A method and system for determining the installed area of a floating photovoltaic device based on water footprint

Abstract

The present invention provides a method for determining the installed area of a floating photovoltaic device based on water footprint, including: determining the water footprint consumed during the production process of the floating photovoltaic device and the water footprint consumed during the construction process of the floating photovoltaic device; determining the comprehensive water footprint consumed for constructing the floating photovoltaic device based on the installed area ratio of the floating photovoltaic device and the water footprint consumed during the production and construction processes of the floating photovoltaic device; determining the water footprint saved by the floating photovoltaic device after its construction; determining the water-saving benefit of the floating photovoltaic device based on the water footprint consumed for the operation and maintenance of the floating photovoltaic device, the comprehensive water footprint consumed for constructing the floating photovoltaic device, and the water footprint saved by the floating photovoltaic device; setting the water-saving benefit of the floating photovoltaic device to 0 to determine the minimum installed area ratio of the floating photovoltaic device. The present invention can construct floating photovoltaics under the condition of meeting the water-saving purpose in arid areas, which is beneficial to alleviating the water resource pressure in arid areas.

Description

Technical Field

[0001] The present invention belongs to the field of floating photovoltaic power generation construction, and more specifically, relates to a method and system for determining the installed area of floating photovoltaic equipment based on water footprint. Background Art

[0002] Water resources are precious resources on which human beings depend for survival and development, and water resources in arid regions are particularly important. The water resource issue has not only been a resource issue, but has become a major strategic issue related to the sustainable economic and social development and long-term stability. Currently, hydropower stations in arid regions mainly undertake functions such as water storage for irrigation and hydropower generation. However, due to the vast area and dry climate of most hydropower stations in arid regions, the evaporation of water resources in hydropower stations every year is particularly prominent. Coupled with the water resources pumped for irrigation and consumed for hydropower, a great deal of waste of water resources in arid regions is caused.

[0003] The concept of water footprint was proposed by Dutch water resources expert Hoekstra on the basis of the research on virtual water theory to describe the impact of human activities on the water resources system. Specifically, the industrial water footprint of a product refers to the total amount of water resources required during the industrial production process of the product. The water footprint is a multi-dimensional indicator that jointly defines all components of the total water footprint in terms of geography and time, including blue water footprint, green water footprint, and grey water footprint. Among them, the blue water footprint refers to the consumption of blue water resources (surface water and groundwater) in the product supply chain; the green water footprint refers to the consumption of green water resources (rainwater stored in the soil, such as soil moisture); and the grey water footprint is related to the amount of pollution and can be defined as the amount of fresh water required to assimilate the pollutant load according to the existing environmental water quality standards.

[0004] Photovoltaic power generation, as an industry vigorously developed by the country in recent years, plays a crucial role in the clean industry committed to reducing energy consumption. However, the high cost of photovoltaic power generation itself, difficult maintenance, and the occupation of land resources cannot be ignored. Developing floating photovoltaics can effectively solve the above problems, especially in hydropower stations in arid regions, which can not only reduce the evaporation of hydropower stations but also reduce power generation energy consumption, further achieving the purpose of water conservation. Therefore, it is very necessary to specifically quantify the consumption and saved water footprint of floating photovoltaic construction in arid regions. Summary of the Invention

[0005] Aiming at the defects of the prior art, the purpose of the present invention is to provide a method and system for determining the installed area of floating photovoltaic equipment based on water footprint, aiming to solve the problem that the prior art does not give how to determine the minimum installed area ratio of floating photovoltaics under the condition of meeting the purpose of water conservation.

