Carbon accounting method and system for city-level power system

Abstract

The invention relates to a carbon accounting method and system for a city-level power system. The method comprises the following steps: acquiring operation data of the city-level power system on a source side, a network side, a load side and an energy storage side; accounting source side carbon emission of the city-level power system based on the operation data of the source side; based on the operation data of the network side, considering the network loss theory in the transmission process from the source side to the load side, and accounting the network side carbon emission of the urban power system in combination with the source side carbon emission; on the basis of the operation data of the load side, the load side carbon emission of the city-level power system is calculated in combination with the source side carbon emission; based on the operation data of the energy storage side, considering the active loss of the energy storage side, and accounting the energy storage side carbon emission of the city-level power system; based on the source side carbon emission, the network side carbon emission, the load side carbon emission and the energy storage side carbon emission, the total carbon emission of the city-level power system is obtained. Compared with the prior art, the method has the advantages of being comprehensive in coverage, high in accuracy, good in real-time performance and the like.

Description

Technical Field

[0001] The present invention relates to the field of carbon emission technology, and in particular to a carbon accounting method and system for a city-level power system. Background Art

[0002] As the main source of greenhouse gas emissions, cities will ultimately directly affect the region's low-carbon economic development and the achievement of carbon peak targets. Currently, carbon emissions from the power system are usually calculated from two dimensions: direct carbon emissions on the source side and indirect carbon emissions on the load side. Specifically:

[0003] 1) Direct carbon emissions are mainly calculated using the macro-statistical method. Total carbon emissions are calculated based on the total fuel consumption for power generation throughout the year and across the province / region.

[0004] 2) Indirect carbon emissions are mainly calculated using the average carbon emission factor method. The indirect carbon emissions from electricity consumption of users are obtained based on the annual average carbon emission factor and electricity consumption at the provincial or regional power grid level.

[0005] However, the existing carbon emission accounting methods have the following problems:

[0006] 1) Incomplete

[0007] When the existing technology is used for carbon accounting, the carbon emissions generated by power generation on the source side and the carbon emissions generated by electricity consumption on the load side are mainly calculated, and the carbon emissions generated by power loss during power transmission on the grid side are often ignored. Especially in recent years, with the development of new urban power systems, the application of energy storage technology in urban power systems has gradually deepened, and the carbon emissions generated by power loss during energy storage charging and discharging cannot be ignored.

[0008] 2) Inaccuracy

[0009] At present, most carbon accounting work draws on the accounting methods and guidelines of the Intergovernmental Panel on Climate Change (IPCC), but the actual conditions in different places are different, resulting in poor pertinence and accuracy. In addition, the average carbon emission factors of the power system currently published are divided into national, regional and provincial levels, and the carbon emission factors are not fine-grained enough. Since the composition and application of the power system in each city are different, it is impossible to accurately calculate the carbon emissions of the city-level power system through the provincial carbon emission factors.

[0010] 3) Poor timeliness

[0011] Both direct and indirect carbon emissions are calculated using statistical methods. The country publishes carbon emission factors once a year. With the acceleration of the construction of new power systems, the rapid development of new energy, and the rapid changes in energy composition, it is obvious that the carbon emission factors published once a year cannot reflect the real-time situation of carbon emissions in a timely manner.

[0012] Therefore, there is currently a lack of a comprehensive, accurate and real-time carbon emissions measurement method for city-level power systems. Summary of the invention

[0013] The purpose of the present invention is to provide a comprehensive carbon accounting method and system for city-level power systems.

