basic_example

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# -*- coding: utf-8 -*-

"""
General description
-------------------

A basic example to show how to model a simple energy system with oemof.solph.

The following energy system is modeled:

.. code-block:: text

                     input/output  bgas     bel
                         |          |        |
                         |          |        |
     wind(FixedSource)   |------------------>|
                         |          |        |
     pv(FixedSource)     |------------------>|
                         |          |        |
     rgas(Commodity)     |--------->|        |
                         |          |        |
     demand(Sink)        |<------------------|
                         |          |        |
                         |          |        |
     pp_gas(Transformer) |<---------|        |
                         |------------------>|
                         |          |        |
     storage(Storage)    |<------------------|
                         |------------------>|


Data
----
basic_example.csv


Installation requirements
-------------------------
This example requires oemof.solph (v0.5.x), install by:

    pip install oemof.solph[examples]

License
-------
`MIT license <https://github.com/oemof/oemof-solph/blob/dev/LICENSE>`_
"""

# ****************************************************************************
# ********** PART 1 - Define and optimise the energy system ******************
# ****************************************************************************

###############################################################################
# imports
###############################################################################

import logging
import os
import pprint as pp
import warnings
from datetime import datetime

import matplotlib.pyplot as plt
import pandas as pd
from oemof.tools import logger

from oemof.solph import EnergySystem
from oemof.solph import Model
from oemof.solph import buses
from oemof.solph import components as cmp
from oemof.solph import create_time_index
from oemof.solph import flows
from oemof.solph import helpers
from oemof.solph import processing
from oemof.solph import views

# Read data file

filename = os.path.join(os.getcwd(), "basic_example.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], "wind": [0.6], "demand_el": [500]})

solver = "cbc"  # 'glpk', 'gurobi',....
debug = False  # Set number_of_timesteps to 3 to get a readable lp-file.
number_of_time_steps = len(data)
solver_verbose = False  # show/hide solver output

# initiate the logger (see the API docs for more information)
logger.define_logging(
    logfile="oemof_example.log",
    screen_level=logging.INFO,
    file_level=logging.INFO,
)

logging.info("Initialize the energy system")
date_time_index = create_time_index(2012, number=number_of_time_steps)

energysystem = EnergySystem(
    timeindex=date_time_index, infer_last_interval=False
)

##########################################################################
# Create oemof object
##########################################################################

logging.info("Create oemof objects")

# The bus objects were assigned to variables which makes it easier to connect
# components to these buses (see below).

# create natural gas bus
bgas = buses.Bus(label="natural_gas")

# create electricity bus
bel = buses.Bus(label="electricity")

# adding the buses to the energy system
energysystem.add(bgas, bel)

# create excess component for the electricity bus to allow overproduction
energysystem.add(cmp.Sink(label="excess_bel", inputs={bel: flows.Flow()}))

# create source object representing the natural gas commodity (annual limit)
energysystem.add(
    cmp.Source(
        label="rgas",
        outputs={bgas: flows.Flow()},
    )
)

# create fixed source object representing wind power plants
energysystem.add(
    cmp.Source(
        label="wind",
        outputs={bel: flows.Flow(fix=data["wind"], nominal_value=1000000)},
    )
)

# create fixed source object representing pv power plants
energysystem.add(
    cmp.Source(
        label="pv",
        outputs={bel: flows.Flow(fix=data["pv"], nominal_value=582000)},
    )
)

# create simple sink object representing the electrical demand
energysystem.add(
    cmp.Sink(
        label="demand",
        inputs={bel: flows.Flow(fix=data["demand_el"], nominal_value=1)},
    )
)

# create simple transformer object representing a gas power plant
energysystem.add(
    cmp.Transformer(
        label="pp_gas",
        inputs={bgas: flows.Flow()},
        outputs={bel: flows.Flow(nominal_value=10e10, variable_costs=50)},
        conversion_factors={bel: 0.58},
    )
)

# create storage object representing a battery
storage = cmp.GenericStorage(
    nominal_storage_capacity=10077997,
    label="storage",
    inputs={bel: flows.Flow(nominal_value=10077997 / 6)},
    outputs={
        bel: flows.Flow(nominal_value=10077997 / 6, variable_costs=0.001)
    },
    loss_rate=0.00,
    initial_storage_level=None,
    inflow_conversion_factor=1,
    outflow_conversion_factor=0.8,
)

energysystem.add(storage)

##########################################################################
# Optimise the energy system and plot the results
##########################################################################

logging.info("Optimise the energy system")

# initialise the operational model
model = Model(energysystem)

# This is for debugging only. It is not(!) necessary to solve the problem and
# should be set to False to save time and disc space in normal use. For
# debugging the timesteps should be set to 3, to increase the readability of
# the lp-file.
if debug:
    filename = os.path.join(
        helpers.extend_basic_path("lp_files"), "basic_example.lp"
    )
    logging.info("Store lp-file in {0}.".format(filename))
    model.write(filename, io_options={"symbolic_solver_labels": True})

# if tee_switch is true solver messages will be displayed
logging.info("Solve the optimization problem")
model.solve(solver=solver, solve_kwargs={"tee": solver_verbose})

logging.info("Store the energy system with the results.")

# The processing module of the outputlib can be used to extract the results
# from the model transfer them into a homogeneous structured dictionary.

# add results to the energy system to make it possible to store them.
energysystem.results["main"] = processing.results(model)
energysystem.results["meta"] = processing.meta_results(model)

# The default path is the '.oemof' folder in your $HOME directory.
# The default filename is 'es_dump.oemof'.
# You can omit the attributes (as None is the default value) for testing cases.
# You should use unique names/folders for valuable results to avoid
# overwriting.

# store energy system with results
energysystem.dump(dpath=None, filename=None)

# ****************************************************************************
# ********** PART 2 - Processing the results *********************************
# ****************************************************************************

logging.info("**** The script can be divided into two parts here.")
logging.info("Restore the energy system and the results.")
energysystem = EnergySystem()
energysystem.restore(dpath=None, filename=None)

# define an alias for shorter calls below (optional)
results = energysystem.results["main"]
storage = energysystem.groups["storage"]

# print a time slice of the state of charge
print("")
print("********* State of Charge (slice) *********")
print(
    results[(storage, None)]["sequences"][
        datetime(2012, 2, 25, 8, 0, 0) : datetime(2012, 2, 25, 17, 0, 0)
    ]
)
print("")


# get all variables of a specific component/bus
custom_storage = views.node(results, "storage")
electricity_bus = views.node(results, "electricity")

# plot the time series (sequences) of a specific component/bus

fig, ax = plt.subplots(figsize=(10, 5))
custom_storage["sequences"].plot(ax=ax, kind="line", drawstyle="steps-post")
plt.legend(
    loc="upper center",
    prop={"size": 8},
    bbox_to_anchor=(0.5, 1.25),
    ncol=2,
)
fig.subplots_adjust(top=0.8)
plt.show()

fig, ax = plt.subplots(figsize=(10, 5))
electricity_bus["sequences"].plot(ax=ax, kind="line", drawstyle="steps-post")
plt.legend(
    loc="upper center", prop={"size": 8}, bbox_to_anchor=(0.5, 1.3), ncol=2
)
fig.subplots_adjust(top=0.8)
plt.show()

# print the solver results
print("********* Meta results *********")
pp.pprint(energysystem.results["meta"])
print("")

# print the sums of the flows around the electricity bus
print("********* Main results *********")
print(electricity_bus["sequences"].sum(axis=0))