Method and system for surplus electricity storage and heat supply control based on spot electricity price

Abstract

The application discloses a method and system for surplus power storage and heat supply control based on spot electricity price, and the method comprises the following steps: obtaining spot real-time electricity price, distributed photovoltaic power generation and local load power consumption; determining surplus power according to power generation and load power consumption; constructing a critical electricity price model based on unit product sales price, non-power consumption cost and unit product power consumption to calculate the critical electricity price for starting and stopping the storage; when the surplus power is greater than zero, the real-time electricity price is less than the critical electricity price, the storage device is not full and there is a heat demand, starting the storage device for storage, otherwise stopping; after the storage is converted into target products, selecting a distribution mode according to the location of the heat user: using pipeline transportation in the same factory area, and using vehicle transportation within a limited distance; completing settlement; the application accurately controls the storage economy through the critical electricity price model, and realizes high-value consumption of distributed photovoltaic surplus power and low-cost heat supply in combination with differentiated distribution rules.

Description

Technical Field

[0001] This invention relates to the field of integrated energy service technology, and in particular to a method and system for surplus electricity storage and heat supply control based on spot electricity prices. Background Technology

[0002] With the rapid growth of distributed photovoltaic (PV) installations and the advancement of electricity spot market construction, distributed PV faces two core issues:

[0003] 1. The challenge of surplus power consumption: Under the distributed photovoltaic "self-consumption with surplus power fed into the grid" model, when the local load cannot fully absorb the generated electricity, the surplus power needs to be fed into the grid. However, during periods of high renewable energy generation, the electricity spot market often experiences floor prices (0 yuan / kWh) or even negative prices, resulting in no profit or even losses from feeding surplus power into the grid.

[0004] 2. Limitations of traditional energy consumption methods: Electrochemical energy storage has high investment costs, limited lifespan, and safety hazards, and is not suitable for long-term, large-scale energy storage; Fixed pipeline heating is only suitable for users within the same plant area or nearby, with limited coverage and unable to flexibly meet the needs of users outside the plant area; Existing electric thermal energy storage technologies are mostly based on fixed electricity prices (such as off-peak electricity), lacking deep coupling with electricity spot market price signals, and the calculation method for critical electricity prices is crude, failing to incorporate core parameters such as product enthalpy and actual energy consumption, which does not conform to the accounting logic of real-world projects; Mobile heating technology is mostly used for waste heat recovery, without forming a synergistic mechanism with distributed photovoltaic waste power consumption, and without limiting a reasonable transportation radius, resulting in high operating costs.

[0005] Therefore, there is an urgent need for a method and system for surplus electricity storage and heat control that can accurately calculate critical electricity prices based on spot electricity price signals and achieve differentiated heat distribution, in order to address the shortcomings of the existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and system for surplus electricity storage and heat supply control based on spot electricity prices, aiming to solve the problem of losses incurred by distributed photovoltaic power generation when surplus electricity is fed into the grid during periods of floor price / negative electricity price in the electricity spot market.

[0007] On the one hand, this application provides a method for surplus electricity storage and heat supply control based on spot electricity prices, including the following steps:

[0008] Step 1: Obtain real-time electricity spot market prices, distributed photovoltaic power generation, local load electricity consumption, enthalpy data of target products and room temperature water, and user heat demand data;

[0009] Step 2: Determine the surplus power based on the power generation and local load consumption;

[0010] Step 3: Calculate the critical electricity price for thermal storage start-up and shutdown under the current operating conditions based on the preset critical electricity price model. The critical electricity price model is constructed based at least on the selling price per unit of target product, the non-electricity cost per unit of target product, and the electricity consumption for producing a unit of target product.

[0011] Step 4: When the residual power is greater than zero, the real-time electricity price is less than the critical electricity price, the heat storage device is not at full capacity, and there is a demand for heat, start the heat storage device to consume the residual power for heat storage; otherwise, stop the heat storage device.

[0012] Step 5: After converting the heat storage into the target product, select the delivery method according to the location relationship between the heat-consuming customer and the distributed photovoltaic: heat-consuming customers located in the same set area are transported by pipeline, and heat-consuming customers located outside the set area and whose transportation distance does not exceed the set maximum value are transported by vehicle.

