Wholesale electricity trading system

Abstract

To provide a wholesale electricity trading system that sets a trading schedule for a next day in advance based on an electricity market price for the next day announced by a wholesale electricity exchange, and always realizes advantageous operation with minimal effort.SOLUTION: In a wholesale electricity trading system 1000 including a control unit (control computer) 1050 connected to an Internet environment (Internet cloud) 3000 via LTE communication or the like, and a server 1010 provided in a cloud and connected to the control unit via the Internet environment, the control unit acquires electricity market price data EPD for a next day announced by the Japan Electric Power Exchange 2000, sets a schedule for purchasing electricity when an electricity market price is lower than a prescribed first reference value PT1 and discharging electricity when the electricity market price is higher than a prescribed second reference value PT2, and charges and stores the purchased electricity in a storage battery 1030. The PT1 and PT2 have a relation of PT1<PT2 or PT1≤PT2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wholesale power trading system for power trading with a Japanese wholesale power exchange or the like.

Background Art

[0002] Due to the liberalization of power, power generation, transmission, and retailing have become independent businesses, and there has been a possibility for operators to earn profits from self-owned power and reduce the cost of supplementing insufficient power.

[0003] For example, the power trading system described in Patent Document 1 relates to a power trading system for obtaining power used in electric vehicles through power trading. A user observes the transaction price that changes every moment on a display screen and determines the operation content. However, the work of continuously observing the display screen is laborious, and it is not easy to always achieve advantageous operation.

[0004] Also, Patent Document 1 relates to the power of one electric vehicle and is difficult to apply to the wholesale power trading of operators with diverse power uses.

[0005]

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to enable an operator to always achieve advantageous operation without the need for the work of observing transaction prices.

Means for Solving the Problems

[0008] The wholesale electricity trading system according to the present invention acquires the electricity market price for the following day announced by the wholesale electricity exchange using an electricity market price acquisition means, calculates first and second reference values ​​from the average value of the electricity market price using a schedule setting means, sets a schedule to purchase electricity and charge the power holding means using a power charging / discharging means when the electricity market price is lower than the first reference value, and discharges from the power holding means using the power charging / discharging means when it is higher than the second reference value, and further sets a schedule to set the operation of the power charging / discharging means using a power charging / discharging final decision means, regardless of the schedule, according to the state of the power holding means and the electricity demand situation, measures electricity demand and its changes using an electricity demand measurement means, and in special situations such as a power outage of the general power supply, restricts the load connected to the power holding means to only specific loads set in advance using a specific load limiting means.

Effects of the Invention

[0009] According to the present invention, a power trading schedule can be easily set based on highly reliable information such as the next day's electricity market price announced by the wholesale power exchange. This eliminates the need to constantly monitor the trading price, which changes moment by moment, and significantly reduces the burden on the user. Furthermore, regardless of the schedule, the operation of the power charging and discharging means can be set by the power charging and discharging final decision means according to the state of the power holding means and the power demand situation. Power demand and its changes can be measured by the power demand measurement means, and in special situations such as power outages of the general power supply, the load connected to the power holding means can be limited to specific loads only by the specific load limiting means. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing one embodiment of the wholesale power trading system and charging / discharging of a storage battery according to the present invention. [Figure 2] Figure 1 is a flowchart showing the scheduling process in the wholesale electricity trading system. [Figure 3] This is a flowchart showing the charge and discharge operations corresponding to the transactions based on the schedule created in Figure 2. [Figure 4] This graph shows the relationship between electricity market prices (announced the previous day) and charging / discharging operations. It clearly illustrates periods of low and high prices. [Figure 5] This graph illustrates battery charging operations that take into account BCP (Business Continuity Plan) measures. It uses an example of electricity market prices where the periods of low and high prices are not clearly defined. [Figure 6] This graph shows the change in electricity market prices over a single day. [Figure 7] Figure 6 is a table showing the electricity bill details for a market-linked electricity contract customer at the electricity market price. [Modes for carrying out the invention]

[0011] Next, an embodiment of the wholesale electricity trading system according to the present invention will be described with reference to the drawings. [Examples]

[0012] As shown in Figure 1, the wholesale electricity trading system 1000 comprises a control unit (control computer) 1050 connected to the internet environment 3000 via LTE communication or the like, and a server 1010 located in the cloud and connected to the control unit 1050 via the internet environment (internet cloud) 3000. The Japan Electric Power Exchange (JEPX) 2000 is connected to the internet environment 3000, and the server 1010 acquires electricity market prices in the market provided by JEPX 2000 and executes electricity transactions. In other words, the server 1010 functions as a means of acquiring electricity market prices.