[0014] The purpose of the present invention can be achieved by the following technical solutions:

[0015] A carbon accounting method for a city-level power system includes the following steps:

[0016] Obtain the operating data of the city-level power system on the source side, grid side, load side, and energy storage side;

[0017] Based on the operating data on the source side, the source-side carbon emissions of the city-level power system are calculated, and real-time dynamic carbon emission factors are introduced in the calculation process;

[0018] Based on the grid-side operation data, the grid-side carbon emissions of the city-level power system are calculated by considering the grid loss theory during the transmission process from the source side to the load side and combining the source-side carbon emissions;

[0019] Based on the load-side operation data and combined with the source-side carbon emissions, the load-side carbon emissions of the city-level power system are calculated;

[0020] Based on the operation data of the energy storage side and considering the active power loss on the energy storage side, the carbon emissions of the energy storage side of the city-level power system are calculated;

[0021] Based on the source-side carbon emissions, grid-side carbon emissions, load-side carbon emissions and energy storage-side carbon emissions, the total carbon emissions of the city-level power system are obtained.

[0022] Furthermore, the source-side carbon emissions include three parts, namely, carbon emissions generated by all self-generated electricity in the city, carbon emissions generated by electricity purchased from outside the city, and carbon emissions generated by electricity exported to other cities. The calculation expression of the source-side carbon emissions is:

[0023] EG t =EG in,t +EG ex,t -EG sl,t

[0024] In the formula, EG t is the source-side carbon emissions, EG in,t For all carbon emissions from self-generated electricity in the city, EG ex,t Carbon emissions from purchasing electricity from outside the city, EG sl,t Carbon emissions generated by exporting electricity to other cities.

[0025] Furthermore, the calculation expression for carbon emissions generated by all self-generated electricity in the city is:

[0026]

[0027] In the formula, EG in,t For all the carbon emissions from the city's own electricity generation, is the carbon emissions generated by thermal power plant k in a period of time t, K is the total number of thermal power plants in the city-level power system, I represents the number of fossil fuels burned by the power plant in the period of time t, i represents the type of fossil fuel, represents the average mass of fossil fuel i burned by the power plant during time period t, δ i represents the carbon emission factor of fossil fuel i.

[0028] Furthermore, the calculation expression for carbon emissions generated by the city's external electricity purchase is:

[0029]

[0030] In the formula, EG ex,t Carbon emissions from purchasing electricity from outside the city, For each external electricity quantity purchased during time period t, α n is the provincial emission factor for each externally purchased electricity location, and N is the total amount of externally purchased electricity in the city-level power system.

[0031] Furthermore, the calculation expression for carbon emissions generated by exporting electricity to other cities is:

[0032] EG sl,t =P t β t

[0033]

[0034] In the formula, EG sl,t Carbon emissions from exporting electricity to other cities, P t is the power output to other cities, β t is the comprehensive carbon emission factor of the urban power system in time period t, EG in,t is the carbon emissions generated by all self-generated electricity in the city during time period t, EG ex,t is the carbon emissions from the city’s external electricity purchases during time period t, ΔQ t It is the total amount of electricity generated by the urban power system during time period t, including clean energy power generation and externally purchased electricity.

[0035] Furthermore, the calculation expression of the grid-side carbon emissions is:

[0036]

[0037] In the formula, ET t is the grid-side carbon emissions, ΔA t is the active power loss of the transmission and distribution network in time period t, β t is the comprehensive carbon emission factor of the urban power system in time period t, EG t is the carbon emission from the source side, ΔQ t It is the total amount of electricity generated by the urban power system during time period t, including clean energy power generation and externally purchased electricity.

[0038] Furthermore, the load-side carbon emissions of the city-level power system are calculated by electricity consumption, and the calculation expression of the load-side carbon emissions is:

[0039]

[0040] In the formula, EL t is the carbon emission on the load side, Q l,t is the load-side power consumption of the city-level power system, β t is the comprehensive carbon emission factor of the urban power system in time period t, ΔA t is the active power loss of the transmission and distribution network in time period t, EG t Source-side carbon emissions.

[0041] Furthermore, the carbon emissions on the energy storage side of the city-level power system are calculated by the active power loss of the energy storage power station. The calculation expression of the carbon emissions on the energy storage side is:

[0042]

[0043] In the formula, ES t is the carbon emission from energy storage, M is the total number of energy storage power stations in the city-level power system, S m,t is the total charge and discharge of energy storage station m in time period t, θ m is the overall efficiency of the energy storage station m, 1-θ m is the active power loss rate of energy storage power station m.

