A method and device for constructing a flexibility package based on energy storage rights

Abstract

The present invention discloses a method and device for constructing a flexibility package based on energy storage rights, which belongs to the field of electric power engineering technology. The method includes: S1: collecting technical parameters of energy storage devices to determine the energy storage capacity of their physical energy storage rights, and dividing the energy storage capacity into several capacity blocks; S2: dividing the capacity rights of the physical energy storage rights into energy capacity rights, power capacity rights and ramping capacity rights; S3: determining the number of capacity blocks according to user needs, and constructing a flexibility package corresponding to the user needs in combination with the energy capacity rights, the power capacity rights, the ramping capacity rights, the initial purchase capacity and the final selling capacity. The present application proposes a flexibility package as a trading product, including energy\power\ramp capacity rights and stored energy sale\recovery. The trading product can cover the characteristics of flexibility and provide a basis for flexibility trading.

Description

Technical Field

[0001] The present invention belongs to the field of electrical engineering technology, and more specifically, relates to a method and device for constructing a flexibility package based on energy storage rights. Background Art

[0002] Renewable energy is widely regarded as the main energy source of the future. Renewable energy has great intermittency, volatility and uncertainty, which brings severe challenges to the safe operation of the power grid. It has become an industry consensus to use energy storage systems to smooth fluctuations and optimize the economic operation of the power grid. As a high-quality flexibility resource, energy storage can be profited by participating in flexibility transactions and participating in auxiliary markets. In recent years, the shared use of energy storage has gradually become a new research hotspot. Energy storage sharing not only helps to improve its own project yield, but also promotes the consumption of new energy electricity from renewable energy power stations and improves power supply security. Therefore, it is of great significance to explore the flexibility transaction varieties between energy storage power stations and energy storage users, and further solve the problem of shared use of energy storage in the market environment.

[0003] At present, there is a relative lack of flexibility trading of energy storage in the power market environment, and the trading results are greatly affected by the trading products. Existing research has explored some trading products that provide flexibility through energy storage, such as general energy trading, insurance contracts, financial energy storage rights, physical energy storage rights, etc. Among them, physical energy storage rights provide an economical way for demanders to obtain the flexibility of energy storage. Traditional physical energy storage rights are auctioned to different entities for their own applications, so it is expected to fully realize the comprehensive value of energy storage. Physical energy storage rights generally include two aspects, namely capacity rights and stored energy. In the concept of capacity rights, energy storage power stations divide their capacity into several capacity blocks for sale, and demanders purchase the capacity blocks they need. When demanders order capacity blocks, they hold the corresponding capacity rights and can use them for their own needs. In the concept of stored energy, demanders can inject energy into or extract energy from energy storage power stations, similar to bank deposits and withdrawals.

[0004] Through physical energy storage rights, demanders do not have to install energy storage themselves, but can dynamically adjust their order quantity according to actual demand. By indirectly participating in different applications of the power system, energy storage power stations can improve their own utilization and further realize their value. However, for flexibility trading, there are still several areas where physical energy storage rights can be improved: 1) Capacity rights and stored energy cannot fully describe the characteristics of flexibility; 2) In particular, capacity rights in existing research mainly refer to power capacity; 3) The call for renewable energy and the behavior of energy storage itself cannot be clearly distinguished. Therefore, if a flexibility trading product suitable for energy storage power stations and demanders can be proposed, flexibility trading can be promoted and the income of energy storage power stations can be increased. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a method and device for constructing a flexibility package based on energy storage rights, which aims to construct a flexible package using energy\power\ramp capacity rights, stored energy sales and stored energy recovery information, thereby solving the technical problems of single data information and poor flexibility of energy storage resources during the transaction process.