[0006] To achieve the above object, in a first aspect, the present invention provides a method for determining the installed area of a floating photovoltaic device based on water footprint, including the following steps:

[0007] Determine the water footprint consumed during the production process of the floating photovoltaic device and the water footprint consumed during the construction process of the floating photovoltaic device;

[0008] Based on the installed area ratio of the floating photovoltaic device and the water footprint consumed during the production and construction processes of the floating photovoltaic device, determine the comprehensive water footprint consumed for constructing the floating photovoltaic device;

[0009] Determine the first reduction amount of the annual evaporation water footprint of the hydropower station after constructing the floating photovoltaic device, the second reduction amount of the water footprint consumed by the floating photovoltaic device relative to hydropower generation after constructing the floating photovoltaic device, and the third reduction amount of the water footprint consumed by pumping groundwater for irrigation after constructing the floating photovoltaic device;

[0010] Add the first reduction amount, the second reduction amount, and the third reduction amount of the water footprint to obtain the water footprint saved by the floating photovoltaic device;

[0011] Based on the water footprint consumed for the operation and maintenance of the floating photovoltaic device, the comprehensive water footprint consumed for constructing the floating photovoltaic device, and the water footprint saved by the floating photovoltaic device, determine the water-saving benefit of the floating photovoltaic device;

[0012] Set the water-saving benefit of the floating photovoltaic device to 0 to determine the minimum installed area ratio of the floating photovoltaic device; when the installed area ratio of the floating photovoltaic device is greater than the minimum installed area ratio, the water-saving benefit is greater than 0, and the floating photovoltaic device can reduce the water resource consumption in the assembled area.

[0013] In an optional example, based on the installed area ratio of the floating photovoltaic device and the water footprint consumed during the production and construction processes of the floating photovoltaic device, determining the comprehensive water footprint consumed for constructing the floating photovoltaic device is specifically:

[0014] CPWF = N * S * (PVWF1 + PVWF2) + S * DWF, where S is the total surface area of the hydropower station; N is the installed area ratio of the floating photovoltaic device; PVWF1 is the production water footprint per unit area of the floating photovoltaic device, PVWF2 is the construction water footprint per unit area of the floating photovoltaic device, and DWF is the water footprint required for configuring relevant equipment around the hydropower station for constructing the floating photovoltaic device.

[0015] In an optional example, determine the first reduction amount of the annual evaporation water footprint of the hydropower station after constructing the floating photovoltaic device, the second reduction amount of the water footprint consumed by the floating photovoltaic device relative to hydropower generation after constructing the floating photovoltaic device, and the third reduction amount of the water footprint consumed by pumping groundwater for irrigation after constructing the floating photovoltaic device; specifically:

[0016] Let EWF be the reduction in the annual evaporative water footprint of the hydropower station after installing the floating PV equipment:

[0017] EWF = S * AEWF * m1;

[0018] Wherein, AEWF is the annual evaporative water footprint per unit area of the hydropower station before installing the floating PV equipment, S is the total surface area of the hydropower station, and m1 is the coefficient of the reduction in evaporation rate of the hydropower station after installing the floating PV equipment;

[0019] Let PWF be the reduction in the water footprint consumed by the floating PV equipment relative to hydropower generation after installing the floating PV equipment:

[0020] PWF = E * (WPWF - PPWF);

[0021] Wherein, WPWF is the water footprint of hydropower generation of the hydropower station, PPWF is the water footprint of photovoltaic power generation of the floating PV equipment, E is the annual power generation of the floating PV equipment, E = N * S * AP * T * t * m2, AP is the power generation power per unit area of the floating PV equipment, T is the number of effective power generation days, t is the effective power generation time in a day, and m2 is the photovoltaic power generation efficiency of the floating PV equipment;

[0022] Let CWF be the reduction in the water footprint consumed by pumping groundwater for irrigation after installing the floating PV equipment:

[0023] CWF = W * C;

[0024] Wherein, W is the pumping volume for irrigation, and C is the loss water footprint for pumping 1 m 3 of groundwater.

[0025] In an optional example, the water footprint saved by the floating PV equipment EPWF = EWF + PWF + CWF.

