Use case identification

ID

System configuration(s)

Name of use case

UC4

SC AIT

Efficient use of local energy generation for the operation of conversion and storage appliances in hybrid thermal-electrical distribution system

Version management

Version No.

Date

Author(s)

Changes

Approval status

1.0

14.06.2017

B. Pesendorfer

First version

Draft

Scope and objectives of use case

Scope

There is significant interest in taking advantage of the hitherto unused synergies by coupling different energy-carrier networks, such as district heating and electrical distribution networks. This could increase the hosting capability of electrical distribution networks for distributed energy resources (DERs), while simultaneously reducing CO2 emissions and primary energy use of district heating systems. To fully exploit the possible synergies, an energy management system has to supervise the efficient use of local renewable energy resources for both electrical as well as thermal demands. This is especially challenging for networks with industrial loads and waste heat.

This multi-energy management system (M-EMS) therefore manages the power flows between the electrical and thermal distribution networks. The two networks are coupled via power-to-heat technologies with additional storages, all operated by the multi-energy management system. The M-EMS receives information about the net electricity generated within the electrical distribution network and sets the energy flows between the networks accordingly.

Objective(s)

O1: Minimize energy flows from external or higher level electricity grid

O2: Minimize energy production of thermal plant for district heating network

Belongs to use case group (if applicable)

Multi-energy management system

Narrative of use case

Short description

This use case describes a multi-energy management system (M-EMS) of a hybrid thermal-electrical distribution network. The electrical distribution system is thereby connected to the district heating network at one or multiple points where electricity can be converted to thermal energy via power-to-heat appliances. The operational goal is to efficiently use energy generation from DERs connected to the electrical energy distribution system. To this end, the M-EMS operates the available power-to-heat and storage appliances with the goal to directly convert or store surplus energy from DERs with respect to future/predicted energy demands.

Complete description

The multi-energy distribution network management system manages power-to-heat conversion technologies and the electrical and thermal storage charging/discharging in a hybrid thermal-electrical distribution system. The objective is to coordinate among multiple DERs, power-to-heat devices, thermal storages, batteries and waste heat from industry to maximize the use of local energy production from DERs. To further outline the scope of this use case, the different energy domains and their role within this use case are described in the following.

Electrical side:

The M-EMS has access to advanced metering infrastructure monitoring all relevant costumers and DERs within the electrical distribution network. Moreover it is able to control and monitor predefined batteries and power-to-heat devices within the network. Based on this information it derives an optimal operational strategy for these power-to-heat devices and batteries in order to fulfil the objectives.

Thermal side:

The M-EMS has access to advanced metering infrastructure monitoring all relevant costumers and producers within the district heating network. Furthermore it also receives data about the status of the power-to-heat devices and thermal storages within the system and has full control of these appliances. The M-EMS also supervises the in-feed into the district heating network from industrial waste heat.

Based on this information the M-EMS operates the defined appliances and activates/deactivates energy flows from the electrical to the thermal distribution network. The storage and power-to-heat technologies are operated in such a way that energy is stored/converted in times of high generation from DERs and used from storages in times of low or no generation from DERs, with respect to the electrical and thermal demands.

Optimality Criteria

ID

Name

Description

Reference to mentioned use case objectives

C1

Efficient use of storages and power-to-heat

Achieve objectives with minimal size and number of storage and power-to-heat technologies

O1, O2

C2

Electrical network stability

Constraints applicable for the electrical distribution network are met

O1

C3

District heating network stability

Constraints applicable for the thermal distribution network are met

O2

C4

Wear minimization

Minimize wear of storage and power-to-heat technologies

O1, O2

Use case conditions

Assumptions

• The M-EMS has full access to data of energy production from DERs, status of the thermal and electrical storages, power flow through the power-to-heat devices, thermal and electrical demands in the network and weather data
• Supply of DH network is guaranteed by other means and can also be met without infeed from power-to-heat or storage devices
• Electrical distribution network is connected to external grid that guarantees supply in cases where demand is not met by local generation from DERs

Prerequisites

The M-EMS has means to monitor all relevant devices within the network and to control the energy producing, storing and consuming appliances.

General remarks

Graphical representation(s) of use case

UML Use case diagram

Actors

Grouping

Group description

System

Device

Hardware-based device which physically implements a technical function

Component

Application

Software-based application or system

Actor name

Actor type

Actor description

Further information specific to this use case

Advanced metering infrastructure (AMI) for electrical distribution

Device

Advanced electric revenue meter capable of two-way communications. Measures, records, displays, and transmits data such as energy usage, generation, text messages, and event logs to authorized systems and provides other advanced utility functions

Advanced metering infrastructure (AMI) for district heating

Device

Advanced thermal revenue meter capable of two-way communications. Measures, records, displays, and transmits data such as energy usage, generation, text messages, and event logs to authorized systems and provides other advanced utility functions

Multi-energy management system (M-EMS)

Application

Application or system responsible for Network Operation.

It receives real-time and forecast data from advanced metering infrastructure as well as from the DSO and determines the optimal operation plan for defined appliances in the the  electrical and thermal distribution network.

It therefore coordinates thermal and electrical storages and power-to-heat devices.

Electrical storages/batteries

Component

Used to store electrical energy for a period of time.

Power-to-heat device(s)

Component

Converts electrical energy into thermal energy.

Thermal storage(s)

Component

Used to store thermal energy for a period of time.

Scenario conditions

No.

Scenario name

Scenario description

Primary actor

Triggering event

Pre-condition

Post-condition

Scenario

Scenario name :

Step No.

Event

Name of process/ activity

Description of process/ activity

Service

Information producer (actor)

Information receiver (actor)

Information exchanged (IDs)

Requirements R-ID

Common terms and definitions

Term

Definition