual value BV m of the ship in the mth year is:

[0068] BV m = S V e -τm

[0069] The depreciation fee F Zm in the mth year is:

[0070] F Zm = (eτ-1)S V e -τm

[0071] The residual value decay energy consumption E dm of the ship in the mth year is:

[0072] E dm = F Zm E PGDP

[0073] (2) Energy efficiency calculation of residual value analysis of whole life cycle after modification

[0074] The energy consumption ES The calculation formula is:

[0075] E S =SE' PGDP

[0076] Where S is the cost of transformation, which is $1.5 million; E′ PGDP To improve the energy consumption per unit GDP in that year, since the energy consumption and GDP data for 2024 have not yet been released in the China Statistical Yearbook, the most recent data for 2023 is used for calculation and analysis. In 2023, China's GDP was RMB 126,058.21 billion, and the total energy consumption was 572 million tons of standard coal. On December 31, 2023, the RMB to USD exchange rate was RMB 7.1884 to USD 1. Therefore, E′ PGDP =3.2618 tons of standard coal / 10,000 US dollars.

[0077] The calculation method for the energy consumption of residual value attenuation of shipbuilding cost is:

[0078] The new “ship cost” is the ship’s residual value (BV) in the 13th year. 13 =S V e -13τ The remaining service life of the ship after transformation is the new “planned service life of the ship” N z 'For 12 years, recalculate the annual residual value of the original ship BV according to the residual value decay depreciation model m and the corresponding depreciation cost F Zm Calculate the residual value attenuation energy consumption E of the shipbuilding cost based on the unit GDP energy consumption in the shipbuilding year dm1 .

[0079] The calculation method for the residual value attenuation energy consumption of the transformation cost is:

[0080] Compare the transformation cost S to the “ship construction cost” and the remaining service life N after transformation z As the new "planned useful life of the ship", the residual value BV of the annual transformation cost is calculated according to the residual value decay depreciation model Sm and the corresponding depreciation cost FZ Sm Calculate the residual value of the transformation cost based on the energy consumption per unit GDP in the transformation year. dm2 .

[0081] 3. Based on a residual value analysis and energy efficiency evaluation method for the entire life cycle of ocean-going ships for new and modified ocean-going ships, the ship's life cycle operation carbon intensity index (CII) L The calculation formula is:

[0082]

[0083] Where CII is the carbon intensity index of ship operations, calculated according to current regulations; C FO is the carbon emission coefficient. The carbon emission coefficient of standard coal recommended by the Energy Research Institute of the National Development and Reform Commission is 0.67 tons of carbon per ton of standard coal, which is converted to 2.4567 tons of carbon dioxide per ton of standard coal; Capacity is the carrying capacity, which is 228,800 tons; D is the actual sailing distance, which is 59,789 nm in 2024 and 65,062 nm in 2023; E dm1 E is the energy consumption of the shipbuilding cost of the modified ship in the mth year; dm2 is the energy consumption of the conversion cost of the converted ship in year m.

[0084] Through the above theoretical calculation, the carbon intensity index CII of the 230,000-ton bulk carrier before and after the transformation is calculated. L As shown in Table 2, it can be seen that after energy-saving transformation, if the full life cycle operation carbon intensity index CII that comprehensively considers the energy consumption in the non-operation stage is used, L Assessing the ship's energy efficiency, taking into account the residual value decay of shipbuilding and conversion costs, the CII of this 230,000-ton bulk carrier is L It decreased from 2.543g·CO2 / (t·nm) to 2.267g·CO2 / (t·nm).

[0085] Table 2 Calculation results of the carbon intensity index of the entire life cycle of a 230,000-ton bulk carrier before and after the transformation

[0086]

[0087] Because energy consumption per unit of GDP varies significantly across industries, converting costs to energy consumption using energy consumption per unit of industrial GDP or shipbuilding GDP would be more accurate. However, many countries do not systematically collect statistics on these parameters. Therefore, this paper uses the energy consumption per unit of GDP for the entire industry as a second best option. In the future, more accurate energy consumption conversion methods for shipbuilding and shipbuilding may also be used if conditions permit.

[0088] The present invention modifies the ship operation carbon intensity index (CII) by introducing shipbuilding energy consumption and transformation energy consumption in the non-operational stage. This method can also be used to modify other energy efficiency evaluation indicators, such as EEDI and EEXI.