[0026] In an optional example, based on the water footprint consumed for the operation and maintenance of the floating PV equipment, the comprehensive water footprint consumed for installing the floating PV equipment, and the water footprint saved by the floating PV equipment, the water-saving benefit Q of the floating PV equipment is determined as follows:

[0027] Q = (EPWF - RWF * N * S) * m3 - CPWF

[0028] Wherein, RWF is the water footprint consumed for the operation and maintenance of the floating PV equipment; m3 is the time coefficient for obtaining the net water-saving benefit from installing the floating PV equipment.

[0029] In a second aspect, the present invention provides a system for determining the installed area of a floating PV equipment based on the water footprint, including:

[0030] The comprehensive water footprint determination unit is used to determine the water footprint consumed during the production process of the floating solar power device and the water footprint consumed during the construction process of the floating solar power device; and determine the comprehensive water footprint consumed for constructing the floating solar power device based on the installed area ratio of the floating solar power device and the water footprint consumed during the production and construction processes of the floating solar power device;

[0031] The water footprint savings determination unit is used to determine the first reduction in the annual evaporation water footprint of the hydropower station after constructing the floating solar power device, the second reduction in the water footprint consumed by the floating solar power device relative to hydropower generation after constructing the floating solar power device, and the third reduction in the water footprint consumed by pumping groundwater for irrigation after constructing the floating solar power device; and add the first reduction, the second reduction, and the third reduction of the water footprint to obtain the water footprint saved by the floating solar power device;

[0032] The minimum installed area determination unit is used to determine the water-saving benefit of the floating solar power device based on the water footprint consumed for the operation and maintenance of the floating solar power device, the comprehensive water footprint consumed for constructing the floating solar power device, and the water footprint saved by the floating solar power device; and set the water-saving benefit of the floating solar power device to 0 to determine the minimum installed area ratio of the floating solar power device; when the installed area ratio of the floating solar power device is greater than the minimum installed area ratio, the water-saving benefit is greater than 0, and the floating solar power device can reduce the water resource consumption in the area where it is installed.

[0033] In an optional example, the comprehensive water footprint determination unit determines the comprehensive water footprint consumed for constructing the floating solar power device based on the installed area of the floating solar power device and the water footprint consumed during the production and construction processes of the floating solar power device. Specifically: CPWF = N * S * (PVWF1 + PVWF2) + S * DWF; where S is the total surface area of the hydropower station, N is the installed area ratio of the floating solar power; PVWF1 is the production water footprint per unit area of the floating solar power device, PVWF2 is the construction water footprint per unit area of the floating solar power; DWF is the water footprint required for configuring relevant equipment around the hydropower station for constructing the floating solar power.

[0034] In an alternative example, the water footprint saving determination unit determines a first reduction in the annual evaporation water footprint of the hydropower station after constructing the floating PV device, a second reduction in the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device, and a third reduction in the water footprint consumed by pumping groundwater for irrigation after constructing the floating PV device; specifically: Let EWF be the reduction in the annual evaporation water footprint of the hydropower station after constructing the floating PV device: EWF = S * AEWF * m1; where AEWF is the annual evaporation water footprint per unit area of the hydropower station before constructing the floating PV device, S is the total surface area of the hydropower station, and m1 is the coefficient of the reduction in the evaporation rate of the hydropower station after constructing the floating PV device; Let PWF be the reduction in the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device: PWF = E * (WPWF - PPWF); where WPWF is the water footprint of hydropower generation of the hydropower station, PPWF is the water footprint of PV power generation of the floating PV device, E is the annual power generation of the floating PV device, E = N * S * AP * T * t * m2, N is the proportion of the installed PV area to the total area of the reservoir, AP is the power generation power per unit area of the floating PV device, T is the number of effective power generation days, t is the effective power generation time in a day, and m2 is the PV power generation efficiency of the floating PV device; Let CWF be the reduction in the water footprint consumed by pumping groundwater for irrigation after constructing the floating PV device: CWF = W * C; where W is the pumping volume for irrigation, and C is the loss water footprint of pumping 1m 3 of groundwater.