[0006] To achieve the above objective, according to one aspect of the present invention, a method for constructing a flexibility package based on energy storage rights is provided, comprising:

[0007] S1: collecting technical parameters of the energy storage device to determine the energy storage capacity of its physical energy storage right, and dividing the energy storage capacity into a number of capacity blocks;

[0008] S2: The capacity right of the physical energy storage right is divided into energy capacity right, power capacity right and climbing capacity right; the energy capacity right is the right of the energy storage user to use energy storage for charging or discharging in a continuous time period, the power capacity right is the right of the energy storage user to use energy storage for charging or discharging in a specific period of time, and the climbing capacity right is the right of the energy storage user to use energy storage flexibility to meet its own climbing or landslide needs in a specific period of time;

[0009] S3: Determine the number of the capacity blocks according to user demand, and construct a flexibility package corresponding to the user demand in combination with the energy capacity right, the power capacity right, the ramp capacity right, the initial purchase capacity and the final sale capacity.

[0010] In one embodiment, the technical parameters in S1 include:

[0011] Energy storage device power limit Energy storage device power limit Energy storage device power capacity Maximum up and down climbing rate of energy storage device Energy storage device charging efficiency η c and the energy storage device discharge efficiency η d .

[0012] In one embodiment, the flexibility package in S3 is:

[0013]

[0014] in, and They are the energy capacity right, power capacity right and ramp capacity right ordered by demander i in time period t respectively; and Represent the initial purchase energy and final sold energy of demander i respectively; the initial purchase energy of the flexibility package is the initial energy when purchased from the energy storage plant, and the final remaining energy of the flexibility package For selling to the energy storage plant, the flexibility package operates under the decoupled capacity rights and restrictions.

[0015] In one embodiment, the constraint model of the energy capacity weight is:

[0016]

[0017]

[0018]

[0019] Wherein, the subscripts i and t represent the user number and time period number respectively; Energy capacity reserved for energy storage plants that can be used for energy arbitrage, and are the initial, maximum and minimum energies of the energy storage power station respectively; and The initial energy and final energy reserved for the energy storage power station that can be used for energy arbitrage.

[0020] In one embodiment, the constraint model of energy arbitrage is:

[0021] Constraints on power state transfer between adjacent time periods:

[0022] Power Constraints:

[0023] The power constraints at the beginning and end of the period are:

[0024] Energy arbitrage charging and discharging power constraints:

[0025] in, and are the energy stored in period t+1 and period t in energy arbitrage, is the charging power in period t in the arbitrage plan; is the discharge power of period t in the arbitrage plan; T is the period length; I ea,t Indicates the charging and discharging status during the arbitrage process, 1 represents charging and 0 represents discharging.

[0026] In one embodiment, the constraint model of the power capacity right is used to identify the power allocation of the energy storage power station between energy arbitrage and power capacity right trading, and the expression is:

[0027]

[0028] in, The power capacity reserved for energy arbitrage by the energy storage power station during period t; is the power capacity of the energy storage power station.

[0029] In one embodiment, the constraint model of the ramp capacity right identifies the ramp allocation of the energy storage power station between energy arbitrage and ramp capacity right trading, and the expression is:

[0030]

[0031] in, The ramp capacity reserved for energy arbitrage by the energy storage power station during period t, is the ramp capacity of the energy storage power station.

[0032] According to another aspect of the present invention, a device for constructing a flexibility package based on energy storage rights is provided, comprising:

[0033] A collection module, used for collecting technical parameters of the energy storage device to determine the energy storage capacity of its physical energy storage right, and dividing the energy storage capacity into a plurality of capacity blocks;

[0034] A division module is used to divide the capacity right of the physical energy storage right into energy capacity right, power capacity right and climbing capacity right; the energy capacity right is the right of the energy storage user to use energy storage for charging or discharging in a continuous time period, the power capacity right is the right of the energy storage user to use energy storage for charging or discharging in a specific period of time, and the climbing capacity right is the right of the energy storage user to use energy storage flexibility to meet its own climbing or landslide needs in a specific period of time;

[0035] A construction module is used to determine the number of the capacity blocks according to user needs, and to construct a flexibility package corresponding to the user needs in combination with the energy capacity right, the power capacity right, the ramp capacity right, the initial purchase capacity and the final sale capacity.