[0044] Furthermore, the calculation expression of the total carbon emissions of the city-level power system is:

[0045] E t =EG t +ET t +EL t +ES t

[0046] In the formula, E t is the total carbon emissions, EG t is the source-side carbon emissions, ET t is the grid-side carbon emissions, ELt For load-side carbon emissions, ES t Carbon emissions on the energy storage side.

[0047] The present invention also provides a carbon accounting system for a city-level power system, comprising:

[0048] Acquisition module: used to obtain the operating data of the city-level power system on the source side, grid side, load side, and energy storage side;

[0049] Source-side accounting module: used to calculate the source-side carbon emissions of the city-level power system based on the source-side operation data, in which real-time dynamic carbon emission factors are introduced for accounting;

[0050] Grid-side accounting module: used to calculate the grid-side carbon emissions of the city-level power system based on the grid-side operation data and taking into account the grid loss theory during the transmission process from the source side to the load side;

[0051] Load-side accounting module: used to calculate the load-side carbon emissions of the city-level power system based on the load-side operation data;

[0052] Energy storage side accounting module: used to calculate the carbon emissions of the energy storage side of the city-level power system based on the operating data of the energy storage side and taking into account the active power loss of the energy storage side;

[0053] Total carbon emission accounting module: used to obtain the total carbon emissions of the city-level power system based on the source-side carbon emissions, grid-side carbon emissions, load-side carbon emissions and energy storage-side carbon emissions.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) Comprehensive coverage: In order to address the problem that existing carbon accounting methods ignore the carbon emission dimension of urban power systems, resulting in incomplete accounting, the present invention covers the four links of the urban power system: source, network, load, and storage. It can calculate the carbon emissions of the entire urban power system and the carbon emissions generated by each link, so as to formulate carbon emission reduction strategies for each link.

[0056] (2) High accuracy: The carbon emission accounting of the source-side power system of the present invention fully considers the composition of the power generation side of the city's electricity, including both spontaneous thermal power generation and spontaneous clean energy power generation, as well as power purchased from outside the city and power exported to other cities. The present invention also takes into account the carbon emissions caused by grid-side transmission line losses and energy storage losses on the energy storage side, making the present invention not only comprehensive but also highly accurate. In addition, the present invention calculates the carbon emission factor based on spontaneous thermal power generation, clean energy power generation and purchased electricity in the city-level power system, which conforms to the characteristics of the power composition in the city-level power system. Affected by the power composition, the carbon emission factor of the city-level power system will change in real time, and its accuracy is significantly improved compared to the existing published national, regional, and provincial carbon emission factors.

[0057] (3) Good real-time performance: The present invention has good real-time performance. On the one hand, the carbon emission factor of a certain time period is calculated in real time based on the self-generated thermal power generation, clean energy power generation and purchased power generation in a certain time period in the city-level power system. On the other hand, the real-time carbon emissions of the entire city-level power system are calculated based on the real-time power generated by each link in the source, network, load and storage of the city power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic diagram of the method flow of the present invention. DETAILED DESCRIPTION

[0059] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0060] This embodiment provides a carbon accounting method for a city-level power system. In this method, the city-level power system mainly includes four links: source, grid, load and storage. Therefore, the process of calculating the carbon emissions of the city-level power system is to calculate the carbon emissions of the source side, grid side, load side and storage side. The carbon emissions of the source side, grid side, load side and storage side of the city-level power system in a certain time period t are respectively recorded as EG t , E.T. t ,EL t ,ES t , the total carbon emissions of the city-level power system in time period t is E t for:

[0061] E t =EG t +ET t +EL t +ES t (1)

[0062] Specifically, Figure 1 As shown, the method comprises the following steps:

[0063] S1. Source-side carbon emission accounting of urban power systems.