[0035] In an alternative example, the water footprint EPWF saved by the floating PV device determined by the water footprint saving determination unit is EPWF = EWF + PWF + CWF.

[0036] In an alternative example, the minimum installed area determination unit determines the water saving benefit Q of the floating PV device based on the water footprint consumed by the operation and maintenance of the floating PV device, the comprehensive water footprint consumed by constructing the floating PV device, and the water footprint saved by the floating PV device; specifically: Q = (EPWF - RWF * N * S) * m3 - CPWF; where RWF is the water footprint consumed by the operation and maintenance of the floating PV device; m3 is the time coefficient for obtaining the net water saving benefit by constructing the floating PV device.

[0037] Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects:

[0038] The present invention provides a method and system for determining the installed area of floating photovoltaic equipment based on water footprint. Aiming at the problems of water shortage in arid areas and serious water resource loss in hydropower stations, the basic concepts of the consumption water footprint (CPWF) and the saved water footprint (EPWF) of floating photovoltaics are respectively proposed and defined, and they are used as the quantitative indicators of the water footprint consumed and saved by the construction of floating photovoltaics in hydropower stations. A calculation system for the CPWF and EPWF of floating photovoltaics is constructed. Finally, a calculation system for the water-saving benefit of floating photovoltaic construction is established, and the minimum installed area of floating photovoltaics in arid area hydropower stations is obtained by solving it, aiming to calculate the minimum installed area of floating photovoltaics in arid area hydropower stations to achieve the purpose of water saving and reduce water resource loss in arid areas.

[0039] The present invention provides a method and system for determining the installed area of floating photovoltaic equipment based on water footprint. The provided method innovatively calculates the minimum installed area of regional floating photovoltaic construction, and can obtain the minimum installed area of floating photovoltaics in hydropower stations under the condition of meeting the water-saving purpose in arid areas, which is beneficial to formulating the standard for selecting the minimum installed area of floating photovoltaics in arid area hydropower stations, obtaining water-saving benefits, and reducing the water resource pressure in arid areas. Brief Description of the Drawings

[0040] Figure 1 is the flowchart of the method for determining the installed area of floating photovoltaic equipment based on water footprint provided by an embodiment of the present invention;

[0041] Figure 2 is the flowchart of a calculation system for the investment payback period of the water footprint of floating photovoltaics in arid area hydropower stations provided by an embodiment of the present invention;

[0042] Figure 3 is the architecture diagram of the system for determining the installed area of floating photovoltaic equipment based on water footprint provided by an embodiment of the present invention. Detailed Embodiments

[0043] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0044] Figure 1 is the flowchart of the method for determining the installed area of floating photovoltaic equipment based on water footprint provided by an embodiment of the present invention; As Figure 1 shown, it includes the following steps:

[0045] S101, determine the water footprint consumed during the production process of floating photovoltaic equipment and the water footprint consumed during the construction process of floating photovoltaic equipment;

[0046] S102. Determine the comprehensive water footprint consumed in constructing the floating PV device based on the proportion of the installed area of the floating PV device and the water footprint consumed during the production and construction of the floating PV device.

[0047] S103. Determine the first reduction in the annual evaporation water footprint of the hydropower station after constructing the floating PV device, the second reduction in the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device, and the third reduction in the water footprint consumed by pumping groundwater for irrigation after constructing the floating PV device.

[0048] S104. Add the first reduction, the second reduction, and the third reduction in the water footprint to obtain the water footprint saved by the floating PV device.

[0049] S105. Determine the water-saving benefit of the floating PV device based on the water footprint consumed in the operation and maintenance of the floating PV device, the comprehensive water footprint consumed in constructing the floating PV device, and the water footprint saved by the floating PV device.

[0050] S106. Set the water-saving benefit of the floating PV device to 0 to determine the minimum proportion of the installed area of the floating PV device. When the proportion of the installed area of the floating PV device is greater than the minimum proportion of the installed area, the water-saving benefit is greater than 0, and the floating PV device can reduce the water consumption in the assembled area.

