An assessment method for total carbon footprint of a wind farm considering carbon sink effect of an ecosystem

Abstract

The application discloses a kind of total carbon footprint evaluation methods of wind farm considering ecosystem carbon sink influence, belong to carbon emission accounting technical field.The present application is used to solve the problem that existing wind farm carbon footprint accounting only focuses on direct carbon emission of whole life cycle, ignores the interference of wind farm to surrounding ecosystem carbon sink function, leading to the deviation of evaluation result.Method includes, obtaining wind farm location data, ecosystem carbon sink data and wind farm life cycle carbon emission data, and the pretreatment of various data is carried out;According to the complexity of terrain, single or double control group strategy is selected to build wind farm area and control group area, and the total influence amount of wind farm on ecosystem carbon sink is calculated;The life cycle carbon emission of wind farm is accounted by parameterized empirical model;Two types of accounting results are superimposed to obtain the total carbon footprint of wind farm, and the carbon footprint per degree of wind farm is further calculated.The application can expand the boundary of carbon footprint accounting, and improve the integrity of evaluation result.

Description

Technical Field

[0001] This invention belongs to the field of carbon emission accounting technology, specifically involving a technology for assessing the carbon footprint of wind farms throughout their entire life cycle by incorporating the impact of ecosystem carbon sinks. Background Technology

[0002] To address climate change, wind power, as a mature and widely used clean energy source, has experienced rapid development in recent years. Large-scale wind power development inevitably disrupts surrounding ecosystems, with its impact on ecosystem carbon sinks being particularly critical. Ecosystem carbon sinks refer to the ability of natural ecosystems such as forests, grasslands, and wetlands to absorb and store carbon dioxide through vegetation and soil, and are an important pathway to maintaining global carbon balance. Throughout the construction and operation lifecycle of wind farms, the impact on ecosystem carbon sinks is mainly reflected in two aspects: First, the construction and operation process requires the occupation of a certain area of ​​land, which may change the original land use patterns, leading to vegetation damage and soil disturbance, directly affecting the region's carbon absorption and storage functions, and even triggering the release of carbon from existing carbon pools. Second, during wind farm operation, the turbulence generated in the wake region alters the distribution of microclimate elements such as near-surface temperature and humidity, indirectly exerting a long-term potential impact on ecosystem carbon sinks through climate effects.

[0003] The carbon footprint of a wind farm refers to the total carbon dioxide emissions directly or indirectly generated by the wind farm, usually measured in equivalent carbon dioxide. It covers emissions throughout the entire life cycle, from energy consumption, transportation, manufacturing, to waste disposal, and is a key indicator for measuring the impact on climate change. Currently, existing technologies for wind farm carbon footprint accounting mainly include methods based on life cycle assessment and methods based on carbon emission factors. However, these methods have significant limitations, focusing only on direct carbon emissions throughout the wind farm's life cycle while neglecting the interference and alteration of the carbon sink function of the surrounding ecosystem caused by wind farm construction and operation. This accounting bias may lead to an overestimation of the overall carbon sink benefits of wind farms, failing to fully reflect the actual contribution of wind power to mitigating climate change. Summary of the Invention

[0004] The purpose of this invention is to provide a method for assessing the total carbon footprint of wind farms that takes into account the impact of ecosystem carbon sinks, in order to solve the problem that existing wind farm carbon footprint accounting only considers direct carbon emissions, resulting in inaccurate assessment results.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for assessing the total carbon footprint of wind farms that considers the impact of ecosystem carbon sinks includes the following steps: Acquire wind farm location data, ecosystem carbon sink data, and wind farm lifecycle carbon emission data; The wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data are preprocessed to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data. Based on the wind farm area data and control group area data, combined with the standardized ecosystem carbon sink data, the impact of the standardized wind farm on the ecosystem carbon sink was calculated. Based on the standardized life cycle carbon emission data, the life cycle carbon emissions of the wind farm are calculated. The total carbon footprint of a wind farm is obtained by superimposing the total carbon impact of the standardized wind farm on the ecosystem and the carbon emissions of the standardized wind farm throughout its life cycle.

[0006] In one possible implementation, the step of preprocessing the wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data includes: The wind farm region is constructed using the wind farm location data, thus obtaining wind farm region data; Based on the wind farm area data, a control group area was constructed, and control group area data was obtained; The ecosystem carbon sink data is cropped and format-converted to obtain standardized ecosystem carbon sink data; The carbon emission data of the wind farm's life cycle are processed to obtain standardized life cycle carbon emission data.

[0007] In one possible implementation, the step of constructing a control group region based on the wind farm area data and obtaining control group region data includes, A first control group region was constructed around the wind farm area to obtain data from the first control group region. Calculate the elevation difference between the wind farm area and the first control group area; When the elevation difference exceeds a preset threshold, a second control group region is constructed in an area that is close to and has similar terrain to the wind farm region, and data from the second control group region is obtained.

