Wood Boiler

The wood boiler represent a device that burns wood to produce heat for space heating and domestic hot water. It is situated in individual buildings and therefore contributes a constant share to the overal heat production. It has a constant efficiency and constant carbon emissions per kWh of energy converted.

For Swiss municipalities, the wood boiler is usually already deployed in some buildings, since it is an often encountered technology. Therefore, an additional replacement capex can be defined. If wood boilers reach the end of their life, this replacement capex defines how much it costs to replace it with a new boiler, without redoing any of the ancillary installations.

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.	True	—	bool
kW_th_max	Maximum thermal capacity (i.e. heat output).	inf	kW	float
hv_wood_MJpkg	Lower heating value of wood.	15	MJ/kg	float
eta	Conversion efficiency from fuel to heat.	0.8	—	float
wood_price_CHFpkg	Wood price (annual fixed value).	0.5	CHF/kg	float
co2_intensity	Carbon-dioxide intensity of technology output (annual average value).	0.027	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
replacement_factor	Used for scenario ‘fossil_heater_retrofit’. Fraction of heating capacity to be replaced by heat pumps.	1	—	float
capex	CAPEX cost of technology per unit of capacity.	4500	CHF/kWp	float
capex_one_to_one_replacement	CAPEX cost of technology per unit of capacity (when device has reached the end of life)	2000		float
maintenance_cost	OPEX cost of technology.	50		float
fixed_demand_share	If set to ‘True’, a fixed share (per timestep) of the total heat demand will be served by this tech. Only relevant if Optimisation is activated.	False	—	bool
fixed_demand_share_val	The share (per timestep) of the total heat demand served by this technology. Only relevant if fixed_demand_share == True and if Optimisation is activated.	0	—	float
only_allow_existing	If set to ‘True’, only the existing (allready installed) capacity can be used. Only relevant if Optimisation is activated. CAREFUL: Avoid conflict with fixed_demand_share.	False	—	bool

The relationship between the in- and outflows is given by

\[\mathtt{v\_h\_wb} = \mathtt{eta} \cdot \mathtt{u\_wd\_wb}\]

The symbols and names of the flows are

u_wd_wb	Inflow Wood
v_h_wb	Outflow Heat