[0051] Figure 2 It is a flowchart of a calculation system for the investment return period of the water footprint of a floating PV system in a hydropower station in an arid area provided by an embodiment of the present invention; as Figure 2 shown:

[0052] The calculation system for the minimum installed area of floating PV construction based on the water footprint provided by the present invention will be divided into three parts: The first part is to propose the consumed water footprint of the floating PV and its calculation system, the second part is to propose the saved water footprint of the floating PV and its calculation system, and the third part is to establish an equation for the water-saving benefit of the floating PV in the arid area and solve it to obtain the minimum proportion of the installed area N of the floating PV construction. The specific steps are as follows:

[0053] The first part: The consumed water footprint of the floating PV and its calculation system.

[0054] Step 1: Propose the consumed water footprint of the floating PV. Develop a water use list, including the direct water footprint of the floating PV device and the water footprint of each process during construction. The consumed water footprint CPWF of the floating PV is an index representing the size of the water footprint of floating PV construction in the region.

[0055] Step 2: Construct a calculation system for the consumed water footprint of the floating PV, as shown in Table 1;

[0056] Table 1

[0057]

[0058] Step 3: Obtain the consumed water footprint of the floating PV according to the following formula. The larger the CPWF, the more water resources it consumes;

[0059] CPWF = N * S * (PVWF1 + PVWF2) + S * DWF, where

[0060] S is the surface area of the hydropower station, N is the proportion of the installed area of the floating PV; PVWF1 is the production water footprint per unit area of the floating PV equipment, PVWF2 is the construction water footprint per unit area of the floating PV; DWF is the water footprint for the configuration of related equipment around the hydropower station for the construction of the floating PV.

[0061] Part II: The saved water footprint of the floating PV and its calculation system.

[0062] Step 1: Propose the saved water footprint of the floating PV. The construction of the floating PV in arid areas can effectively reduce the evaporation of surface water resources of the hydropower station. By replacing hydropower generation with photovoltaic power generation, water resource loss and the water footprint of the energy consumption for pumping are reduced. The saved water footprint EPWF of the floating PV characterizes the water footprint saved by the construction of the floating PV for the hydropower station in arid areas and is a quantitative indicator of the saved water resources.

[0063] Step 2: Construct the calculation system for the saved water footprint of the floating PV, as shown in Table 2:

[0064] Table 2

[0065]

[0066]

[0067] Step 3: Obtain the saved water footprint EPWF of the floating PV according to the following formula. The larger the EPWF value, the more water resources it saves.

[0068] EPWF = EWF + PWF + CWF, where EWF = S * AEWF * m1 * N; AEWF is the annual evaporation water footprint per unit area before the construction of the floating PV, m1 is the coefficient for reducing the evaporation rate by constructing the floating PV power station;

[0069] PWF = E * (WPWF - PPWF), WPWF is the water footprint of hydropower, PPWF is the water footprint of photovoltaic power, E is the annual power generation of the PV power station, E = N * S * AP * T * t * m2, AP is the power generation power per unit area of the floating PV power station, T is the number of effective power generation days, t is the effective power generation time within a day, m2 is the power generation efficiency of the floating PV power station;

[0070] CWF = W * C, W is the amount of groundwater pumped, C is for pumping 1m3 The consumptive water footprint of groundwater.

[0071] Part Three: Establish the water-saving benefit equation of floating solar in arid areas, and solve it to obtain the minimum installed area ratio N of floating solar.

[0072] Step 1: Construct the water-saving benefit equation of floating solar in arid areas, as shown in Table 3:

[0073] Table 3

[0074]

[0075] Step 2: Solve the following equation to obtain the minimum installed area ratio of floating solar.

[0076] Q = (EPWF - RWF * N * S) * m3 - CPWF

[0077] Where: m3 is the time coefficient for obtaining the net water-saving benefit of floating solar construction; Q is the net water-saving benefit of floating solar construction. When Q = 0, N is the minimum installed area ratio of floating solar.