[0008] In one possible implementation, the step of calculating the standardized impact of the wind farm on the ecosystem carbon sequestration based on the wind farm area data and the control group area data, combined with the standardized ecosystem carbon sequestration data, includes: Extract total primary productivity data and ecosystem respiration data from the standardized ecosystem carbon sink data; Net ecosystem productivity data is calculated based on the total primary productivity data and ecosystem respiration data. Based on the data from the wind farm area and the control group area, the net difference in ecosystem productivity between the wind farm area and the control group area was calculated. Based on the time series of the net ecosystem productivity difference, the trend of the difference value change was fitted. Based on the trend of the difference value and the assessment period, the unit area impact of the wind farm on the ecosystem carbon sink was calculated. Based on the unit area impact and the area of ​​the wind farm region, the total impact of the wind farm on the ecosystem carbon sink is calculated. The total impact is converted into carbon dioxide equivalent to obtain the standardized total impact of wind farms on ecosystem carbon sinks.

[0009] In one possible implementation, the step of calculating the net ecosystem productivity difference between the wind farm area and the control group area based on the wind farm area data and the control group area data includes: When only the first control group region exists, the difference between the net ecosystem productivity of the wind farm region and the net ecosystem productivity of the first control group region is calculated to obtain the net ecosystem productivity difference value. When a first control group region and a second control group region exist, calculate the average net ecosystem productivity of the first control group region and the second control group region. The difference between the net ecosystem productivity of the wind farm area and the average value is calculated to obtain the net ecosystem productivity difference value.

[0010] In one possible implementation, the step of calculating the lifecycle carbon emissions of the wind farm based on the standardized lifecycle carbon emission data includes, Extract the rated power and quantity data of wind turbine units from the standardized life cycle carbon emission data; Based on the rated power data of the wind turbine, the carbon emissions of a single wind turbine over its entire life cycle are calculated. The total carbon emissions of the wind farm throughout its entire life cycle are calculated based on the carbon emissions of a single wind turbine and the number of wind turbines. The total carbon emissions over the entire life cycle are allocated to the design service life to obtain the annual life cycle carbon emissions of the wind farm.

[0011] In one possible implementation, the step of superimposing the standardized wind farm's total carbon footprint on the ecosystem and the standardized wind farm's lifecycle carbon emissions to obtain the total carbon footprint of the wind farm includes, The annual impact of the wind farm on the ecosystem carbon sink is added to the annual life cycle carbon emissions of the standardized wind farm to obtain the total annual carbon footprint of the wind farm. The annual power generation of the wind farm is calculated based on the total installed capacity and capacity factor of the wind farm. The carbon footprint per kilowatt-hour of electricity generated by the wind farm is calculated based on the wind farm’s total annual carbon footprint and annual power generation.

[0012] In one possible implementation, the step of constructing a wind farm region using the wind farm location data to obtain wind farm region data includes, The area corresponding to the wind farm location data is covered by a grid with a preset resolution; Filter the grids that contain at least one wind turbine; The filtered grids are merged to obtain the wind farm area data.

[0013] In one possible implementation, the step of fitting the trend of change in the net ecosystem productivity difference value based on the time series of the net ecosystem productivity difference value includes: The time series of net ecosystem productivity differences were linearly fitted using the least squares method to obtain the trend of the differences.

[0014] In one possible implementation, the step of calculating the total life-cycle carbon emissions of a single wind turbine based on the rated power data of the wind turbine includes, Using a parametric empirical model constructed based on literature meta-analysis, the rated power data of the wind turbine were calculated to obtain the carbon emissions of a single wind turbine throughout its entire life cycle.

[0015] Compared with the prior art, the advantages of this invention are as follows: This invention integrates the carbon emissions of wind farms throughout their entire life cycle with the impact of ecosystem carbon sinks into the accounting framework. Compared with existing methods that only calculate direct carbon emissions, it expands the accounting boundary of carbon footprint and makes the assessment results more consistent with the actual situation of ecosystem carbon cycle.

[0016] This invention employs a differentiated control group setting strategy based on terrain complexity. A single control group is used in areas with gentle terrain, while a second control group is introduced in areas with dramatic terrain undulations. Compared with the single control group method, this reduces the interference of spatial heterogeneity in hydrothermal energy caused by terrain gradients and improves the reliability of carbon sink impact assessment under different geomorphic conditions.

[0017] This invention employs a parametric empirical model constructed based on literature meta-analysis, using the rated power of wind turbine units as a single independent variable to estimate life-cycle carbon emissions. Compared with traditional methods that require a large amount of activity data and emission factors, this reduces the difficulty of data acquisition and is suitable for rapid assessment across a wide range of sites.

[0018] Empirical results show that in the application of two typical grassland wind farms in northern my country, the impact of ecosystem carbon sinks accounts for 41.7% and 25.4% of the total carbon footprint, respectively, indicating that this impact plays a significant role in the carbon budget of wind farms. Including this impact makes the assessment of the total carbon footprint of wind farms more reflective of their actual impact on climate change, providing a more reliable basis for the scientific planning and optimized design of wind farms. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram showing the location distribution of the wind farm and the dual control group in an embodiment of the present invention; Figure 2 This is a trend diagram illustrating the impact of wind farms on net ecosystem productivity according to an embodiment of the present invention. Figure 3 This is a comparison chart of the total carbon footprint of wind farms, average annual power generation, and carbon footprint per kilowatt-hour in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the method for assessing the total carbon footprint of wind farms that considers the impact of ecosystem carbon sinks, as an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] Example: It should be noted that the terms "comprising" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0023] See Figure 4 This embodiment of a method for assessing the total carbon footprint of a wind farm considering the impact of ecosystem carbon sinks includes the following steps: Step 101: Obtain wind farm location data, ecosystem carbon sink data, and wind farm life cycle carbon emission data.

