Computer-implemented method for managing a plurality of assets of a virtual power plant

Abstract

According to an embodiment, a computer-implemented method (100) for managing a plurality of assets of a vir- tual power plant, wherein each asset in the plurality of assets comprises at least one energy storage unit for per- forming power grid frequency balancing using the asset, comprises: obtaining (101) at least one performance character- istic for each asset in the plurality of assets; dividing (102) the plurality of assets into a plurality of performance classes according to the at least one per- formance characteristic of each asset; and in response to receiving an activa- tion signal for power grid frequency bal- ancing, performing (103) the power grid frequency balancing using the plurality of assets by transmitting charge / dis- charge commands to at least one of the plurality of assets according to the plu- rality of performance classes.

Description

COMPUTER- IMPLEMENTED METHOD FOR MANAGING A PLURALITYOF ASSETS OF A VIRTUAL POWER PLANTTECHNICAL FIELD

[0001] The present disclosure relates to distributed energy storage systems , and more particularly to a computer-implemented method for managing a plurality of as sets of a virtual power plant , a computing device , a virtual power plant , and a computer program product .BACKGROUND

[0002] A virtual power plant (VPP) can comprise a large number of assets with energy storage units . When working in national frequency reserve markets , the market operator can require each participant to del iver a selected amount of power grid frequency balancing capacity . The performance characteristics of the assets can be heterogeneous . Thus , utili zing the assets for power grid frequency balancing in an efficient manner can be challenging .SUMMARY

[0003] This summary is provided to introduce a selection of concepts in a s implif ied form that are further described below in the detailed description . This summary is not intended to identify key features or essential features of the claimed subj ect matter, nor is it intended to be used to limit the scope of the claimed subj ect matter .

[0004] It is an obj ective to provide a computer-implemented method for managing a plurality of assets ofa virtual power plant , a computing device , a virtual power plant , and a computer program product . The foregoing and other obj ectives are achieved by the features of the independent claims . Further implementation forms are apparent from the dependent claims , the description and the figures .

[0005] According to a first aspect , computer-implemented method for managing a plurality of assets of a virtual power plant , wherein each asset in the plurality of assets comprises at least one energy storage unit for performing power grid frequency balancing using the asset , comprises : obtaining at least one performance characteristic for each asset in the plurality of assets ; dividing the plurality of assets into a plurality of performance classes according to the at least one performance characteristic of each asset ; and in response to receiving an activation signal for power grid frequency balancing, performing the power grid frequency balancing using the plurality of assets by transmitting charge / discharge commands to at least one of the plurality of as sets according to the plural ity of performance classes .

[0006] In an implementation form of the first aspect , the at least one performance characteristic comprises at least one of : a reaction delay of an asset to the charge / discharge commands ; an energy storage capability of the at least one energy storage unit of an asset ; and / or an up regulation and / or down regulation capability of an asset .

[0007] In another implementation form of the first aspect , the plurality of performance classes comprisesat least a low performance asset class and a high performance asset class , wherein assets in the high performance asset class have at least one special performance characteristic that assets in the low performance asset class do not have , and the method further comprises : activating at least one asset in the high performance asset class for performing the power grid frequency balancing; and in response to , during the performing the power grid frequency balancing, the at least one special performance characteristic not being needed, reducing an activation level of the at least one as set in the high performance asset class and increasing an activation level of at least one asset in the low performance asset class .

[0008] In another implementation form of the first aspect , the plurality of performance classes comprises at least a slow asset class and a fast asset class , wherein assets in the slow asset class have a longer reaction delay to the charge / discharge commands than as sets in the fast asset class , and the method further comprises : monitoring an activation level of the plurality of assets during the performing the power grid frequency balancing; and in response to the activation level of assets in the slow asset class increasing, reducing the activation level of assets in the fast asset class .

[0009] In another implementation form of the first aspect , the method further comprises , in response to at least one asset in the slow asset class reaching a threshold activation level , balancing a state of charge of at least one asset in the fast asset class using the at least one asset in the slow asset class .

[0010] In another implementation form of the first aspect , the at least one energy storage unit compri ses at least one battery and / or at least one supercapacitor .

[0011] In another implementation form of the first aspect , at least one asset in the plurality of assets further comprises at least one power source .

[0012] In another implementation form of the first aspect , the obtaining the at least one performance characteristic for each asset in the plurality of assets comprises obtaining the at least one performance characteristic for each asset in the plurality of assets according to a state of each asset .

