Modifying emission factors for biomass

[Timon Renzelmann]

Hi there,

I am new to using PyPSA and would like to introduce/modify different emission factors for different types of biomass. 

Do you happen to know how this could be done?

Thanks and kind regards,

Timon

[Hannes Koch]

EDIT: I had to repost my answer as there was a typo in my MWE.

Hi Timon,

I myself am quite new to using PyPSA but I have dealt with this issue recently. However, please take my solution with a grain of salt - there may be better ways. :)

Assuming you have one bus for biomass in any node, you can define a variety of carriers and assign individual emission factors to each of them. In your model, you can then define the different generators that use these different carriers and connect them all to the same biomass bus. PyPSA then sorts out the usage of the individual carriers and the resulting CO2 emissions according to your model constraints internally.

I adjusted a MWE for you to try out. It uses a cheaper biomass carrier with CO2 emissions and a more expensive one that has zero emissions. By calling "n.generators_t.p" after optimisation, you can see that PyPSA uses exactly as much of the cheaper carrier as the CO2 emission constraints allows for.

Hope it helps! Kind regards,

Hannes

--------------------------------------------

import pypsa
import numpy as np

n = pypsa.Network()
n.set_snapshots(np.arange(10))


# note: although you define a specific carrier here,
# pyPSA can handle other carriers on this bus
n.add("Bus", name = "biomass", carrier = "biomass_1")
n.add("Bus", name = "district_heating")

n.add("Carrier",
    "biomass_1",
    co2_emissions = 0.2
    )
n.add("Carrier",
    "biomass_2",
    co2_emissions = 0
    )

n.add("Generator",
    "source_biomass_1",
    bus="biomass",
    carrier="biomass_1",
    marginal_cost = 1,
    p_nom_extendable = True,
    )
n.add("Generator",
    "source_biomass_2",
    bus="biomass",
    carrier="biomass_2",
    marginal_cost = 2,
    p_nom_extendable = True,
    )


# n.add("Load",
#     "biomass_demand",
#     bus="biomass",
#     p_set = 10)
n.add("Load",
    "district heating demand",
    bus = "district_heating",
    p_set = 5)

n.add("Link",
    name = "bm_boiler",
    carrier = "biomass_1",
    bus0 = "biomass",
    bus1 = "district_heating",
    efficiency = 0.8,
    capital_cost = 0,
    marginal_cost = 0,
    p_nom_extendable = True
    )

n.add("GlobalConstraint",
    name = "co2 limit",
    carrier_attribute = "co2_emissions",
    sense = "<=",
    constant = 2
    )


def calculate_co2_emissions(n):
    return n.generators_t.p["source_biomass_2"].sum() * 0.0 + n.generators_t.p["source_biomass_1"].sum() * 0.2

n.optimize()
print("CO2 Emissions: ", calculate_co2_emissions(n))
print(n.generators_t.p)