[0013] Step 6: Complete heat supply and settle heat transactions based on user heat metering data. By dynamically comparing real-time electricity prices with critical prices, and combining multiple conditions such as surplus electricity status, heat storage capacity, and heat demand, this invention can precisely control the heat storage device to operate only within economically feasible ranges such as spot floor prices or negative electricity prices, avoiding losses from surplus electricity being fed into the grid. At the same time, it selects pipeline or vehicle delivery based on location differences, effectively reducing heating costs and realizing an economical closed loop of high-value utilization of distributed photovoltaic surplus electricity and clean heating.

[0014] Furthermore, in step 3, the critical electricity price for thermal storage start-up and shutdown under the current operating conditions is calculated based on a preset critical electricity price model. The specific formula is as follows:

[0015] ,

[0016] in, This refers to the critical electricity price for thermal energy storage start-up and shutdown, expressed in yuan / kWh. The unit target product selling price; The total non-electricity cost per unit of the target product. The amount of electricity consumed to produce the target product for a production unit.

[0017] Furthermore, the formula for calculating the electricity consumed by the target product per production unit is as follows:

[0018] ,

[0019] in, η represents the theoretical thermal energy per unit target product; η represents the overall conversion efficiency of the electric thermal storage system; and 3600 represents the equivalent thermal energy coefficient corresponding to 1 kWh of electricity.

[0020] Furthermore, the formula for calculating the theoretical thermal energy per unit target product is as follows:

[0021] ,

[0022] in, The enthalpy value per unit of the target product; 1000 represents the enthalpy of water at room temperature; 1000 is the unit conversion factor.

[0023] Furthermore, the same designated area refers to an area where the heating customer and the distributed photovoltaic are located within the same land parcel boundary or directly adjacent through the property boundary.

[0024] Furthermore, the heat demand includes: heat demand located within the same set area, or heat demand located outside the set area and whose transportation distance does not exceed the set maximum value; heat demand exceeding the set maximum value does not trigger the heat storage start-up.

[0025] Furthermore, the heat storage device is composed of multiple sub-heat storage units connected in parallel, and the sum of the rated power of the multiple sub-heat storage units is equal to 90% to 100% of the predicted maximum peak surplus power of the distributed photovoltaic system.

[0026] Furthermore, after the thermal storage device is shut down, the remaining power is either fed into the grid or abandoned according to grid rules; the critical electricity price is dynamically adjusted according to the project's profit target, or the spot electricity floor price is directly adopted as the critical electricity price.

[0027] On the other hand, this application provides a surplus electricity thermal storage and heating control system based on spot electricity prices, including:

[0028] Distributed photovoltaic units are used to generate electricity and measure the amount of electricity generated and the amount of electricity consumed.

[0029] The electricity spot price acquisition module is used to obtain real-time electricity spot market price data;

[0030] The intelligent control decision module has a built-in critical electricity price calculation algorithm, which is used to output thermal storage start-up and shutdown commands;

[0031] Multi-element electric thermal energy storage device, used to consume surplus electricity and convert electrical energy into thermal energy for storage;

[0032] The heat output and distribution module is used to convert stored heat energy into steam or hot water, and selects pipeline or vehicle delivery according to the location of the heat-consuming customer.

[0033] The user-side management module is used for heat metering, demand response, and billing.

[0034] Furthermore, the multi-element electric thermal storage device is selected from at least one of solid thermal storage devices, molten salt thermal storage devices, thermal storage electric boilers, and heat pump and water thermal storage combined systems.

[0035] The substantial effects of this invention:

[0036] 1. In this invention, a critical electricity price decision model based on spot electricity price signals is established. This model uses the enthalpy difference between the product and room temperature water to calculate theoretical heat energy, uses the electricity-heat energy conversion coefficient and the system's overall conversion efficiency to calculate the unit product's power consumption, and combines the unit product's selling price and non-electricity costs to calculate the critical electricity price for starting and stopping thermal storage. This enables accurate judgment of the economic viability of distributed photovoltaic surplus electricity consumption, solves the problem of consumption loss caused by fixed electricity prices or extensive time-of-use electricity price control in existing technologies, and ensures that the thermal storage device operates only within the economically feasible range such as floor price or negative electricity price, converting low-value surplus electricity into high-value heat energy.