[0036] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0037] 1. A flexibility package is proposed as a trading product, which consists of energy, power, ramp capacity rights and stored energy sale and recovery. The trading product can cover the characteristics of flexibility and provide a basis for flexibility trading.

[0038] 2. Energy storage users can customize the composition of flexibility packages according to their own needs, increase the willingness of energy storage power stations and energy storage users to participate in flexibility trading, promote flexibility trading, and increase the income of energy storage power stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A flow chart of a method for constructing a flexibility package based on energy storage rights provided in one embodiment of the present invention;

[0040] Figure 2 A schematic diagram of a flexibility package provided in accordance with an embodiment of the present invention;

[0041] Figure 3a A schematic diagram of real-time calling of power capacity rights in a flexibility package provided by an embodiment of the present invention;

[0042] Figure 3b A schematic diagram of real-time calling of energy capacity rights in a flexibility package provided by an embodiment of the present invention;

[0043] Figure 3c A schematic diagram of real-time calling of ramp capacity rights in a flexibility package provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] Consider a 40MW / 80MWh energy storage power station and three 80MW renewable energy power stations as energy storage users in flexibility trading. For the energy storage power station, the ramp capacity is assumed to be infinite, and the charging and discharging efficiency is set to 95%. The minimum SoC is 20% and the initial SoC is 60%. The simulation analysis of 24 time periods before the day is carried out with a time interval of 1h, that is, T=24. It is set that the amount of energy storage is maintained at a certain value after each trading cycle. The charging efficiency of energy storage is 0.9 and the discharging efficiency is 1.

[0046] As attached Figure 1 As shown, the main steps of this example include:

[0047] Step 1: Collect the technical parameters of energy storage components. The energy storage power station divides the energy storage capacity into several capacity blocks.

[0048] In order to formulate a reasonable flexibility sales plan, the energy storage power station needs to collect the technical parameters of the energy storage device, including:

[0049] 1) Upper limit of energy storage device capacity Lower limit

[0050] 2) Power capacity of energy storage device

[0051] 3) Maximum up and down climbing rate of energy storage device

[0052] 4) Charging efficiency of energy storage device η c , discharge efficiency η d ;

[0053] Traditional physical energy storage rights generally include two aspects, namely capacity rights and stored energy. In the concept of capacity rights, energy storage power stations divide their capacity into several capacity blocks for sale, and demanders purchase the capacity blocks they need. When demanders order capacity blocks, they hold the corresponding capacity rights and can use them for their own needs. Therefore, based on the collected technical parameters of energy storage components, energy storage power stations divide their capacity into several capacity blocks for sale.

[0054] It should be noted that in the present invention, the energy storage power station owns the energy storage, and the energy storage user owns the energy storage use right. If the user does not own the energy storage, the energy storage use right can be obtained through market transactions, etc., and the energy storage can be shared to achieve the optimal utilization of energy storage resources.

[0055] Step 2: Divide the capacity rights into energy capacity rights, power capacity rights and ramp capacity rights.

[0056] In order to promote flexible transactions between energy storage power stations and users, on the one hand, it is necessary to maximize the interests of energy storage investors, thereby promoting their cost recovery and creating conditions for the large-scale development of energy storage; on the other hand, it is necessary to provide an economical way for demanders to obtain energy storage flexibility and stimulate the trading willingness of energy storage users.

[0057] In order to meet the differentiated demands of different users for energy storage resources and fully reflect the flexibility characteristics, the present invention divides the capacity right into energy capacity right, power capacity right and climbing capacity right according to the three indicators describing flexibility, namely energy, power and climbing.