[0024] Specifically, wind farm location data can include the latitude and longitude of the wind turbine generators, construction time, and turbine model information; ecosystem carbon sink data can include carbon flux data reflecting the region's carbon absorption and release capacity; and wind farm lifecycle carbon emission data can include the rated power, capacity factor, and design service life data of the wind turbine generators. For example, wind farm location data can be sourced from the US wind turbine generator database; ecosystem carbon sink data can be sourced from the FLUXCOM carbon flux dataset; and wind farm lifecycle carbon emission data can include the rated power and annual power generation data of a single turbine generator.

[0025] Step 102: Preprocess the wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data.

[0026] The step of preprocessing the wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data includes, The wind farm region is constructed using the wind farm location data, thus obtaining wind farm region data; Based on the wind farm area data, a control group area was constructed, and control group area data was obtained; The ecosystem carbon sink data is cropped and format-converted to obtain standardized ecosystem carbon sink data; The carbon emission data of the wind farm's life cycle are processed to obtain standardized life cycle carbon emission data.

[0027] Specifically, the wind farm area can be a spatial range covering all wind turbine units; the control group area can be an area similar to the ecological background of the wind farm that has not been affected by wind power development; cropping can be the operation of extracting data within a specified spatial range; format conversion can be the operation of converting NetCDF format to GeoTIFF format; standardized life cycle carbon emission data can be wind farm technical parameter data with a unified format and unit. For example, the wind farm area is constructed using a 1×1km grid, and the grid containing at least one wind turbine unit is selected and the union is obtained; the control group area is a buffer zone within a few kilometers around the wind farm; standardized ecosystem carbon sink data is cropped to the spatial range of the wind farm and the control group; standardized life cycle carbon emission data includes the rated power and capacity factor of each unit.

[0028] Furthermore, the step of constructing a control group region based on the wind farm area data and obtaining control group region data includes: A first control group region was constructed around the wind farm area to obtain data from the first control group region. Calculate the elevation difference between the wind farm area and the first control group area; When the elevation difference exceeds a preset threshold, a second control group region is constructed in an area that is close to and has similar terrain to the wind farm region, and data from the second control group region is obtained.

[0029] Specifically, the first control group area can be a control area formed by a buffer zone around the wind farm; the elevation difference can be the difference between the average elevation of the wind farm area and the average elevation of the first control group area; the preset threshold can be the elevation threshold for determining whether a second control group is needed; the second control group area can be a control area with terrain similar to that of the wind farm. For example, the first control group area is a buffer zone within 5km around the wind farm; the preset threshold is set to 100m; the second control group area is selected from ridges or terraces close to the wind farm; the area of ​​the second control group area is similar to the area of ​​the wind farm area.

[0030] Furthermore, the step of constructing a wind farm region using the wind farm location data to obtain wind farm region data includes, The area corresponding to the wind farm location data is covered by a grid with a preset resolution; Filter the grids that contain at least one wind turbine; The filtered grids are merged to obtain the wind farm area data.

[0031] Specifically, the preset resolution grid can be a geographic grid cell with a pre-defined size; grid filtering can be an operation to determine whether a grid contains wind turbine units; grid merging can be an operation to merge multiple adjacent grids into a continuous area. For example, the preset resolution is 1×1km; the grid coverage includes the latitude and longitude range of all wind turbine units; the filtering condition is that the grid contains at least one wind turbine unit; the merged area is the actual impact range of the wind farm.

[0032] Step 103: Based on the wind farm area data and the control group area data, combined with the standardized ecosystem carbon sink data, calculate the standardized impact of the wind farm on the ecosystem carbon sink.

[0033] Specifically, the impact of standardized wind farms on ecosystem carbon sequestration can be the change in regional carbon sequestration caused by wind farm operation.

[0034] The step of calculating the standardized impact of wind farms on ecosystem carbon sequestration based on the wind farm area data, control group area data, and the standardized ecosystem carbon sequestration data includes: Extract total primary productivity data and ecosystem respiration data from the standardized ecosystem carbon sink data; Net ecosystem productivity data is calculated based on the total primary productivity data and ecosystem respiration data. Based on the data from the wind farm area and the control group area, the net difference in ecosystem productivity between the wind farm area and the control group area was calculated. Based on the time series of the net ecosystem productivity difference, the trend of the difference value change was fitted. Based on the trend of the difference value and the assessment period, the unit area impact of the wind farm on the ecosystem carbon sink was calculated. Based on the unit area impact and the area of ​​the wind farm region, the total impact of the wind farm on the ecosystem carbon sink is calculated. The total impact is converted into carbon dioxide equivalent to obtain the standardized total carbon impact of wind farms on the ecosystem.

[0035] Specifically, gross primary productivity (GMP) can be the total amount of carbon fixed by ecosystem producers through photosynthesis; ecosystem respiration can be the total carbon flux released by the ecosystem; net ecosystem productivity (NPFP) can be the net accumulation of carbon in the ecosystem; the difference in NFP can be the difference between the net ecosystem productivity of the wind farm and the control group; the trend of the difference can be the linear slope of the difference over time; the impact per unit area can be the cumulative impact of the wind farm on the carbon sink per unit area; carbon dioxide equivalent can be a unified unit for measuring the effects of different greenhouse gases; the trend of the difference is obtained by least squares fitting; the unit of impact per unit area is gC·m³. -2 The coefficient for converting carbon mass to carbon dioxide equivalent is 3.67.