[0037] 2. In this invention, by setting differentiated heating distribution rules, namely, direct pipeline supply to users in the same factory area and delivery to users in different factory areas using dedicated heat energy vehicles with strict limits on transportation distance, the problem of time and space mismatch between distributed photovoltaic surplus electricity consumption and the heating demand of users in different locations is solved, and effective control of transportation costs and heat loss is achieved, ineffective long-distance transportation is avoided, and the economically feasible heating radius is expanded.

[0038] 3. In this invention, by adopting a combination of multiple electric thermal storage devices, including at least one of solid thermal storage, molten salt thermal storage, thermal storage electric boiler, heat pump and water thermal storage system, and flexibly selecting the appropriate type according to the user's requirements for the temperature and scale of steam or hot water, intelligent adaptation to different heat use scenarios is achieved, solving the problem that a single thermal storage technology cannot meet the needs of multiple types of demand such as high-parameter industrial steam and low-temperature domestic hot water. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of Example 1.

[0041] Figure 2 This is a system principle block diagram of Example 2. Detailed Implementation

[0042] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Example 1:

[0044] Reference Figure 1 As shown, a method for surplus electricity storage and heat supply control based on spot electricity prices includes the following steps:

[0045] Step 1: Obtain real-time electricity spot market prices, distributed photovoltaic power generation, local load electricity consumption, enthalpy data of target products and room temperature water, and user heat demand data;

[0046] Step 2: Determine the surplus power based on power generation and local load consumption;

[0047] Step 3: Calculate the critical electricity price for thermal storage start-up and shutdown under the current operating conditions based on the preset critical electricity price model. The critical electricity price model is constructed based at least on the selling price per unit of target product, the non-electricity cost per unit of target product, and the electricity consumption for producing a unit of target product.

[0048] Step 4: When the residual power is greater than zero, the real-time electricity price is less than the critical electricity price, the thermal storage device is not at full capacity, and there is a demand for heat, start the thermal storage device to consume the residual power for heat storage; otherwise, stop the thermal storage device.

[0049] Step 5: After converting the heat storage into the target product, select the delivery method according to the location relationship between the heat customer and the distributed photovoltaic: heat customers located in the same set area are transported by pipeline, and heat customers located outside the set area and whose transportation distance does not exceed the set maximum value are transported by vehicle.

[0050] Step 6: Complete heat supply and settle heat transactions based on user heat metering data. Through a closed-loop cost-benefit control across the entire chain of "surplus electricity, heat storage, heat supply, and settlement," the value of surplus electricity from distributed photovoltaic power generation is maximized, user heat costs are significantly reduced, and the investment payback period for photovoltaic projects is shortened. At the same time, it promotes the consumption of new energy sources, reduces carbon emissions, and achieves significant economic, social, and technological benefits.

[0051] As one implementation method, in step 3, the critical electricity price for thermal storage start-up and shutdown under the current operating conditions is calculated according to a preset critical electricity price model. The specific formula is as follows:

[0052] ,

[0053] in, This refers to the critical electricity price for thermal energy storage start-up and shutdown, expressed in yuan / kWh. The unit price of the target product is yuan / ton; The total non-electricity cost per unit of the target product, including transportation costs, operation and management fees, personnel costs, consumable costs, equipment investment depreciation costs, and tap water intake costs, is expressed in kWh / t. The amount of electricity consumed to produce the target product for a production unit.

[0054] As one implementation method, the formula for calculating the electricity consumed per unit of target product is:

[0055] ,

[0056] in, η represents the theoretical thermal energy per unit target product; η represents the overall conversion efficiency of the electric thermal storage system; and 3600 represents the equivalent thermal energy coefficient corresponding to 1 kWh of electricity.

[0057] As one implementation method, the formula for calculating the theoretical thermal energy per unit of target product is as follows (for calculating the theoretical thermal energy of 1 t of hot water):

[0058] ,

[0059] in, The theoretical thermal energy per unit target product. The enthalpy value is the unit of the target product, expressed in kJ / kg. The value is the enthalpy of water at room temperature, expressed in kJ / kg; 1000 is the unit conversion factor.

[0060] As one implementation method, the same designated area refers to the area where the heat customer and the distributed photovoltaic are located within the same land parcel boundary or directly adjacent through the property boundary; the maximum value is set at 10 kilometers.

