Volume configuration method for wind and light steam storage and production system

Abstract

The invention belongs to the field of green electricity steam production, and provides a wind and light steam storage and production system capacity configuration method, which comprises the following steps: S1, acquiring wind energy and solar energy resource data and industrial steam demand parameters of a project location; s2, calculating hourly output of a wind power station, hourly output of a photovoltaic power station, a steam heat load and fused salt heat power of a fused salt heat storage system; s3, determining the limit of the wind power maximum installed capacity and the photovoltaic maximum installed capacity; s4, sequentially selecting a plurality of to-be-evaluated heat storage duration, wind power installed capacity and photovoltaic installed capacity combination schemes according to the limitation and the step length; s5, for each combination scheme, calculation and evaluation are carried out; and S6, comparing the internal return rates of the project capital fund of all the combination schemes, and outputting the combination scheme with the highest return rate as the optimal capacity configuration scheme. The configuration capacity of wind power, photovoltaic and energy storage in the system can be determined, and a stable and clean energy source is provided for industrial steam.

Description

Technical Field

[0001] This invention relates to the field of green electricity steam generation, and more specifically, to a method for configuring the capacity of a wind-solar-storage steam generation system. Background Technology

[0002] Industrial heat consumption accounts for over 70% of the national total, representing a major sector of heat consumption in my country. This demand is continuous, requiring high-quality steam parameters and necessitating large-scale steam production. Currently, industrial steam is generated from the combustion of fossil fuels such as coal, natural gas, and oil, which heat feedwater in boilers to produce steam at a specific temperature and pressure. However, the combustion of fossil fuels inevitably produces significant amounts of air pollutants, such as sulfur dioxide, sulfur trioxide, nitrogen oxides, and carbon dioxide, contributing to air pollution and greenhouse gas emissions.

[0003] Unlike fossil fuels, wind and solar energy are renewable and environmentally friendly resources. Therefore, in industrial heating scenarios, wind-solar-storage steam generation systems can be constructed, using electricity generated by wind and solar power as an energy source to heat feedwater and produce steam, providing the steam needed for industry. However, wind and solar energy suffer from intermittency and volatility, resulting in significant fluctuations in the power supply from wind and solar power plants. To stabilize the power supply, molten salt energy storage systems are added to the system. The National Development and Reform Commission and the National Energy Administration issued a "Notice on Relevant Matters Concerning the Orderly Promotion of Green Power Direct Connection Development," which states that the type and installed capacity of new energy power sources should be scientifically determined according to the principle of "source determined by load." In wind-solar-green power direct connection industrial steam generation systems, determining the capacity configuration of wind power, solar power, and energy storage within the system and ensuring a stable power supply to the steam system are urgent problems to be solved.

[0004] Patent CN202310447473.5 discloses a method for determining integrated wind, solar, and energy storage systems in areas with weak power grids. This invention's application scenario differs from the heating scenario described in this invention. Furthermore, patent CN202310447473.5 uses total investment as the optimization objective, considering only the project's investment and construction costs. This invention, however, uses the internal rate of return on equity as the optimization objective, considering the project's investment and construction costs, operating costs, financing-related costs, and end-user costs, making it more aligned with practical engineering needs. Summary of the Invention