[0036] Further, the step of calculating the net difference in ecosystem productivity between the wind farm area and the control group area based on the wind farm area data and the control group area data includes, When only the first control group region exists, the difference between the net ecosystem productivity of the wind farm region and the net ecosystem productivity of the first control group region is calculated to obtain the net ecosystem productivity difference value. When a first control group region and a second control group region exist, calculate the average net ecosystem productivity of the first control group region and the second control group region. The difference between the net ecosystem productivity of the wind farm area and the average value is calculated to obtain the net ecosystem productivity difference value.

[0037] Specifically, the first control group area can be an area unaffected by wind power development, formed by a buffer zone surrounding the wind farm; the second control group area can be an area unaffected by wind power development with similar topographical conditions to the wind farm; the average net ecosystem productivity can be the arithmetic mean of the net ecosystem productivity of the two control group areas. For example, when the elevation difference between the wind farm and the first control group is 80m, the difference value is calculated using the first control group; when the elevation difference is 150m, the average value is calculated using both control groups; the average net ecosystem productivity of the first wind farm's two control groups is 215 gC·m³. -2 ·yr -1 .

[0038] Furthermore, the step of fitting the trend of change of the net ecosystem productivity difference value based on the time series of the net ecosystem productivity difference value includes, The time series of net ecosystem productivity differences were linearly fitted using the least squares method to obtain the trend of the differences.

[0039] Specifically, the least squares method can be a statistical method that finds the best function fit for the data by minimizing the sum of squared errors; linear fitting can be a method that approximates the relationship between variables using a linear function; and the trend of the difference value can be the linear slope of the net ecosystem productivity difference value over time. For example, the time series length is 18 years, covering 2001 to 2018; the unit of the trend of the difference value is gC·m. -2 ·yr -1 The variation trend of the difference value of the first wind farm is -1.37 gC·m. -2 ·yr -1 The variation trend of the difference value of the second wind farm is -1.06 gC·m. -2 ·yr -1 .

[0040] Step 104: Calculate the life cycle carbon emissions of the wind farm based on the standardized life cycle carbon emission data.

[0041] Specifically, the lifecycle carbon emissions of a wind farm can be the total direct carbon emissions at each stage of the wind farm's entire lifecycle.

[0042] The step of calculating the lifecycle carbon emissions of a wind farm based on the standardized lifecycle carbon emission data includes, Extract the rated power and quantity data of wind turbine units from the standardized life cycle carbon emission data; Based on the rated power data of the wind turbine, the carbon emissions of a single wind turbine over its entire life cycle are calculated. The total carbon emissions of the wind farm throughout its entire life cycle are calculated based on the carbon emissions of a single wind turbine and the number of wind turbines. The total carbon emissions over the entire life cycle are allocated to the design service life to obtain the annual life cycle carbon emissions of the wind farm.

[0043] Specifically, the rated power of a wind turbine can be the output power of the wind turbine under rated operating conditions; the total life-cycle carbon emissions of a single wind turbine can be the total cumulative carbon emissions of a single turbine from manufacturing to decommissioning; the total life-cycle carbon emissions of a wind farm can be the sum of the life-cycle carbon emissions of all turbines in the wind farm; and the design service life can be the designed operating years of the wind turbines. For example, the rated power of a wind turbine is in kW; the total life-cycle carbon emissions of a single turbine is in gCO2e; the design service life is taken as 20 years; the first wind farm has a total of 2362 wind turbines with an average rated power of 1568.02kW.

[0044] The step of calculating the total life-cycle carbon emissions of a single wind turbine based on its rated power data includes: Using a parametric empirical model constructed based on literature meta-analysis, the rated power data of the wind turbine were calculated to obtain the carbon emissions of a single wind turbine throughout its entire life cycle.

[0045] Specifically, meta-analysis can be a method of comprehensive statistical analysis of a large amount of relevant literature data; parametric empirical models can be empirical formulas constructed based on statistical data with rated power as the independent variable. For example, when the rated power is 1568kW, the carbon emissions of a single wind turbine over its entire life cycle are 1192.5tCO2e; the model is applicable to onshore wind turbines in the mainstream power range.

[0046] Step 105: Superimpose the total carbon footprint of the wind farm on the ecosystem and the life cycle carbon emissions of the standardized wind farm to obtain the total carbon footprint of the wind farm.

[0047] Specifically, the total carbon footprint of a wind farm can be considered as the total carbon emission equivalent, taking into account both direct carbon emissions and the impact of ecological carbon sinks. The total carbon footprint of a wind farm is measured in equivalent carbon dioxide.

[0048] The step of superimposing the standardized wind farm's total carbon footprint on the ecosystem and the standardized wind farm's life-cycle carbon emissions to obtain the total carbon footprint of the wind farm includes the following steps: The annual impact of the wind farm on the ecosystem carbon sink is added to the annual life cycle carbon emissions of the standardized wind farm to obtain the total annual carbon footprint of the wind farm. The annual power generation of the wind farm is calculated based on the total installed capacity and capacity factor of the wind farm. The carbon footprint per kilowatt-hour of electricity generated by the wind farm is calculated based on the wind farm’s total annual carbon footprint and annual power generation.