[0061] As one implementation method, the heat demand includes: heat demand located within the same set area, or heat demand located outside the set area and whose transportation distance does not exceed the set maximum value; heat demand exceeding the set maximum value does not trigger the heat storage start-up.

[0062] In one implementation, the thermal storage device consists of at least two sub-thermal storage units with the same rated power connected in parallel, and the sum of the rated power of each sub-thermal storage unit is equal to 90% to 100% of the predicted maximum peak surplus power of the distributed photovoltaic system.

[0063] As one implementation method, after the thermal storage device is shut down, the remaining power is fed into the grid or abandoned according to the grid rules; the critical electricity price is dynamically adjusted according to the project's profit target, or the spot electricity floor price is directly adopted as the critical electricity price.

[0064] Example 2:

[0065] Reference Figure 2 As shown, this embodiment is basically the same as embodiment 1, except that it provides a surplus electricity storage and heating control system based on spot electricity prices, including:

[0066] Distributed photovoltaic units are used to generate electricity and measure the amount of electricity generated and the amount of electricity consumed.

[0067] The electricity spot price acquisition module is used to obtain real-time electricity spot market price data;

[0068] The intelligent control decision module has a built-in critical electricity price calculation algorithm, which is used to output thermal storage start-up and shutdown commands;

[0069] Multi-element electric thermal energy storage device, used to consume surplus electricity and convert electrical energy into thermal energy for storage;

[0070] The heat output and distribution module is used to convert stored heat energy into steam or hot water, and selects pipeline or vehicle delivery according to the location of the heat user, with a maximum transportation distance of 10 kilometers for vehicle delivery.

[0071] The user-side management module is used for heat metering, demand response, and billing.

[0072] As one implementation method, the multi-element electric thermal storage device is a combination of solid thermal storage device, molten salt thermal storage device, thermal storage electric boiler, heat pump and water thermal storage; in the heat energy output and distribution module, when the transportation distance of the vehicle exceeds 15 kilometers, it is not included in the dispatch range.

[0073] Example 3: 10MW Distributed Photovoltaic Power Generation in Industrial Park + Solid Thermal Storage + Piped / Vehicle-Mounted Steam Heating

[0074] This embodiment is based on the method described in Embodiment 1 and applied to an industrial park scenario. It includes:

[0075] Basic operating conditions:

[0076] Distributed photovoltaic capacity: 10MWp;

[0077] Stable local load at the plant: 5MW;

[0078] Peak power generation of photovoltaic power at noon: 10MW;

[0079] Peak surplus power: 10MW - 5MW = 5MW;

[0080] Surrounding heating customers: 2 industrial steam users in the same factory area and 5 industrial users in other factory areas (transportation distance controlled within 10km);

[0081] Required medium: 1.0MPa saturated industrial steam.

[0082] System Configuration:

[0083] Solid-state electric thermal energy storage device: equipped with two sets of 2.5MW rated power (in parallel), thermal energy storage temperature of 300℃, and effective thermal energy storage capacity of 8MWh;

[0084] Steam generator: matched with 5MW thermal storage output, rated steam production capacity of 10t / h;

[0085] Delivery method: Direct heat pipeline for users within the same factory area; dedicated steam transport vehicles (3 vehicles, each with a capacity of 5t) for users outside the factory area, with a transportation radius of ≤10km.

[0086] Parameter assignment:

[0087] Price of 1 t 1.0MPa saturated steam (unit target product price) =240 yuan / t;

[0088] Non-electric comprehensive cost per ton of steam (total non-electric cost per unit of target product) =85 yuan / t (including transportation, equipment depreciation, labor, water treatment, consumables, etc., calculated based on a 2-year payback period);

[0089] The comprehensive cost of steam production and operation (excluding depreciation) is Cproduction = 128.5 yuan / ton.

[0090] 1.0 MPa saturated steam enthalpy (enthalpy per unit of target product) = 2777.7 KJ / kg;

[0091] Enthalpy of water at 20℃ (enthalpy of water at room temperature per unit) = 83.96 kJ / kg;

[0092] The overall system efficiency η = 0.95;

[0093] The electrical energy to heat energy conversion factor is 3600 kJ / kWh.