[0078] The following example takes a calculation system for the investment payback period of the water footprint of floating solar in a hydropower station in arid areas as an example. The first part takes the calculation of the consumptive water footprint of floating solar as an example, the second part takes the calculation of the water-saving footprint of floating solar as an example, and the third part establishes the water-saving benefit equation of floating solar in arid areas, and solves it to obtain the minimum installed area ratio N of floating solar in arid areas.

[0079] This example takes the minimum installed area of floating solar in a hydropower station in arid areas as the calculation object, and selects a hydropower station in the northwest as the research object, with a surface area of 3,700,000 m 2 , according to local data and relevant research, the annual effective power generation days of floating solar are 300 days, the average daily effective power generation time is 12 h, m1 = 0.5, m2 = 0.20, m3 = 2.0.

[0080] Part One: Develop a water use list to obtain the consumptive water footprint of floating solar, and the results are shown in Table 4.

[0081] Table 4

[0082]

[0083] Part Two: Obtain the water-saving footprint of floating solar, and the results are shown in Table 5:

[0084] Table 5

[0085]

[0086] Part III: Establishing the water-saving benefit equation for floating solar in arid regions:

[0087] Q = (EPWF - RWF * N * S) * m3 - CPWF. Let Q = 0, and solve for N ≈ 15.64%

[0088] Through example calculations, it can be seen that for a certain reservoir in the northwest, the minimum installed area S1 = S * N ≈ 578722.37 m 2 , accounting for approximately 15.64% of the total area. To achieve the goal of water conservation, the actual installed area should not be less than this area.

[0089] Figure 3 is the system architecture diagram of the installed area determination of floating solar equipment based on water footprint provided by the embodiments of the present invention. As Figure 3 shown, it includes:

[0090] The comprehensive water footprint determination unit 310 is used to determine the water footprint consumed during the production process of the floating solar equipment and the water footprint consumed during the construction process of the floating solar equipment; and determine the comprehensive water footprint consumed for constructing the floating solar equipment based on the installed area ratio of the floating solar equipment and the water footprint consumed during the production and construction processes of the floating solar equipment;

[0091] The water footprint savings determination unit 320 is used to determine the first reduction in the annual evaporation water footprint of the hydropower station after constructing the floating solar equipment, the second reduction in the water footprint consumed by the floating solar equipment relative to hydropower generation after constructing the floating solar equipment, and the third reduction in the water footprint consumed by pumping groundwater for irrigation after constructing the floating solar equipment; and add the first reduction, the second reduction, and the third reduction of the water footprint to obtain the water footprint saved by the floating solar equipment;

[0092] The minimum installed area determination unit 330 is used to determine the water-saving benefit of the floating solar equipment based on the water footprint consumed for the operation and maintenance of the floating solar equipment, the comprehensive water footprint consumed for constructing the floating solar equipment, and the water footprint saved by the floating solar equipment; and set the water-saving benefit of the floating solar equipment to 0 to determine the minimum installed area ratio of the floating solar equipment; when the installed area ratio of the floating solar equipment is greater than the minimum installed area ratio, the water-saving benefit is greater than 0, and the floating solar equipment can reduce the water resource consumption in the assembled area.

[0093] It should be noted that Figure 3 For the detailed functional implementation of each unit in , reference can be made to the introduction in the foregoing method embodiments, and details are not described herein.

