Simple heat and power dispatch¶
Linear dispatch optimization¶
General description¶
This example shows how to create an energysystem with oemof objects and solve it with the solph module. Results are plotted with solph.
Dispatch modelling is a typical thing to do with solph. However cost does not have to be monetary but can be emissions etc. In this example a least cost dispatch of different generators that meet an inelastic demand is undertaken. Some of the generators are renewable energies with marginal costs of zero. Additionally, it shows how combined heat and power units may be easily modelled as well.
Code¶
Download source code: simple_dispatch.py
Click to display code
import os
import warnings
import matplotlib.pyplot as plt
import pandas as pd
from oemof.solph import Bus
from oemof.solph import EnergySystem
from oemof.solph import Flow
from oemof.solph import Model
from oemof.solph import create_time_index
from oemof.solph import views
from oemof.solph.components import Sink
from oemof.solph.components import Source
from oemof.solph.components import Converter
def main():
# Read data file
filename = os.path.join(os.getcwd(), "input_data.csv")
try:
data = pd.read_csv(filename)
except FileNotFoundError:
msg = "Data file not found: {0}. Only one value used!"
warnings.warn(msg.format(filename), UserWarning)
data = pd.DataFrame(
{
"pv": [0.3, 0.7],
"wind": [0.6, 0.5],
"demand_el": [500, 400],
"demand_th": [400, 300],
}
)
solver = "cbc"
# Create an energy system and optimize the dispatch at least costs.
# ####################### initialize and provide data #####################
datetimeindex = create_time_index(2016, number=len(data))
energysystem = EnergySystem(
timeindex=datetimeindex, infer_last_interval=False
)
# ######################### create energysystem components ################
# resource buses
bcoal = Bus(label="coal", balanced=False)
bgas = Bus(label="gas", balanced=False)
boil = Bus(label="oil", balanced=False)
blig = Bus(label="lignite", balanced=False)
# electricity and heat
bel = Bus(label="bel")
bth = Bus(label="bth")
energysystem.add(bcoal, bgas, boil, blig, bel, bth)
# an excess and a shortage variable can help to avoid infeasible problems
energysystem.add(Sink(label="excess_el", inputs={bel: Flow()}))
# shortage_el = Source(label='shortage_el',
# outputs={bel: Flow(variable_costs=200)})
# sources
energysystem.add(
Source(
label="wind",
outputs={bel: Flow(fix=data["wind"], nominal_value=66.3)},
)
)
energysystem.add(
Source(
label="pv", outputs={bel: Flow(fix=data["pv"], nominal_value=65.3)}
)
)
# demands (electricity/heat)
energysystem.add(
Sink(
label="demand_el",
inputs={bel: Flow(nominal_value=85, fix=data["demand_el"])},
)
)
energysystem.add(
Sink(
label="demand_th",
inputs={bth: Flow(nominal_value=40, fix=data["demand_th"])},
)
)
# power plants
energysystem.add(
Converter(
label="pp_coal",
inputs={bcoal: Flow()},
outputs={bel: Flow(nominal_value=20.2, variable_costs=25)},
conversion_factors={bel: 0.39},
)
)
energysystem.add(
Converter(
label="pp_lig",
inputs={blig: Flow()},
outputs={bel: Flow(nominal_value=11.8, variable_costs=19)},
conversion_factors={bel: 0.41},
)
)
energysystem.add(
Converter(
label="pp_gas",
inputs={bgas: Flow()},
outputs={bel: Flow(nominal_value=41, variable_costs=40)},
conversion_factors={bel: 0.50},
)
)
energysystem.add(
Converter(
label="pp_oil",
inputs={boil: Flow()},
outputs={bel: Flow(nominal_value=5, variable_costs=50)},
conversion_factors={bel: 0.28},
)
)
# combined heat and power plant (chp)
energysystem.add(
Converter(
label="pp_chp",
inputs={bgas: Flow()},
outputs={
bel: Flow(nominal_value=30, variable_costs=42),
bth: Flow(nominal_value=40),
},
conversion_factors={bel: 0.3, bth: 0.4},
)
)
# heat pump with a coefficient of performance (COP) of 3
b_heat_source = Bus(label="b_heat_source")
energysystem.add(b_heat_source)
energysystem.add(
Source(label="heat_source", outputs={b_heat_source: Flow()})
)
cop = 3
energysystem.add(
Converter(
label="heat_pump",
inputs={bel: Flow(), b_heat_source: Flow()},
outputs={bth: Flow(nominal_value=10)},
conversion_factors={bel: 1 / 3, b_heat_source: (cop - 1) / cop},
)
)
# ################################ optimization ###########################
# create optimization model based on energy_system
optimization_model = Model(energysystem=energysystem)
# solve problem
optimization_model.solve(
solver=solver, solve_kwargs={"tee": True, "keepfiles": False}
)
# write back results from optimization object to energysystem
optimization_model.results()
# ################################ results ################################
# subset of results that includes all flows into and from electrical bus
# sequences are stored within a pandas.DataFrames and scalars e.g.
# investment values within a pandas.Series object.
# in this case the entry data['scalars'] does not exist since no investment
# variables are used
data = views.node(optimization_model.results(), "bel")
data["sequences"].info()
print("Optimization successful. Showing some results:")
# see: https://pandas.pydata.org/pandas-docs/stable/visualization.html
node_results_bel = views.node(optimization_model.results(), "bel")
node_results_flows = node_results_bel["sequences"]
fig, ax = plt.subplots(figsize=(10, 5))
node_results_flows.plot(
ax=ax, kind="bar", stacked=True, linewidth=0, width=1
)
ax.set_title("Sums for optimization period")
ax.legend(loc="upper right", bbox_to_anchor=(1, 1))
ax.set_xlabel("Energy (MWh)")
ax.set_ylabel("Flow")
plt.legend(loc="center left", prop={"size": 8}, bbox_to_anchor=(1, 0.5))
fig.subplots_adjust(right=0.8)
dates = node_results_flows.index
tick_distance = int(len(dates) / 7) - 1
ax.set_xticks(range(0, len(dates), tick_distance), minor=False)
if tick_distance > 0:
ax.set_xticklabels(
[
item.strftime("%d-%m-%Y")
for item in dates.tolist()[0::tick_distance]
],
rotation=90,
minor=False,
)
plt.show()
node_results_bth = views.node(optimization_model.results(), "bth")
node_results_flows = node_results_bth["sequences"]
fig, ax = plt.subplots(figsize=(10, 5))
node_results_flows.plot(
ax=ax, kind="bar", stacked=True, linewidth=0, width=1
)
ax.set_title("Sums for optimization period")
ax.legend(loc="upper right", bbox_to_anchor=(1, 1))
ax.set_xlabel("Energy (MWh)")
ax.set_ylabel("Flow")
plt.legend(loc="center left", prop={"size": 8}, bbox_to_anchor=(1, 0.5))
fig.subplots_adjust(right=0.8)
dates = node_results_flows.index
tick_distance = int(len(dates) / 7) - 1
ax.set_xticks(range(0, len(dates), tick_distance), minor=False)
if tick_distance > 0:
ax.set_xticklabels(
[
item.strftime("%d-%m-%Y")
for item in dates.tolist()[0::tick_distance]
],
rotation=90,
minor=False,
)
plt.show()
if __name__ == "__main__":
main()
Data¶
Download data: input_data.csv
Installation requirements¶
This example requires oemof.solph (v0.5.x), install by:
pip install oemof.solph[examples]