[0013] In another implementation form of the first aspect , the state of each asset comprises at least one of : a state of charge of the at least one energy storage unit of the asset ; a load of the asset ; a current flowing into / from the at least one energy storage unit of the as set ; an operating temperature of the asset ; and / or a state of health of the at least one energy storage unit of the asset .

[0014] According to a second aspect , a computing device compri ses at least one processor and at least one memory including computer program code , the at least one memory and the computer program code being configured to , with the at least one proces sor, cause the computing device to perform the method according to the first aspect .

[0015] According to a third aspect , a virtual power plant comprises the computing device according the second aspect and a plurality of assets coupled to a power grid, wherein each asset in the plurality of assets comprises at least one energy storage unit .

[0016] According to a fourth aspect , a computer program product comprises program code configured to perform the method according to the first aspect when the computer program product is executed on a computer .

[0017] Many of the attendant features wil l be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings .DESCRIPTION OF THE DRAWINGS

[0018] In the following, example embodiments are described in more detail with reference to the attached figures and drawings , in which :

[0019] Fig . 1 illustrates a flow chart representation of a method according to an embodiment ;

[0020] Fig . 2 illustrates a schematic representation of virtual power plant assets according to an embodiment ;

[0021] Fig . 3 illustrates a schematic representation of a virtual power plant as set according to an embodi ment ;

[0022] Fig . 4 illustrates a plot representation of asset activation according to an embodiment ;

[0023] Fig . 5 illustrates a plot representation of asset activation according to another embodiment ;

[0024] Fig . 6 illustrates a schematic representation of a computing device according to an embodiment ; and

[0025] Fig . 7 illustrates a schematic representation of a virtual power plant according to an embodiment .

[0026] In the following, like reference numerals are used to des ignate li ke parts in the accompanying drawings .DETAILED DESCRIPTION

[0027] In the following description, reference is made to the accompanying drawings , which form part of the disclosure , and in which are shown, by way of illustration, specific aspects in which the present disclosure may be placed . It is understood that other aspects may be utilised, and structural or logical changes may be made without departing from the scope of the present disclosure . The following detailed description, therefore , is not to be taken in a limiting sense , as the scope of the present disclosure is defined by the appended claims .

[0028] For instance , it is understood that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa . For example , if a specific method step is described, a corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or il lustrated in the f igures . On the other hand, for example , if a specific apparatus is described based on functional units , a corresponding method may include a step performing the described functionality, even if such step is not explicitly described or illustrated in the figures . Further, it is understood that the features of the various example aspects described herein may be combined with each other, unless specifically noted otherwise .

[0029] Fig . 1 illustrates a flow chart representation of a method according to an embodiment .

[0030] According to an embodiment , a computer-implemented method 100 for managing a plurality of assets of a virtual power plant , wherein each asset in the plurality of assets compri ses at least one energy storage unit for performing power grid frequency balancing using the asset , comprises : obtaining 101 at least one performance characteristic for each asset in the plurality of assets .

[0031] Herein, an asset of a virtual power plant may refer to a physical site comprising at least one energy storage unit . For example , an asset may comprise a residential building, a base station of a communications network, or any other building or structure comprising at least one energy storage unit . Some assets may further comprise a power source , such as solar panels , a wind turbine , or similar .

[0032] An asset may also be referred to as a physical asset , a node , a unit , a distributed energy resource , a site , a battery site , or similar .

[0033] Herein, a virtual power plant (VPP) may refer to a distributed power plant compris ing a plural ity of assets . A VPP can aggregate the capacities of the plurality of assets and control the plurality of assets in a centrali zed manner .

[0034] The at least one performance characteristic of an as set may comprise , for example , any feature of the asset that can affect the utili zation of the asset in power grid frequency balancing .

[0035] The obtaining 101 the at least one performance characteristic for each asset in the plurality of assetsmay comprise , for example , obtaining the at least one performance characteristic from a database or any other source and / or performing measurements using the plurality of assets in order to determine the at least one performance characteristic .

[0036] The method 100 may further comprise dividing 102 the plurality of assets into a plurality of performance classes according to the at least one performance characteristic of each asset .

[0037] A performance class may also be referred to as a group, an asset group, a category, an asset category, a performance rank, or similar .

[0038] The plurality of performance classes may comprise any number of performance classes . For example , in some embodiments , the plurality of performance classes may compri se at least a high performance class and a low performance clas s . In some embodiments , the plurality of performance classes may comprise more specific performance classes , such as a low delay clas s , a high speed class , a high delay class , a low speed class , etc .