[0005] The present invention aims to provide a method for configuring the capacity of a wind, solar, and energy storage steam system, which can determine the configuration capacity of wind power, photovoltaic power, and energy storage in the system, and provide a stable and clean energy source for industrial steam.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution, comprising the following steps: S1: Obtain wind and solar energy resource data and industrial steam demand parameters for the project site; S2: Based on the wind and solar energy resource data and the industrial steam demand parameters, calculate the hourly output of the wind power station, the hourly output of the photovoltaic power station, the steam heat load, and the molten salt thermal power of the molten salt thermal storage system. S3: Based on the molten salt thermal power, the average annual utilization hours of the wind power station, the average annual utilization hours of the photovoltaic power station, and the efficiency of the molten salt electric heater, determine the limits on the maximum installed capacity of wind power and the maximum installed capacity of photovoltaic power. S4: Set the preset minimum thermal storage duration, maximum thermal storage duration, thermal storage time step, wind power installed capacity step, and photovoltaic installed capacity step, and select multiple combinations of thermal storage duration, wind power installed capacity, and photovoltaic installed capacity to be evaluated in sequence according to the restrictions and step. S5: For each of the aforementioned combination schemes, perform the following calculations and evaluations: S5.1: Calculate the maximum and minimum heat storage capacity of the molten salt tank based on the selected heat storage duration and molten salt thermal power. S5.2: Simulate the annual energy balance hourly to determine whether there is an energy surplus or shortage, and determine the amount of wind and solar power curtailment and the amount of grid power supplementation. S5.3: Based on the wind power installed capacity, photovoltaic installed capacity, molten salt electric heater power, thermal storage capacity, steam generation system power, and the mains power supplement of the combined scheme, calculate the project equity internal rate of return of the combined scheme. The calculation takes into account the project's investment and construction costs, operating costs, financing-related costs, and end-user costs. S6: Compare the internal rate of return on project capital for all the aforementioned combination schemes, and output the combination scheme with the highest rate of return as the optimal capacity allocation scheme.

[0007] Preferably, obtaining wind and solar energy resource data in step S1 includes obtaining hourly meteorological parameters of the project location; calculating the hourly output of the wind power station and the photovoltaic power station in step S2 is based on the meteorological parameters, the rated capacity of the wind power station and the photovoltaic power station, the operating characteristic curves, and the power generation efficiency-related parameters.

[0008] Preferably, obtaining the industrial steam demand parameters in step S1 includes obtaining the required industrial steam temperature, pressure, flow rate, and related parameters; calculating the steam heat load in step S2 is based on the enthalpy of the industrial steam, the enthalpy of the feedwater, the industrial steam flow rate, the efficiency of the steam generation system, and the efficiency of the thermal storage system and pipelines; calculating the molten salt thermal power in step S2 is based on the steam heat load and the efficiency of the thermal storage system and pipelines.

[0009] Preferably, the maximum installed capacity limit for wind power in step S3 is calculated based on the molten salt thermal power, the average annual utilization hours of the wind power station, and the efficiency of the molten salt electric heater; the maximum installed capacity limit for photovoltaic power in step S3 is calculated based on the molten salt thermal power, the average annual utilization hours of the photovoltaic power station, and the efficiency of the molten salt electric heater.

[0010] Preferably, in step S4, the range of the thermal storage duration is set to be between the minimum thermal storage duration and the maximum thermal storage duration, and increases in increments of the thermal storage time; the range of the wind power installed capacity is set to be between zero and the maximum wind power installed capacity, and increases in increments of the wind power installed capacity; the range of the photovoltaic installed capacity is set to be between zero and the maximum photovoltaic installed capacity, and increases in increments of the photovoltaic installed capacity.

[0011] Preferably, the maximum heat storage capacity of the molten salt storage tank in step S5.1 is calculated based on the molten salt thermal power, the selected heat storage duration, and the molten salt amplification factor; the minimum heat storage capacity of the molten salt storage tank in step S5.1 is calculated based on the molten salt amplification factor, the density of hot and cold molten salt, the height of the hot and cold molten salt storage tank, and the dead water level at the bottom of the tank. The range of heat that the molten salt storage tank can store is between the minimum heat storage capacity and the maximum heat storage capacity.

[0012] Preferably, step S5.2, which involves simulating the annual energy balance hourly, includes: Calculate the hourly power generation of wind and solar power plants and convert it into heat after passing through an electric molten salt heater; When the converted heat is greater than the molten salt heat power, the excess energy is sent to the storage tank for storage. If the energy of the storage tank exceeds the maximum heat storage capacity, part of the wind and solar input energy is discarded. When the converted heat is less than the molten salt heat power, energy is released from the storage tank; if the energy of the storage tank is lower than the minimum heat storage capacity, energy is supplemented from the power grid.