[0094] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for determining the installed area of a floating photovoltaic device based on water footprint, characterized in that, It includes the following steps: Determine the water footprint consumed during the production process of the floating PV device and the water footprint consumed during the construction process of the floating PV device; Determine the comprehensive water footprint consumed for constructing the floating PV device based on the installed area ratio of the floating PV device and the water footprints consumed during the production and construction processes of the floating PV device; Determine the first reduction amount of the annual evaporation water footprint of the hydropower station after constructing the floating PV device, the second reduction amount of the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device, and the third reduction amount of the water footprint consumed by pumping groundwater for irrigation after constructing the floating PV device; Add the first reduction amount, the second reduction amount, and the third reduction amount of the water footprint to obtain the water footprint saved by the floating PV device; Determine the water-saving benefit of the floating PV device based on the water footprint consumed for the operation and maintenance of the floating PV device, the comprehensive water footprint consumed for constructing the floating PV device, and the water footprint saved by the floating PV device; Set the water-saving benefit of the floating PV device to 0 to determine the minimum installed area ratio of the floating PV device; when the installed area ratio of the floating PV device is greater than the minimum installed area ratio, the water-saving benefit is greater than 0, and the floating PV device can reduce the water resource consumption in the area where it is installed.

2. The method according to claim 1, wherein Determine the comprehensive water footprint consumed for constructing the floating PV device based on the installed area ratio of the floating PV device and the water footprints consumed during the production and construction processes of the floating PV device. Specifically: CPWF = N * S * (PVWF1 + PVWF2) + S * WF; In the formula, S is the total surface area of the hydropower station; N is the installed area ratio of the floating PV device; PVWF1 is the production water footprint per unit area of the floating PV device, PVWF2 is the construction water footprint per unit area of the floating PV device, and DWF is the water footprint required for configuring relevant equipment around the hydropower station for constructing the floating PV device.

3. The method according to claim 1, wherein Determine the first reduction amount of the annual evaporation water footprint of the hydropower station after constructing the floating PV device, the second reduction amount of the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device, and the third reduction amount of the water footprint consumed by pumping groundwater for irrigation after constructing the floating PV device. Specifically: Let EWF be the reduction amount of the annual evaporation water footprint of the hydropower station after constructing the floating PV device: EWF = S * AEWF * m1; In the formula, AEWF is the annual evaporation water footprint per unit area of the hydropower station before constructing the floating PV device, S is the total surface area of the hydropower station, and m1 is the coefficient of the reduction rate of evaporation of the hydropower station after constructing the floating PV device; Let PWF be the reduction amount of the water footprint consumed by the floating PV device relative to hydropower generation after constructing the floating PV device: PWF = E * (F - PPWF); In the formula, WPWF is the water footprint of hydropower generation of the hydropower station, PPWF is the water footprint of photovoltaic power generation of the floating PV device, E is the annual power generation of the floating PV device, E = N * S * AP * T * t * m2, AP is the power generation power per unit area of the floating PV device, T is the number of effective power generation days, t is the effective power generation time within a day, and m2 is the photovoltaic power generation efficiency of the floating PV device; Let CWF be the reduction in the water footprint consumed by pumping groundwater for irrigation after the construction of the floating PV device: CWF = W * C; Where W is the irrigation pumping volume and C is the consumptive water footprint of pumping 1 m 3 of groundwater.

4. The method according to claim 3, wherein The water footprint saved by the floating PV device, EPWF = EWF + PWF + CWF.

5. The method according to claim 4, wherein Based on the water footprint consumed for the operation and maintenance of the floating PV device, the comprehensive water footprint consumed for the construction of the floating PV device, and the water footprint saved by the floating PV device, determine the water-saving benefit Q of the floating PV device, specifically: Q = (EPWF - RWF * N * S) * m3 - CPWF In the formula, RWF is the water footprint consumed for the operation and maintenance of the floating PV device; m3 is the time coefficient for obtaining the net water-saving benefit from the construction of the floating PV device.