[0039] The method 100 may further comprise , in response to receiving an activation signal for power grid frequency balancing, performing 103 the power grid frequency balancing using the plurality of assets by transmitting charge / discharge commands to at least one of the plurality of as sets according to the plurality of performance classes .

[0040] The charge / discharge commands may comprise , for example , a separate charge command, a separate discharge command, and / or a combined charge / discharge command .

[0041] A charge command may indicate to an asset that the asset should charge the at least one energy storage unit of the as set us ing power from the power grid . Alternatively or additionally, the charge command may indicate to an asset that the asset should charge the at least one energy storage unit using power production of the asset instead of feeding the power to the power grid . Thus , the asset can be used for down regulation . The charge command may further indicate how much power the asset should take from the power grid for the charging and / or a total amount of energy that the asset should take from the power grid .

[0042] A discharge command may indicate to an asset that the asset should discharge the at least one energy storage unit of the asset by feeding power to the power grid . Alternatively or additionally, the discharge command may indicate to an asset that the asset should discharge the at least one energy storage by feeding power to a system load of the asset instead of taking the power from the power grid . Thus , the asset can be used for up regulation . The discharge command may further indicate how much power the asset should feed to the power grid for the discharging and / or a total amount of energy that the asset should feed to the power grid .

[0043] Frequency balancing of a power grid may be arranged for example using automatic Frequency Restoration Reserve ( aFRR) capacity market . aFRR is a centrali zed automatically activated reserve . Its activation is based on a power change signal calculated on the base of the frequency deviation in the Nordic synchroni zed area . Its purpose is to return the frequency of the power grid to the nominal value .

[0044] In the future , there will be a new energy market , Picasso , and the activation signal in the aFRR market will be based on energy bids , not capacity bids . Capacity bids will be used as an incentive to bid energy because once a participant bids capacity they should bid the same amount also in energy .

[0045] Frequency balancing of electric grid may also be arranged using, for example , Frequency Containment Reserve for Normal Operation ( FCR-N) or Frequency Containment Reserve for Disturbances ( FCR-D) that are active power reserves that are automatically controlled based on the frequency deviation . Their purpose is to contain the frequency during normal operation and disturbances . FCR is an active power reserve that is automatically controlled based on the frequency deviation . FCR may be Frequency Containment Reserve for Normal Operation, FCR-N, or Frequency Containment Reserve for Disturbances , FCR-D . Their purpose is to contain the frequency during normal operation and disturbances .

[0046] Typically, aFRR or FCR-D market activities are done with large "grid-scale" units , such as hydro power plants . One unit can either be providing up regulation, down regulation, or not participating at all .

[0047] I f a VPP is implemented with a large number of distributed assets , some subset or all the assets can typically be pooled together to provide up regulation, down regulation, or not participating at all .

[0048] Market participation, in for example FCR-D, typically has several technical requirements with respect to , for example , reaction speed to market needs . I f these requirements are very strict , only some of the assets may be capable of fulfilling the requirements orsome assets are only able to ful fil these requirements when in specific state , such as with no load or full load .

[0049] At least some embodiments disclosed herein can enable heterogenous asset pool management in a way that a pool of highly capable assets can be made available to respond to market commitments and less capable assets can be rotated to replace highly capable assets when their special performance characteristic, such as reaction speed, is no longer required . This can allow the aggregate system to utili ze , for example , the full energy reserves of all assets , even if not all assets are capable of performing all market actions on their own .

[0050] The frequency balancing may comprise up regulation and / or down regulation . Up regulation can comprise increasing power production and / or decreasing power consumption . Down regulation can comprise decreasing power production and / or increasing power consumption .

[0051] The activation signal may be provided by, for example , a grid operator . When working in national frequency reserve markets , the grid operator can require each participant to deliver a selected amount of frequency balancing capacity for the market during the time of resource activation . The activated frequency balancing capacity is usually not allowed to fluctuate significantly from its intended setpoint , and the participants can be sanctioned in case the participant is not able to deliver steady frequency balancing capacity for the market .

[0052] Frequency balancing capacity may refer to the amount of power that can be of f ered / allocated for powergrid frequency balancing by the VPP . Frequency balancing capacity may also be referred to as capacity, aggregated capacity, regulation capacity, or similar .