[0013] Preferably, when calculating the internal rate of return on equity of the project in step S5.3, the investment and construction costs include the construction costs of the wind power station, photovoltaic power station, molten salt energy storage system, steam generation system and supporting facilities; the operating costs include equipment maintenance, fuel or electricity procurement, and labor costs; the financing-related costs include loan interest; and the terminal costs include the residual value disposal or demolition costs at the end of the project, with the electricity downloaded from the grid being counted as input costs, and wind and solar power curtailment not being counted as revenue.

[0014] Preferably, step S6 outputs the optimal capacity configuration scheme, which includes sorting the internal rate of return on equity of all combined schemes and selecting the scheme with the highest internal rate of return on equity as the final capacity configuration scheme for the wind, solar, energy storage and steam generation system.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention adopts a green electricity direct supply mode, using wind power, photovoltaic and molten salt thermal storage technology to form a complementary system. Wind and solar green electricity provide continuous and stable heat, reducing carbon emissions from the combustion of fossil energy.

[0016] 2. To ensure continuous and stable heating for 24 hours, the system needs to draw power from the grid when energy storage is insufficient. This invention balances the relationship between total project investment, wind and solar power curtailment, and grid power draw. Under the constraints of the project, the internal rate of return on equity is used as the indicator to determine the scale of wind power installation, photovoltaic installation, and thermal storage capacity, so that the scheme has the optimal return throughout the entire project cycle.

[0017] 3. Direct green electricity supply reduces carbon emissions from burning fossil fuels while simultaneously increasing the absorption of new energy sources. This invention can quickly and accurately determine the configuration of wind, solar, energy storage, and steam generation systems, reducing the uncertainty of wind, solar, energy storage, and steam generation engineering projects. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a flow chart of the wind, solar, and energy storage steam system of the present invention. Detailed Implementation

[0019] Example 1: As Figures 1-2 As shown, this invention proposes a method for configuring the capacity of a wind-solar-storage-steam system, used to determine the configuration capacity of wind power, photovoltaic power, and energy storage, providing a stable and clean energy source for industrial steam, including the following steps. Obtain wind and solar energy resource data for the project site, and calculate wind and solar power output; Obtain steam temperature and pressure requirements, and calculate steam heat load and molten salt heat power; Calculate the maximum installed capacity of wind power and solar power; Based on the limitations of thermal storage duration, wind power, and photovoltaic installed capacity, thermal storage duration, wind power, and photovoltaic installed capacity are selected in that order. Calculate the maximum and minimum thermal storage capacity of the molten salt storage tank; calculate the annual energy balance on an hourly basis. Calculate the total investment and internal rate of return on equity for the project; iterate through multiple options and output the option with the highest return on equity.

[0020] The method steps proposed in this invention are as follows: Step 1: Obtain wind and solar energy resource data for the project site and calculate the hourly output of the wind power station. Photovoltaic power stations output power hourly. .

[0021] Step 2: Obtain the required industrial steam parameters and calculate the steam heat load. molten salt thermal power .

[0022] In the formula: For the required industrial steam enthalpy value, For the enthalpy value of the feedwater, For industrial steam flow rate, For the efficiency of the steam generation system, For the efficiency of thermal storage systems and pipelines.

[0023] Step 3: Calculate the maximum installed capacity of wind power based on the thermal power of molten salt and the output of wind and solar power respectively. Maximum installed capacity of photovoltaic power .

[0024] In the formula: This refers to the average annual utilization hours of the wind power station. This refers to the average annual utilization hours of the photovoltaic power station. The efficiency of the molten salt electric heater.

[0025] Step 4: You can set the minimum and maximum thermal storage duration and time step, and the thermal storage time range. Set the time step for wind power and solar power.