[0049] Specifically, the annual total carbon footprint of a standardized wind farm can be the comprehensive carbon emission equivalent generated by the wind farm each year; the total installed capacity can be the sum of the rated power of all units in the wind farm; the capacity factor can be the ratio of the actual power generation of the wind farm to its theoretical maximum power generation; the annual power generation can be the total power generation of the wind farm in one year; and the carbon footprint per kilowatt-hour can be the carbon emission equivalent corresponding to each kilowatt-hour generated by the wind farm. For example, the unit of total installed capacity is kW; the capacity factor is 0.232; the unit of annual power generation is kWh; and the unit of carbon footprint per kilowatt-hour is gCO2e·kWh. -1 The annual total carbon footprint of the first wind farm is 2.42 × 10⁵ tCO₂e.

[0050] This embodiment provides a method for assessing the total carbon footprint of wind farms that takes into account the impact of ecosystem carbon sinks. The carbon footprint assessment of wind farms in this method consists of an assessment of ecosystem carbon sink impacts and a life cycle carbon emission assessment.

[0051] First, an assessment of the carbon sink impact of the wind farm ecosystem is conducted. Net ecosystem productivity is a key indicator characterizing the carbon budget balance of an ecosystem. Its value can be directly extracted from regional carbon flux data products, or it can be indirectly calculated based on the difference between gross primary productivity and ecosystem respiration. Gross primary productivity is the total amount of carbon fixed by all producers in the ecosystem through photosynthesis per unit time and per unit area. Ecosystem respiration mainly includes the sum of carbon fluxes released by autotrophic respiration of vegetation and heterotrophic respiration of soil per unit time and per unit area. Net ecosystem productivity is the remainder after subtracting ecosystem respiration from gross primary productivity; it represents the net accumulation of carbon in the ecosystem per unit time and per unit area, and is an important indicator for measuring the carbon sink or carbon source function of an ecosystem. Its calculation method is as follows:

[0052] In the formula, Net ecosystem productivity per year, expressed in gC·m³. -2 .when When the value is greater than 0, the ecosystem acts as a carbon sink, net absorbing and storing carbon dioxide from the atmosphere. When... When the value is less than 0, the ecosystem acts as a carbon source, emitting net carbon dioxide into the atmosphere.

[0053] To mitigate the interannual fluctuations in natural background factors such as temperature, precipitation, topography, and soil conditions, and to reduce accounting errors caused by spatial heterogeneity, a control group is needed to quantify the impact of wind farm operation. Furthermore, a differentiated control group setup strategy should be adopted based on topographic complexity. For areas with relatively flat terrain, the time-series difference value can be constructed by subtracting the net ecosystem productivity per unit area between the wind farm and the control area. The calculation formula is as follows:

[0054] In the formula, It is the difference in net ecosystem productivity of vegetation, expressed in gC·m³. -2 . and These represent the average net ecosystem productivity within the wind farm control group region. When A value greater than 0 indicates that the carbon sequestration capacity of the wind farm area is stronger than that of the control area. When A value less than 0 indicates that the carbon sequestration capacity of the wind farm area is less than that of the control area.

[0055] For complex geomorphic units with dramatic topographic relief, such as ridges, plateaus, mountain corridors, and river valley slopes, a dual control group strategy is needed to correct for significant background differences caused by topographic gradients. The formula for calculating the net ecosystem productivity anomaly of wind farms in this region is:

[0056] In the formula, It is the difference in net ecosystem productivity of vegetation, expressed in gC·m³. -2 . , and These represent the average net ecosystem productivity for the wind farm, the first control group, and the second control group, respectively. A value greater than 0 indicates that the carbon sequestration function of the wind farm area is stronger than the average level of the two control groups. A value less than 0 indicates that the wind farm has a weakening effect on the regional carbon sequestration function.

[0057] Using each period in a long time series The time variation trend can be fitted using methods such as the least squares method. This trend term quantitatively characterizes the interannual dynamic direction and rate of the impact of wind farm operations on net ecosystem productivity, and can further quantify the persistent cumulative effect of local ecosystem carbon sinks. The unit area impact of wind farms on ecosystem carbon sinks. The cumulative total disturbance offset of net ecosystem productivity per unit area in the wind farm area can be calculated using the following formula:

[0058] In the formula, This represents the area-specific impact of wind farms on ecosystem carbon sequestration, expressed in gC·m². -2 . express The slope of the linear trend in the time series characterizes the interannual rate of change of carbon sinks under the influence of wind farms, with units of gC·m. -2 ·yr -1 . This indicates the length of the evaluation year relative to the starting year, in years. The larger the absolute value, the more significant the cumulative impact of wind farms on local ecological carbon sinks.

[0059] For the entire wind farm, Weighted multiplication by wind farm area Obtain the average annual impact of wind farms on ecosystem carbon sinks. The calculation formula is:

[0060] In the formula, This represents the average annual impact of ecosystem carbon sinks, expressed in gC. A value greater than 0 indicates that the wind farm has weakened the local carbon sequestration function. A value less than 0 indicates that the wind farm has enhanced its local carbon sequestration function. This represents the land area occupied by the wind farm, in m². The negative sign is used in the formula to maintain consistency with the directional definition of the carbon emission accounting system.