[0053] Herein, performing the power grid frequency balancing using the plurality of assets may comprise configuring the at least one asset to which the charge / discharge commands are transmitted to be used for the power grid frequency balancing . For example , when an as set is activated for power grid frequency balancing, the asset can be configured to, for example , in the case of up regulation, feed power to the power grid from the at least energy storage unit of the asset or to , in the case of down regulation, charge the at least one energy storage unit of the asset using power from the power grid .

[0054] In some embodiments disclosed herein, some functionality may be disclosed in terms of a three-layer VPP architecture . This architecture is only a non-limiting example and the functionality disclosed herein may also implemented in various other ways and / or using various other architectures .

[0055] A first control layer of the three-layer VPP architecture may be referred to as a planner and may be configured to determine in advance an operating plan for the VPP for a plurality of time slots of a first time period based on aggregated properties of the VPP, wherein the operating plan comprises allocation of aggregated capacity of the VPP for the plurality of time slots and convey the operating plan to a second control layer .

[0056] The planner can produce a plan of market commitments and associated technical performance requirements for each committed asset . The planner can also perform mapping of performance characteristic of individual assets against the performance requirement . The performance characteristic of individual assets may be different for different states of the asset .

[0057] The second control layer of the three-layer VPP architecture may be referred to as a supervisor and may be configured to determine rules for selecting assets of the VPP for obtaining the allocated aggregated capacity of the operating plan, monitor operation of the VPP in real time and responsively adj ust the rules ; and convey the rules to the third control layer .

[0058] The supervisor can track the availability of high-performance assets and the state , such as the state of charge ( SOC) , of high-performance and low-performance units .

[0059] The supervisor can initiate swapping of activated high-performance assets to activated low-performance assets in order to , for example , ensure availability of high-performance assets against market commitments or in order to ensure that state , such as SoC, of high-performance assets does not deviate too far from all assets . For example , if the SOC is too high or too low the assets cannot serve to activations to a speci fic activation direction anymore . Activation direction may refer to up regulation or down regulation .

[0060] A third control layer of the three-layer VPP architecture may be referred to as a controller and can be configured to execute selection and activation ofindividual assets of the VPP in accordance with the rules .

[0061] The controller can perform the swapping as per instructions ( rules / limits ) set by supervisor .

[0062] Fig . 2 illustrates a schematic representation of virtual power plant assets according to an embodiment .

[0063] Distributed energy storage ( DES ) systems and other VPP solutions can control , for example , thousands of assets in the plurality of assets 201 at different sites .

[0064] The assets are typically heterogeneous in terms of , for example , the energy capacity of the at least one energy storage unit . Also , the associated power characteristics in different assets , such as the maximum charging and discharging power of the at least one energy storage unit , adj ustable and non-ad ustable local power consumption, and possible local power generation can be heterogeneous . Further, the reaction speed / delay to charge / discharge commands , such as from zero to up regulation or down regulation or from up regulation or down regulation to zero or the opposite direction, can be heterogeneous .

[0065] The VPP can be used to provide at least one ancillary market service to support power grid frequency balancing, in for example , aFRR or FCR-D market . For that purpose , the VPP can provide up regulation and down regulation activities towards the power grid .

[0066] According to an embodiment , the at least one performance characteristic comprises at least one of : a reaction delay of an asset to the charge / discharge commands ; an energy storage capability of the at least oneenergy storage unit of an asset ; and / or an up regulation and / or down regulation capability of an asset .

[0067] The reaction delay of an asset to the charge / discharge commands can be measured, for example , from transmitting the charge / discharge command to the as set to when the as set starts to charge / discharge the at least one energy storage unit . Alternatively, the reaction delay of an asset to the charge / discharge commands can be measured, for example , from transmitting the charge / discharge command to the asset to when the asset reaches a specific level of charge / discharge current . The specific level of charge / discharge current may be , for example , preconfigured to a specific value or it may be some fraction of a maximum charge / discharge current of the asset . An asset can be considered as activated once the charge / discharge current has significantly risen or dropped from the state before the activation .

[0068] An energy storage capability of the at least one energy storage unit of an asset may comprise , for example , the energy storage capacity of the at least one energy storage unit , measured for example in kilowatt- hours .

[0069] The up regulation and / or down regulation capability of an asset may refer to how much power the asset can provided for up regulation or down regulation, measured for example in kilowatts .

[0070] According to an embodiment , the plurality of performance classes comprises at least a low performance asset class and a high performance asset class , wherein assets in the high performance asset class have at least one special performance characteristic that assets inthe low performance asset class do not have , and the method further comprises : activating at least one asset in the high performance as set class for performing the power grid frequency balancing; and in response to , during the performing the power grid frequency balancing, the at least one special performance characteristic not being needed, reducing an activation level of the at least one asset in the high performance asset class and increasing an activation level of at least one asset in the low performance asset class .