[0026] Thermal storage duration limit: Wind power installed capacity limits: Photovoltaic installed capacity limitations: Based on the limitations of thermal storage duration, wind power installed capacity, and photovoltaic installed capacity, and their respective time steps, the thermal storage duration, wind power installed capacity, and photovoltaic installed capacity are determined sequentially.

[0027] Step 5: Based on the heat storage duration The maximum and minimum heat storage capacity of the molten salt storage tank are calculated based on the molten salt thermal power.

[0028] In the formula: The maximum amount of heat that the storage tank can store. The minimum amount of heat that the storage tank can store. Considering the residual molten salt in the pipeline and steam generation system, denoted as the molten salt amplification factor, , These are the densities of hot and cold molten salt, respectively. , The height of the hot and cold molten salt storage tank. This is the dead water level at the bottom of the storage tank.

[0029] The range of heat that the storage tank can store is: Step 6: Calculate the energy balance hourly (1) Calculate the hourly power generation of wind power and photovoltaic power stations. The heat generated per hour after being converted by the molten salt heater .

[0030] (2) When Greater than the thermal power of molten salt At that time, excess energy is stored in the storage tank, and the stored energy is The energy in the storage tank is : 1) If the storage tank has energy Greater than It is necessary to discard some of the energy input from the wind and light. The energy in the storage tank is the maximum energy it can store. ; (3) When Less than the thermal power of molten salt At that time, energy needs to be released from the storage tank, and the released energy is The energy in the storage tank is : 1) If the storage tank has energy Less than It needs to supplement some energy from the power grid. The energy in the storage tank is the minimum energy that can be stored. ; Step 7: Based on the calculated wind power and photovoltaic installed capacity, molten salt electric heater power, thermal storage capacity, and steam generation system power, calculate the static investment and internal rate of return of the project's equity, and download electricity from the grid. Due to investment costs, wind and solar power curtailment is not considered for revenue. In the formula: CFt represents the cash flow in year t, r is the discount rate, and I is the initial investment.

[0031] Step 8: Based on the various schemes in Step 4, repeat steps 4 to 7 until all schemes are calculated. The scheme with the highest internal rate of return on capital is the optimal scheme.

[0032] Example 2: The implementation process of the present invention will be described in detail below through a specific example.

[0033] Step 1: The proposed project site is a certain city. Through resource analysis, the hourly output of wind power and photovoltaic power is calculated. The total annual output of photovoltaic power is 1607.54h, and the total annual output of wind power is 3297.09h.

[0034] Step 2: The required steam flow rate is set at 9 t / h, steam temperature at 320℃, steam pressure at 8 MPa, and feedwater temperature at 60℃; binary molten salt is used, with a maximum design temperature of 560℃ and a minimum design temperature of 290℃; the efficiency of the steam generation system is 0.98, and the efficiency of the thermal storage system and pipelines is 0.99. Calculations show: Step 3: If the efficiency of the molten salt electric heater is set at 0.95, then the maximum installed capacity of the wind power plant can be determined. Maximum installed capacity of photovoltaic power They are respectively: Step 4: The minimum and maximum values ​​can be set according to the project. In this calculation case, the minimum and maximum thermal storage durations are set to 10h and 20h, respectively. Therefore, the limitations on thermal storage duration, wind power, and photovoltaic power are as follows: Thermal storage duration limit: Wind power installed capacity limits: Photovoltaic installed capacity limitations: The thermal storage time, wind power and photovoltaic limitations, and step size settings can be adjusted according to actual conditions. Since this is only a calculation example, to reduce the number of project options, the thermal storage time step is set to 2 hours. There are a total of 6 thermal storage durations; the wind power time step is 5MW, and the minimum installed capacity for wind power is 5MW. There are a total of four wind power installed capacities; the photovoltaic time step is 5MW, and the minimum photovoltaic installed capacity is 10MW. There are a total of 7 photovoltaic (PV) installed capacities. Therefore, there are 6 × 4 × 7 = 168 different schemes, as shown in Table 1 below. Scheme 1 represents a PV installed capacity of 10 MWp, a wind power installed capacity of 5 MW, and a thermal storage duration of 10 h; Scheme 168 represents a PV installed capacity of 39 MWp, a wind power installed capacity of 19 MW, and a thermal storage duration of 20 h.