[0061] To standardize the unit of measurement for lifecycle carbon emissions, it is necessary to convert carbon mass into carbon dioxide equivalents based on the mass ratio between carbon atoms and carbon dioxide molecules. The calculation formula is as follows:

[0062] In the formula, This represents the carbon dioxide equivalent of the impact of a wind farm on the ecosystem's carbon sink, expressed in gCO2e. The positive and negative signs correspond to the weakening and enhancing effects of carbon sinks, respectively. The larger the absolute value, the more significant the impact of wind farms on local ecosystem carbon sinks.

[0063] Next, we will perform lifecycle carbon emission accounting. Traditional wind farm lifecycle carbon emission assessments require data on the types and quantities of materials used in the manufacturing, transportation, construction, and decommissioning stages of the wind farm, as well as transportation distances. These data must be retrieved from a professional lifecycle inventory database, and the equivalent CO2 emissions must be calculated using specialized lifecycle assessment software. However, the supporting data for these methods is difficult to obtain, and they face significant data availability constraints in large-scale, multi-site applications. This method utilizes a literature meta-analysis to construct a parameterized empirical model, using the rated power of the wind turbine as a single independent variable to directly estimate the lifecycle carbon emissions of a single wind turbine in a wind farm. The calculation formula is as follows:

[0064] In the formula, This represents the total cumulative carbon dioxide emissions of a single standardized wind turbine over its entire lifecycle, expressed in gCO2e. This refers to the rated power of the wind turbine, measured in kW.

[0065] Based on this, by summing the lifecycle carbon emissions of all units in the wind farm and allocating them over the operating years, the annual carbon emissions of the wind farm over its entire lifecycle can be obtained. The calculation formula is:

[0066] In the formula, This represents the annual carbon emissions over the lifecycle of a wind farm, expressed in gCO2e·yr. -1 The higher the value, the more carbon emissions the wind farm produces per unit year. This represents the total cumulative carbon emissions of the i-th wind turbine over its entire lifecycle, expressed in gCO2e. The design lifespan of the wind turbine is typically between 20 and 25 years. k represents the number of wind turbines in the wind farm.

[0067] After obtaining the average annual impact of wind farms on ecosystem carbon sinks and their annual life-cycle carbon emissions, the annual carbon footprint of wind farms can be calculated by combining these figures. The calculation formula is:

[0068] In the formula, This represents the total annual carbon footprint of a wind farm, expressed in gCO2e. This represents the annual carbon emissions over the traditional lifecycle of a wind farm. This represents the annual impact of wind farm operations on ecosystem carbon sinks.

[0069] To take into account the potential impact of wind farms on ecosystem carbon sinks and comprehensively assess their carbon reduction capacity, the carbon footprint per kilowatt-hour is used to characterize the actual carbon reduction contribution of wind farms. First, the total installed capacity of the wind farm is calculated. The calculation formula is:

[0070] In the formula, This represents the total installed capacity of the wind farm, expressed in kW. Let be the rated power of the i-th wind turbine, in kW. k is the number of wind turbines in the wind farm.

[0071] Then calculate the total annual power generation of the wind farm. The calculation formula is:

[0072] In the formula, This represents the total annual power generation of the wind farm, in kW•h. 8760 represents the number of hours per year. The capacity factor of a wind farm can be calculated as the ratio of the actual annual power generation of the wind farm to the power generation under the condition of operating at rated power for one year.

[0073] Based on this, the carbon footprint per kilowatt-hour of wind farms This is the ratio of total annual carbon footprint to annual electricity generation. The calculation formula is:

[0074] In the formula, The total carbon footprint intensity of a wind farm is expressed in gCO2e·kWh. -1 This indicator comprehensively represents the carbon intensity of the ecosystem carbon balance and traditional life-cycle carbon emissions corresponding to a unit of wind power generation, and can accurately measure the carbon intensity of a unit of wind farm power generation.

[0075] To verify the effectiveness of the above method, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. This embodiment is used to evaluate the comprehensive impact of wind farms on regional carbon budgets, and two grassland wind farms in northern my country are selected as research objects, referred to as the first wind farm and the second wind farm, respectively.

[0076] First, data on the location, rated power, and annual power generation of each wind turbine in the wind farm were obtained from the wind farm operator. To eliminate the potential interference of terrain factors on carbon footprint assessment, wind farms and a first control group were constructed using 1×1km grid cells, and the average elevation of each region was calculated. The location distribution of the wind farms and the dual control group in this embodiment of the invention is as follows: Figure 1 As shown, Figure 1 This is a schematic diagram showing the location distribution of the wind farm and the dual control group in an embodiment of the present invention. The results show that the vertical undulation gradient of the terrain is large, and the average base elevation of the entire wind farm area is more than 150m higher than that of the single blank parallel control area, far exceeding the critical correction threshold of 100m terrain difference. The single control difference model is difficult to effectively offset the interference of terrain-induced hydrothermal spatial heterogeneity. Therefore, this method uses a dual control group to carry out relevant calculations.