[0013] The JEPX2000 market includes a "one-day-ahead spot market," a "hourly-ahead market," and a "decentralized green electricity sales market," but this invention focuses particularly on the "one-day-ahead spot market." The one-day-ahead spot market trades electricity for the following day, divided into 48 products in 30-minute units, allowing users to know the next day's electricity market price the day before. This is highly reliable information. Electricity market prices are announced as area prices for each region in Japan: Hokkaido, Tohoku, Tokyo, Chubu, Hokuriku, Kansai, Chugoku, Shikoku, and Kyushu. The data can be obtained in CSV (Conma Separated Value) format (hereinafter referred to as EPD).

[0014] Server 1010 obtains data EPD of the next day's electricity market price in the region where wholesale electricity trading is performed (for example, the region where the wholesale electricity trading system 1000 exists) from JEPX2000, and compares the market prices PP1 to PP48 for 48 products every 30 minutes with a first reference value PT1 and a second reference value PT2.

[0015] When the server 1010 compares the market prices PP1 to PP48 with PT1 and finds that PPi (i = 1 to 48) is lower than PT1, it purchases power and charges the battery 1030 (described later). When PPi (i = 1 to 48) is higher than PT2, it discharges power and sets a schedule (hereinafter referred to as SCH). That is, the server 1010 functions as a schedule setting means. The power discharged here may be used within the business premises or sold to other consumers or the power company.

[0016] For the first reference value PT1, for example, the average value of the power market price of the data EPD may be adopted, or some specific market price may be adopted. The same applies to the second reference value PT2. PT1 and PT2 are in the relationship of PT1 < PT2 or PT1 ≦ PT2.

[0017] The control unit 1050 is connected to a power conditioner 1040, which is a power charge / discharge means, through an interface such as RS485. The purchased power (alternating current) PAI is charged from the power grid 4000 through the charging system 4010 to the power conditioner 1040. The sold power (alternating current) PAO is discharged from the power conditioner 1040 through the discharging system 4020 to the power grid 4000 and delivered to the consumer load. And a power measurement unit 4030 is provided to measure the amounts of the purchased power and the sold power.

[0018] A battery 1030, which is a power holding means, is connected to the power conditioner 1040. The charged power PAI is stored in the battery 1030 as power (direct current) PDI. Also, the discharged power PAO is the power (direct current) PDO discharged from the battery 1030. That is, the power conditioner 1040 has a converter function of converting the alternating current power PAI into the direct current power PDI and an inverter function of converting the direct current power PDO into the alternating current power PAO.

[0019] The control unit 1050 monitors the power charge supplied to the battery 1030 by the power conditioner 1040, thereby allowing the server 1010 to constantly monitor the charge level of the battery 1030 (hereinafter referred to as CH).

[0020] Furthermore, the control unit 1050 is equipped with a demand power measurement unit 1060, which is a means for measuring power demand. The demand power measurement unit 1060 measures the current power demand (hereinafter referred to as DM) and its change (hereinafter referred to as DDM). The server 1010 obtains the power demand DM and change DDM through the control unit 1050. When the power demand DM is low, there is little benefit in discharging from the battery 1030. Also, when power demand decreases rapidly, there is a possibility that power will be supplied in excess to consumers, causing a reverse power flow phenomenon, so discharge should be stopped.

[0021] In other words, server 1010 operates electricity trading while taking into account not only the schedule SCH based on data EPD, but also the battery charge amount CH, power demand DM, and power demand change amount DDM.

[0022] Furthermore, a specific load switching switch 1070 is connected to the control unit 1050, enabling power supply from the battery 1030 to specific loads in a business premises where the wholesale power trading system 1000 is installed. For example, when the general power supply used by a business premises goes out, the battery 1030 needs to be used as an emergency power source. However, in order to carry out operations using only the power of the battery 1030 until power is restored, it is necessary to supply power only to essential specific loads. The server 1010 operates the specific load switching switch 1070 via the control unit 1050 to supply power only to specific loads.

[0023] Furthermore, a solar panel 1090 can also be connected to the power conditioner 1040, and the electricity generated by the solar panel 1090 can be used as charging power PDI and discharging power PAO.

[0024] Server 1010 is connected to the Internet cloud 3000 and can be operated using a general Internet browser from a personal computer. It can also be operated from the screen of smartphone 1020. In addition, software written in languages such as html and Java script is placed in server 1010, and a database for storing data is also placed.