[0058] Energy capacity rights refer to the right of energy storage users to use energy storage for charging or discharging within a certain continuous period of time. The charging and discharging power can be flexibly determined by the energy storage user according to the usage. By exercising energy capacity rights, users can flexibly respond to a series of problems such as power imbalance and power quality caused by the random volatility of new energy, and profit from ancillary services.

[0059] Power capacity rights refer to the rights of energy storage users to use energy storage for charging or discharging during a specific period of time, and the charging and discharging power is fixed. Power rights can be further subdivided into charging power rights and discharging power rights according to the charging and discharging status. By exercising power rights, energy storage users can achieve peak-valley arbitrage.

[0060] The ramp capacity right refers to the right of energy storage users to use energy storage flexibility to meet their own ramping or landslide needs during a specific period of time. By exercising the ramp right, energy storage users can make real-time adjustments to deal with the net load fluctuations that may occur in the next period of time, and play a role in regulating and buffering the penalties or load shedding problems caused by insufficient system ramping capacity.

[0061] Step 3: Propose a flexibility package consisting of energy / power / ramp capacity rights and stored energy sale / recovery, and establish a constraint model for the transaction.

[0062] The flexibility package based on physical energy storage rights is shown in the attached diagram. Figure 2 shown.

[0063] In addition to capacity rights, the flexibility package must also include stored energy content. In traditional physical energy storage rights, stored energy can be expressed as the ability of demanders to inject energy into or extract energy from energy storage power stations, similar to bank deposits and withdrawals. Compared to viewing energy storage power stations as banks, this study views energy storage power stations as sellers and recyclers of energy, where demanders can purchase the required energy from energy storage power stations or sell the remaining energy to them. Based on this, the initial purchase energy and the final sold energy are designed.

[0064] Therefore, a flexibility package consisting of energy capacity rights, power capacity rights, ramp capacity rights, initial purchased energy, and final sold energy is proposed as follows:

[0065]

[0066] in, and They are the energy capacity right, power capacity right and ramp capacity right ordered by demander i in time period t respectively; and They represent the initial purchase energy and final sold energy of demander i respectively;

[0067] From the perspective of the demander, the flexibility package can be regarded as a virtual battery with limited energy / power / ramp capacity and fixed initial / final energy state. However, its energy / power / ramp capacity can change over time, and the initial and final energy states can be different. The flexibility package purchases initial energy from the energy storage power station. The remaining energy Selling capacity rights to energy storage plants, whose operation is decoupled and The flexibility package can be clearly distinguished from the behavior of the energy storage power station itself. The significant advantage of the flexibility package is that the demander can customize the composition of the flexibility package according to their own needs, which will promote flexibility trading.

[0068] Considering the coordination between the flexibility trading of energy storage power stations and their energy arbitrage, the constraint model of energy, power, ramp capacity rights and the constraint model of energy arbitrage will be established. According to the predicted electricity price, the energy storage power station arranges its charging and discharging plan for energy arbitrage. In addition to the flexibility occupied by the arbitrage plan, other flexibility can be allocated to different users to obtain additional profits.

[0069] (3.1) Constraint model of energy capacity weight

[0070]

[0071]

[0072]

[0073] Wherein, the subscripts i and t represent the user number and time period number respectively; c / η d is the charge / discharge efficiency; Energy capacity reserved for energy storage plants that can be used for energy arbitrage; and are the initial, maximum and minimum energies of the energy storage power station respectively; and The initial energy and final energy reserved for the energy storage power station that can be used for energy arbitrage.

[0074] The constraint model of energy capacity rights describes the various constraints of energy storage power stations in the process of energy capacity rights trading and its energy arbitrage coordination. Among them, formula (2) represents the flexibility allocation of energy storage power stations between energy arbitrage and energy capacity rights trading; formulas (3) and (4) represent the energy constraints of the initial and end periods of energy arbitrage and flexibility trading of energy storage power stations.