[0064] The source side of the city-level power system is the power generation side. The power sources of the city-level power system include the city's own power generation and external power purchase. The city-level power system also has surplus power output. In a certain period of time, the carbon emissions generated by the city's own power generation are recorded as EG in,t , the carbon emissions generated by externally purchased electricity are recorded as EG ex,t , the carbon emissions generated by exporting electricity to other cities are recorded as EG sl,t , then the carbon emissions from the source side of the city-level power system in this period of time EG t for:

[0065] EG t =EG in,t +EG ex,t -EG sl,t (2)

[0066] Power sources include thermal power generation, hydropower generation, wind and solar power generation, geothermal power generation, etc. Among them, thermal power generation produces carbon emissions due to the combustion of fossil fuels, while the rest of the power generation is clean energy and does not produce carbon emissions.

[0067] 1) For thermal power generation in urban self-generation, it is generally calculated using the real-time consumption of fossil fuels in the power generation process. The carbon emissions generated by a thermal power plant k in a period of time t are:

[0068]

[0069] In the formula, I represents the number of fossil fuels burned by the power plant in time period t, i represents a certain fossil fuel, represents the average mass of fossil fuel i burned by the power plant during time period t, δ i represents the carbon emission factor of fossil fuel i.

[0070] If there are K thermal power plants in the city-level power system, the carbon emissions generated by all self-generated electricity in the city-level power system are:

[0071]

[0072] 2) For the electricity purchased from outside the city, since it is impossible to accurately know the composition of the externally purchased electricity, the provincial power grid emission factor is used for estimation. If there are N externally purchased electricity in the city-level power system, the amount of each external electricity purchased in time period t is The provincial emission factor for each externally purchased electricity is denoted as αn , Carbon emissions from externally purchased electricity EG ex,t for:

[0073]

[0074] 3) If the total amount of electricity generated by the city's power system during time period t is ΔQ t , ΔQ t It is the sum of the city's self-generated thermal power, self-generated hydropower, wind and solar power and other clean energy power generation, as well as externally purchased electricity.

[0075] Then, the comprehensive carbon emission factor β of the urban power system in time period t is t :

[0076]

[0077] If the power output of the city power system to other cities is P during the time period t t , then the carbon emissions generated by exporting electricity to other cities are sl,t for:

[0078] EG sl,t = P t β t (7)

[0079] S2. Grid-side carbon emission accounting of urban power systems.

[0080] The grid-side carbon emissions of urban power systems refer to the carbon emissions generated by active power losses in the process of electricity transmission from the source side to the load side.

[0081] The Guidelines for Theoretical Calculation of Line Losses in Transmission and Distribution Networks (Enterprise Standard of State Grid Corporation of China, Q / GDW 11988-2019) defines the use of the power flow method to calculate the active power loss ΔA of the transmission and distribution network within a certain time period t. t method (because the present invention does not involve this calculation method, the calculation process will not be repeated here).

[0082] Then the grid-side carbon emissions ET in a certain period of time t t for:

[0083]

[0084] In addition, the carbon emissions of each line can be obtained based on the real-time dynamic carbon emission factor combined with the grid-side line loss.

[0085] S3. Calculation of carbon emissions on the load side of urban power systems.

[0086] The load-side carbon emissions of the city-level power system are calculated by the power consumption on the power consumption side. Assume that in the time period t, the load-side power consumption of the city-level power system is Q l,t , then the total carbon emissions generated by the load side are EL t for:

[0087]

[0088] S4. Calculation of carbon emissions from energy storage in urban power systems.

[0089] In city-level power systems, the active power loss of energy storage power stations mainly comes from the energy loss of battery charging and discharging cycles, the power consumption of air-conditioning systems and the efficiency loss of energy storage inverters. The active power loss of other equipment is relatively small.

[0090] Assume that there are M energy storage power stations in the city-level power system, and the energy storage station m charges and discharges S in a time period t. m,t , the overall efficiency of the energy storage station m is recorded as θ m , 1-θ m Then it is the active power loss rate of the energy storage power station. m Usually it is 80% to 85%.