[0025] As shown in FIG. 2, when creating schedule SCH in server 1010, the following processing is executed. Step S201: Obtain the electricity market price data EPD for the next day from JEPX2000. Step S202: Calculate the average values of the market prices PP1 to PP48 of 48 products every 30 minutes in the electricity market price data EPD, and use them as the values of PT1 and PT2, but they can be changed by the administrator. Step S203: Initialize the product number "i" to "1" to compare with the market prices PP1 to PP48 of 48 products. Step S204: Determine whether PP1 <PT1. If PP1 <PT1, proceed to step S205; if PP1 <PT1 is not true, proceed to step S206. Step S205: Enter a charging prompt in the schedule. As a result, charging will be executed for product 1 (electricity in the first time period) in schedule SCH. Step S206: Determine whether PP1> PT2. If PP1> PT2, proceed to step S207; if PP1> PT2 is not true, proceed to step S208. [[ID=!17]] Step S207: Enter a discharging prompt in the schedule. As a result, discharging will be executed for product 1 (electricity in the first time period) in schedule SCH. Step S208: Determine whether the product number i is the final 48. When the process is completed up to the final product, end the process. When i <48, proceed to step S209. Step S209: Increment the product number i by "1" and return to step S204. Subsequently, in steps S204 to S207, the decision processing for i=2 to 48 (steps S204, S206) and prompt processing (S205, S207) are repeated, and the process terminates when a termination decision is made in step S208. Based on the above, it will be clearly specified whether charging or discharging should be performed in the scheduled SCH.

[0026] As shown in Figure 3, the charging and discharging operation process in server 1010 is executed as follows. Step S301: First, determine whether the battery 1030 is below the minimum charge level required for BCP measures. If it is below, proceed to step S302; otherwise, proceed to step S303. Step S302: Charge the power conditioner 1040 with power PAI and return to step S301. That is, charging is performed until the battery 1030 reaches the minimum charge level required for BCP measures. Step S303: Refer to the clock built into server 1010 and proceed to step S304. Step S304: If it is midnight, the scheduled execution start time, start execution and proceed to step S305. If it is before midnight, return to step S303. Step S305: Determine whether a charging prompt is listed in schedule SCH. If it is listed, proceed to step S306; otherwise, proceed to step S308. Step S306: Determine whether the battery 1030 is fully charged or not. If it is fully charged, proceed to step S312; otherwise, proceed to step S307. Step S307: Charge power PAI into power conditioner 1040 and proceed to step S312. Step S308: Determine whether a discharge prompt is listed in the schedule SCH. If it is listed, proceed to step S309; ​​otherwise, proceed to step S312. Step S309: Determine whether the current power demand (DM) is greater than a predetermined value. If it is greater, proceed to step S310; otherwise, proceed to step S312. Step S310: Determine whether the decrease in current electricity demand is less than a predetermined value. If it is less, proceed to step S311; otherwise, proceed to step S312. Step S311: Discharge the power PAO from the power conditioner 1040 and proceed to step S312. Step S312: Refer to the clock built into server 1010 and proceed to step S313. Step S313: Determine whether the end time of the charge / discharge operation has passed 24:00 or later. If it has passed 24:00 or later, terminate the process; otherwise, proceed to step S313. Step S314: Adjust the execution details of schedule SCH to the current time, and return to step S305. As a result, charging and discharging operations are performed based on the schedule SCH, and also flexibly, taking into account the power demand DM, the power demand reduction DDM, and the charge amount CH of the battery 1030, regardless of the schedule SCH. In other words, the server 1010 functions as a final power charging and discharging determination means that sets the operation of the power charging and discharging means according to the state of the power holding means and the power demand situation, regardless of the schedule SCH.

[0027] Figure 4 is a graph showing the status of charge and discharge operations based on the SCH schedule, in relation to the 24-hour change in electricity market prices. On the graph, the charging reference value PT1 and the discharging reference value PT2 are set equally at 8 yen / kWh. Discharging occurs from 0:00 to 7:30 when the market price is higher than this value, charging occurs from 7:30 to 15:00 when the market price is lower than this value, and discharging occurs from 15:00 to 24:00 when the market price is higher than this value. Since server 1010 automatically performs these charging and discharging operations based on the schedule, there is no burden on the operators.

[0028] Figure 5 illustrates a case where, for example, the electricity market price for the next day is higher even during the daytime hours when prices are normally lower, due to a forecast of cloudy or rainy weather in the area of ​​the electricity market. This is because solar power generation in the area is low, resulting in higher demand and higher electricity prices even during the day. Conversely, when there is a clear difference between the low and high prices in the electricity market—that is, when the weather is good and solar power generation is high—electricity prices are lower during the day, allowing for sufficient charging of the battery during that time, thus enabling immediate charging of power for business continuity planning (BCP). The graph in Figure 5 shows the situations in which charge / discharge operations based on the schedule SCH and charge / discharge operations that take into account the charge amount CH of the battery 1030 were performed. On the graph, the market price fell below the baseline value PT1 around 0:30, and charging began. However, during charging, the charge level CH of battery 1030 was lower than the minimum charge level required for BCP measures. Therefore, even though the market price rose above the baseline value PT1 at 12:00, charging continued until 16:30 when the charge level exceeded the minimum charge level required for BCP measures. In other words, the first half of the total charging time was based on the schedule SCH, but the rest was charged to ensure the minimum charge level required for BCP. This kind of flexible charge and discharge operation enables a sound wholesale electricity trading business.