[0075] (3.2) Constraint model of power capacity weight

[0076]

[0077] in, The power capacity reserved for energy arbitrage by the energy storage power station during period t; is the power capacity of the energy storage power station. Formula (5) is the power allocation of the energy storage power station between energy arbitrage and power capacity rights trading.

[0078] (3.3) Constraint model of ramp capacity right

[0079]

[0080] in, The ramp capacity reserved for energy arbitrage by the energy storage power station during period t, is the ramp capacity of the energy storage power station. Formula (6) is the ramp allocation of the energy storage power station between energy arbitrage and ramp capacity rights trading.

[0081] (3.4) Constraint model of energy arbitrage

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] in, and are the energy stored in period t+1 and period t in energy arbitrage, is the charging power in period t in the arbitrage plan; is the discharge power of period t in the arbitrage plan; T is the period length, I ea,t Indicates the charging and discharging status during the arbitrage process, 1 represents charging and 0 represents discharging.

[0088] Among them, formula (7) is the power state transfer constraint of adjacent time periods in energy arbitrage; formula (8) is the power constraint in energy arbitrage; formula (9) is the power constraint in the initial and ending time periods in energy arbitrage. Formulas (10) and (11) are the charging and discharging power constraints of energy arbitrage.

[0089] (3.5) Constraint model for calling energy storage capacity rights

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096] Where T is the time period length; and are the real-time charging power and discharging power of the flexibility pack, respectively; is the stored energy in the flexibility package. The called constraint model describes various constraints when users exercise energy capacity rights. Among them, formula (12) is the energy storage flexibility trading power transfer state constraint in adjacent time periods; formula (13) is the power constraint of energy storage used for flexibility trading; formula (14) is the energy storage flexibility trading power constraint in the initial and ending periods. Formula (15) describes the constraints when users exercise power capacity rights. Formula (16) is the charge / discharge power constraint of energy storage used for flexibility trading. Formula (17) is the ramp capacity constraint of energy storage used for flexibility trading.

[0097] Furthermore, a price model for the flexibility package is established based on the predicted electricity price.

[0098] From the perspective of energy storage power stations, the flexibility package occupies part of its flexibility, and only the remaining flexibility can be used for energy arbitrage. Therefore, it is necessary to set a suitable flexibility price to coordinate flexibility trading and energy arbitrage. Correspondingly, the flexibility package price is modeled as follows.

[0099]

[0100] in, and are the prices of energy capacity right, power capacity right and ramp capacity right respectively. is the price at which energy is initially sold to the flexibility package, is the price at which energy is ultimately purchased from the flexibility package. and are set as the maximum and minimum values ​​of the predicted electricity price, respectively, which reflects the opportunity cost of energy storage arbitrage. and According to the transaction model decision in the next section, the energy storage power station benefits are maximized. It should be noted that considering the SoC restoration of the energy storage power station in a scheduling cycle and reducing the computational burden, it is assumed that and Remains unchanged throughout the scheduling cycle.

[0101] Furthermore, users can customize the purchase flexibility package according to their own needs.

[0102] Users can analyze their own charging needs, discharging needs, power needs and capacity needs, flexibly declare single or multiple varieties, selectively purchase flexibility packages that include energy, power and ramp capacity rights, utilize energy storage sharing, increase their overall interests, and achieve the effect of optimizing the allocation of energy storage resources.

[0103] According to the actual operation of renewable energy power stations, the actual flexibility of energy storage users can be simulated, as shown in the attached figure. Figure 3a , Figure 3b and Figure 3c, reducing the risk of power supply shortage, which will greatly improve the safety and economy of power system operation.