[0071] For example , in the embodiment of Fig . 2 , the plurality of assets 201 comprises a first performance class 202 and a second performance class 203 . The first performance class 202 can compri se for example , a high performance asset class and the second performance class 203 can comprise a low performance asset class .

[0072] In some embodiments all of the assets in the plurality of assets 201 may be divided into the plurality of performance classes . In other embodiments , only some of the plurality of assets may be divided into the plurality of performance classes .

[0073] The at least one special performance characteristic may comprise , for example , an asset having a performance characteristic greater than a threshold value or less than a threshold value . For example , the high performance asset class may comprise assets that have a performance characteristic greater than a threshold value and the low performance asset clas s may comprise assets that have the performance characteristics less than a threshold value .

[0074] In some embodiments , the high performance asset class comprises assets that have a reaction delay to thecharge / discharge commands less than a threshold reaction delay the low performance asset class comprises assets that have a reaction delay to the charge / discharge commands greater than the threshold reaction delay .

[0075] In some embodiments , the high performance asset clas s comprises assets that have an energy storage capability greater than a threshold energy storage capability and the low performance asset class comprises assets that have an energy storage capability less than the threshold energy storage capability .

[0076] In some embodiments , the high performance asset class comprises assets that have an up regulation capability greater than a threshold up regulation capability and the low performance asset class comprises assets that have an up regulation capability less than the threshold up regulation capability .

[0077] In some embodiments , the high performance asset class comprises assets that have a down regulation capability greater than a threshold down regulation capability and the low performance asset class comprises assets that have a down regulation capability less than the threshold down regulation capability .

[0078] In some embodiments , the at least one special performance characteristic may comprise a ratio between an up / down regulation capability and an energy storage capability of an as set . For example , if an asset has a small energy storage capability and a small system load, the asset may not be considered a low-performance asset because the asset may be able to dissipate the energy from the at least one energy storage unit in the same time as a large asset with a large energy storage capability .

[0079] Fig . 3 illustrates a schematic representation of a virtual power plant as set according to an embodi ment .

[0080] According to an embodiment , at least one asset in the plurality of assets further comprises at least one power source 301 .

[0081] Each asset 300 can comprise at least one power source 301 . The power source 301 may comprise , for example , a rectifier electrically coupled to the power grid . Alternatively or additionally, the power source 301 may comprise some other type of power source , such as at least one renewable energy power source . For example , the power source 301 may comprise at least one solar panel , at least one wind turbine , at least one hydro turbine , and / or similar .

[0082] According to an embodiment , each asset 300 in the plurality of assets comprises a rectifier for charging the at least one energy storage unit 303 using power from the power grid and / or each asset 300 in the plurality of assets comprises an inverter 306 for feeding power to the power grid from the at least one energy storage unit 303 .

[0083] According to an embodiment , the at least one energy storage unit 303 comprises at least one battery and / or at least one supercapacitor .

[0084] For example , in some embodiments , at least one asset may comprise at least one supercapacitor and a hydropower based power source or at least one battery unit and a hydropower based power source .

[0085] For example , if the asset 300 comprises a direct current ( DC) system, such as in the embodiment of Fig . 3 , the at least one power source 301 can compriseat least one rectifier for converting the alternating current (AC) to DC compatible with the asset 300 . For example , the at least one rectifier can convert 230 - volt AC to 48 -volt DC . The at least one power source 301 can be used to drive a system load 302 . The at least one power source 301 can also be used to provide power to the at least one energy storage unit 303 .

[0086] In other embodiments , the at least one energy storage unit 303 may comprise , for example , at least one battery unit , at least one capacitor , at least one supercapacitor, and / or similar .

[0087] The rectifier can be "partly" used if the terminal voltage of the rectifier is set slightly lower than the battery voltage . In such a configuration, some current is drawn to the system load 302 from the rectifier and some from the at least one energy storage unit 303 .

[0088] The at least one energy storage unit 303 can be used to drive the system load 302 when being controlled to , and to receive charge from the power source 301 during recharge periods . The current from / to the at least one energy storage unit 303 is not always its theoretical maximum due to various factors , such as those disclosed herein .

[0089] The system load 302 can comprise , for example , various equipment consuming power, the type of the equipment can be anything consuming electricity . I f the power source 301 is partly pushing current to the system load 302 , the frequency balancing capacity for up regulation of the asset 300 may not be equal to its power consumption but less .