[0094] Calculation process:

[0095] 1) Theoretical thermal energy: =(2777.7-83.96)×1000=2693740KJ / t.

[0096] 2) Power consumption: =2693740 / (0.95×3600)≈787.64kWh / t.

[0097] 3) Critical electricity price: =(240-85) / 787.64≈0.1968 yuan / kWh.

[0098] Running result:

[0099] The average daily effective operation period during the low-price period for spot trading is 4 hours.

[0100] Daily full-load thermal energy consumption: 5MW × 4h = 20,000kWh;

[0101] Daily steam production: 20000 / 787.64≈25.39t;

[0102] Distribution: 8 tons supplied via pipeline within the same plant area, and 17.39 tons supplied via truck to external plants;

[0103] Daily earnings: 25.39 × (240 - 128.5) ≈ 2830.99 yuan;

[0104] Total equipment investment: 5 million yuan;

[0105] Annual return (300 days): approximately RMB 849,300, with an investment payback period of approximately 5.89 years.

[0106] Example 4: 5MW Distributed Photovoltaic Power Generation + Heat Pump + Water Storage + Domestic Hot Water Heating System in a Commercial Park

[0107] This embodiment is based on the method described in Embodiment 1 and applied to a commercial park scenario. It includes:

[0108] Basic operating conditions:

[0109] Photovoltaic installed capacity: 5MWp;

[0110] Local load of the industrial park: 2MW;

[0111] Peak surplus power: 5MW - 2MW = 3MW;

[0112] Required medium: 55℃ domestic hot water;

[0113] Heating customers: Hotels and apartments within the park (directly supplied by pipelines within the same plant area), and 3 surrounding residential communities (transportation distance ≤ 10km, hot water delivered by truck).

[0114] System Configuration:

[0115] Multi-electrode electric thermal storage device: 3 sets of 1MW air source heat pumps + water thermal storage system, thermal storage temperature 90℃, total effective thermal storage capacity 15MWh;

[0116] Hot water exchanger: Output temperature 50-60℃, rated water supply 20t / h;

[0117] Delivery method: Direct supply through pipelines within the same factory area; or dedicated hot water transport vehicles (4 vehicles, each with a capacity of 10t) outside the factory area, with a transportation radius of ≤10km.

[0118] Parameter assignment:

[0119] Price of 1 ton of 55℃ domestic hot water (unit target product price) =35 yuan / t;

[0120] Non-electric comprehensive cost per ton of hot water (total non-electric cost per unit of target product) =28 yuan / t (including equipment depreciation, transportation, labor, tap water, etc., excluding electricity costs);

[0121] The production and operating cost per ton of hot water (excluding depreciation) is Cproduction = 13.5 yuan / ton.

[0122] Enthalpy of hot water at 55℃ (enthalpy of target product per unit) =230.29 kJ / kg;

[0123] Enthalpy of water at 20℃ (enthalpy of water at room temperature per unit) = 83.96 kJ / kg;

[0124] System overall performance coefficient (average annual energy efficiency ratio of heat pump)

[0125] η=2.5;

[0126] The electrical energy to heat energy conversion factor is 3600 kJ / kWh.

[0127] Calculation process:

[0128] 1) Theoretical thermal energy: =(230.29-83.96)×1000=146330KJ / t.

[0129] 2) Power consumption: =146330 / (2.5×3600)≈16.26kWh / t.

[0130] 3) Critical electricity price: =(35-28) / 16.26≈0.43 yuan / kWh.

[0131] Running result:

[0132] During periods of low spot prices, the system operates effectively for an average of 4 hours per day, with an average output coefficient of 0.75.

[0133] Daily thermal energy consumption: 3MW × 4h × 0.75 = 9,000kWh;

[0134] Daily hot water supply: 9,000 / 16.26≈553.5t;

[0135] Distribution: 153.5 tons supplied via pipeline within the same plant area, and 400 tons supplied via truck to external plants area;

[0136] Daily earnings: 553.5 × (35 - 13.5) ≈ 11,900.25 yuan;

[0137] Total equipment investment: 5.2 million yuan;

[0138] Annual return (300 days): approximately 3.57 million yuan, with an investment payback period of approximately 1.46 years.