[0035] Table 1 Calculation Scheme Step 5: Begin calculations starting with Scheme 1. Scheme 1 has a thermal storage duration of 10 hours, a photovoltaic installed capacity of 10 MWp, and a wind power installed capacity of 5 MW. Calculate the maximum and minimum heat capacity stored in the molten salt tank based on the 10-hour thermal storage duration. Molten salt amplification factor. The dead water level at the bottom of the storage tank is .

[0036] The range of heat that the storage tank can store is: Step 6: Calculate the energy balance of Scheme 1 hourly. Based on hourly calculations over 8760 hours throughout the year, the annual power generation from wind and solar power under Option 1 is 32560.86 MWh. To maintain a stable 24-hour heating supply, electricity needs to be drawn from the grid. The amount of power wasted by the system was 29401.40 MWh. It is 0.

[0037] Step 7: Based on the energy storage, wind power, and photovoltaic installations in Scheme 1, calculate the static investment and internal rate of return (IRR) of Scheme 1. The calculation shows that Scheme 1 requires... Total investment: Internal rate of return on equity: -12.02% Step 8: Based on the various schemes in Step 4, calculate schemes 2 to 168 sequentially, iterating through steps 4 to 7 until all schemes are calculated. The scheme with the highest internal rate of return (IRR) is the optimal scheme. The results after calculation are shown in Table 2 below. Scheme 1 (10MWp photovoltaic capacity, 5MW wind power capacity, and 10h thermal storage duration) has an IRR of -12.02%; Scheme 168 (39MWp photovoltaic capacity, 29MW wind power capacity, and 20h thermal storage duration) has an IRR of 1.75%.

[0038] Table 2 Calculation Results Note: In engineering projects, the internal rate of return (IRR) reflects the maximum rate of return that the project investment can achieve during normal operation. The higher the IRR, the greater the project's profitability. Generally, an IRR below 6% is considered infeasible, while an IRR above 6% is considered feasible.

[0039] Table 2 shows that Scheme 81, with a thermal storage duration of 14 hours, a photovoltaic capacity of 25 MWp, and a wind power capacity of 10 MW, has the highest internal rate of return on equity. Therefore, under the input boundary conditions, the optimal scheme is determined to be a thermal storage duration of 14 hours, a photovoltaic capacity of 25 MWp, and a wind power capacity of 10 MW.