[0090] For example , the asset 300 may be embodied in a base station of a telecommunications network . The system load 302 may comprise equipment of the base station . The at least one energy storage unit 303 can be used for power redundancy of the base station in addition to power grid frequency balancing .

[0091] The asset 300 can further comprise at least one inverter 306 that can be electrically coupled to the at least one energy storage unit 303 and to the power grid . The at least one inverter 306 can be used to feed electricity back to the power grid from the at least one energy storage unit 303 .

[0092] Different energy storage , rectifier, and / or inverter combinations in assets can have different reaction speeds / delays to charge / discharge commands . Some may react in seconds , many of them may require tens of seconds . In a typical combination, the maj ority of assets can be slow reacting type . These slow assets may still offer most of the frequency balancing capacity . For example , FCR can require a 7 . 5 second activation time and many telecommunications rectifier-battery combinations cannot reach this target .

[0093] Fig . 4 illustrates a plot representation of asset activation according to an embodiment .

[0094] According to an embodiment , the plurality of performance classes comprises at least a slow asset class and a fast asset class , wherein assets in the slow asset class have a longer reaction delay to the charge / discharge commands than assets in the fast asset class , and the method further comprises : monitoring an activation level of the plurality of as sets during the performing the power grid frequency balancing; and inresponse to the activation level of assets in the s low asset class increasing, reducing the activation level of assets in the fast asset class .

[0095] Herein, an activation level of an asset may refer to the amount of power the asset is providing for up regulation or for down regulation . The activation level may be expressed in various ways . For example , the activation level of an asset may be expressed as a percentage of a maximum power that the asset can achieve for power grid frequency balancing . Alternatively or additionally, the activation level can be expressed as a percentage of some other value , such as an amount of power required for power grid frequency balancing in the activation signal . In some cases , the activation level may comprise an aggregate activation level of a plurality of assets , such as assets in the fast asset class or assets in the slow asset class .

[0096] For example , in the embodiment of Fig . 4 , activation levels of slow assets and fast assets in response to charge / discharge commands are illustrated . At 401 , approximately at 2 seconds , an activation signal is received, and assets are activated for power grid frequency balancing .

[0097] Curve 402 corresponds to the activation level of assets in a fast asset class . At approximately 4 seconds , the fast assets have reached a 50 % activation level . In the embodiment of Fig . 4 , the activation level s are scaled with respect to an activation level required by the activation signal . Thus , a 100 % activation corresponds to fulfilling the activation required by the activation signal . At approximately 6 seconds , the fast assets reach a 100 % activation .

[0098] The reducing the activation level of assets in the fast asset class in response to the activation level of assets in the slow asset class increasing may comprise, for example, reducing the activation level of assets in the fast asset class in such a way that an activation level required by the activation signal is substantially fulfilled during the performing the power grid frequency balancing.

[0099] For example, in the embodiment of Fig. 4, curve 403 corresponds to the activation level of assets in a slow asset class. At 404, approximately at 10 seconds, the slow assets have reached a 20% activation level, and the activation level of the fast assets can be reduced to 80% .

[0100] At 405, approximately at 26 seconds, the slow assets have reached a 100% activation level, and the fast assets have been reduced to a 0% activation level, i.e. deactivated.

[0101] According to an embodiment, the method further comprises, in response to at least one asset in the slow asset class reaching a threshold activation level, balancing a state of charge of at least one asset in the fast asset class using the at least one asset in the slow asset class.

[0102] The balancing the state of charge of at least one asset in the fast asset class using the at least one asset in the slow asset class may comprise, for example, configuring the at least one asset in the fast asset class to charge the at least one energy storage unit using power from the power grid and configuring the at least one asset in the slow asset class to feed a corresponding amount of power to the power grid. Thus, whenslow assets have reached a sufficient activation level to fulfil the activation required by the activation signal, the slow assets can be used to recharge the fast assets so that the fast assets have sufficient charge when they are needed for, for example, another activation.

[0103] For example, in the embodiment of Fig. 4, from 405 to 406, approximately at 60 seconds, the activation level of the slow assets is increased over 100% in order to recharge the fast assets. Correspondingly, the activation level of the fast assets is illustrated as negative because they are being recharged. This can be continued, for example, until the fast assets have reached a target SOC.