[0091] Therefore, during the energy storage process of the urban power system, the carbon emissions EL generated by the active power loss in the time period t is t for:

[0092]

[0093] S5. Calculation of total carbon emissions from city-level power systems.

[0094] According to the summation formula of formula (1), the total carbon emissions of the city-level power system can be accurately and comprehensively obtained.

[0095] In summary, this embodiment covers the four links of source, network, load and storage of the urban power system. It can not only calculate the carbon emissions of the entire urban power system, but also calculate the carbon emissions generated by each link, so as to formulate carbon emission reduction strategies for each link. It can even obtain the carbon emissions of each line based on the real-time dynamic carbon emission factor combined with the grid-side line loss, and draw a real-time carbon emission network.

[0096] Example 2

[0097] This embodiment provides a carbon accounting system for a city-level power system, including:

[0098] Acquisition module: used to obtain the operating data of the city-level power system on the source side, grid side, load side, and energy storage side;

[0099] Source-side accounting module: used to calculate the source-side carbon emissions of the city-level power system based on the source-side operation data, in which real-time dynamic carbon emission factors are introduced for accounting;

[0100] Grid-side accounting module: used to calculate the grid-side carbon emissions of the city-level power system based on the grid-side operation data and taking into account the grid loss theory during the transmission process from the source side to the load side;

[0101] Load-side accounting module: used to calculate the load-side carbon emissions of the city-level power system based on the load-side operation data;

[0102] Energy storage side accounting module: used to calculate the carbon emissions of the energy storage side of the city-level power system based on the operating data of the energy storage side and taking into account the active power loss of the energy storage side;

[0103] Total carbon emission accounting module: used to obtain the total carbon emissions of the city-level power system based on the source-side carbon emissions, grid-side carbon emissions, load-side carbon emissions and energy storage-side carbon emissions.

[0104] The rest is the same as in Example 1.

[0105] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0106] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A carbon accounting method for city-level power systems, characterized in that: The following steps are involved: Obtain the operating data of the city-level power system on the source side, grid side, load side, and energy storage side; Based on the operating data on the source side, the source-side carbon emissions of the city-level power system are calculated, and real-time dynamic carbon emission factors are introduced in the calculation process; Based on the grid-side operation data, the grid-side carbon emissions of the city-level power system are calculated by considering the grid loss theory during the transmission process from the source side to the load side and combining the source-side carbon emissions; Based on the load-side operation data and combined with the source-side carbon emissions, the load-side carbon emissions of the city-level power system are calculated; Based on the operation data of the energy storage side and considering the active power loss on the energy storage side, the carbon emissions of the energy storage side of the city-level power system are calculated; Based on the source-side carbon emissions, grid-side carbon emissions, load-side carbon emissions and energy storage-side carbon emissions, the total carbon emissions of the city-level power system are obtained.

2. A carbon accounting method for city-level power systems according to claim 1, characterized in that: The source-side carbon emissions include three parts, namely, the carbon emissions generated by all self-generated electricity in the city, the carbon emissions generated by electricity purchased from outside the city, and the carbon emissions generated by electricity exported to other cities. The calculation expression of the source-side carbon emissions is: EG t =EG in,t +EG ex,t -EG sl,t In the formula, EG t is the source-side carbon emissions, EG in,t For all carbon emissions from self-generated electricity in the city, EG ex,t Carbon emissions from purchasing electricity from outside the city, EG sl,t Carbon emissions generated by exporting electricity to other cities.

3. A carbon accounting method for city-level power systems according to claim 2, characterized in that: The calculation expression for carbon emissions from all self-generated electricity in the city is: In the formula, EG in, For all the carbon emissions from the city's own electricity generation, is the carbon emissions generated by thermal power plant k in a period of time t, K is the total number of thermal power plants in the city-level power system, I represents the number of fossil fuels burned by the power plant in the period of time t, i represents the type of fossil fuel, represents the average mass of fossil fuel i burned by the power plant during time period t, δ i represents the carbon emission factor of fossil fuel i.