[0029] Figure 6 is a graph of the electricity price for the "one-day advance spot market" on April 26, 2023, as actually published by JEPX2000, and Figure 7 shows an example of how a customer operates in relation to this electricity price.

[0030] As shown in Table 1 of Figure 7, one customer contracted with a power company for a contracted power of 90 kW and used 11,177 kWh of electricity in April 2023. As shown in Table 2 of Figure 7, the electricity bill for April 2023 was 287,611 yen.

[0031] The graph in Figure 6 shows that from 0:00 to 7:00, electricity prices fluctuated between 6 yen / kWh and 15 yen / kWh, then decreased to 0.1 yen / kWh until 14:00, after which they rose to a peak of around 18 yen, and settled at around 12 yen / kWh at 24:00. In other words, there is a clear period when prices decrease, making it easier to plan charging and discharging schedules. In response to these price fluctuations, consumers purchased electricity between 8:00 AM and 2:00 PM to charge their batteries, and discharged the batteries for use within their businesses during the rest of the time. As shown in Table 1, the battery capacity is 20 kW.

[0032] Table 2 shows the basic charge, transmission charge (daytime), transmission charge (nighttime), kW surcharge, electricity charge, and renewable energy surcharge, which are the price breakdown when a general consumer purchases electricity through a market-linked electricity system. The total of 452,927 yen is approximately 63% of the electricity charge of 287,611 yen calculated using a variable price system. Furthermore, assuming a clear price fluctuation trend with distinct charging and discharging timings, as shown in Figure 6, where extremely low and high price periods occur 50% of the time in a month, the electricity consumption reduction effect from battery discharge for electricity users is equivalent to 16%. Multiplying this by the aforementioned 63%, the monthly electricity price reduction effect is 0.16 × 0.63 = 0.1, or approximately 10%. Here, the 16% reduction in electricity consumption is based on the assumption that a typical electricity consumer with the above electricity rates installs a 20kW power conditioner and a 120kWh battery, fully charging it for 6 hours each day for 15 days (1 month), and charging it at a price of approximately 0.1 yen / kWh. Therefore, the cumulative monthly charge amount is 20kW × 6h × 15 days = 1800kWh, which is 16% of the total monthly electricity consumption of 11,177kWh.

[0033] As shown in Figure 6, charging the battery 1030 when electricity prices are low and discharging it when prices are high overturns the conventional idea that batteries do not generate revenue. By charging and discharging the battery 1030, it is possible to effectively reduce electricity consumption and save on electricity costs. Therefore, the battery 1030 is a powerful tool for BCP measures, energy conservation, and electricity cost reduction. As a result, consumers can generate economic benefits similar to those of installing solar power panels, even without installing solar power panels for self-consumption, simply by using a battery. [Industrial applicability]

[0034] Although the above embodiments relate to electricity used in a business establishment, it goes without saying that the present invention can also be applied to power operation for electric vehicles, as described in Patent Document 1. [Explanation of Symbols]

[0035] CH charge amount DM power demand DDM (Delivery Method Module) Change in Electricity Demand EPD Area Price Data PAI AC charging PAI purchased electricity (AC) PAO sold electricity (AC) PDI charging power (DC) PDO discharge power (DC) PP1~PP48 Product Market Price PT1 First Reference Value PT2 Second Reference Value SCH Schedule 1000 Wholesale Electricity Trading System 1010 Server 1020 Smartphone 1030 Battery 1040 Power Conditioner 1050 Control Unit 1060 Demand Power Measurement Unit 1070 Specific Load Selector Switch 1080A~1080N load 1090 Solar Panels 2000 Japan Electric Power Exchange 3000 Internet environment (Internet cloud) 4000 power system 4010 Charging system 4020 Discharge system 4030 Power Measurement Unit

Claims

[Claim 1] Power holding means for holding power, A means of obtaining electricity market prices, which are the electricity market prices for the following day announced by the wholesale electricity exchange, A scheduling means for setting the charging and discharging schedule of electricity based on the aforementioned electricity market price, Based on the aforementioned schedule, the power charging and discharging means purchases power and charges the power holding means during power charging, and discharges power from the power holding means during power discharging, Regardless of the aforementioned schedule, a power charging / discharging final determination means sets the operation of the power charging / discharging means according to the state of the power holding means, power demand, and the amount of change in power demand, A means for measuring electricity demand and its changes, A specific load limiting means that restricts the load connected to the power holding means to only specific loads that have been set in advance, Equipped with, The scheduling means calculates first and second reference values ​​from the average value of the electricity market price, and sets a schedule to purchase and charge electricity when the electricity market price is lower than the first reference value, and to discharge electricity when it is higher than the second reference value. Wholesale electricity trading system.

Images