[0104] Thus, in the embodiment of Fig. 4, fast and slow assets can be activated at 401. Then, with closed loop control, fast assets can be de-activated as slow assets get activated. When all slow assets reach full activation, the slow assets can be activated to over 100% to balance the SOC of the fast assets. When the SOC of the fast assets has been balanced, the slow assets can return to 100% activation at 406.

[0105] Fig. 5 illustrates a plot representation of asset activation according to another embodiment.

[0106] In the embodiment of Fig. 5, curve 501 corresponds to the total activation due to the slow and fast assets in the embodiment of Fig. 4. Due to utilizing the fast assets first due to their lower delay and deactivating the fast assets as the activation level of the fast assets increases, the total activation level 501 increases to 100% according to the delay of the fastassets and is maintained at substantially 100 % through the power grid frequency balancing .

[0107] According to an embodiment , the obtaining the at least one performance characteristic for each asset in the plurality of assets comprises obtaining the at least one performance characteristic for each asset in the plurality of assets according to a state of each asset .

[0108] The state of an asset may affect the performance of the as set . The state of an asset may comprise any temporary factor that can affect the performance of the asset . For example , if the SOC of a fast asset is so low that it cannot be used for up regulation, it may not be beneficial to place such an asset in the fast asset class for up regulation . Similarly, if the SOC of an as set is high, the asset may not be able to perform down regulation efficiently . Thus , obtaining the at least one performance characteristic for each asset in the plurality of assets according to a state of each as set can take such factors into account . For example , even if the delay of an asset should be low but the SOC of the asset is also low, such as asset may be considered as a slow asset or not be used for power grid frequency balancing .

[0109] According to an embodiment , the state of each asset comprises at least one of : a state of charge of the at least one energy storage unit of the asset ; a load of the asset ; a current flowing into / from the at least one energy storage unit of the asset ; an operating temperature of the asset ; and / or a state of health of the at least one energy storage unit of the asset .

[0110] The load of an asset may comprise, for example, the amount of power the system load 302 of an asset is consuming. A high load may affect the capability of the asset to perform up / down regulation. Similarly, the current flowing into / from the at least one energy storage unit of the asset, the operating temperature of the asset, and / or the state of health of the at least one energy storage unit of the asset can affect the capability of the asset to perform up / down regulation.

[0111] Fig. 6 illustrates a schematic representation of a computing device according to an embodiment.

[0112] According to an embodiment, a computing device 600 comprises at least one processor 601 and at least one memory 602 including computer program code, the at least one memory 602 and the computer program code configured to, with the at least one processor 601, cause the computing device 600 to perform the method 100.

[0113] The computing device 600 may comprise at least one processor 601. The at least one processor 601 may comprise, for example, one or more of various processing devices, such as a co-processor, a microprocessor, a digital signal processor (DSP) , a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) , a microprocessor unit (MCU) , a hardware accelerator, a special-purpose computer chip, or the like.

[0114] The computing device 600 may further comprise a memory 602. The memory 602 may be configured to store, for example, computer programs and the like. The memory 602 may comprise one or more volatile memory devices,one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and nonvolatile memory devices. For example, the memory 602 may be embodied as magnetic storage devices (such as hard disk drives, magnetic tapes, etc.) , optical magnetic storage devices, and semiconductor memories (such as mask ROM, PROM (programmable ROM) , EPROM (erasable PROM) , flash ROM, RAM (random access memory) , etc.) .

[0115] The computing device 600 may further comprise other components not illustrated in the embodiment of Fig. 6. The computing device 600 may comprise, for example, an input / output bus for connecting the computing device 600 to other devices.

[0116] When the computing device 600 is configured to implement some functionality, some component and / or components of the computing device 600, such as the at least one processor 601 and / or the memory 602, may be configured to implement this functionality. Furthermore, when the at least one processor 601 is configured to implement some functionality, this functionality may be implemented using program code comprised, for example, in the memory.

[0117] The computing device 600 may be implemented at least partially using, for example, a computer, some other computing device, or similar.

[0118] Fig. 7 illustrates a schematic representation of a virtual power plant according to an embodiment.

[0119] According to an embodiment, a virtual power plant 700 comprises the computing device 600 a plurality of assets 300 coupled to a power grid 701, wherein each asset in the plurality of assets 300 comprises at least one energy storage unit.

[0120] The virtual power plant 700 may also be referred to as a virtual power plant system, a distributed energy storage system, or similar .

[0121] Each asset in the plurality of assets 300 may be coupled to the computing device 600 . Thus , the computing device 600 may be configured to control each asset 300 in the plurality of assets according to the method 100 .