Claims

1. A method for capacity configuration of a wind-solar-thermal storage-steam system, comprising: S1: obtaining wind and solar energy resource data and industrial steam demand parameters of a project site; S2: calculating wind power station hourly output, photovoltaic power station hourly output, steam heat load, and molten salt heat power of a molten salt thermal storage system according to the wind and solar energy resource data and the industrial steam demand parameters; S3: determining wind power maximum installed capacity and photovoltaic maximum installed capacity limits according to the molten salt heat power, wind power station annual average utilization hours, photovoltaic power station annual average utilization hours, and molten salt electric heater efficiency; S4: setting a preset minimum thermal storage time length, a preset maximum thermal storage time length, a preset thermal storage time step, a preset wind power installed capacity step, and a preset photovoltaic installed capacity step, and sequentially selecting a plurality of combinations of thermal storage time length, wind power installed capacity, and photovoltaic installed capacity to be evaluated according to the limits and steps; and S5: for each combination, performing the following calculations and evaluations: S5.1: calculating maximum and minimum molten salt storage capacities according to the selected thermal storage time length and molten salt heat power; S5.2: simulating annual energy balance hour by hour to determine energy surplus or deficit, and determine the amount of abandoned wind and solar energy and the amount of grid power supplement; S5.3: calculating the project capital internal rate of return of the combination according to the wind power installed capacity, photovoltaic installed capacity, molten salt electric heater power, storage capacity, steam generation system power, and grid power supplement of the combination, wherein the calculation takes into account the investment and construction cost, operation period cost, financing related cost, and terminal cost of the project; and S6: comparing the project capital internal rate of return of all combinations, and outputting the combination with the highest return rate as the optimal capacity configuration scheme. In the step S1, the wind and solar energy resource data are obtained by obtaining meteorological parameters hour by hour; and in the step S2, the wind power station hourly output and the photovoltaic power station hourly output are calculated according to the meteorological parameters, rated capacity, operating characteristic curve, and power generation efficiency related parameters of the wind power station and the photovoltaic power station. In the step S1, the industrial steam demand parameters are obtained by obtaining required industrial steam temperature, pressure, flow rate, and related parameters; in the step S2, the steam heat load is calculated according to the enthalpy of the industrial steam, enthalpy of the feed water, industrial steam flow rate, steam generation system efficiency, and efficiency of the thermal storage system and pipeline; and in the step S2, the molten salt heat power is calculated according to the steam heat load and efficiency of the thermal storage system and pipeline. In the step S3, the wind power maximum installed capacity limit is calculated according to the molten salt heat power, wind power station annual average utilization hours, and molten salt electric heater efficiency; and in the step S3, the photovoltaic maximum installed capacity limit is calculated according to the molten salt heat power, photovoltaic power station annual average utilization hours, and molten salt electric heater efficiency. ​ ​ ​ ​ ​ ​ 2. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, characterized in that: ​ 3. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, characterized in that: ​ 4. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, characterized in that: ​ 5. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, wherein, The step S4 sets the heat storage time range between the minimum heat storage time and the maximum heat storage time, and increments by the heat storage time step; sets the wind power installed capacity range between zero and the maximum wind power installed capacity, and increments by the wind power installed capacity step; sets the photovoltaic installed capacity range between zero and the maximum photovoltaic installed capacity, and increments by the photovoltaic installed capacity step.

6. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, wherein, The maximum heat storage capacity of the molten salt storage tank in the step S5.1 is calculated according to the molten salt heat power, the selected heat storage time, and the molten salt amplification coefficient; the minimum heat storage capacity of the molten salt storage tank in the step S5.1 is calculated according to the molten salt amplification coefficient, the density of hot and cold molten salt, the height of the hot and cold molten salt storage tank, and the dead water level at the bottom of the storage tank, and the heat storage range of the molten salt storage tank is between the minimum heat storage capacity and the maximum heat storage capacity.

7. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, wherein, The hourly simulation of annual energy balance in the step S5.2 includes: calculating the hourly power generation of wind power and photovoltaic power stations, and converting it into heat after the electric molten salt heater; when the converted heat is greater than the molten salt heat power, the excess energy is sent to the storage tank for storage, and if the storage tank energy exceeds the maximum heat storage capacity, part of the wind and light input energy is abandoned; when the converted heat is less than the molten salt heat power, release energy from the storage tank, and if the storage tank energy is lower than the minimum heat storage capacity, supplement energy from the power grid. 8.The capacity configuration method of a wind-solar-storage-steam system according to claim 1, wherein, In the step S5.3 of calculating the internal rate of return of the project capital of the combined scheme, the investment construction cost includes the construction cost of wind power stations, photovoltaic power stations, molten salt energy storage systems, steam generation systems, and supporting facilities; the operating cost includes equipment maintenance, fuel or power purchase, labor cost; the financing related cost includes loan interest; the terminal cost includes residual value processing or demolition cost at the end of the project, and the electricity downloaded from the municipal power is calculated as input cost, and the wind and light abandoned electricity is not calculated as income.

9. The capacity configuration method of a wind-solar-storage-steam system according to claim 1, wherein, The step S6 outputs the optimal capacity configuration scheme, including sorting the internal rate of return of capital of all combined schemes, and selecting the scheme with the highest internal rate of return of capital as the final capacity configuration scheme of the wind light storage steam system.

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