Hub Objects

This section presents an in-depth description of all objects available in SAInt to model a hub system. A hub system aims at modeling coupled energy systems, and at assessing interdependencies and cascading effects. Figure 1 shows the hierarchy and the parent-child relationships between base objects. Table 1 gives a quick and short description of the base objects.

For example, the top-level base object in a hub system model is the "hub system" object HUBS. A hub system contains only one energy hub HUB, which is a child of the system. An energy hub contains many other different base objects, such as, for example, gas-fired generator GFG, power-to-gas facilities P2G, or electric-driven gas storages EDGSTR. A hub system object has no parents but only children. A hub component object GFG cannot be a parent but only a child. See the schematic below for a visual representation of the complete hierarchical object structure for a hub system model in SAInt.

Relationship between objects in a hub system. A child object is indicated by the head of a pointed arrow, while a parent is by the tail.
Figure 1. Relationship between objects in a hub system. A child object is indicated by the head of a pointed arrow, while a parent is by the tail.
Table 1. Icons and descriptions of object types in a hub system.
Icon ObjType Display Name Description

hubs

HUBS

Hub System

Models the operation of facilities coupling different energy network types. Serves as a container for all hub objects

gfg

GFG

Gas-Fired Generator

Models the coupling between a Fuel Generator (FGEN) and a Gas Demand (GDEM)

p2g

P2G

Power-To-Gas Facility

Models the coupling between an Electric Demand (EDEM) and a Gas Supply (GSUP). A prime example of a Power-To-Gas Facility is an electrolyzer plant, in which electric power is used to convert water into oxygen and hydrogen. The latter is then injected into the gas network

edgcs

EDGCS

Electric-Driven Gas Compressor

Models the coupling between an Electric Demand (EDEM) and a Gas Compressor (GCS). In an Electric-Driven Gas Compressor, electric power is converted into the mechanical power needed to increase the gas pressure

edgstr

EDGSTR

Electric-Driven Gas Storage

Models the coupling between an Electric Demand (EDEM) and a Gas Storage (GSTR). It models the electricity consumption needed to operate the gas storage

edlng

EDLNG

Electric-Driven LNG Terminal

Models the coupling between an Electric Demand (EDEM) and an LNG Terminal (LNG). It models the electric power consumption needed to operate the LNG terminal

1. Gas-electric hubs (HUBS)

The hub network contains objects representing coupling points between objects from different network types. Coupling between objects is unique; thus a coupled object cannot be coupled to a third object. A coupled object can be either electric or gas driven. Coupled objects are visualized in the map window with a cyan dash line when the hub is turned on.

The events assigned to the coupled objects are not created on the hub network. For example, for an EDGCS, the POSET event for the gas compressor is applied on the gas network.

Summaries for the properties and the events of HUBS.

1.1. Electric-driven gas compressor (EDGCS)

The electric-driven gas compressor EDGCS is an object allowing to model the coupling between a gas compressor station (GCS) and an electric demand (EDEM). The object describes the electric power consumption needed to operate the gas compressor. The gas event leads to the combined simulation. For example, by setting the POSET (pressure outlet set point) event for a gas compressor, the simulation determines the required electric demand P to achieve the POSET. If a PSET (active power set point) event is assigned to the electric demand, it will be neglected.

The only considered events for the EDEM object are OFF, ON, and PMAX events. For example, if the EDEM has an OFF event, the EDGCS will not operate.

Summaries for the properties and the events of EDGCS.

1.2. Electric-driven gas storage (EDGSTR)

The electric-driven gas storage EDGSTR is an object allowing to model the coupling between a gas storage (GSTR) and an electric demand (EDEM). The object describes the electric power consumption needed to operate the gas storage. The gas event leads to the combined simulation. For example, by setting the QSET (flow set point) event for a gas storage, the simulation determines the required electric demand P to achieve the QSET. If a PSET (power set point) event is assigned to the electric demand, it will be neglected.

The only considered events for the EDEM object are OFF, ON, and PMAX events. For example, if the EDEM has an OFF event, the EDGSTR will not operate.

Summaries for the properties and the events of EDGSTR.

1.3. Electric-driven LNG terminal (EDLNG)

The electric-driven LNG terminal EDLNG is an object allowing to model the coupling between a LNG terminal (LNG) and an electric demand (EDEM). The object describes the electric power consumption needed to operate the terminal. The gas event leads to the combined simulation. For example, by setting the QSET (flow set point) event for a gas LNG terminal, the simulation determines the required electric demand P to achieve the QSET. If a PSET (power set point) event is assigned to the electric demand, it will be neglected.

The only considered events for the EDEM object are OFF, ON, and PMAX events. For example, if the EDEM has an OFF event, the EDLNG will not operate.

Summaries for the properties and the events of EDLNG.

1.4. Gas-fired generator (GFG)

The gas-fired generator GFG is an object allowing to model the coupling between a generator (FGEN) and a gas demand (GDEM). The object describes the gas demand needed to operate the gas generator. The electric event leads the combined simulation. For example, by setting the PSET (active power set point) event for a fuel generator, the simulation determines the required gas demand Q to achieve the PSET. If a QSET (flow set point) event is assigned to the gas demand, it will be neglected.

The only considered events for the GDEM object are OFF, ON, PMIN, and QMAX events. For example, if the GDEM has an QMAX event, the GFG operation will be constrained by the maximum flow of the gas demand.

Summaries for the properties and the events of GFG.

1.5. Power-to-gas facility (P2G)

The power-to-gas facility P2G is an object allowing to model the coupling between an electric demand (EDEM) and a gas supply (GSUP). The object describes the electric power consumption needed to operate the gas supply (e.g., electrolyzer). The electric event leads the combined simulation. For example, by setting the PSET (active power set point) event for an electric demand, the simulation determines the amount of gas (Q) that can be delivered by the gas supply. If a QSET (flow set point) event is assigned to the Gas Supply, it will be neglected. The gas quality and composition delivered by the gas supply can be modified by the user.

The only considered events for the GSUP object are OFF, ON, and QMAX events. For example, if the GSUP has an OFF event, the P2G will not operate.

Summaries for the properties and the events of P2G.