[0139] It should be noted that while the preferred embodiments of the present invention are provided in the specification and accompanying drawings, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of the present invention; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of the present invention. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of the present invention specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for surplus electricity storage and heat supply control based on spot electricity prices, characterized in that, Includes the following steps: Step 1: Obtain real-time electricity spot market prices, distributed photovoltaic power generation, local load electricity consumption, enthalpy data of target products and room temperature water, and user heat demand data; Step 2: Determine the surplus power based on the power generation and local load consumption; Step 3: Calculate the critical electricity price for thermal storage start-up and shutdown under the current operating conditions based on the preset critical electricity price model. The critical electricity price model is constructed based at least on the selling price per unit of target product, the non-electricity cost per unit of target product, and the electricity consumption for producing a unit of target product. Step 4: When the residual power is greater than zero, the real-time electricity price is less than the critical electricity price, the heat storage device is not at full capacity, and there is a demand for heat, start the heat storage device to consume the residual power for heat storage; otherwise, stop the heat storage device. Step 5: After converting the heat storage into the target product, select the delivery method according to the location relationship between the heat-consuming customer and the distributed photovoltaic: heat-consuming customers located in the same set area are transported by pipeline, and heat-consuming customers located outside the set area and whose transportation distance does not exceed the set maximum value are transported by vehicle. Step 6: Complete the heat supply and complete the heat transaction settlement based on the user's heat metering data.

2. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 1, characterized in that, In step 3, the critical electricity price for thermal storage start-up and shutdown under the current operating conditions is calculated based on a preset critical electricity price model. The specific formula is as follows: ， in, This refers to the critical electricity price for thermal energy storage start-up and shutdown, expressed in yuan / kWh. The unit target product selling price; The total non-electricity cost per unit of the target product. The amount of electricity consumed to produce the target product for a production unit.

3. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 2, characterized in that, The formula for calculating the electricity consumed by the target product of the production unit is as follows: ， in, η represents the theoretical thermal energy per unit target product; η represents the overall conversion efficiency of the electric thermal storage system; and 3600 represents the equivalent thermal energy coefficient corresponding to 1 kWh of electricity.

4. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 3, characterized in that, The formula for calculating the theoretical thermal energy per unit target product is as follows: ， in, The enthalpy value per unit of the target product; 1000 represents the enthalpy of water at room temperature; 1000 is the unit conversion factor.

5. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 1, characterized in that, The same designated area refers to the area where the heating customer and the distributed photovoltaic are located within the same land parcel boundary or directly adjacent through the property boundary.

6. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 1, characterized in that, The heat demand includes: heat demand located within the same set area, or heat demand located outside the set area and whose transportation distance does not exceed the set maximum value; heat demand exceeding the set maximum value will not trigger the heat storage start-up.

7. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 1, characterized in that, The heat storage device consists of multiple sub-heat storage units connected in parallel, and the sum of the rated power of the multiple sub-heat storage units is equal to 90% to 100% of the predicted maximum peak surplus power of the distributed photovoltaic system.

8. The method for surplus electricity storage and heat supply control based on spot electricity prices according to claim 1, characterized in that, After the thermal storage device is shut down, the remaining power is either fed into the grid or abandoned according to the grid rules; the critical electricity price is dynamically adjusted according to the project's profit target, or the spot electricity floor price is directly adopted as the critical electricity price.

9. A control system for surplus electricity storage and heat supply based on spot electricity prices, used to implement the control method as described in any one of claims 1-8, characterized in that, include: Distributed photovoltaic units are used to generate electricity and measure the amount of electricity generated and the amount of electricity consumed. The electricity spot price acquisition module is used to obtain real-time electricity spot market price data; The intelligent control decision module has a built-in critical electricity price calculation algorithm, which is used to output thermal storage start-up and shutdown commands; Multi-element electric thermal energy storage device, used to consume surplus electricity and convert electrical energy into thermal energy for storage; The heat output and distribution module is used to convert stored heat energy into steam or hot water, and selects pipeline or vehicle delivery according to the location of the heat-consuming customer. The user-side management module is used for heat metering, demand response, and billing.

10. The surplus electricity storage and heat supply control system based on spot electricity prices according to claim 9, characterized in that, The multi-element electric thermal storage device is selected from at least one of solid thermal storage devices, molten salt thermal storage devices, thermal storage electric boilers, and heat pump and water thermal storage combined systems.

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