[0077] Based on this, the total primary productivity, ecosystem respiration, and net ecosystem productivity of FLUXCOM were calculated for the wind farm areas of the two wind farms and the first and second control groups during the growing season from May to September 2001 to 2018. Subsequently, the annual differences between the wind farms and the two control groups were calculated (Formula 3), and the trend of change was further calculated using the least squares method. The trend of the wind farm's impact on net ecosystem productivity in this embodiment of the invention is as follows: Figure 2 As shown, Figure 2 This is a trend diagram showing the impact of wind farms on net ecosystem productivity according to an embodiment of the present invention. Figure 2The slope of the trend of the carbon sink difference value of the first wind farm is -1.37, and the slope of the trend of the carbon sink difference value of the second wind farm is -1.06. This result reveals that wind farms have a long-term dynamic impact on the carbon sink function of the ecosystem.

[0078] Based on the above analysis, the impact of the first wind farm on the net ecosystem productivity per unit area is calculated to be -1.37 gC·m. -2 ·yr -1 The impact of the second wind farm on net ecosystem productivity per unit area is -1.06 gC·m. -2 ·yr -1 The cumulative impact of wind farm operations from 2001 to 2018 is converted into the annual equivalent carbon sink impact of the entire wind farm (Formulas 4, 5, and 6). The unit area impact of the first wind farm on the ecosystem carbon sink is -24.69 g C·m. -2 The total ecosystem carbon sink loss of the weighted wind farm, covering an area of ​​1113 km², is calculated to be 2.75 × 10⁻⁶. 10 gC, converted to the equivalent carbon dioxide equivalent is 1.01 × 10¹¹ gCO₂e (1.01 × 10 5 (tCO2e). The unit area impact of the second wind farm on ecosystem carbon sink is -19.11 C·m⁻², and the total annual ecosystem carbon sink loss calculated based on a weighted area of ​​538 km² is 1.03 × 10⁻⁶. 10 gC corresponds to an equivalent carbon dioxide amount of 3.77 × 10⁻⁶. 10 gCO2e (3.77×10) 4 tCO2e).

[0079] To comprehensively assess the total carbon footprint of wind farms, it is also necessary to calculate the anthropogenic carbon emissions throughout the entire life cycle of the wind farms. The first wind farm has 2362 wind turbines with a total installed capacity of 3703675 kW and an average rated power per turbine of 1568.02 kW. The second wind farm has 1858 wind turbines with a total installed capacity of 2913475 kW and an average rated power per turbine of 1568.07 kW. Based on the wind farm's design lifespan of 20 years (Formula 7), and by summing the emission factors at each stage of the wind farm and amortizing them to each year, the annual life cycle carbon emissions are calculated. The calculation results show that the first wind farm's single-unit carbon emissions over the entire life cycle are 1192.5 tCO2e, and the annual carbon emissions over the entire life cycle reach 1.41 × 10⁻⁶. 5 The second wind farm's total carbon emissions over its entire lifecycle are 1192.53 tCO2e, with an annual carbon emission of 1.11 × 10⁻⁶ tCO2e. 5 tCO2e.

[0080] To uniformly measure the contribution of carbon emissions from different sources to unit power generation, it is necessary to calculate the annual power generation by combining the installed capacity and measured capacity factor of the wind farm, and then calculate the carbon footprint per kilowatt-hour. The capacity factor of both wind farms is 0.232, and their annual power generation, calculated based on the rated power (Formula 11), is 7.53 × 10⁻⁶. 9 kWh and 5.92×10 9 kWh. Taking into account the annual ecosystem carbon sink impact and life-cycle carbon emissions of the wind farm (Formula 12), its carbon footprint per kilowatt-hour is calculated. The annual average power generation and carbon footprint per kilowatt-hour of the wind farm in this embodiment of the invention are compared as follows: Figure 3 As shown, Figure 3 This is a comparison chart of the total carbon footprint of a wind farm, the average annual power generation, and the carbon footprint per kilowatt-hour in an embodiment of the present invention.