[0122] Any range or device value given herein may be extended or altered without losing the effect sought . Also any embodiment may be combined with another embodiment unless explicitly disallowed .

[0123] Although the subj ect matter has been described in language specific to structural features and / or acts , it is to be understood that the subj ect matter defined in the appended claims is not necessarily limited to the specific features or acts described above . Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims .

[0124] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments . The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages . It wil l further be understood that reference to ' an ' item may refer to one or more of those items .

[0125] The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate . Additionally, individual blocks maybe deleted from any of the methods without departing from the spirit and scope of the subj ect matter described herein . Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought .

[0126] The term ' comprising ' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements .

[0127] It will be understood that the above description is given by way of example only and that various modif ications may be made by those ski lled in the art . The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments . Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments , those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification .

Claims

CLAIMS :1 . A computer-implemented method ( 100 ) for managing a plurality of assets of a virtual power plant , wherein each asset in the plurality of assets comprises at least one energy storage unit for performing power grid frequency balancing using the asset , the method ( 100 ) comprising : obtaining ( 101 ) at least one performance characteristic for each asset in the plurality of assets ; dividing ( 102 ) the plurality of assets into a plurality of performance classes according to the at least one performance characteristic of each asset ; and in response to receiving an activation signal for power grid frequency balancing, performing ( 103 ) the power grid frequency balancing using the plurality of assets by transmitting charge / discharge commands to at least one of the plurality of assets according to the plurality of performance classes ; wherein the at least one performance characteristic comprises at least a reaction delay of an asset to the charge / discharge commands .2 . The computer-implemented method ( 100 ) according to claim 1 , wherein the at least one performance characteristic further comprises at least one of : an energy storage capability of the at least one energy storage unit of an asset ; and / or an up regulation and / or down regulation capability of an asset .3 . The computer-implemented method ( 100 ) according to claim 1 or claim 2 , wherein the plurality ofperformance classes comprises at least a low performance asset class and a high performance asset class , wherein assets in the high performance asset class have at least one special performance characteristic that assets in the low performance asset class do not have , and the method ( 100 ) further comprises : activating at least one asset in the high performance asset class for performing the power grid frequency balancing; and in response to , during the performing the power grid frequency balancing, the at least one special performance characteristic not being needed, reducing an activation level of the at least one asset in the high performance asset class and increas ing an activation level of at least one asset in the low performance asset class .4 . The computer-implemented method ( 100 ) according to any preceding claim, wherein the plurality of performance classes comprises at least a slow as set class and a fast asset class , wherein assets in the slow asset class have a longer reaction delay to the charge / discharge commands than assets in the fast asset class , and the method further comprises : monitoring an activation level of the plurality of assets during the performing the power grid frequency balancing; and in response to the activation level of assets in the s low asset class increas ing, reducing the acti vation level of assets in the fast asset class .

5. The computer-implemented method (100) according to claim 4, the method (100) further comprising, in response to at least one asset in the slow asset class reaching a threshold activation level, balancing a state of charge of at least one asset in the fast asset class using the at least one asset in the slow asset class.

6. The computer-implemented method (100) according to any preceding claim, wherein the at least one energy storage unit comprises at least one battery and / or at least one supercapacitor.

7. The computer-implemented method (100) according to any preceding claim, wherein at least one asset in the plurality of assets further comprises at least one power source.

8. The computer-implemented method (100) according to any preceding claim, wherein the obtaining the at least one performance characteristic for each asset in the plurality of assets comprises obtaining the at least one performance characteristic for each asset in the plurality of assets according to a state of each asset .

9. The computer-implemented method (100) according to claim 8, wherein the state of each asset comprises at least one of: a state of charge of the at least one energy storage unit of the asset; a load of the asset;a current flowing into / from the at least one energy storage unit of the asset; an operating temperature of the asset; and / or a state of health of the at least one energy storage unit of the asset.

10. A computing device (600) comprising at least one processor (601) and at least one memory (602) including computer program code, the at least one memory (602) and the computer program code configured to, with the at least one processor (601) , cause the computing device (600) to perform the method (100) according to any preceding claim.

11. A virtual power plant (700) comprising the computing device (600) according to claim 10 and a plurality of assets (300) coupled to a power grid (701) , wherein each asset in the plurality of assets (300) comprises at least one energy storage unit.

12. A computer program product comprising program code configured to perform the method (100) according to any of claims 1 - 9 when the computer program product is executed on a computer.

Images