[0104] It will be easily understood by those skilled in the art 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 substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for constructing a flexibility package based on energy storage rights, characterized in that: include: S1: collecting technical parameters of the energy storage device to determine the energy storage capacity of its physical energy storage right, and dividing the energy storage capacity into a number of capacity blocks; S2: The capacity right of the physical energy storage right is divided into energy capacity right, power capacity right and climbing capacity right; the energy capacity right is the right of the energy storage user to use energy storage for charging or discharging in a continuous time period, the power capacity right is the right of the energy storage user to use energy storage for charging or discharging in a specific period of time, and the climbing capacity right is the right of the energy storage user to use energy storage flexibility to meet its own climbing or landslide needs in a specific period of time; S3: Determine the number of the capacity blocks according to user demand, and construct a flexibility package corresponding to the user demand by combining the energy capacity right, the power capacity right, the ramp capacity right, the initial purchase capacity and the final sale capacity; The constraint model of the energy capacity weight is: The subscripts i and t represent the user number and time period number, respectively; Energy capacity reserved for energy storage plants that can be used for energy arbitrage, and are the initial, maximum and minimum energies of the energy storage power station respectively; and They are respectively the initial energy and final energy reserved by the energy storage power station and available for energy arbitrage; is the energy capacity right ordered by demander i in time period t, is the final remaining energy of the flexibility package; The constraint model of energy arbitrage is: Constraints on power state transfer between adjacent time periods: Power Constraints: The power constraints at the beginning and end of the period: Energy arbitrage charging and discharging power constraints: and are the energy stored in period t+1 and period t in energy arbitrage, is the charging power in time periods t and t+1 in the arbitrage plan; is the discharge power in time periods t and t+1 in the arbitrage plan; T is the time period length, I ea,t Indicates the charging and discharging status during the arbitrage process, 1 represents charging and 0 represents discharging; η c and η d are the charging efficiency and discharging efficiency of the energy storage device, respectively; The power capacity reserved for energy arbitrage by the energy storage power station during period t; The ramp capacity reserved for energy arbitrage by the energy storage power station during period t; The constraint model of the power capacity right is used to identify the power allocation of the energy storage power station between energy arbitrage and power capacity right trading, and the expression is: is the power capacity of the energy storage power station; The constraint model of the ramp capacity right identifies the ramp allocation of the energy storage power station between energy arbitrage and ramp capacity right trading, and the expression is: is the ramp capacity of the energy storage power station, and They are respectively the power capacity right and ramp capacity right ordered by demander i in time period t.

2. The method for constructing a flexibility package based on energy storage rights according to claim 1, characterized in that: The technical parameters of S1 include: Energy storage device power limit Energy storage device power limit Energy storage device power capacity Maximum up and down climbing rate of energy storage device Energy storage device charging efficiency η c and the energy storage device discharge efficiency η d .

3. The method for constructing a flexibility package based on energy storage rights according to claim 2, characterized in that: The flexibility package in S3 is: in, and Represent the initial purchase energy and final sold energy of demander i respectively; the initial purchase energy of the flexibility package is the initial energy when purchased from the energy storage plant, and the final remaining energy of the flexibility package For selling to the energy storage plant, the flexibility package operates under the decoupled capacity rights and restrictions.

4. A flexibility package construction device based on energy storage rights, characterized in that: The method for constructing a flexibility package based on energy storage rights according to any one of claims 1 to 3 comprises: A collection module, used for collecting technical parameters of the energy storage device to determine the energy storage capacity of its physical energy storage right, and dividing the energy storage capacity into a plurality of capacity blocks; A division module is used to divide the capacity right of the physical energy storage right into energy capacity right, power capacity right and climbing capacity right; the energy capacity right is the right of the energy storage user to use energy storage for charging or discharging in a continuous time period, the power capacity right is the right of the energy storage user to use energy storage for charging or discharging in a specific period of time, and the climbing capacity right is the right of the energy storage user to use energy storage flexibility to meet its own climbing or landslide needs in a specific period of time; A construction module is used to determine the number of the capacity blocks according to user needs, and to construct a flexibility package corresponding to the user needs in combination with the energy capacity right, the power capacity right, the ramp capacity right, the initial purchase capacity and the final sale capacity.

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