6. A system for determining the installed area of a floating photovoltaic device based on water footprint, characterized in that, Including: A comprehensive water footprint determination unit for determining the water footprint consumed during the production process of the floating PV device and the water footprint consumed during the construction process of the floating PV device; and determining the comprehensive water footprint consumed for the construction of the floating PV device based on the installed capacity area ratio of the floating PV device and the water footprint consumed during the production and construction processes of the floating PV device; A water footprint saving determination unit for determining the first reduction in the annual evaporation water footprint of the hydropower station after the construction of the floating PV device, the second reduction in the water footprint consumed by the floating PV device relative to hydropower generation after the construction of the floating PV device, and the third reduction in the water footprint consumed by pumping groundwater for irrigation after the construction of the floating PV device; and adding the first reduction, the second reduction, and the third reduction of the water footprint to obtain the water footprint saved by the floating PV device; A minimum installed capacity area determination unit for determining the water-saving benefit of the floating PV device based on the water footprint consumed for the operation and maintenance of the floating PV device, the comprehensive water footprint consumed for the construction of the floating PV device, and the water footprint saved by the floating PV device; and setting the water-saving benefit of the floating PV device to 0 to determine the minimum installed capacity area ratio of the floating PV device; when the installed capacity area ratio of the floating PV device is greater than the minimum installed capacity area ratio, the water-saving benefit is greater than 0, and the floating PV device can reduce the water consumption in the assembled area.

7. The system according to claim 6, wherein The comprehensive water footprint determination unit determines the comprehensive water footprint consumed for the construction of the floating PV device based on the installed capacity area ratio of the floating PV device and the water footprint consumed during the production and construction processes of the floating PV device, specifically: CPWF = N * S * (PVWF1 + PVWF2) + S * WF. In the formula, S is the total surface area of the hydropower station; N is the installed capacity area ratio of the floating PV device; PVWF1 is the production water footprint per unit area of the floating PV device, PVWF2 is the construction water footprint per unit area of the floating PV device, and DWF is the water footprint required for the relevant equipment configuration around the hydropower station for the construction of the floating PV device.

8. The system according to claim 6, wherein The water footprint reduction determination unit determines the first reduction in the annual evaporation water footprint of the hydropower station after the construction of the floating solar power equipment, the second reduction in the water footprint consumed by the floating solar power equipment relative to hydropower generation after the construction of the floating solar power equipment, and the third reduction in the water footprint consumed by groundwater extraction for irrigation after the construction of the floating solar power equipment; specifically: Let EWF be the reduction in the annual evaporation water footprint of the hydropower station after the construction of the floating solar power equipment: EWF = S * AEWF * m1; where AEWF is the annual evaporation water footprint per unit area of the hydropower station before the construction of the floating solar power equipment, S is the total surface area of the hydropower station, and m1 is the coefficient of the reduction in evaporation rate of the hydropower station after the construction of the floating solar power equipment; Let PWF be the reduction in the water footprint consumed by the floating solar power equipment relative to hydropower generation after the construction of the floating solar power equipment: PWF = E * (-PPWF); where WPWF is the water footprint of hydropower generation in the hydropower station, PPWF is the water footprint of photovoltaic power generation of the floating solar power equipment, E is the annual power generation of the floating solar power equipment, E = N * S * AP * T * t * m2, AP is the power generation power per unit area of the floating solar power equipment, T is the number of effective power generation days, t is the effective power generation time in a day, and m2 is the photovoltaic power generation efficiency of the floating solar power equipment; Let CWF be the reduction in the water footprint consumed by groundwater extraction for irrigation after the construction of the floating solar power equipment: CWF = W * C; where W is the irrigation water extraction volume, and C is the loss water footprint of extracting 1m 3 groundwater.

9. The system according to claim 8, wherein The water footprint saved by the floating PV device determined by the water footprint saving determination unit, EPWF = EWF + PWF + CWF.

10. The system according to claim 9, wherein, The minimum installed area determination unit determines the water-saving benefit Q of the floating PV device based on the water footprint consumed for the operation and maintenance of the floating PV device, the comprehensive water footprint consumed for the construction of the floating PV device, and the water footprint saved by the floating PV device. Specifically, Q = (EPWF - RWF * N * S) * m3 - CPWF; where RWF is the water footprint consumed for the operation and maintenance of the floating PV device; m3 is the time coefficient for obtaining the net water-saving benefit from the construction of the floating PV device.

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