[0089] Explanation of terms:

[0090] EEDI: Ship Energy Efficiency Design Index; EEXI: Existing Ship Energy Efficiency Index; EEOI: Ship Energy Efficiency Operation Index; CII: Ship Operation Carbon Intensity Index; CII r : Ship residual value decay carbon intensity index;

[0091] CII r1: Carbon Intensity Index of Shipbuilding Cost Partial Ship Residual Value Decline; CII r2 : Carbon intensity index of ship residual value attenuation of conversion cost part; CII L : Ship life cycle operation carbon intensity index; S V : Shipbuilding cost; GDP: Gross domestic product; E PGDP : Energy consumption per unit GDP; E B : Shipbuilding energy consumption; F Z : Annual depreciation; △S V : The residual value of the ship at the end of its planned service life; N Z : The planned service life of the ship; F Zm : depreciation expense in the mth year; SYD: years plus total; BV m : residual value in the mth year; τ: exponential depreciation coefficient; E dm : Energy consumption of ship residual value decay in the mth year; E dm1 : Energy consumption of the shipbuilding cost of the transformed ship in the mth year after the transformation; E dm2 : Energy consumption of the conversion cost portion of the converted ship in the mth year after the conversion;

[0092] E S : Energy consumption of ship transformation; k: transformation year; S: transformation investment cost; S V ': residual value after transformation; N Z ': Remaining useful life after transformation; C FO : Carbon emission coefficient; Capacity: carrying capacity; D: actual sailing distance.

[0093] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for energy efficiency evaluation of residual value analysis over the entire life cycle of new and rebuilt ocean-going vessels, comprising: S1: Calculate shipbuilding energy consumption based on shipbuilding cost and energy consumption per unit GDP; S2: Calculate the carbon intensity index (CII) of ship residual value attenuation r ; For newly built ships, the ship residual value decay model is used to calculate the current ship residual value decay carbon intensity index (CII) in combination with the unit GDP energy consumption in the shipbuilding year. r ; For the converted ships, the residual value attenuation energy consumption of the shipbuilding cost is combined with the unit GDP energy consumption in the shipbuilding year to calculate the carbon intensity index (CII) of the residual value attenuation of the shipbuilding cost. r1 The residual value of the renovation cost is calculated by combining the energy consumption per unit GDP in the renovation year to calculate the carbon intensity index (CII) of the residual value of the renovation cost. r2 , and sum to get the current ship residual value attenuation carbon intensity index CII r ; S3: Compare the existing ship operation carbon intensity index CII with the current ship residual value attenuation carbon intensity index CII r Add up to get the ship's life cycle operation carbon intensity index CII L .

2. The method for energy efficiency evaluation of residual value analysis of the entire life cycle of new and rebuilt ocean-going vessels according to claim 1, characterized in that: Ship Life Cycle Operation Carbon Intensity Index (CII) L The calculation expression is: Where: CII is the carbon intensity index of ship operation; C FO is the carbon emission coefficient; Capacity is the carrying capacity; D is the actual sailing distance; F Zm F represents the depreciation of the ship construction cost in the mth year; ZSm represents the depreciation of the transformation cost in the mth year; E PGDP E′ is the energy consumption per unit GDP in the year of ship construction; PGDP The energy consumption per unit GDP in the year of ship transformation.

3. The method for energy efficiency evaluation of residual value analysis of the entire life cycle of new and rebuilt ocean-going vessels according to claim 2, characterized in that: In the process of calculating the residual value decay energy consumption of the shipbuilding cost, the ship residual value decay models used include; straight-line depreciation method, years' digits and sum of depreciation method, and declining balance depreciation method.

4. The method for energy efficiency evaluation of residual value analysis throughout the life cycle of new and rebuilt ocean-going vessels according to claim 3, characterized in that: The annual depreciation expense calculation expression for the straight-line depreciation method is: Where, F Z is the annual depreciation expense; △S V is the residual value of the ship when it reaches its planned service life; Nz is the expected service life of the ship. The depreciation cost in the mth year can be obtained by multiplying the annual depreciation cost by the number of years of use.

5. The method for energy efficiency evaluation of residual value analysis of the entire life cycle of new and rebuilt ocean-going vessels according to claim 4, characterized in that: The expression for the years-and-the-slots depreciation method is: Where, F Zm represents the depreciation expense in year m.

6. The method for energy efficiency evaluation of residual value analysis throughout the life cycle of new and rebuilt ocean-going vessels according to claim 5, characterized in that: In the declining balance depreciation method, the expression for the depreciation expense in the mth year is: F Zm =(e τ -1)S V e -τm Where: τ is the exponential depreciation coefficient.

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