Gas Tank Energy Storage (GTES)

The GTES technology represents a gas tank. It can be charged from the gas network, either by gas bought from the grid or by locally produced biogas. It is modelled like a battery. It has a given maximum capacity that can be set by the optimizer if optimization is activated. When charging and discharging, a fixed loss rate is applied. Furthermore, the storage loses energy at a constant rate.

Using the parameter force_asynchronous_prod_con, the optimizer can be forced to never charge and discharge the storage at the same time. This can be useful to prevent the energy system from disposing of gas using the charging and discharging losses of the storage.

The initial charge of the storage is usually set to be optimized. Then, the constraint is that the initial and final storage level have to be equal. Alternatively, a fixed initial state of charge can be defined.

Attribute	Description	Standard value	Unit	Data type
deployment	If set to ‘true’, the technology will be considered in the energy system model (this does not necessarily mean it will be used). Only relevant for optimisation.	False	—	bool
force_asynchronous_prod_con	If set to ‘true’, the storage cannot be charged and discharged simultaneously	True	—	bool
eta_chg_dchg	Charging and discharging efficiency (fixed). Roundtrip-efficiency is calculated as eta_chg_dchg*eta_chg_dchg.	0.95	—	float
gtes_gamma	Loss rate: fraction of gas lost during one timestep (e.g. 1 hour)	0	1/timestep	float
capacity_kWh	Storage capacity.	inf	kWh	str
chg_dchg_per_cap_max	Max. charge/discharge (kW) per storage cap (kWh) per timestep.	0.1	1/timestep	float
initial_charge	Initial charge of gas tank (fraction of total storage capacity)	0	—	float
optimized_initial_charge	If True, initial_charge is determined within the optimization s.t. the initial charge and the final charge are the same	True	—	bool
co2_intensity	Carbon-dioxide intensity of technology output (annual average value).	0	kg CO2/kWh	float
lifetime	Expected lifetime of technology before replacement is required.	25	years	int
interest_rate	Interest rate for computing levelised costs (if required).	0.025	—	float
capex	CAPEX cost of technology per unit of capacity.	0.2	CHF/kWh	float
maintenance_cost	OPEX of the technology	0.01	CHF/kWh/year	float

The symbols and names of the flows are