[0081] Calculations show that the annual total carbon footprint of the first wind farm is 2.42 × 10⁻⁶. 5 The total annual carbon footprint of the second wind farm is 1.49 × 10⁻¹ gCO₂e, with a combined carbon footprint intensity of 32.11 gCO₂e·kWh⁻¹. 5 The carbon footprint intensity per kilowatt-hour (tCO2e) reached 25.08 gCO2e·kWh⁻¹. In 2018, the ecosystem carbon footprint of the first and second wind farms accounted for 41.7% and 25.4% of the total annual carbon footprint, respectively, indicating that the contribution of ecosystem carbon sinks caused by wind farm operations is an indispensable part of wind farm carbon footprint accounting. Against the backdrop of continuous expansion of global wind power installed capacity, the land area occupied by wind farms and the number of wind turbines are constantly increasing, and their cumulative disturbance effect on the local ecosystem carbon balance may be further amplified. If traditional carbon footprint assessment methods still do not incorporate ecosystem carbon sinks into the accounting framework, the resulting bias will become increasingly apparent as the scale of wind farms expands. Therefore, constructing a comprehensive assessment method that takes into account both anthropogenic carbon emissions and ecosystem carbon sinks throughout the entire life cycle of wind farms will help improve the scientific rigor and completeness of wind farm carbon footprint accounting, providing important methodological support and decision-making basis for the scientific site selection, optimized planning, and comprehensive ecological effect assessment of wind farms.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks, characterized in that, Includes the following steps: Acquire wind farm location data, ecosystem carbon sink data, and wind farm lifecycle carbon emission data; The wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data are preprocessed to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data. Based on the wind farm area data and control group area data, combined with the standardized ecosystem carbon sink data, the impact of the standardized wind farm on the ecosystem carbon sink was calculated. Based on the standardized life cycle carbon emission data, the life cycle carbon emissions of the wind farm are calculated. The total carbon footprint of a wind farm is obtained by superimposing the standardized wind farm's total carbon impact on the ecosystem and the wind farm's life cycle carbon emissions. The step of calculating the standardized impact of wind farms on ecosystem carbon sequestration based on the wind farm area data, control group area data, and the standardized ecosystem carbon sequestration data includes: Extract total primary productivity data and ecosystem respiration data from the standardized ecosystem carbon sink data; Net ecosystem productivity data is calculated based on the total primary productivity data and ecosystem respiration data. Based on the data from the wind farm area and the control group area, the net difference in ecosystem productivity between the wind farm area and the control group area was calculated. Based on the time series of the net ecosystem productivity difference, the trend of the difference value change was fitted. Based on the trend of the difference value and the assessment period, the unit area impact of the wind farm on the ecosystem carbon sink was calculated. Based on the impact per unit area and the area of ​​the wind farm region, the total impact of the wind farm on the ecosystem carbon sink is calculated. The total impact is converted into carbon dioxide equivalent to obtain the standardized total carbon impact of wind farms on the ecosystem.

2. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 1, characterized in that, The steps of preprocessing the wind farm location data, ecosystem carbon sink data, and life cycle carbon emission data to obtain wind farm area data, control group area data, standardized ecosystem carbon sink data, and standardized life cycle carbon emission data include: The wind farm region is constructed using the wind farm location data, thus obtaining wind farm region data; Based on the wind farm area data, a control group area was constructed, and control group area data was obtained; The ecosystem carbon sink data is cropped and format-converted to obtain standardized ecosystem carbon sink data; The life cycle carbon emission data of the wind farm are processed to obtain standardized life cycle carbon emission data.

3. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 2, characterized in that, The step of constructing a control group region based on the wind farm area data and obtaining control group region data includes: A first control group region was constructed around the wind farm area to obtain data from the first control group region. Calculate the elevation difference between the wind farm area and the first control group area; When the elevation difference exceeds a preset threshold, a second control group region is constructed in an area that is close to and has similar terrain to the wind farm region, and data from the second control group region is obtained.

4. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 1, characterized in that, The step of calculating the net ecosystem productivity difference between the wind farm area and the control group area based on the wind farm area data and the control group area data includes: When only the first control group region exists, the difference between the net ecosystem productivity of the wind farm region and the net ecosystem productivity of the first control group region is calculated to obtain the net ecosystem productivity difference value. When a first control group region and a second control group region exist, calculate the average net ecosystem productivity of the first control group region and the second control group region. The difference between the net ecosystem productivity of the wind farm area and the average value is calculated to obtain the net ecosystem productivity difference value.

5. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 1, characterized in that, The step of calculating the lifecycle carbon emissions of the wind farm based on the standardized lifecycle carbon emission data includes: Extract the rated power and quantity data of wind turbine units from the standardized life cycle carbon emission data; Based on the rated power data of the wind turbine, the carbon emissions of a single wind turbine over its entire life cycle are calculated. The total carbon emissions of the wind farm throughout its entire life cycle are calculated based on the carbon emissions of a single wind turbine and the number of wind turbines. The total carbon emissions over the entire life cycle are allocated to the design service life to obtain the annual life cycle carbon emissions of the wind farm.

6. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 1, characterized in that, The step of superimposing the standardized total carbon impact of the wind farm on the ecosystem and the life-cycle carbon emissions of the wind farm to obtain the total carbon footprint of the wind farm includes, The annual carbon footprint of the wind farm is obtained by adding the annual impact of the wind farm on the ecosystem carbon sink to the life cycle carbon emissions of the wind farm. The annual power generation of the wind farm is calculated based on the total installed capacity and capacity factor of the wind farm. The carbon footprint per kilowatt-hour of electricity generated by the wind farm is calculated based on the wind farm’s total annual carbon footprint and annual power generation.

7. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 2, characterized in that, The step of constructing a wind farm region using the wind farm location data to obtain wind farm region data includes: The area corresponding to the wind farm location data is covered by a grid with a preset resolution; Filter the grids that contain at least one wind turbine; The filtered grids are merged to obtain the wind farm area data.

8. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 1, characterized in that, The step of fitting the trend of change of the net ecosystem productivity difference value based on the time series of the net ecosystem productivity difference value includes: The time series of net ecosystem productivity differences were linearly fitted using the least squares method to obtain the trend of the differences.

9. The method for assessing the total carbon footprint of wind farms considering the impact of ecosystem carbon sinks according to claim 5, characterized in that, The step of calculating the total life-cycle carbon emissions of a single wind turbine based on the rated power data of the wind turbine includes: Using a parametric empirical model constructed based on literature meta-analysis, the rated power data of the wind turbine were calculated to obtain the carbon emissions of a single wind turbine throughout its entire life cycle.

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