4. A carbon accounting method for city-level power systems according to claim 2, characterized in that: The calculation expression of carbon emissions generated by the city's external electricity purchase is: In the formula, EG ex, Carbon emissions from purchasing electricity from outside the city, For each external electricity quantity purchased during time period t, α n is the provincial emission factor for each externally purchased electricity location, and N is the total amount of externally purchased electricity in the city-level power system.

5. A carbon accounting method for city-level power systems according to claim 2, characterized in that: The calculation expression for carbon emissions generated by exporting electricity to other cities is: EG sl, =P t β t In the formula, EG sl, Carbon emissions from exporting electricity to other cities, P t is the output power to other cities, β t is the comprehensive carbon emission factor of the urban power system in time period t, EG in,t is the carbon emissions generated by all self-generated electricity in the city during time period t, EG ex, is the carbon emissions from the city’s external electricity purchases during time period t, ΔQ t It is the total amount of electricity generated by the urban power system during time period t, including clean energy power generation and externally purchased electricity.

6. A carbon accounting method for city-level power systems according to claim 1, characterized in that: The calculation expression of the grid-side carbon emissions is: In the formula, ET t is the grid-side carbon emissions, ΔA t is the active power loss of the transmission and distribution network in time period t, β t is the comprehensive carbon emission factor of the urban power system in time period t, EG t is the carbon emission from the source side, ΔQ t It is the total amount of electricity generated by the urban power system during time period t, including clean energy power generation and externally purchased electricity.

7. A carbon accounting method for city-level power systems according to claim 1, characterized in that: The load-side carbon emissions of the city-level power system are calculated by electricity consumption. The calculation expression of the load-side carbon emissions is: In the formula, EL t is the carbon emission on the load side, Q l,t is the load-side power consumption of the city-level power system, β t is the comprehensive carbon emission factor of the urban power system in time period t, ΔA t is the active power loss of the transmission and distribution network in time period t, EG t Source-side carbon emissions.

8. The carbon accounting method for city-level power systems according to claim 1 is characterized in that: The energy storage side carbon emissions of the city-level power system are calculated by the active power loss of the energy storage power station. The calculation expression of the energy storage side carbon emissions is: Where, ES t is the carbon emission from energy storage, M is the total number of energy storage power stations in the city-level power system, S m,t is the total charge and discharge of energy storage station m in time period t, θ m is the overall efficiency of the energy storage station m, 1θ m is the active power loss rate of energy storage power station m.

9. A carbon accounting method for city-level power systems according to claim 1, characterized in that: The calculation expression of the total carbon emissions of the city-level power system is: E t =EG t +AND t +EL t +ES t In the formula, E t is the total carbon emissions, EG t is the source-side carbon emissions, ET t is the grid-side carbon emissions, EL t For load-side carbon emissions, ES t Carbon emissions on the energy storage side.

10. A carbon accounting system for city-level power systems, characterized in that: include: Acquisition module: used to obtain the operating data of the city-level power system on the source side, grid side, load side, and energy storage side; Source-side accounting module: used to calculate the source-side carbon emissions of the city-level power system based on the source-side operation data, in which real-time dynamic carbon emission factors are introduced for accounting; Grid-side accounting module: used to calculate the grid-side carbon emissions of the city-level power system based on the grid-side operation data and taking into account the grid loss theory during the transmission process from the source side to the load side; Load-side accounting module: used to calculate the load-side carbon emissions of the city-level power system based on the load-side operation data; Energy storage side accounting module: used to calculate the carbon emissions of the energy storage side of the city-level power system based on the operating data of the energy storage side and taking into account the active power loss of the energy storage side; Total carbon emission accounting module: used to obtain the total carbon emissions of the city-level power system based on the source-side carbon emissions, grid-side carbon emissions, load-side carbon emissions and energy storage-side carbon emissions.

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